ISO-8859-1

Question

如果你有java.io.InputStream个对象，你应该如何处理该对象并生成String？

假设我有InputStream包含文本数据，我想将其转换为String，例如我可以将其写入日志文件。

采用InputStream并将其转换为String的最简单方法是什么？

public String convertStreamToString(InputStream is) {
    // ???
}

Answer 1

执行此操作的一种好方法是使用Apache commons IOUtils将InputStream复制到StringWriter ...类似

StringWriter writer = new StringWriter();
IOUtils.copy(inputStream, writer, encoding);
String theString = writer.toString();

甚至

// NB: does not close inputStream, you'll have to use try-with-resources for that
String theString = IOUtils.toString(inputStream, encoding);

或者，如果您不想混合Streams和Writers，可以使用ByteArrayOutputStream

Answer 2

这是一种仅使用标准Java库的方法（请注意，流未关闭，您的里程可能会有所不同）。

static String convertStreamToString(java.io.InputStream is) {
    java.util.Scanner s = new java.util.Scanner(is).useDelimiter("\\A");
    return s.hasNext() ? s.next() : "";
}

我从"Stupid Scanner tricks"文章中学到了这个技巧。它起作用的原因是因为Scanner迭代了流中的标记，在这种情况下我们使用“输入边界的开头”（\ A）分隔标记，因此只给我们一个标记来表示整个内容。流。

注意，如果您需要具体了解输入流的编码，可以为Scanner构造函数提供第二个参数，指示要使用的字符集（例如“UTF-8”）。 /强>

帽子小贴士也转到Jacob，曾经指出我的那篇文章。

Answer 3

总结其他答案我找到了11种主要方法（见下文）。我写了一些性能测试（见下面的结果）：

将InputStream转换为String的方法：

使用IOUtils.toString（Apache Utils）

String result = IOUtils.toString(inputStream, StandardCharsets.UTF_8);

使用CharStreams（番石榴）

String result = CharStreams.toString(new InputStreamReader(
      inputStream, Charsets.UTF_8));

使用Scanner（JDK）

Scanner s = new Scanner(inputStream).useDelimiter("\\A");
String result = s.hasNext() ? s.next() : "";

使用 Stream API （Java 8）。警告：此解决方案会将不同的换行符（例如\r\n）转换为\n。

String result = new BufferedReader(new InputStreamReader(inputStream))
  .lines().collect(Collectors.joining("\n"));

使用并行Stream API （Java 8）。警告：此解决方案会将不同的换行符（例如\r\n）转换为\n。

String result = new BufferedReader(new InputStreamReader(inputStream)).lines()
   .parallel().collect(Collectors.joining("\n"));

使用InputStreamReader和StringBuilder（JDK）

final int bufferSize = 1024;
final char[] buffer = new char[bufferSize];
final StringBuilder out = new StringBuilder();
Reader in = new InputStreamReader(inputStream, "UTF-8");
for (; ; ) {
    int rsz = in.read(buffer, 0, buffer.length);
    if (rsz < 0)
        break;
    out.append(buffer, 0, rsz);
}
return out.toString();

使用StringWriter和IOUtils.copy（Apache Commons）

StringWriter writer = new StringWriter();
IOUtils.copy(inputStream, writer, "UTF-8");
return writer.toString();

使用ByteArrayOutputStream和inputStream.read（JDK）

ByteArrayOutputStream result = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int length;
while ((length = inputStream.read(buffer)) != -1) {
    result.write(buffer, 0, length);
}
// StandardCharsets.UTF_8.name() > JDK 7
return result.toString("UTF-8");

使用BufferedReader（JDK）。警告：此解决方案将不同的换行符（如\n\r）转换为line.separator系统属性（例如，在Windows中转换为＆＃34; \ r \ n＆＃34;）

String newLine = System.getProperty("line.separator");
BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
StringBuilder result = new StringBuilder();
boolean flag = false;
for (String line; (line = reader.readLine()) != null; ) {
    result.append(flag? newLine: "").append(line);
    flag = true;
}
return result.toString();

使用BufferedInputStream和ByteArrayOutputStream（JDK）

BufferedInputStream bis = new BufferedInputStream(inputStream);
ByteArrayOutputStream buf = new ByteArrayOutputStream();
int result = bis.read();
while(result != -1) {
    buf.write((byte) result);
    result = bis.read();
}
// StandardCharsets.UTF_8.name() > JDK 7
return buf.toString("UTF-8");

使用inputStream.read()和StringBuilder（JDK）。警告：此解决方案存在Unicode问题，例如使用俄语文本（仅适用于非Unicode文本）
```
int ch;
StringBuilder sb = new StringBuilder();
while((ch = inputStream.read()) != -1)
    sb.append((char)ch);
reset();
return sb.toString();
```

警告：

解决方案4,5和9将不同的换行符转换为一个。

解决方案11无法正确使用Unicode文本

效果测试

小String（长度= 175）的性能测试，github中的网址（模式=平均时间，系统= Linux，得分1,343是最佳）：

Benchmark Mode Cnt Score Error Units 8. ByteArrayOutputStream and read (JDK) avgt 10 1,343 ± 0,028 us/op 6. InputStreamReader and StringBuilder (JDK) avgt 10 6,980 ± 0,404 us/op 10. BufferedInputStream, ByteArrayOutputStream avgt 10 7,437 ± 0,735 us/op 11. InputStream.read() and StringBuilder (JDK) avgt 10 8,977 ± 0,328 us/op 7. StringWriter and IOUtils.copy (Apache) avgt 10 10,613 ± 0,599 us/op 1. IOUtils.toString (Apache Utils) avgt 10 10,605 ± 0,527 us/op 3. Scanner (JDK) avgt 10 12,083 ± 0,293 us/op 2. CharStreams (guava) avgt 10 12,999 ± 0,514 us/op 4. Stream Api (Java 8) avgt 10 15,811 ± 0,605 us/op 9. BufferedReader (JDK) avgt 10 16,038 ± 0,711 us/op 5. parallel Stream Api (Java 8) avgt 10 21,544 ± 0,583 us/op

大String（长度= 50100）的性能测试，github中的网址（模式=平均时间，系统= Linux，得分200,715是最佳）：

Benchmark Mode Cnt Score Error Units 8. ByteArrayOutputStream and read (JDK) avgt 10 200,715 ± 18,103 us/op 1. IOUtils.toString (Apache Utils) avgt 10 300,019 ± 8,751 us/op 6. InputStreamReader and StringBuilder (JDK) avgt 10 347,616 ± 130,348 us/op 7. StringWriter and IOUtils.copy (Apache) avgt 10 352,791 ± 105,337 us/op 2. CharStreams (guava) avgt 10 420,137 ± 59,877 us/op 9. BufferedReader (JDK) avgt 10 632,028 ± 17,002 us/op 5. parallel Stream Api (Java 8) avgt 10 662,999 ± 46,199 us/op 4. Stream Api (Java 8) avgt 10 701,269 ± 82,296 us/op 10. BufferedInputStream, ByteArrayOutputStream avgt 10 740,837 ± 5,613 us/op 3. Scanner (JDK) avgt 10 751,417 ± 62,026 us/op 11. InputStream.read() and StringBuilder (JDK) avgt 10 2919,350 ± 1101,942 us/op

图表（性能测试取决于Windows 7系统中的输入流长度）

性能测试（平均时间）取决于Windows 7系统中的输入流长度：

length 182 546 1092 3276 9828 29484 58968 test8 0.38 0.938 1.868 4.448 13.412 36.459 72.708 test4 2.362 3.609 5.573 12.769 40.74 81.415 159.864 test5 3.881 5.075 6.904 14.123 50.258 129.937 166.162 test9 2.237 3.493 5.422 11.977 45.98 89.336 177.39 test6 1.261 2.12 4.38 10.698 31.821 86.106 186.636 test7 1.601 2.391 3.646 8.367 38.196 110.221 211.016 test1 1.529 2.381 3.527 8.411 40.551 105.16 212.573 test3 3.035 3.934 8.606 20.858 61.571 118.744 235.428 test2 3.136 6.238 10.508 33.48 43.532 118.044 239.481 test10 1.593 4.736 7.527 20.557 59.856 162.907 323.147 test11 3.913 11.506 23.26 68.644 207.591 600.444 1211.545

Answer 4

Apache Commons允许：

String myString = IOUtils.toString(myInputStream, "UTF-8");

当然，您可以选择除UTF-8之外的其他字符编码。

另见：（documentation）

Answer 5

考虑到文件一应首先获得java.io.Reader个实例。然后可以将其读取并添加到StringBuilder（如果我们不在多个线程中访问它，我们不需要StringBuffer，并且StringBuilder更快）。这里的诀窍是我们在块中工作，因此不需要其他缓冲流。块大小已参数化，以便进行运行时性能优化。

public static String slurp(final InputStream is, final int bufferSize) {
    final char[] buffer = new char[bufferSize];
    final StringBuilder out = new StringBuilder();
    try (Reader in = new InputStreamReader(is, "UTF-8")) {
        for (;;) {
            int rsz = in.read(buffer, 0, buffer.length);
            if (rsz < 0)
                break;
            out.append(buffer, 0, rsz);
        }
    }
    catch (UnsupportedEncodingException ex) {
        /* ... */
    }
    catch (IOException ex) {
        /* ... */
    }
    return out.toString();
}

Answer 6

使用：

InputStream in = /* Your InputStream */;
StringBuilder sb = new StringBuilder();
BufferedReader br = new BufferedReader(new InputStreamReader(in));
String read;

while ((read=br.readLine()) != null) {
    //System.out.println(read);
    sb.append(read);
}

br.close();
return sb.toString();

Answer 7

如果您使用的是Google-Collections / Guava，则可以执行以下操作：

InputStream stream = ...
String content = CharStreams.toString(new InputStreamReader(stream, Charsets.UTF_8));
Closeables.closeQuietly(stream);

请注意，InputStreamReader的第二个参数（即Charsets.UTF_8）不是必需的，但如果你知道它，你应该指定编码通常是个好主意（你应该这样做！）

Answer 8

这是我的纯Java和Android解决方案，它运行良好......

public String readFullyAsString(InputStream inputStream, String encoding)
        throws IOException {
    return readFully(inputStream).toString(encoding);
}

public byte[] readFullyAsBytes(InputStream inputStream)
        throws IOException {
    return readFully(inputStream).toByteArray();
}

private ByteArrayOutputStream readFully(InputStream inputStream)
        throws IOException {
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    byte[] buffer = new byte[1024];
    int length = 0;
    while ((length = inputStream.read(buffer)) != -1) {
        baos.write(buffer, 0, length);
    }
    return baos;
}

Answer 9

这是我在经过一些实验后想出的最优雅，纯Java（无库）解决方案：

public static String fromStream(InputStream in) throws IOException
{
    BufferedReader reader = new BufferedReader(new InputStreamReader(in));
    StringBuilder out = new StringBuilder();
    String newLine = System.getProperty("line.separator");
    String line;
    while ((line = reader.readLine()) != null) {
        out.append(line);
        out.append(newLine);
    }
    return out.toString();
}

Answer 10

使用：

import java.io.BufferedInputStream;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.io.IOException;

public static String readInputStreamAsString(InputStream in)
    throws IOException {

    BufferedInputStream bis = new BufferedInputStream(in);
    ByteArrayOutputStream buf = new ByteArrayOutputStream();
    int result = bis.read();
    while(result != -1) {
      byte b = (byte)result;
      buf.write(b);
      result = bis.read();
    }
    return buf.toString();
}

Answer 11

为了完整性，这里是 Java 9 解决方案：

public static String toString(InputStream input) throws IOException {
    return new String(input.readAllBytes(), StandardCharsets.UTF_8);
}

readAllBytes目前处于JDK 9主代码库中，因此可能会出现在该版本中。您现在可以使用JDK 9 snapshot builds尝试。

Answer 12

我在这里做了14个不同答案的基准测试（很抱歉没有提供学分，但重复次数太多了。）

结果非常令人惊讶。事实证明，Apache IOUtils 是最慢的，ByteArrayOutputStream是最快的解决方案：

首先，这是最好的方法：

public String inputStreamToString(InputStream inputStream) throws IOException {
    try(ByteArrayOutputStream result = new ByteArrayOutputStream()) {
        byte[] buffer = new byte[1024];
        int length;
        while ((length = inputStream.read(buffer)) != -1) {
            result.write(buffer, 0, length);
        }

        return result.toString(UTF_8);
    }
}

基准测试结果，20个周期内20 MB随机字节

以毫秒为单位的时间

ByteArrayOutputStreamTest：194
NioStream：198
Java9ISTransferTo：201
Java9ISReadAllBytes：205
BufferedInputStreamVsByteArrayOutputStream：314
ApacheStringWriter2：574
GuavaCharStreams：589
ScannerReaderNoNextTest：614
ScannerReader：633
ApacheStringWriter：1544
StreamApi：错误
ParallelStreamApi：错误
BufferReaderTest：错误
InputStreamAndStringBuilder：错误

基准源代码

import com.google.common.io.CharStreams;
import org.apache.commons.io.IOUtils;

import java.io.*;
import java.nio.ByteBuffer;
import java.nio.channels.Channels;
import java.nio.channels.ReadableByteChannel;
import java.nio.channels.WritableByteChannel;
import java.util.Arrays;
import java.util.List;
import java.util.Random;
import java.util.stream.Collectors;

/**
 * Created by Ilya Gazman on 2/13/18.
 */
public class InputStreamToString {


    private static final String UTF_8 = "UTF-8";

    public static void main(String... args) {
        log("App started");
        byte[] bytes = new byte[1024 * 1024];
        new Random().nextBytes(bytes);
        log("Stream is ready\n");

        try {
            test(bytes);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private static void test(byte[] bytes) throws IOException {
        List<Stringify> tests = Arrays.asList(
                new ApacheStringWriter(),
                new ApacheStringWriter2(),
                new NioStream(),
                new ScannerReader(),
                new ScannerReaderNoNextTest(),
                new GuavaCharStreams(),
                new StreamApi(),
                new ParallelStreamApi(),
                new ByteArrayOutputStreamTest(),
                new BufferReaderTest(),
                new BufferedInputStreamVsByteArrayOutputStream(),
                new InputStreamAndStringBuilder(),
                new Java9ISTransferTo(),
                new Java9ISReadAllBytes()
        );

        String solution = new String(bytes, "UTF-8");

        for (Stringify test : tests) {
            try (ByteArrayInputStream inputStream = new ByteArrayInputStream(bytes)) {
                String s = test.inputStreamToString(inputStream);
                if (!s.equals(solution)) {
                    log(test.name() + ": Error");
                    continue;
                }
            }
            long startTime = System.currentTimeMillis();
            for (int i = 0; i < 20; i++) {
                try (ByteArrayInputStream inputStream = new ByteArrayInputStream(bytes)) {
                    test.inputStreamToString(inputStream);
                }
            }
            log(test.name() + ": " + (System.currentTimeMillis() - startTime));
        }
    }

    private static void log(String message) {
        System.out.println(message);
    }

    interface Stringify {
        String inputStreamToString(InputStream inputStream) throws IOException;

        default String name() {
            return this.getClass().getSimpleName();
        }
    }

    static class ApacheStringWriter implements Stringify {

        @Override
        public String inputStreamToString(InputStream inputStream) throws IOException {
            StringWriter writer = new StringWriter();
            IOUtils.copy(inputStream, writer, UTF_8);
            return writer.toString();
        }
    }

    static class ApacheStringWriter2 implements Stringify {

        @Override
        public String inputStreamToString(InputStream inputStream) throws IOException {
            return IOUtils.toString(inputStream, UTF_8);
        }
    }

    static class NioStream implements Stringify {

        @Override
        public String inputStreamToString(InputStream in) throws IOException {
            ReadableByteChannel channel = Channels.newChannel(in);
            ByteBuffer byteBuffer = ByteBuffer.allocate(1024 * 16);
            ByteArrayOutputStream bout = new ByteArrayOutputStream();
            WritableByteChannel outChannel = Channels.newChannel(bout);
            while (channel.read(byteBuffer) > 0 || byteBuffer.position() > 0) {
                byteBuffer.flip();  //make buffer ready for write
                outChannel.write(byteBuffer);
                byteBuffer.compact(); //make buffer ready for reading
            }
            channel.close();
            outChannel.close();
            return bout.toString(UTF_8);
        }
    }

    static class ScannerReader implements Stringify {

        @Override
        public String inputStreamToString(InputStream is) throws IOException {
            java.util.Scanner s = new java.util.Scanner(is).useDelimiter("\\A");
            return s.hasNext() ? s.next() : "";
        }
    }

    static class ScannerReaderNoNextTest implements Stringify {

        @Override
        public String inputStreamToString(InputStream is) throws IOException {
            java.util.Scanner s = new java.util.Scanner(is).useDelimiter("\\A");
            return s.next();
        }
    }

    static class GuavaCharStreams implements Stringify {

        @Override
        public String inputStreamToString(InputStream is) throws IOException {
            return CharStreams.toString(new InputStreamReader(
                    is, UTF_8));
        }
    }

    static class StreamApi implements Stringify {

        @Override
        public String inputStreamToString(InputStream inputStream) throws IOException {
            return new BufferedReader(new InputStreamReader(inputStream))
                    .lines().collect(Collectors.joining("\n"));
        }
    }

    static class ParallelStreamApi implements Stringify {

        @Override
        public String inputStreamToString(InputStream inputStream) throws IOException {
            return new BufferedReader(new InputStreamReader(inputStream)).lines()
                    .parallel().collect(Collectors.joining("\n"));
        }
    }

    static class ByteArrayOutputStreamTest implements Stringify {

        @Override
        public String inputStreamToString(InputStream inputStream) throws IOException {
            try(ByteArrayOutputStream result = new ByteArrayOutputStream()) {
                byte[] buffer = new byte[1024];
                int length;
                while ((length = inputStream.read(buffer)) != -1) {
                    result.write(buffer, 0, length);
                }

                return result.toString(UTF_8);
            }
        }
    }

    static class BufferReaderTest implements Stringify {

        @Override
        public String inputStreamToString(InputStream inputStream) throws IOException {
            String newLine = System.getProperty("line.separator");
            BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
            StringBuilder result = new StringBuilder(UTF_8);
            String line;
            boolean flag = false;
            while ((line = reader.readLine()) != null) {
                result.append(flag ? newLine : "").append(line);
                flag = true;
            }
            return result.toString();
        }
    }

    static class BufferedInputStreamVsByteArrayOutputStream implements Stringify {

        @Override
        public String inputStreamToString(InputStream inputStream) throws IOException {
            BufferedInputStream bis = new BufferedInputStream(inputStream);
            ByteArrayOutputStream buf = new ByteArrayOutputStream();
            int result = bis.read();
            while (result != -1) {
                buf.write((byte) result);
                result = bis.read();
            }

            return buf.toString(UTF_8);
        }
    }

    static class InputStreamAndStringBuilder implements Stringify {

        @Override
        public String inputStreamToString(InputStream inputStream) throws IOException {
            int ch;
            StringBuilder sb = new StringBuilder(UTF_8);
            while ((ch = inputStream.read()) != -1)
                sb.append((char) ch);
            return sb.toString();
        }
    }

    static class Java9ISTransferTo implements Stringify {

        @Override
        public String inputStreamToString(InputStream inputStream) throws IOException {
            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            inputStream.transferTo(bos);
            return bos.toString(UTF_8);
        }
    }

    static class Java9ISReadAllBytes implements Stringify {

        @Override
        public String inputStreamToString(InputStream inputStream) throws IOException {
            return new String(inputStream.readAllBytes(), UTF_8);
        }
    }

}

Answer 13

我使用了一些Java 8技巧。

public static String streamToString(final InputStream inputStream) throws Exception {
    // buffering optional
    try
    (
        final BufferedReader br
           = new BufferedReader(new InputStreamReader(inputStream))
    ) {
        // parallel optional
        return br.lines().parallel().collect(Collectors.joining("\n"));
    } catch (final IOException e) {
        throw new RuntimeException(e);
        // whatever.
    }
}

基本上和其他一些答案一样，除了更简洁。

Answer 14

我进行了一些时间测试，因为时间很重要，总是。

我试图以不同的方式将响应变为String 3。（如下所示）
为了便于阅读，我遗漏了try / catch块。

为了给出上下文，这是所有3种方法的前面的代码：

   String response;
   String url = "www.blah.com/path?key=value";
   GetMethod method = new GetMethod(url);
   int status = client.executeMethod(method);

1）

 response = method.getResponseBodyAsString();

2）

InputStream resp = method.getResponseBodyAsStream();
InputStreamReader is=new InputStreamReader(resp);
BufferedReader br=new BufferedReader(is);
String read = null;
StringBuffer sb = new StringBuffer();
while((read = br.readLine()) != null) {
    sb.append(read);
}
response = sb.toString();

3）

InputStream iStream  = method.getResponseBodyAsStream();
StringWriter writer = new StringWriter();
IOUtils.copy(iStream, writer, "UTF-8");
response = writer.toString();

因此，在使用相同的请求/响应数据对每个方法运行500次测试之后，这里是数字。再一次，这些是我的发现，你的发现可能不完全一样，但我写这篇文章是为了向其他人说明这些方法的效率差异。

排名：
方法＃1
方法＃3 - 比＃1低2.6％方法＃2 - 比＃1

慢4.3％

这些方法中的任何一种都是抓取响应并从中创建字符串的合适解决方案。

Answer 15

使用Stream的纯Java解决方案，自Java 8开始工作。

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.stream.Collectors;

// ...
public static String inputStreamToString(InputStream is) throws IOException {
    try (BufferedReader br = new BufferedReader(new InputStreamReader(is))) {
        return br.lines().collect(Collectors.joining(System.lineSeparator()));
    }
}

正如other answer下面的ChristofferHammarström所提到的，明确指定Charset更安全。即InputStreamReader构造函数可以更改如下：

new InputStreamReader(is, Charset.forName("UTF-8"))

Answer 16

这是或多或少的sampath的答案，清理了一点并表示为一个函数：

String streamToString(InputStream in) throws IOException {
  StringBuilder out = new StringBuilder();
  BufferedReader br = new BufferedReader(new InputStreamReader(in));
  for(String line = br.readLine(); line != null; line = br.readLine()) 
    out.append(line);
  br.close();
  return out.toString();
}

Answer 17

如果您喜欢冒险，可以将Scala和Java混合使用，最后得到：

scala.io.Source.fromInputStream(is).mkString("")

混合Java和Scala代码和库有它的好处。

请在此处查看完整说明：Idiomatic way to convert an InputStream to a String in Scala

Answer 18

如果你不能使用Commons IO（FileUtils / IOUtils / CopyUtils），这是一个使用BufferedReader逐行读取文件的例子：

public class StringFromFile {
    public static void main(String[] args) /*throws UnsupportedEncodingException*/ {
        InputStream is = StringFromFile.class.getResourceAsStream("file.txt");
        BufferedReader br = new BufferedReader(new InputStreamReader(is/*, "UTF-8"*/));
        final int CHARS_PER_PAGE = 5000; //counting spaces
        StringBuilder builder = new StringBuilder(CHARS_PER_PAGE);
        try {
            for(String line=br.readLine(); line!=null; line=br.readLine()) {
                builder.append(line);
                builder.append('\n');
            }
        } 
        catch (IOException ignore) { }

        String text = builder.toString();
        System.out.println(text);
    }
}

或者如果你想要原始速度，我建议改变一下Paul de Vrieze的建议（避免使用StringWriter（在内部使用StringBuffer）：

public class StringFromFileFast {
    public static void main(String[] args) /*throws UnsupportedEncodingException*/ {
        InputStream is = StringFromFileFast.class.getResourceAsStream("file.txt");
        InputStreamReader input = new InputStreamReader(is/*, "UTF-8"*/);
        final int CHARS_PER_PAGE = 5000; //counting spaces
        final char[] buffer = new char[CHARS_PER_PAGE];
        StringBuilder output = new StringBuilder(CHARS_PER_PAGE);
        try {
            for(int read = input.read(buffer, 0, buffer.length);
                    read != -1;
                    read = input.read(buffer, 0, buffer.length)) {
                output.append(buffer, 0, read);
            }
        } catch (IOException ignore) { }

        String text = output.toString();
        System.out.println(text);
    }
}

Answer 19

这是一个改编自org.apache.commons.io.IOUtils source code的答案，适用于那些希望实现apache但不想要整个库的人。

private static final int BUFFER_SIZE = 4 * 1024;

public static String inputStreamToString(InputStream inputStream, String charsetName)
        throws IOException {
    StringBuilder builder = new StringBuilder();
    InputStreamReader reader = new InputStreamReader(inputStream, charsetName);
    char[] buffer = new char[BUFFER_SIZE];
    int length;
    while ((length = reader.read(buffer)) != -1) {
        builder.append(buffer, 0, length);
    }
    return builder.toString();
}

Answer 20

如果您使用流阅读器

，请务必在结尾处关闭流

private String readStream(InputStream iStream) throws IOException {
    //build a Stream Reader, it can read char by char
    InputStreamReader iStreamReader = new InputStreamReader(iStream);
    //build a buffered Reader, so that i can read whole line at once
    BufferedReader bReader = new BufferedReader(iStreamReader);
    String line = null;
    StringBuilder builder = new StringBuilder();
    while((line = bReader.readLine()) != null) {  //Read till end
        builder.append(line);
        builder.append("\n"); // append new line to preserve lines
    }
    bReader.close();         //close all opened stuff
    iStreamReader.close();
    //iStream.close(); //EDIT: Let the creator of the stream close it!
                       // some readers may auto close the inner stream
    return builder.toString();
}

编辑：在JDK 7+上，您可以使用try-with-resources构造。

/**
 * Reads the stream into a string
 * @param iStream the input stream
 * @return the string read from the stream
 * @throws IOException when an IO error occurs
 */
private String readStream(InputStream iStream) throws IOException {

    //Buffered reader allows us to read line by line
    try (BufferedReader bReader =
                 new BufferedReader(new InputStreamReader(iStream))){
        StringBuilder builder = new StringBuilder();
        String line;
        while((line = bReader.readLine()) != null) {  //Read till end
            builder.append(line);
            builder.append("\n"); // append new line to preserve lines
        }
        return builder.toString();
    }
}

Answer 21

以下是在不使用任何第三方库的情况下将InputStream转换为String的完整方法。将StringBuilder用于单线程环境，否则使用StringBuffer。

public static String getString( InputStream is) throws IOException {
    int ch;
    StringBuilder sb = new StringBuilder();
    while((ch = is.read()) != -1)
        sb.append((char)ch);
    return sb.toString();
}

Answer 22

String inputStreamToString(InputStream inputStream, Charset charset) throws IOException {
    try (
            final StringWriter writer = new StringWriter();
            final InputStreamReader reader = new InputStreamReader(inputStream, charset)
        ) {
        reader.transferTo(writer);
        return writer.toString();
    }
}

纯Java标准库解决方案-没有库
从Java 10开始-https://spark.apache.org/docs/latest/monitoring.html
无环解决方案
没有换行符处理

Answer 23

以下是使用字节数组缓冲区仅使用JDK的方法。这实际上是commons-io IOUtils.copy()方法的工作原理。如果您从byte[]而不是char[]进行复制，则可以将Reader替换为InputStream。

import java.io.ByteArrayOutputStream;
import java.io.InputStream;

...

InputStream is = ....
ByteArrayOutputStream baos = new ByteArrayOutputStream(8192);
byte[] buffer = new byte[8192];
int count = 0;
try {
  while ((count = is.read(buffer)) != -1) {
    baos.write(buffer, 0, count);
  }
}
finally {
  try {
    is.close();
  }
  catch (Exception ignore) {
  }
}

String charset = "UTF-8";
String inputStreamAsString = baos.toString(charset);

Answer 24

使用Java 9支持的java.io.InputStream.transferTo(OutputStream)和使用charset名称的ByteArrayOutputStream.toString(String)：

<ion-header-bar class="bar-positive" align-title="center">
    <h1 class="title">Login</h1>
</ion-header-bar>

<ion-view hide-nav-bar="true">
 <!-- Login content goes here -->
</ion-view>

Answer 25

另一个，对所有Spring用户来说：

client = pubsub.Client()
topic = client('events')
topic.create()
subscription = topic.subscription('test_push', push_endpoint='http://localhost:5000/_ah/push-handlers/events')
subscription.create()
topic.publish('{"test": 123}')

import java.nio.charset.StandardCharsets; import org.springframework.util.FileCopyUtils; public String convertStreamToString(InputStream is) throws IOException { return new String(FileCopyUtils.copyToByteArray(is), StandardCharsets.UTF_8); }中的实用程序方法与org.springframework.util.StreamUtils中的实用程序方法类似，但它们在完成后会保持打开状态。

Answer 26

Kotlin用户只需：

println(InputStreamReader(is).readText())

而

readText()

是Kotlin标准库的内置扩展方法。

Answer 27

这个很好，因为：

Charset的手部安全。
您可以控制读取缓冲区大小。
您可以设置构建器的长度，但可能不完全正确。
没有库依赖项。
适用于Java 7或更高版本。

用于什么？

public static String convertStreamToString(InputStream is) throws IOException {
   StringBuilder sb = new StringBuilder(2048); // Define a size if you have an idea of it.
   char[] read = new char[128]; // Your buffer size.
   try (InputStreamReader ir = new InputStreamReader(is, StandardCharsets.UTF_8)) {
     for (int i; -1 != (i = ir.read(read)); sb.append(read, 0, i));
   } catch (Throwable t) {}
   return sb.toString();
}

对于JDK 9

public static String inputStreamString(InputStream inputStream) throws IOException {
    try (inputStream) {
        return new String(inputStream.readAllBytes(), StandardCharsets.UTF_8);
    }
}

Answer 28

JDK中最简单的方法是使用以下代码snipplet。

String convertToString(InputStream in){
    String resource = new Scanner(in).useDelimiter("\\Z").next();
    return resource;
}

Answer 29

这是我基于 Java 8 的解决方案，该解决方案使用新的Stream API 来收集InputStream中的所有行：

public static String toString(InputStream inputStream) {
    BufferedReader reader = new BufferedReader(
        new InputStreamReader(inputStream));
    return reader.lines().collect(Collectors.joining(
        System.getProperty("line.separator")));
}

Answer 30

就reduce和concat而言，它可以在Java 8中表示为：

String fromFile = new BufferedReader(new   
InputStreamReader(inputStream)).lines().reduce(String::concat).get();

Answer 31

In Groovy

inputStream.getText()

Answer 32

基于the accepted Apache Commons answer的第二部分，但填补了小差距以便始终关闭流：

    String theString;
    try {
        theString = IOUtils.toString(inputStream, encoding);
    } finally {
        IOUtils.closeQuietly(inputStream);
    }

Answer 33

Raghu K Nair 是唯一使用扫描仪的人。我使用的代码有点不同：

>>> Book('hamlet', 50) & Book('macbeth', 60)
'hamlet, macbeth'

关于分隔符：How do I use a delimiter in Java Scanner?

Answer 34

Guava provides更短的高效自动闭关解决方案，以防输入流来自类路径资源（这似乎是热门任务）：

byte[] bytes = Resources.toByteArray(classLoader.getResource(path));

或

String text = Resources.toString(classLoader.getResource(path), StandardCharsets.UTF_8);

还有ByteSource和CharSource的一般概念，可以轻轻地打开和关闭流。

因此，例如，而不是显式打开一个小文件来读取其内容：

String content = Files.asCharSource(new File("robots.txt"), StandardCharsets.UTF_8).read();
byte[] data = Files.asByteSource(new File("favicon.ico")).read();

或只是

String content = Files.toString(new File("robots.txt"), StandardCharsets.UTF_8);
byte[] data = Files.toByteArray(new File("favicon.ico"));

Answer 35

InputStream is = Context.openFileInput(someFileName); // whatever format you have

ByteArrayOutputStream bos = new ByteArrayOutputStream();

byte[] b = new byte[8192];
for (int bytesRead; (bytesRead = is.read(b)) != -1;) {
    bos.write(b, 0, bytesRead);
}

String output = bos.toString(someEncoding);

Answer 36

我写了一个这样做的课程，所以我想我会和大家分享。有时候你不想只为一件事添加Apache Commons，并且想要一些比扫描器更笨的东西不会检查内容。

用法如下

// Read from InputStream
String data = new ReaderSink(inputStream, Charset.forName("UTF-8")).drain();

// Read from File
data = new ReaderSink(file, Charset.forName("UTF-8")).drain();

// Drain input stream to console
new ReaderSink(inputStream, Charset.forName("UTF-8")).drainTo(System.out);

以下是ReaderSink的代码：

import java.io.*;
import java.nio.charset.Charset;

/**
 * A simple sink class that drains a {@link Reader} to a {@link String} or
 * to a {@link Writer}.
 *
 * @author Ben Barkay
 * @version 2/20/2014
 */
public class ReaderSink {
    /**
     * The default buffer size to use if no buffer size was specified.
     */
    public static final int DEFAULT_BUFFER_SIZE = 1024;

    /**
     * The {@link Reader} that will be drained.
     */
    private final Reader in;

    /**
     * Constructs a new {@code ReaderSink} for the specified file and charset.
     * @param file      The file to read from.
     * @param charset   The charset to use.
     * @throws FileNotFoundException    If the file was not found on the filesystem.
     */
    public ReaderSink(File file, Charset charset) throws FileNotFoundException {
        this(new FileInputStream(file), charset);
    }

    /**
     * Constructs a new {@code ReaderSink} for the specified {@link InputStream}.
     * @param in        The {@link InputStream} to drain.
     * @param charset   The charset to use.
     */
    public ReaderSink(InputStream in, Charset charset) {
        this(new InputStreamReader(in, charset));
    }

    /**
     * Constructs a new {@code ReaderSink} for the specified {@link Reader}.
     * @param in    The reader to drain.
     */
    public ReaderSink(Reader in) {
        this.in = in;
    }

    /**
     * Drains the data from the underlying {@link Reader}, returning a {@link String} containing
     * all of the read information. This method will use {@link #DEFAULT_BUFFER_SIZE} for
     * its buffer size.
     * @return  A {@link String} containing all of the information that was read.
     */
    public String drain() throws IOException {
        return drain(DEFAULT_BUFFER_SIZE);
    }

    /**
     * Drains the data from the underlying {@link Reader}, returning a {@link String} containing
     * all of the read information.
     * @param bufferSize    The size of the buffer to use when reading.
     * @return  A {@link String} containing all of the information that was read.
     */
    public String drain(int bufferSize) throws IOException {
        StringWriter stringWriter = new StringWriter();
        drainTo(stringWriter, bufferSize);
        return stringWriter.toString();
    }

    /**
     * Drains the data from the underlying {@link Reader}, writing it to the
     * specified {@link Writer}. This method will use {@link #DEFAULT_BUFFER_SIZE} for
     * its buffer size.
     * @param out   The {@link Writer} to write to.
     */
    public void drainTo(Writer out) throws IOException {
        drainTo(out, DEFAULT_BUFFER_SIZE);
    }

    /**
     * Drains the data from the underlying {@link Reader}, writing it to the
     * specified {@link Writer}.
     * @param out           The {@link Writer} to write to.
     * @param bufferSize    The size of the buffer to use when reader.
     */
    public void drainTo(Writer out, int bufferSize) throws IOException {
        char[] buffer = new char[bufferSize];
        int read;
        while ((read = in.read(buffer)) > -1) {
            out.write(buffer, 0, read);
        }
    }
}

Answer 37

以下代码对我有用。

URL url = MyClass.class.getResource("/" + configFileName);
BufferedInputStream bi = (BufferedInputStream) url.getContent();
byte[] buffer = new byte[bi.available() ];
int bytesRead = bi.read(buffer);
String out = new String(buffer);

请注意，根据Java文档，available()方法可能不适用于InputStream，但始终适用于BufferedInputStream。如果您不想使用available()方法，我们可以随时使用以下代码

URL url = MyClass.class.getResource("/" + configFileName);
BufferedInputStream bi = (BufferedInputStream) url.getContent();
File f = new File(url.getPath());
byte[] buffer = new byte[ (int) f.length()];
int bytesRead = bi.read(buffer);
String out = new String(buffer);

我不确定是否会出现编码问题。如果代码有任何问题，请发表评论。

Answer 38

嗯，你可以自己编程......这并不复杂......

String Inputstream2String (InputStream is) throws IOException
    {
        final int PKG_SIZE = 1024;
        byte[] data = new byte [PKG_SIZE];
        StringBuilder buffer = new StringBuilder(PKG_SIZE * 10);
        int size;

        size = is.read(data, 0, data.length);
        while (size > 0)
        {
            String str = new String(data, 0, size);
            buffer.append(str);
            size = is.read(data, 0, data.length);
        }
        return buffer.toString();
    }

Answer 39

使用Okio：

String result = Okio.buffer(Okio.source(inputStream)).readUtf8();

Answer 40

试试这4个陈述..

根据Fred回忆的那一点，我们不建议在String运算符附加+=，因为每次将新char附加到现有String时再次创建新的String对象并将其地址分配给st，而旧的st对象变为垃圾。

public String convertStreamToString(InputStream is)
{
    int k;
    StringBuffer sb=new StringBuffer();
    while((k=fin.read()) != -1)
    {
        sb.append((char)k);
    }
    return sb.toString();
}

不推荐，但这也是一种方式

public String convertStreamToString(InputStream is) { 
    int k;
    String st="";
    while((k=is.read()) != -1)
    {
        st+=(char)k;
    }
    return st;
}

Answer 41

您可以使用Apache Commons。

在IOUtils中，您可以找到带有三个有用实现的toString方法。

public static String toString(InputStream input) throws IOException {
        return toString(input, Charset.defaultCharset());
}

public static String toString(InputStream input) throws IOException {
        return toString(input, Charset.defaultCharset());
}

public static String toString(InputStream input, String encoding)
            throws IOException {
        return toString(input, Charsets.toCharset(encoding));
}

Answer 42

JDK 7/8回答关闭流并仍然抛出IOException：

StringBuilder build = new StringBuilder();
byte[] buf = new byte[1024];
int length;
try (InputStream is = getInputStream()) {
  while ((length = is.read(buf)) != -1) {
    build.append(new String(buf, 0, length));
  }
}

Answer 43

public String read(InputStream in) throws IOException {
    try (BufferedReader buffer = new BufferedReader(new InputStreamReader(in))) {
        return buffer.lines().collect(Collectors.joining("\n"));
    }
}

Answer 44

InputStreamReader i = new InputStreamReader(s);
BufferedReader str = new BufferedReader(i);
String msg = str.readLine();
System.out.println(msg);

这是您的InputStream对象，它将转换为String

Answer 45

ISO-8859-1

如果您知道输入流的编码是ISO-8859-1或ASCII，则

这是一种非常的高性能方法。它（1）避免了StringWriter内部StringBuffer中出现的不必要的同步，（2）避免了InputStreamReader的开销，并且（3）最小化了{{1} }的内部StringBuilder数组必须被复制。

char

UTF-8

对于使用UTF-8编码的流，可以使用相同的通用策略：

public static String iso_8859_1(InputStream is) throws IOException {
    StringBuilder chars = new StringBuilder(Math.max(is.available(), 4096));
    byte[] buffer = new byte[4096];
    int n;
    while ((n = is.read(buffer)) != -1) {
        for (int i = 0; i < n; i++) {
            chars.append((char)(buffer[i] & 0xFF));
        }
    }
    return chars.toString();
}

其中public static String utf8(InputStream is) throws IOException { StringBuilder chars = new StringBuilder(Math.max(is.available(), 4096)); byte[] buffer = new byte[4096]; int n; int state = 0; while ((n = is.read(buffer)) != -1) { for (int i = 0; i < n; i++) { if ((state = nextStateUtf8(state, buffer[i])) >= 0) { chars.appendCodePoint(state); } else if (state == -1) { //error state = 0; chars.append('\uFFFD'); //replacement char } } } return chars.toString(); }函数的定义如下：

nextStateUtf8()

自动检测编码

如果您的输入流是使用ASCII或ISO-8859-1或UTF-8编码的，但是您不确定哪种编码，我们可以使用与上一种类似的方法，但是要使用一个附加的编码检测组件自动检测编码，然后返回字符串。

/**
 * Returns the next UTF-8 state given the next byte of input and the current state.
 * If the input byte is the last byte in a valid UTF-8 byte sequence,
 * the returned state will be the corresponding unicode character (in the range of 0 through 0x10FFFF).
 * Otherwise, a negative integer is returned. A state of -1 is returned whenever an
 * invalid UTF-8 byte sequence is detected.
 */
static int nextStateUtf8(int currentState, byte nextByte) {
    switch (currentState & 0xF0000000) {
        case 0:
            if ((nextByte & 0x80) == 0) { //0 trailing bytes (ASCII)
                return nextByte;
            } else if ((nextByte & 0xE0) == 0xC0) { //1 trailing byte
                if (nextByte == (byte) 0xC0 || nextByte == (byte) 0xC1) { //0xCO & 0xC1 are overlong
                    return -1;
                } else {
                    return nextByte & 0xC000001F;
                }
            } else if ((nextByte & 0xF0) == 0xE0) { //2 trailing bytes
                if (nextByte == (byte) 0xE0) { //possibly overlong
                    return nextByte & 0xA000000F;
                } else if (nextByte == (byte) 0xED) { //possibly surrogate
                    return nextByte & 0xB000000F;
                } else {
                    return nextByte & 0x9000000F;
                }
            } else if ((nextByte & 0xFC) == 0xF0) { //3 trailing bytes
                if (nextByte == (byte) 0xF0) { //possibly overlong
                    return nextByte & 0x80000007;
                } else {
                    return nextByte & 0xE0000007;
                }
            } else if (nextByte == (byte) 0xF4) { //3 trailing bytes, possibly undefined
                return nextByte & 0xD0000007;
            } else {
                return -1;
            }
        case 0xE0000000: //3rd-to-last continuation byte
            return (nextByte & 0xC0) == 0x80 ? currentState << 6 | nextByte & 0x9000003F : -1;
        case 0x80000000: //3rd-to-last continuation byte, check overlong
            return (nextByte & 0xE0) == 0xA0 || (nextByte & 0xF0) == 0x90 ? currentState << 6 | nextByte & 0x9000003F : -1;
        case 0xD0000000: //3rd-to-last continuation byte, check undefined
            return (nextByte & 0xF0) == 0x80 ? currentState << 6 | nextByte & 0x9000003F : -1;
        case 0x90000000: //2nd-to-last continuation byte
            return (nextByte & 0xC0) == 0x80 ? currentState << 6 | nextByte & 0xC000003F : -1;
        case 0xA0000000: //2nd-to-last continuation byte, check overlong
            return (nextByte & 0xE0) == 0xA0 ? currentState << 6 | nextByte & 0xC000003F : -1;
        case 0xB0000000: //2nd-to-last continuation byte, check surrogate
            return (nextByte & 0xE0) == 0x80 ? currentState << 6 | nextByte & 0xC000003F : -1;
        case 0xC0000000: //last continuation byte
            return (nextByte & 0xC0) == 0x80 ? currentState << 6 | nextByte & 0x3F : -1;
        default:
            return -1;
    }
}

如果您的输入流的编码既不是ISO-8859-1也不是ASCII也不是UTF-8，那么我要参考已经存在的其他答案。

Answer 46

您可以使用Cactoos：

UTF-8编码是默认编码。如果你需要另一个：

String text = new TextOf(inputStream).asString();

Answer 47

以下内容并未解决原始问题，而是解决了一些问题。

几个回复表明形式的循环

String line = null;
while((line = reader.readLine()) != null) {
  // ...
}

或

for(String line = reader.readLine(); line != null; line = reader.readLine()) {
    // ...
}

第一种形式通过声明变量＆＃34; read＆＃34;来污染封闭范围的命名空间。在封闭范围内，不会用于for循环之外的任何内容。第二种形式重复了readline（）调用。

这是一种在Java中编写这种循环的更简洁的方法。事实证明，for循环中的第一个子句不需要实际的初始化值。这保持了变量＆＃34; line＆＃34;的范围。在for循环体内。更优雅！我没有看到任何人在任何地方使用这种形式（我在一天前随机发现它），但我一直都在使用它。

for (String line; (line = reader.readLine()) != null; ) {
    //...
}

Answer 48

InputStream  inputStream = null;
BufferedReader bufferedReader = null;
try {
    BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
    String stringBuilder = new StringBuilder();
    String content;
    while((content = bufferedReader.readLine()) != null){
        stringBuilder.append(content);
    }
    System.out.println("content of file::" + stringBuilder.toString());
}
catch (IOException e) {
            e.printStackTrace();
        }finally{           
            if(bufferedReader != null){
                try{
                    bufferedReader.close();
                }catch(IoException ex){
                   ex.printStackTrace();
            }

Answer 49

将inputStream转换为String

的方法

public static String getStringFromInputStream(InputStream inputStream) {

    BufferedReader bufferedReader = null;
    StringBuilder stringBuilder = new StringBuilder();
    String line;

    try {
        bufferedReader = new BufferedReader(new InputStreamReader(
                inputStream));
        while ((line = bufferedReader.readLine()) != null) {
            stringBuilder.append(line);
        }
    } catch (IOException e) {
        logger.error(e.getMessage());
    } finally {
        if (bufferedReader != null) {
            try {
                bufferedReader.close();
            } catch (IOException e) {
                logger.error(e.getMessage());
            }
        }
    }
    return stringBuilder.toString();
}

Answer 50

此片段位于\ sdk \ samples \ android-19 \ connectivity \ NetworkConnect \ NetworkConnectSample \ src \ main \ java \ com \ example \ android \ networkconnect \ MainActivity.java中，该许可在Apache License，Version 2.0和由谷歌撰写。

/** Reads an InputStream and converts it to a String.
 * @param stream InputStream containing HTML from targeted site.
 * @param len Length of string that this method returns.
 * @return String concatenated according to len parameter.
 * @throws java.io.IOException
 * @throws java.io.UnsupportedEncodingException
 */
private String readIt(InputStream stream, int len) throws IOException, UnsupportedEncodingException {
    Reader reader = null;
    reader = new InputStreamReader(stream, "UTF-8");
    char[] buffer = new char[len];
    reader.read(buffer);
    return new String(buffer);
}

Answer 51

这个问题的解决方案并不是最简单的，但由于没有提到NIO流和通道，这里有一个使用NIO通道和ByteBuffer将流转换为字符串的版本。

public static String streamToStringChannel(InputStream in, String encoding, int bufSize) throws IOException {
    ReadableByteChannel channel = Channels.newChannel(in);
    ByteBuffer byteBuffer = ByteBuffer.allocate(bufSize);
    ByteArrayOutputStream bout = new ByteArrayOutputStream();
    WritableByteChannel outChannel = Channels.newChannel(bout);
    while (channel.read(byteBuffer) > 0 || byteBuffer.position() > 0) {
        byteBuffer.flip();  //make buffer ready for write
        outChannel.write(byteBuffer);
        byteBuffer.compact(); //make buffer ready for reading
    }
    channel.close();
    outChannel.close();
    return bout.toString(encoding);
}

以下是如何使用它的示例：

try (InputStream in = new FileInputStream("/tmp/large_file.xml")) {
    String x = streamToStringChannel(in, "UTF-8", 1);
    System.out.println(x);
}

此方法的性能应该适用于大型文件。

Answer 52

使用：

String theString = IOUtils.toString(inputStream, encoding);

Answer 53

注意：这可能不是一个好主意。此方法使用递归，因此将很快达到StackOverflowError：

public String read (InputStream is) {
    byte next = is.read();
    return next == -1 ? "" : next + read(is); // Recursive part: reads next byte recursively
}

请不要仅仅因为它是一个糟糕的选择而不能使用它;这主要是创造性的：）

Answer 54

我已经创建了此代码，并且可以正常工作。没有必需的外部插件。

有将String转换为Stream和将Stream转换为String ...

import java.io.ByteArrayInputStream;
import java.io.InputStream;

public class STRINGTOSTREAM {

    public static void main(String[] args)
    {
        String text = "Hello Bhola..!\nMy Name Is Kishan ";

        InputStream strm = new ByteArrayInputStream(text.getBytes());    // Convert String to Stream

        String data = streamTostring(strm);

        System.out.println(data);
    }

    static String streamTostring(InputStream stream)
    {
        String data = "";

        try
        {
            StringBuilder stringbuld = new StringBuilder();
            int i;
            while ((i=stream.read())!=-1)
            {
                stringbuld.append((char)i);
            }
            data = stringbuld.toString();
        }
        catch(Exception e)
        {
            data = "No data Streamed.";
        }
        return data;
    }

Answer 55

如果您需要将字符串转换为特定的字符集 不使用外部库 然后：

public String convertStreamToString(InputStream is) throws IOException {
  try( ByteArrayOutputStream baos = new ByteArrayOutputStream(); ) {
    is.transferTo( baos );
    return baos.toString( StandardCharsets.UTF_8 );
  }
}

Answer 56

对于该问题，我建议使用 StringWriter 类。

StringWriter wt= new StringWriter();
IOUtils.copy(inputStream, wt, encoding);
String st= wt.toString();

Answer 57

此代码适用于Java新手：

     private String textDataFromFile;

public String getFromFile(InputStream myInputStream) throws FileNotFoundException, IOException {

      BufferedReader bufferReader = new BufferedReader (new InputStreamReader(myInputStream));

       StringBuilder stringBuilder = new StringBuilder();

  String eachStringLine;

    while((eachStringLine=bufferReader.readLine()) != null){          
        stringBuilder.append(eachStringLine).append("\n");
    }

   textDataFromFile = stringBuilder.toString(); 



  return textDataFromFile;

}

Answer 58

const images = { test: /\.(jpe?g|svg|png|gif)$/i, exclude: /node_modules/, loader:'url-loader', options: { limit: 10, name: '[path][name].[ext]?[hash]' } };

Answer 59

您也可以从指定的资源路径获取InputStream：

public static InputStream getResourceAsStream(String path)
{
    InputStream myiInputStream = ClassName.class.getResourceAsStream(path);
    if (null == myiInputStream)
    {
        mylogger.info("Can't find path = ", path);
    }

    return myiInputStream;
}

从特定路径获取InputStream：

public static URL getResource(String path)
{
    URL myURL = ClassName.class.getResource(path);
    if (null == myURL)
    {
        mylogger.info("Can't find resource path = ", path);
    }
    return myURL;
}

Answer 60

我有log4j可用，所以我能够使用org.apache.log4j.lf5.util.StreamUtils.getBytes来获取字节，我可以使用String ctor将其转换为字符串

String result = new String(StreamUtils.getBytes(inputStream));

Answer 61

  InputStream IS=new URL("http://www.petrol.si/api/gas_prices.json").openStream();   

  ByteArrayOutputStream BAOS=new ByteArrayOutputStream();
  IOUtils.copy(IS, BAOS);
  String d= new String(BAOS.toByteArray(),"UTF-8");           

System.out.println(d);

Answer 62

首先，您必须知道要转换的字符串的编码。因为java.io.InputStream操作基础的字节数组，所以字符串由需要编码的字符数组组成，例如UTF-8，JDK将采用默认编码

System.getProperty("file.encoding","UTF-8"); 

byte[] bytes=new byte[inputStream.available()];
inputStream.read(bytes);
String s = new String(bytes);

如果inputStream的字节数组很大，你可以循环执行。

Answer 63

快速简便：

String result = (String)new ObjectInputStream( inputStream ).readObject();

如何在Java中读取/转换InputStream为String？

63 个答案:

基准测试结果，20个周期内20 MB随机字节

基准源代码

ISO-8859-1

UTF-8

自动检测编码