Question

我知道这可能是使用Streams的，但我不确定正确的语法。

我想将一个字符串传递给Save方法并让它gzip字符串并将其上传到Amazon S3，而不必写入磁盘。当前方法在两者之间低效地读取/写入磁盘。

S3 PutObjectRequest有一个带有InputStream输入的构造函数作为选项。

import java.io.*;
import java.util.zip.GZIPOutputStream;

import com.amazonaws.auth.PropertiesCredentials;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3Client;
import com.amazonaws.services.s3.model.PutObjectRequest;

public class FileStore {

    public static void Save(String data) throws IOException
    {
        File file = File.createTempFile("filemaster-", ".htm");
        file.deleteOnExit();

        Writer writer = new OutputStreamWriter(new FileOutputStream(file));
        writer.write(data);
        writer.flush();
        writer.close();

        String zippedFilename = gzipFile(file.getAbsolutePath());
        File zippedFile = new File(zippedFilename);
        zippedFile.deleteOnExit();

        AmazonS3 s3 = new AmazonS3Client(new PropertiesCredentials(
                new FileInputStream("AwsCredentials.properties")));

        String bucketName = "mybucket";
        String key = "test/" + zippedFile.getName();

        s3.putObject(new PutObjectRequest(bucketName, key, zippedFile));

    }

    public static String gzipFile(String filename) throws IOException
    {
        try {
            // Create the GZIP output stream
            String outFilename = filename + ".gz";
            GZIPOutputStream out = new GZIPOutputStream(new FileOutputStream(outFilename));

            // Open the input file
            FileInputStream in = new FileInputStream(filename);

            // Transfer bytes from the input file to the GZIP output stream
            byte[] buf = new byte[1024];
            int len;
            while ((len = in.read(buf)) > 0) {
                out.write(buf, 0, len);
            }
            in.close();

            // Complete the GZIP file
            out.finish();
            out.close();

            return outFilename;
        } catch (IOException e) {
            throw e;
        }
    }


}

Answer 1

我会使用以下内容：

ByteArrayOutputStream byteOut = new ByteArrayOutputStream();
GZipOuputStream gzipOut = new GZipOutputStream(byteOut);
// write your stuff
byte[] bites = byteOut.toByteArray();
//write the bites to the amazon stream

您正在将压缩值写入字节流，然后获取字节值，您可以将其写入其他流。您还可以将流包装到amazon站点（即来自http连接的输出流或类似的东西）并避免整个ByteArrayOutputStream。

编辑：我注意到你的最后一句话 - 布鲁阿。您可以获取您创建的字节，使用它们创建ByteArrayInputStream，然后将其作为输入流传递：

ByteArrayInputStream byteInStream = new ByteArrayInputStream(bites);

如果我正在理解您正确描述的内容，它应该从输入流读取到输出流。否则，您只需写入输出流即可。

Answer 2

这基本上是aperkins建议的。我不知道AS3的接口，所以他建议在字节数组上创建ByteArrayInputStream可能就是这样。

import java.io.*;
import java.util.zip.GZIPOutputStream;

import com.amazonaws.auth.PropertiesCredentials;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3Client;
import com.amazonaws.services.s3.model.PutObjectRequest;

public class FileStore {
    public static void Save(String data) throws IOException {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();

        Writer writer = new OutputStreamWriter(baos);
        writer.write(data);
        writer.flush();
        writer.close();

        byte[] zippedBytes = gzipFile(baos.toByteArray());

        AmazonS3 s3 = new AmazonS3Client(new PropertiesCredentials(
            new FileInputStream("AwsCredentials.properties")));

        String bucketName = "mybucket";
        String key = "test/" + zippedFile.getName();

        s3.putObject(new PutObjectRequest(bucketName, key,
            new ByteArrayInputStream(zippedBytes));
    }

    public static byte[] gzipFile(byte[] bytes) throws IOException {
        try {
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            GZIPOutputStream out = new GZIPOutputStream(baos);
            out.write(bytes, 0, bytes.length);
            // Complete the GZIP file
            out.finish();
            out.close();

            return baos.toByteArray();
        } catch (IOException e) {
            throw e;
        }
    }
}

是否可以将此字符串gzip并上传到Amazon S3而无需写入磁盘？

2 个答案: