Question

我正在尝试使用jquery插件裁剪/调整用户个人资料图片的大小，即crop.js，它通过ajax将用户图像作为base64发送到我的控制器

$.ajax({
         type: "post",
         dataType: "json",
         url: "${g.createLink(controller: 'personalDetail', action:'uploadUserImage')}",
         data: { avatar: canvas.toDataURL() }

        });

但我无法解码此base64

'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAPAAAADwCAYAAAA+VemSAAAgAEl...=='

string as image，你能指导我如何将base64字符串保存为服务器上的图像吗？

Answer 1

在服务器中，执行以下操作：

假设

String data = 'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAPAAAADwCAYAAAA+VemSAAAgAEl...=='

然后：

String base64Image = data.split(",")[1];
byte[] imageBytes = javax.xml.bind.DatatypeConverter.parseBase64Binary(base64Image);

然后你可以用以下字节做任何你喜欢的事情：

BufferedImage img = ImageIO.read(new ByteArrayInputStream(imageBytes));

Answer 2

这假定了一些事情，您知道输出文件名是什么以及您的数据是否为字符串。我确定您可以修改以下内容以满足您的需求：

// Needed Imports
import java.io.ByteArrayInputStream;
import sun.misc.BASE64Decoder;


def sourceData = 'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAPAAAADwCAYAAAA+VemSAAAgAEl...==';

// tokenize the data
def parts = sourceData.tokenize(",");
def imageString = parts[1];

// create a buffered image
BufferedImage image = null;
byte[] imageByte;

BASE64Decoder decoder = new BASE64Decoder();
imageByte = decoder.decodeBuffer(imageString);
ByteArrayInputStream bis = new ByteArrayInputStream(imageByte);
image = ImageIO.read(bis);
bis.close();

// write the image to a file
File outputfile = new File("image.png");
ImageIO.write(image, "png", outputfile);

请注意，这只是涉及哪些部分的示例。我根本没有对这段代码进行优化，而且它已经在我的脑海中写下了。

Answer 3

#include <mutex> #include <stdio.h> class A { private: bool _is; std::mutex _mutex; } // this function runs in Thread A void A::read() { _mutex.lock(); printf("%d", _is); _mutex.unlock(); } // this function runs in Thread B void A::write() { _mutex.lock(); printf("%d", _is); _is = !_is; _mutex.unlock(); }将默认压缩图像-压缩后的图像尺寸较小，但有时看起来很奇怪。我使用ImageIO.write()保存字节数组数据-这将保留原始图像大小。

代码如下：

BufferedOutputStream

Answer 4

要解码：

byte[] image = Base64.getDecoder().decode(base64string);

要编码：

String text = Base64.getEncoder().encodeToString(imageData);

Answer 5

服务器端编码文件/图像到base64String已准备好供客户端使用

public Optional<String> InputStreamToBase64(Optional<InputStream> inputStream) throws IOException{
    if (inputStream.isPresent()) {
        ByteArrayOutputStream output = new ByteArrayOutputStream();
        FileCopyUtils.copy(inputStream.get(), output);
        //TODO retrieve content type from file, & replace png below with it
        return Optional.ofNullable("data:image/png;base64," + DatatypeConverter.printBase64Binary(output.toByteArray()));
    }

    return Optional.empty();
}

服务器端base64图像/文件解码器

public Optional<InputStream> Base64InputStream(Optional<String> base64String)throws IOException {
    if (base64String.isPresent()) {
        return Optional.ofNullable(new ByteArrayInputStream(DatatypeConverter.parseBase64Binary(base64String.get())));
    }

    return Optional.empty();
}

Answer 6

  public Optional<String> InputStreamToBase64(Optional<InputStream> inputStream) throws IOException{
    if (inputStream.isPresent()) {
        ByteArrayOutputStream outpString base64Image = data.split(",")[1];
byte[] imageBytes = javax.xml.bind.DatatypeConverter.parseBase64Binary(base64Image);

然后你可以用以下字节做任何你喜欢的事情：

BufferedImage img = ImageIO.read(new ByteArrayInputStream(imageBytes));ut = new ByteArrayOutputStream();
        FileCopyUtils.copy(inputStream.get(), output);
        //TODO retrieve content type from file, & replace png below with it
        return Optional.ofNullable("data:image/png;base64," + DatatypeConverter.printBase64Binary(output.toByteArray()));
    }

    return Optional.empty();

Answer 7

嗨这是我的解决方案

Javascript代码

var base64before = document.querySelector('img').src;
var base64 = base64before.replace(/^data:image\/(png|jpg);base64,/, "");
var httpPost = new XMLHttpRequest();
var path = "your url";
var data = JSON.stringify(base64);

httpPost.open("POST", path, false);
// Set the content type of the request to json since that's what's being sent
httpPost.setRequestHeader('Content-Type', 'application/json');
httpPost.send(data);

这是我的Java代码。

public void saveImage（InputStream imageStream）{ InputStream inStream = imageStream;

try {
    String dataString = convertStreamToString(inStream);

    byte[] imageBytes = javax.xml.bind.DatatypeConverter.parseBase64Binary(dataString);
    BufferedImage image = ImageIO.read(new ByteArrayInputStream(imageBytes));
    // write the image to a file
    File outputfile = new File("/Users/paul/Desktop/testkey/myImage.png");
    ImageIO.write(image, "png", outputfile);

    }catch(Exception e) {
        System.out.println(e.getStackTrace());
    }
}


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

将base64字符串转换为图像

7 个答案: