Java中Base64类型的字符串与图片的相互转换

使用Html5绘制图表，前端返回的是Base64字符串，如果想在后台将Base64字符串转换为图片，保存在本地，在Java中经常需要做如下处理，下文介绍了Base64字符串与图片的相互转换过程。

具体Java代码如下：

示例代码1

/**
 * 
 * @site 四个空格-https://www.4spaces.org/
 * @author michael
 * 
 */
public class Base64StringToImage {
    public static void main(String[] args) {
        String imgStr = "/9j/4AAQSkZ...";
        generateImage(imgStr, "D:\\wangyc.jpg"); //
        System.out.println(getImageStr("d:\\wangyc.jpg"));
    }

    /**
     * 将图片转换为Base64类型字符串
     * 
     * @param imgFilePath
     * @return
     */
    public static String getImageStr(String imgFilePath) {
        byte[] data = null;
        try {
            InputStream in = new FileInputStream(imgFilePath);
            data = new byte[in.available()];
            in.read(data);
            in.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        BASE64Encoder encoder = new BASE64Encoder();
        return encoder.encode(data);
    }

    /**
     * 将Base64类型字符串转换为图片
     * 
     * @param imgStr
     * @param imgFilePath
     * @return
     */
    public static boolean generateImage(String imgStr, String imgFilePath) {
        if (imgStr == null)
            return false;
        BASE64Decoder decoder = new BASE64Decoder();
        try {
            byte[] bytes = decoder.decodeBuffer(imgStr);
            for (int i = 0; i < bytes.length; ++i) {
                if (bytes[i] < 0) {
                    bytes[i] += 256;
                }
            }
            OutputStream out = new FileOutputStream(imgFilePath);
            out.write(bytes);
            out.flush();
            out.close();
            return true;
        } catch (Exception e) {
            return false;
        }
    }

示例代码2

String imgStr = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgA...";

String imgFilePath = "D:\root\xf-service\upload-path\37\a.jpg";

generateImage(imgStr, imgFilePath);

 /**
     * 将Base64类型字符串转换为图片
     *
     * @param imgStr
     * @param imgFilePath
     * @return
     */
    private boolean generateImage(String imgStr, String imgFilePath) {
        if (imgStr == null) {
            return false;
        }
        String base64Image = imgStr.split(",")[1];
        byte[] imageBytes = javax.xml.bind.DatatypeConverter.DatatypeConverter.parseBase64Binary(base64Image);

        java.awt.image.BufferedImage.BufferedImage image = null;
        try {
            image = javax.imageio.ImageIO.ImageIO.read(new ByteArrayInputStream(imageBytes));
            // write the image to a file
            File outputfile = new File(imgFilePath);
            ImageIO.write(image, "png", outputfile);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return true;
    }