/**
 * 将图片转换成二进制
 *
 * @return
 */
static String getImageBinary() {
     BASE64Encoder encoder = new sun.misc.BASE64Encoder();
    //本地图片
    File f = new File("D:/voice/picture/企业微信截图_15302624613767.png");
    BufferedImage bi;
    try {
        bi = ImageIO.read(f);
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        //图片格式
        ImageIO.write(bi, "png", baos);
        byte[] bytes = baos.toByteArray();

        return encoder.encodeBuffer(bytes).trim();
    } catch (IOException e) {
        e.printStackTrace();
    }
    return null;
}

/**
 * 将二进制转换为图片
 *
 * @param base64String
 */
static void base64StringToImage(String base64String) {
    BASE64Decoder decoder = new sun.misc.BASE64Decoder();
    try {
        byte[] bytes1 = decoder.decodeBuffer(base64String);

        ByteArrayInputStream bais = new ByteArrayInputStream(bytes1);
        BufferedImage bi1 = ImageIO.read(bais);
        //图片存储本地路径及名称
        File w2 = new File("D:/voice/2.png");
        if(!w2.exists()){
            w2.createNewFile();
        }
        ImageIO.write(bi1, "jpg", w2);
    } catch (IOException e) {
        e.printStackTrace();
    }
}
//调用方法测试

@GetMapping
public String test(){
    base64StringToImage(getImageBinary());
    return "test01";}