Java Base64解码错误及解决方法

时间:2022-09-03 00:13:39

问题提出:

自己在做一个小网站充当练手,但是前端图片经过base64加密后传往后端在解码。但是一直都有问题,请大神赐教

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public static String base64ToImg(String src) throws IOException {
  String uuid = UUID.randomUUID().toString();
  StringBuilder newPath = new StringBuilder(IMG_ROOT_PATH);
  newPath.append(separator).
      append(uuid).
      append(IMG_SUFFIX);
  if(src == null){
    return null;
  }
  byte[] data = null;
  Base64.Decoder decoder = Base64.getDecoder();
  try (OutputStream out = new FileOutputStream(newPath.toString())) {
    data = decoder.decode(src);
    out.write(data);
    return newPath.toString();
  } catch (IOException e) {
    throw new IOException();
  }
}
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java.lang.IllegalArgumentException: Input byte array has wrong 4-byte ending unit

以上是相关的异常信息。我试图将前端的base64码粘贴到记事本然后自己在试着解码,也是同样问题。

解决办法:

IllegalArgumentException:非法参数异常,

试下这个,应该可以。

给你讲述下过程:

去了*,debug。最后发现data为null,,加油吧,我们需要学的还很多

下次遇到问题debug下,看是哪条代码出现问题了,通过回答你,我也学到了很多

关键点在这里: throw new IOException();

Java Base64解码错误及解决方法

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try (OutputStream out = new FileOutputStream(newPath.toString())) {
      out.write(data);
    } catch (IOException e) {
      e.printStackTrace();
      throw new RuntimeException("异常是这么抛出的");
      //throw new RuntimeException(e);
    }
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public static String base64ToImg(String src) throws IOException {
    String uuid = UUID.randomUUID().toString();
    StringBuilder newPath = new StringBuilder("xx");
    newPath.append("xx").
        append(uuid).
        append("xx");
    if (src == null) {
      return null;
    }
    byte[] data = Base64.getDecoder().decode(src);
    try (OutputStream out = new FileOutputStream(newPath.toString())) {
      out.write(data);
    } catch (IOException e) {
      e.printStackTrace();
    }
    return newPath.toString();
  }

补充另外一种常用关闭资源:

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public static String base64ToImg(String src) throws IOException {
   String uuid = UUID.randomUUID().toString();
   StringBuilder newPath = new StringBuilder("xx");
   newPath.append("xx").
       append(uuid).
       append("xx");
   if (src == null) {
     return null;
   }
   byte[] data = null;
   OutputStream out = null;
   Base64.Decoder decoder = Base64.getDecoder();
   try {
     out = new FileOutputStream(newPath.toString());
     data = decoder.decode(src);
     out.write(data);
   } catch (IOException e) {
     e.printStackTrace();
   } finally {
     if (out != null) {
       out.close();
     }
   }
   return newPath.toString();
 }