1     public static byte[] base64String2ByteFun(String base64Str){
 2         BASE64Decoder decoder = new BASE64Decoder();
 3         byte[] b = null;
 4         try {
 5             b = decoder.decodeBuffer(base64Str);
 6             for (int i = 0; i < b.length; ++i) {
 7                 if (b[i] < 0) {
 8                     b[i] += 256;
 9                 }
10             }
11         } catch (IOException e) {
12             e.printStackTrace();
13         }
14
15         return b;
16     }
17     public static String getImageStr(String imgFile) {
18         InputStream inputStream = null;
19         byte[] data = null;
20         try {
21             inputStream = new FileInputStream(imgFile);
22             data = new byte[inputStream.available()];
23             inputStream.read(data);
24             inputStream.close();
25         } catch (IOException e) {
26             e.printStackTrace();
27         }
28         BASE64Encoder encoder = new BASE64Encoder();
29         return encoder.encode(data);
30     }

提示：

sun.misc.BASE64Encoder找不到jar包的解决方法

右键项目-》属性-》java bulid path-》jre System Library-》access rules-》resolution选择accessible，下面填上** 点击确定即可！！！

原文地址：https://www.cnblogs.com/xinzheng/p/8422679.html