JAVA将图片（本地或者网络资源）转为Base64字符串，将base64字符串存储为本地图片

代码如下：

 package com.futuredata.dataservice.util;

 import java.io.ByteArrayOutputStream;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.net.HttpURLConnection;
 import java.net.URL;

 import sun.misc.BASE64Decoder;
 import sun.misc.BASE64Encoder;

 @SuppressWarnings("restriction")
 public class Base64Utils {

    public static void main(String[] args) throws Exception {

       //本地图片地址
       String url = "C:/Users/Administrator/Desktop/628947887489084892.jpg";
       //在线图片地址
       String string = "http://bpic.588ku.com//element_origin_min_pic/17/03/03/7bf4480888f35addcf2ce942701c728a.jpg";

       String str = Base64Utils.ImageToBase64ByLocal(url);

       String ste = Base64Utils.ImageToBase64ByOnline(string);

       System.out.println(str);

       Base64Utils.Base64ToImage(str, "C:/Users/Administrator/Desktop/test1.jpg");

       Base64Utils.Base64ToImage(ste, "C:/Users/Administrator/Desktop/test2.jpg");
    }

    /**
     * 本地图片转换成base64字符串
     *
     * @param imgFile 图片本地路径
     * @return
     * @author ZHANGJL
     * @dateTime 2018-02-23 14:40:46
     */
    public static String ImageToBase64ByLocal(String imgFile) {// 将图片文件转化为字节数组字符串，并对其进行Base64编码处理

       InputStream in = null;
       byte[] data = null;

       // 读取图片字节数组
       try {
          in = new FileInputStream(imgFile);

          data = new byte[in.available()];
          in.read(data);
          in.close();
       } catch (IOException e) {
          e.printStackTrace();
       }
       // 对字节数组Base64编码
       BASE64Encoder encoder = new BASE64Encoder();

       return encoder.encode(data);// 返回Base64编码过的字节数组字符串
    }

    /**
     * 在线图片转换成base64字符串
     *
     * @param imgURL 图片线上路径
     * @return
     * @author ZHANGJL
     * @dateTime 2018-02-23 14:43:18
     */
    public static String ImageToBase64ByOnline(String imgURL) {
       ByteArrayOutputStream data = new ByteArrayOutputStream();
       try {
          // 创建URL
          URL url = new URL(imgURL);
          byte[] by = new byte[1024];
          // 创建链接
          HttpURLConnection conn = (HttpURLConnection) url.openConnection();
          conn.setRequestMethod("GET");
          conn.setConnectTimeout(5000);
          InputStream is = conn.getInputStream();
          // 将内容读取内存中
          int len = -1;
          while ((len = is.read(by)) != -1) {
             data.write(by, 0, len);
          }
          // 关闭流
          is.close();
       } catch (IOException e) {
          e.printStackTrace();
       }
       // 对字节数组Base64编码
       BASE64Encoder encoder = new BASE64Encoder();
       return encoder.encode(data.toByteArray());
    }

    /**
     * base64字符串转换成图片
     *
     * @param imgStr      base64字符串
     * @param imgFilePath 图片存放路径
     * @return
     * @author ZHANGJL
     * @dateTime 2018-02-23 14:42:17
     */
    public static boolean Base64ToImage(String imgStr, String imgFilePath) { // 对字节数组字符串进行Base64解码并生成图片

       if (isEmpty(imgStr)) // 图像数据为空
          return false;

       BASE64Decoder decoder = new BASE64Decoder();
       try {
          // Base64解码
          byte[] b = decoder.decodeBuffer(imgStr);
          for (int i = 0; i < b.length; ++i) {
             if (b[i] < 0) {// 调整异常数据
                b[i] += 256;
             }
          }

          OutputStream out = new FileOutputStream(imgFilePath);
          out.write(b);
          out.flush();
          out.close();

          return true;
       } catch (Exception e) {
          return false;
       }

    }

    public static boolean isEmpty(String input) {
       return input == null || input.equals("");
    }

 }