图片转码成base64的两种方式，为什么需要两种呢，第一种是用sun公司的sun.misc.BASE64Encoder; jar包进行转码，会有一些特殊字符比如\r \n 之类的，这些字符在写到url中的时候，会造成url换行之类的效果，从而导致请求出错，第二种方式是用com.sun.org.apache.xerces.internal.impl.dv.util.Base64; jar包来进行转码，这个会把特殊字符转换成_ - 之类的合法字符，比较nice

import java.io.*;

import  com.sun.org.apache.xerces.internal.impl.dv.util.Base64;

import sun.misc.BASE64Encoder;

import java.net.HttpURLConnection;
import java.net.URL;

/**
 * Created with pengyouqi
 * 图片转码
 * 2019/6/24 16:48
 */

public class Base64Utils {

    /**
     * @Description: 根据图片地址转换为base64编码字符串
     * @Author:
     * @CreateTime:
     * @return
     */
    public static String imgBase64(String imgURL) {
        ByteArrayOutputStream outPut = new ByteArrayOutputStream();
        byte[] data = new byte[1024];
        try {
            // 创建URL
            URL url = new URL(imgURL);
            // 创建链接
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setRequestMethod("GET");
            conn.setConnectTimeout(10 * 1000);

            if(conn.getResponseCode() != HttpURLConnection.HTTP_OK) {
                return "fail";//连接失败/链接失效/图片不存在
            }
            InputStream inStream = conn.getInputStream();
            int len = -1;
            while ((len = inStream.read(data)) != -1) {
                outPut.write(data, 0, len);
            }
            inStream.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        // 对字节数组Base64编码
        BASE64Encoder encoder = new BASE64Encoder();
        return encoder.encode(outPut.toByteArray());
    }

   /**
     * 将图片转换成字符串 2
     * @param filePath 文件的路径
     * @return String
     */
    public  static String encode(String filePath)  {
        BufferedInputStream inputStream = null;
        byte [] b = null;
        try {
            inputStream = new BufferedInputStream(new FileInputStream(filePath));
            b = new byte [inputStream.available()];
            inputStream.read(b);
            inputStream.close();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (null != inputStream){
                try {
                    inputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        System.out.println(Base64.encode(b));
        return Base64.encode(b);
    }
}



     /**
     * base64字符串转化成图片
     * @param imgStr base64字符串
     * @param imageName 本地路径
     */
    public static boolean GenerateImage(String imgStr,String imageName)
    {   //对字节数组字符串进行Base64解码并生成图片
        if (imgStr == null) //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;
                }
            }
            //生成jpeg图片
            String imgFilePath = imageName;//新生成的图片
            OutputStream out = new FileOutputStream(imgFilePath);
            out.write(b);
            out.flush();
            out.close();
            return true;
        }
        catch (Exception e)
        {
            return false;
        }
    }