图片和base64编码字符串 互相转换，图片和byte数组互相转换

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

import java.io.*;

/**
 * @author lishupeng
 * @create 2017-05-06 下午 2:56
 **/
public class Base64Test {
    public static void main(String[] args) {
        String strImg = GetImageStr();
        System.out.println(strImg);
        GenerateImage(strImg);
    }

    //图片转化成base64字符串
    public static String GetImageStr() {//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
        String imgFile = "C:\\Users\\Administrator\\Desktop\\a\\1.png";//待处理的图片
        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
    }

    //base64字符串转化成图片
    public static boolean GenerateImage(String imgStr) {   //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 = "d://222.jpg";//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;
        }
    }

import javax.imageio.stream.FileImageInputStream;
import javax.imageio.stream.FileImageOutputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;

/**
 * @author lishupeng
 * @create 2017-05-06 下午 3:48
 **/
public class Image2Byte {

    public static void main(String[] args){
        byte[] data = image2byte("C:\\Users\\Administrator\\Desktop\\a\\1.png");
        System.out.println(data.toString());
        byte2image(data,"d://222.jpg");
    }

    //图片到byte数组
    public static  byte[] image2byte(String path) {
        byte[] data = null;
        FileImageInputStream input = null;
        try {
            input = new FileImageInputStream(new File(path));
            ByteArrayOutputStream output = new ByteArrayOutputStream();
            byte[] buf = new byte[1024];
            int numBytesRead = 0;
            while ((numBytesRead = input.read(buf)) != -1) {
                output.write(buf, 0, numBytesRead);
            }
            data = output.toByteArray();
            output.close();
            input.close();
        } catch (FileNotFoundException ex1) {
            ex1.printStackTrace();
        } catch (IOException ex1) {
            ex1.printStackTrace();
        }
        return data;
    }

    //byte数组到图片
    public static void byte2image(byte[] data, String path) {
        if (data.length < 3 || path.equals("")) return;
        try {
            FileImageOutputStream imageOutput = new FileImageOutputStream(new File(path));
            imageOutput.write(data, 0, data.length);
            imageOutput.close();
            System.out.println("Make Picture success,Please find image in " + path);
        } catch (Exception ex) {
            System.out.println("Exception: " + ex);
            ex.printStackTrace();
        }
    }

    //byte数组到16进制字符串
    public String byte2string(byte[] data) {
        if (data == null || data.length <= 1) return "0x";
        if (data.length > 200000) return "0x";
        StringBuffer sb = new StringBuffer();
        int buf[] = new int[data.length];
        //byte数组转化成十进制
        for (int k = 0; k < data.length; k++) {
            buf[k] = data[k] < 0 ? (data[k] + 256) : (data[k]);
        }
        //十进制转化成十六进制
        for (int k = 0; k < buf.length; k++) {
            if (buf[k] < 16) sb.append("0" + Integer.toHexString(buf[k]));
            else sb.append(Integer.toHexString(buf[k]));
        }
        return "0x" + sb.toString().toUpperCase();
    }
}