图片加密解密操作

package csdn.java3;

import org.junit.Test;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;


public class PicTest {

    //图片的加密（异或运算加密）
    @Test
    public void test1() {
        FileInputStream fis = null;
        FileOutputStream fos = null;
        try {
            fis = new FileInputStream("爱情与友情.jpg");
            fos = new FileOutputStream("爱情与友情secret.jpg");

            byte[] buffer = new byte[20];
            int len;
            while ((len = fis.read(buffer)) != -1) {
                //字节数组进行修改，体现加密
                //错误的
                /*for(byte b : buffer){
                    b = (byte) (b ^ 5);
                }*/
                //正确的
                for (int i = 0; i < len; i++) {
                    buffer[i] = (byte) (buffer[i] ^ 5);
                }

                fos.write(buffer, 0, len);
            }
        } catch (IOException e) {
            e.printStackTrace();