编码加密知识点二---Json的MD5加密(无法在进行解密还原)

一、Md5的加密，此加密方式没有解密还原，只能单向的进行加密

package com.fdx.test;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class MD5 {
	public static void main(String[] args) {
		String name ="樊樊樊";
		String grade ="河南大学";
		String json = "{\"name\":"+name+",\"grade\","+grade+"}";
		System.out.println("没加密之前的json样式如下："+json);
		MD5 md = new MD5();
		String md55 = md.MD5Util(json);
		System.out.println("MD5加密之后："+md55);
	}
	//MD5的加密方法
	public final String MD5Util(String str){
		//char[] digit ={'1','2','3','4','5','6','7','8','9','A','B','C','D','E,'F'};
		char[] digit ={'1','2','3','4','5','6','7','8','9','a','b','c','d','e','f'};
		byte[] input = str.getBytes();
		//获得md5摘要算法的MessageDigest
		MessageDigest mDigetst;
		try {
			mDigetst = MessageDigest.getInstance("MD5");
			//使用指定的字节更新摘要
			mDigetst.update(input);
			//获得密文
			byte[] md = mDigetst.digest();
			//把密文转换成十六进制的字符串形式
			int i = md.length;
			char s[] = new char[i*2];
			int k = 0;
			for(int j =0;j<i;j++){
				byte byte0 = md[j];
				s[k++] = digit[byte0 >>> 4 & 0xf];
                s[k++] = digit[byte0 & 0xf];
			}
			return new String(s);
 		} catch (NoSuchAlgorithmException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			return null;
		}
	}
}