MD5加密

package com.md5.test;

import java.security.MessageDigest;

public class MD5_Test {

/**
* MD5加密
*/
public final static String MD5(String oldStr){
char hexDigits[] = {'0','1','2','3','4','5','6','7','8','9','a','b','c',
'd','e','f'};
try {
//参数oldStr表示要加密的字符串
//转换成字节流
byte[] oldBytes = oldStr.getBytes();
//得到对象
MessageDigest md = MessageDigest.getInstance("MD5");
//初始化
md.update(oldBytes);
//运行加密算法
byte[] newBytes = md.digest();
//构造长度为2倍的字符串
char newStr[] = new char[32];
//循环进行处理
for (int i = 0; i < 16; i++) {
byte tmp = newBytes[i];
newStr[2*i] = hexDigits[tmp>>>4&0xf];
newStr[2*i+1] = hexDigits[tmp&0xf];
}
return new String(newStr);
} catch (Exception e) {
return null;
}
}
public static void main(String[] args) {
System.out.println(MD5_Test.MD5("testStr"));
}
}