java安全5
package com.ngsn.security;import java.security.MessageDigest;/** * 数字摘要应用 * MD5 或 SHA 算法 加密 * @author John.Yao */public class SecretKeyTest4 {public static void main(String[] args) throws Exception{String str = md5("abcd");System.out.println("str--->"+str.toUpperCase());}public static String md5(String str) throws Exception{String md5=null;// MessageDigest 类为应用程序提供信息摘要算法的功能，如 MD5 或 SHA 算法MessageDigest md = MessageDigest.getInstance("MD5");md.update(str.getBytes());byte[] result = md.digest();System.out.println("result length--->"+result.length);md5 = toHex(result);System.out.println("md5--->"+md5);return md5;}/** * 将二进制的字节数组转换成16进制的字符串 * @param buf * @return */public static String toHex(byte[] buf){StringBuilder sb = new StringBuilder();for(int i=0;i<buf.length;i++){//高位int high = ((buf[i]>>4) & 0x0f);//低位int lo = buf[i] & 0x0f;sb.append(high > 9 ? (char)((high-10)+'a'):(char)(high+'0'));sb.append(lo > 9 ? (char)((lo-10)+'a'):(char)(lo+'0'));}return sb.toString();}}