package com.taobao.tddl.monitor.utils;
import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.concurrent.locks.ReentrantLock;
public class MD5Maker {
private static MD5Maker md5Maker = new MD5Maker();
private static char[] digits = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd',
'e', 'f' };
private static MessageDigest mHasher;
private ReentrantLock opLock = new ReentrantLock();
public MD5Maker(){
try {
mHasher = MessageDigest.getInstance("MD5");
} catch (NoSuchAlgorithmException e) {
throw new IllegalStateException("should not be here,cant find md5 instance?", e);
}
}
public static MD5Maker getInstance() {
return md5Maker;
}
/**
* ��һ���ֽ�����ת��Ϊ�ɼ���ַ�
*
* @param bt
* @return
*/
public String bytes2string(byte[] bt) {
int l = bt.length;
char[] out = new char[l << 1];
for (int i = 0, j = 0; i < l; i++) {
out[j++] = digits[(0xF0 & bt[i]) >>> 4];
out[j++] = digits[0x0F & bt[i]];
}
return new String(out);
}
/**
* 获取字符窗的md5信息
*
* @param str
* @return md5 byte[16]
*/
public byte[] getMD5bytes(String str) {
opLock.lock();
try {
byte[] bt = mHasher.digest(str.getBytes("UTF-8"));
if (null == bt || bt.length != 16) {
throw new IllegalArgumentException("md5 need");
}
return bt;
} catch (UnsupportedEncodingException e) {
throw new RuntimeException("unsupported utf-8 encoding", e);
} finally {
opLock.unlock();
}
}
public String getMD5(String str) {
return bytes2string(getMD5bytes(str));
}
}