MD5算法加密（16位、32位、64位）

package com.util;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import sun.misc.BASE64Encoder;

public class MD5{ 

	public static final String Md(String plainText,boolean judgeMD) { 
		StringBuffer buf = new StringBuffer(""); 
		try { 
		MessageDigest md = MessageDigest.getInstance("MD5"); 
		md.update(plainText.getBytes()); 
		byte b[] = md.digest(); 
		int i; 
		for (int offset = 0; offset < b.length; offset++) { 
			i = b[offset]; 
			if(i<0) i+= 256; 
			if(i<16) 
			buf.append("0"); 
			buf.append(Integer.toHexString(i)); 
		} 
//		System.out.println("32位：result: " + buf.toString());//32位的加密 
//		System.out.println("16位：result: " + buf.toString().substring(8,24));//16位的加密 

		} catch (NoSuchAlgorithmException e) { 
		// TODO Auto-generated catch block 
		e.printStackTrace(); 
		} 
		if(judgeMD == true){
			return buf.toString();
		}else{
			return buf.toString().substring(8,24);
		}
		
	} 
	public static final String EncoderPwdByMd5(String str) throws NoSuchAlgorithmException, UnsupportedEncodingException {
		// 确定计算方法
		MessageDigest md5 = MessageDigest.getInstance("MD5");
		BASE64Encoder base64en = new BASE64Encoder();
		// 加密后的字符串
		String newstr = base64en.encode(md5.digest(str.getBytes("utf-8")));
		return newstr;
	}
//测试 
	public static void main(String[] args) { 
		Md("a", true); 
		try {
			System.out.println("64位：result: " + EncoderPwdByMd5("12345678") + "**");
		} catch (NoSuchAlgorithmException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (UnsupportedEncodingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
}