与百度及博客上的各位大大深入合作，侵删，不足之处请谅解

package cn.ljs.util;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Random;

import org.apache.commons.codec.binary.Hex;

/**
 * MD5加盐加密
 * @author Administrator
 *
 */
public class MD5 {
    
    public static String makeMD5(String plainText) {
        plainText=plainText+"A";//A是自定义盐值，随便填什么都可以
        try {  
            MessageDigest md = MessageDigest.getInstance("MD5");  
            md.update(plainText.getBytes());  
           byte b[] = md.digest();  
           int i;  
           StringBuffer buf = new StringBuffer("");  
           for (int offset = 0; offset < b.length; offset++) {  
               i = b[offset];  
               if (i < 0)  
                   i += 256;  
               if (i < 16)  
                   buf.append("0C");  
               buf.append(Integer.toHexString(i));  
           }  
           //32位加密  
           return buf.toString();  
           // 16位的加密  
           //return buf.toString().substring(8, 24);  
       } catch (NoSuchAlgorithmException e) {  
           e.printStackTrace();  
           return null;  
       }  
   }
    
    /**
     * 生成含有随机盐的密码
     */
/*    public static String generate(String password) {
        Random r = new Random();
        StringBuilder sb = new StringBuilder(16);
        sb.append(r.nextInt(99999999)).append(r.nextInt(99999999));
        int len = sb.length();
        if (len < 16) {
            for (int i = 0; i < 16 - len; i++) {
                sb.append("0");
            }
        }
        String salt = sb.toString();
        password = md5Hex(password + salt);
        char[] cs = new char[48];
        for (int i = 0; i < 48; i += 3) {
            cs[i] = password.charAt(i / 3 * 2);
            char c = salt.charAt(i / 3);
            cs[i + 1] = c;
            cs[i + 2] = password.charAt(i / 3 * 2 + 1);
        }
        return new String(cs);
    }*/
    /**
     * 校验密码是否正确
     */
/*    public static boolean verify(String password, String md5) {
        char[] cs1 = new char[32];
        char[] cs2 = new char[16];
        for (int i = 0; i < 48; i += 3) {
            cs1[i / 3 * 2] = md5.charAt(i);
            cs1[i / 3 * 2 + 1] = md5.charAt(i + 2);
            cs2[i / 3] = md5.charAt(i + 1);
        }
        String salt = new String(cs2);
        return md5Hex(password + salt).equals(new String(cs1));
    }*/
    /**
     * 获取十六进制字符串形式的MD5摘要
     */
/*    public static String md5Hex(String src) {
        try {
            MessageDigest md5 = MessageDigest.getInstance("MD5");
            byte[] bs = md5.digest(src.getBytes());
            return new String(new Hex().encode(bs));
        } catch (Exception e) {
            return null;
        }
    }*/


}