java md5 3

import java.security.*;
public class MD5{

    //十六进制下数字到字符的映射数组 
    private final static String[] hexDigits =

{"0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f"};

/**把inputString加密*/ 
public static String md5(String inputString){ 
return encodeByMD5(inputString); 
}

/** 
* 验证输入的密码是否正确 
* @param password 真正的密码（加密后的真密码） 
* @param inputString 输入的字符串 
* @return 验证结果，boolean类型 
*/ 
public static boolean compare(String md5Str,String inputString){ 
if(md5Str.equals(encodeByMD5(inputString))){ 
return true; 
}else{ 
return false; 
} 
}

/**对字符串进行MD5编码*/ 
private static String encodeByMD5(String originString){ 
    if(originString != null){ 
    try{ 
    //创建具有指定算法名称的信息摘要 
    MessageDigest md = MessageDigest.getInstance("MD5"); 
    //使用指定的字节数组对摘要进行最后更新，然后完成摘要计算 
    byte[] results = md.digest(originString.getBytes()); 
    //将得到的字节数组变成字符串返回 
    String resultString = byteArrayToHexString(results); 
    return resultString.toUpperCase(); 
    }catch(Exception ex){ 
        ex.printStackTrace(); 
       } 
    } 
      return null; 
}

/** 
* 轮换字节数组为十六进制字符串 
* @param b 字节数组 
* @return 十六进制字符串 
*/ 
private static String byteArrayToHexString(byte[] b){ 
StringBuffer resultSb = new StringBuffer(); 
for(int i=0;i<b.length;i++){
resultSb.append(byteToHexString(b[i])); 
} 
return resultSb.toString(); 
}

/** 
* 将一个字节转化成十六进制形式的字符串 
*/ 
private static String byteToHexString(byte b){ 
int n = b; 
if(n<0) 
n=256+n; 
int d1 = n/16; 
int d2 = n%16; 
return hexDigits[d1] + hexDigits[d2]; 
}

public static void main(String[] args){ 
String password = MD5.md5("admin"); 
System.out.println("对admin用MD5摘要后的字符串："+password); 
String inputString = "tianshi0253"; 
System.out.println("tianshi0253与密码匹配?"+MD5.compare(password, inputString)); 
inputString = "admin"; 
System.out.println("admin与密码匹配?"+MD5.compare(password, inputString)); 
}

}