java自带的MessageDigest实现文本的md5加密算法

/** 
 *@Description: 将字符串转化为MD5 
 */ 
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
public class ParseMD5 { 
  /**
   * @param str 
   * @return  
   * @Description: 32位小写MD5 
   */
  public static String parseStrToMd5L32(String str){ 
    String reStr = null;
    try{
      MessageDigest md5 = MessageDigest.getInstance("MD5");
      byte[] bytes = md5.digest(str.getBytes()); 
      StringBuffer stringBuffer = new StringBuffer();
      for(byte b : bytes){ 
        int bt = b & 0xff;
        if(bt < 16){
          stringBuffer.append(0);
        } 
        stringBuffer.append(Integer.toHexString(bt));
      }
      reStr = stringBuffer.toString(); 
    }catch(NoSuchAlgorithmException e) { 
      e.printStackTrace();
    }
    return reStr;
  }
  /**
   * @param str 
   * @return  
   * @Description: 32位大写MD5 
   */
  public static String parseStrToMd5U32(String str){ 
    String reStr = parseStrToMd5L32(str); 
    if(reStr != null){
      reStr = reStr.toUpperCase(); 
    }
    return reStr;
  }
  /**
   * @param str 
   * @return 
   * @Description: 16位小写MD5 
   */
  public static String parseStrToMd5U16(String str){ 
    String reStr = parseStrToMd5L32(str); 
    if(reStr != null){
      reStr = reStr.toUpperCase().substring(8,24);
    }
    return reStr;
  }
  /**
   * @param str 
   * @return 
   * @Description: 16位大写MD5 
   */
  public static String parseStrToMd5L16(String str){ 
    String reStr = parseStrToMd5L32(str); 
    if(reStr != null){
      reStr = reStr.substring(8,24);
    }
    return reStr;
  }
}

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import org.apache.commons.lang.StringUtils;
public class MD5Util {
/**
* 1.对文本进行32位小写MD5加密
* @param plainText 要进行加密的文本
* @return 加密后的内容
*/
public static String textToMD5L32(String plainText){
String result = null;
}
//首先判断是否为空
if(String Utils.isBlank(plainText)){
return null;
}
try{
//首先进行实例化和初始化
MessageDigest md = MessageDigest.getInstance("MD5");
//得到一个操作系统默认的字节编码格式的字节数组
byte[] btInput = plainText.getBytes();
//对得到的字节数组进行处理
md.update(btInput);
//进行哈希计算并返回结果
byte[] btResult = md.digest();
//进行哈希计算后得到的数据的长度
StringBuffer sb = newStringBuffer();
for(byteb : btResult){
intbt = b & 0xff;
if(bt<16){
sb.append(0);
}
sb.append(Integer.toHexString(bt));
}
result = sb.toString();
}catch(NoSuchAlgorithmException e){
e.printStackTrace();
}
return result;
}
/**
* 2.对文本进行32位MD5大写加密
* @param plainText 要进行加密的文本
* @return 加密后的内容
*/
public static String textToMD5U32(String plainText){
if(StringUtils.isBlank(plainText)){
return null;
}
String result = textToMD5L32(plainText);
return result.toUpperCase();
}

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
/*
 * MD5 算法
*/
public class MD5 {
  // 全局数组
  private final static String[] strDigits = { "0","1","2","3","4","5",
      "6","7","8","9","a","b","c","d","e","f"};
  public MD5() {
  }
  // 返回形式为数字跟字符串
  private static String byteToArrayString(byte bByte) {
    int iRet = bByte;
    // System.out.println("iRet="+iRet);
    if(iRet < 0) {
      iRet += 256;
    }
    int iD1 = iRet / 16;
    int iD2 = iRet % 16;
    return strDigits[iD1] + strDigits[iD2];
  }
  // 返回形式只为数字
  private static String byteToNum(byte bByte) {
    int iRet = bByte;
    System.out.println("iRet1="+ iRet);
    if(iRet < 0) {
      iRet += 256;
    }
    return String.valueOf(iRet);
  }
  // 转换字节数组为16进制字串
  private static String byteToString(byte[] bByte) {
    StringBuffer sBuffer = new StringBuffer();
    for(int i = 0; i < bByte.length; i++) {
      sBuffer.append(byteToArrayString(bByte[i]));
    }
    return sBuffer.toString();
  }
  public static String GetMD5Code(String strObj) {
    String resultString = null;
    try{
      resultString = new String(strObj);
      MessageDigest md = MessageDigest.getInstance("MD5");
      // md.digest() 该函数返回值为存放哈希值结果的byte数组
      resultString = byteToString(md.digest(strObj.getBytes()));
    }catch(NoSuchAlgorithmException ex) {
      ex.printStackTrace();
    }
    return resultString;
  }
  public static void main(String[] args) {
    MD5 getMD5 = new MD5();
    System.out.println(getMD5.GetMD5Code("000000"));
  }
}