package com.pb;

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

/*
 * 驗證MD5
 * 1.初始化MessageDigest信息摘要對象
 * 2.傳入需要計算的字符串更新摘要信息
 * 3.計算信息摘要
 * 4.將byte[] 轉(zhuǎn)換為找度為32位的16進(jìn)制字符串
 */
public class MD5 {
  /*
   * 生成md5 有傳入?yún)?shù)字符串
   */
  public void generateMD5(String input){
    
    try {
      //1.初始化MessageDigest信息摘要對象,并指定為MD5不分大小寫都可以
      MessageDigest md=MessageDigest.getInstance("md5");
       //2.傳入需要計算的字符串更新摘要信息，傳入的為字節(jié)數(shù)組byte[],
      //將字符串轉(zhuǎn)換為字節(jié)數(shù)組使用getBytes()方法完成
      //指定時其字符編碼 為utf-8
      md.update(input.getBytes("utf-8"));
       //3.計算信息摘要digest()方法
      //返回值為字節(jié)數(shù)組
      byte [] hashCode=md.digest();
       //4.將byte[] 轉(zhuǎn)換為找度為32位的16進(jìn)制字符串
        //聲明StringBuffer對象來存放最后的值
      StringBuffer sb=new StringBuffer();
      //遍歷字節(jié)數(shù)組
      for(byte b:hashCode){
        //對數(shù)組內(nèi)容轉(zhuǎn)化為16進(jìn)制，
        sb.append(Character.forDigit(b>>4&0xf, 16));
        //換2次為32位的16進(jìn)制
        sb.append(Character.forDigit(b&0xf, 16));
      }
      System.out.println("加密后的結(jié)果是:"+sb.toString());
    } catch (NoSuchAlgorithmException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    } catch (UnsupportedEncodingException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
  }

  public static void main(String[] args) {
    //聲明加密MD5類的對象
    MD5 md5=new MD5();
    //使用Scanner來輸入一個字符
    Scanner scanner=new Scanner(System.in);
    System.out.println("請輸入要加密的內(nèi)容:");
    String input = scanner.nextLine();
    //調(diào)用加密方法
    md5.generateMD5(input);

  }
  
}

package test.md5;

import java.security.MessageDigest;

public class MD5Util {
  public final static String MD5(String s) {
    char hexDigits[]={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};    

    try {
      byte[] btInput = s.getBytes();
      // 獲得MD5摘要算法的 MessageDigest 對象
      MessageDigest mdInst = MessageDigest.getInstance("MD5");
      // 使用指定的字節(jié)更新摘要
      mdInst.update(btInput);
      // 獲得密文
      byte[] md = mdInst.digest();
      // 把密文轉(zhuǎn)換成十六進(jìn)制的字符串形式
      int j = md.length;
      char str[] = new char[j * 2];
      int k = 0;
      for (int i = 0; i < j; i++) {
        byte byte0 = md[i];
        str[k++] = hexDigits[byte0 >>> 4 & 0xf];
        str[k++] = hexDigits[byte0 & 0xf];
      }
      return new String(str);
    } catch (Exception e) {
      e.printStackTrace();
      return null;
    }
  }

  public static void main(String[] args) {
    System.out.println(MD5Util.MD5("20121221"));
    System.out.println(MD5Util.MD5("加密"));
  }
}

package other;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
/*
 * MD5 算法
*/
public class MD5 {
  
  // 全局?jǐn)?shù)組
  private final static String[] strDigits = { "0", "1", "2", "3", "4", "5",
      "6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };

  public MD5() {
  }

  // 返回形式為數(shù)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];
  }

  // 返回形式只為數(shù)字
  private static String byteToNum(byte bByte) {
    int iRet = bByte;
    System.out.println("iRet1=" + iRet);
    if (iRet < 0) {
      iRet += 256;
    }
    return String.valueOf(iRet);
  }

  // 轉(zhuǎn)換字節(jié)數(shù)組為16進(jìn)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() 該函數(shù)返回值為存放哈希值結(jié)果的byte數(shù)組
      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"));
  }
}