java常用工具类 Random随机数、MD5加密工具类

本文实例为大家分享了java常用工具类的具体代码，供大家参考，具体内容如下

Random随机数工具类

package com.jarvis.base.util;

import java.util.Random;


public class RandomHelper {
 
 private final static int RANDOM_base = 10;

 
 public static String getRandomStr(int length) {
 Random random = new Random();
 String randStr = "";
 for (int i = 0; i < length; i++) {
 String randItem = String.valueOf(random.nextInt(RANDOM_base));
 randStr += randItem;
 }
 return randStr;
 }

 
 public static String generateChatAndNumberIdentifyCode(int len) {
 char[] identifyStr = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' };
 // char[] identifyStr={'0','1','2','3','4','5','6','7','8','9'};
 // 生成随机类
 // Random random = new Random();
 int min = 0;
 int maxnum = identifyStr.length;
 String codeStr = "";
 for (int i = 0; i < len; i++) {
 int num = (int) ((maxnum - min) * Math.random() + min);
 codeStr += identifyStr[num];
 }
 return codeStr;
 }

 
 public static String generateIdentifyCode(int len) {
 char[] identifyStr = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R',
 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' };
 // char[] identifyStr={'0','1','2','3','4','5','6','7','8','9'};
 // 生成随机类
 // Random random = new Random();
 int min = 0;
 int maxnum = identifyStr.length;
 String codeStr = "";
 for (int i = 0; i < len; i++) {
 int num = (int) ((maxnum - min) * Math.random() + min);
 codeStr += identifyStr[num];
 }
 return codeStr;
 }

}

MD5加密 生成32位md5码

package com.jarvis.base.util;
import java.security.MessageDigest;

public class MD5Util {
 
 public static String md5Encode(String inStr) throws Exception {
 MessageDigest md5 = null;
 try {
 md5 = MessageDigest.getInstance("MD5");
 } catch (Exception e) {
 System.out.println(e.toString());
 e.printStackTrace();
 return "";
 }
 byte[] byteArray = inStr.getBytes("UTF-8");
 byte[] md5Bytes = md5.digest(byteArray);
 StringBuffer hexValue = new StringBuffer();
 for (int i = 0; i < md5Bytes.length; i++) {
 int val = ((int) md5Bytes[i]) & 0xff;
 if (val < 16) {
 hexValue.append("0");
 }
 hexValue.append(Integer.toHexString(val));
 }
 return hexValue.toString();
 }
 
 public static String md5(String inStr) {
 MessageDigest md5 = null;
 try {
 md5 = MessageDigest.getInstance("MD5");
 } catch (Exception e) {
 System.out.println(e.toString());
 e.printStackTrace();
 return "";
 }
 char[] charArray = inStr.toCharArray();
 byte[] byteArray = new byte[charArray.length];

 for (int i = 0; i < charArray.length; i++)
 byteArray[i] = (byte) charArray[i];
 byte[] md5Bytes = md5.digest(byteArray);
 StringBuffer hexValue = new StringBuffer();
 for (int i = 0; i < md5Bytes.length; i++) {
 int val = ((int) md5Bytes[i]) & 0xff;
 if (val < 16)
 hexValue.append("0");
 hexValue.append(Integer.toHexString(val));
 }
 return hexValue.toString();

 }

 
 public static String convertMD5(String inStr) {

 char[] a = inStr.toCharArray();
 for (int i = 0; i < a.length; i++) {
 a[i] = (char) (a[i] ^ 't');
 }
 String s = new String(a);
 return s;

 }
 public static String md5Decode(String str) {
 return convertMD5(convertMD5(str));
 }

 public static void main(String[] args) {
 String s = new String("13917114404");
 System.out.println(md5Decode("a6aeb3ffa55fc7d664406af9c3bd0f1b"));
 System.out.println("原始：" + s);
 System.out.println("MD5后：" + md5(s));
 System.out.println("加密的：" + convertMD5(s));
 System.out.println("解密的：" + convertMD5(convertMD5(s)));
 System.out.println(md5("13917114404"));
 }
}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持考高分网。