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;

/**
*
*
* @Title: RandomHelper.java
* @Package com.jarvis.base.util
* @Description: 随机数工具类
* @version V1.0
*/
public class RandomHelper {
/**
* RANDOM 基数
*/
private final static int RANDOM_BASE = 10;

/**
* 产生指定长度的数字值随机数
*
* @param length
* 需要产生的长度
* @return
*/
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;
}

/**
* 描述：手机验证码生成带字符，包含数字和字符 作者： 时间：Oct 29, 2008 3:40:07 PM
*
* @param len
* 生成手机验证码长度
* @return
*/
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;
}

/**
* 描述：手机验证码生成带字符不包含数字
*
* @param len
* 生成手机验证码长度
* @return
*/
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 {
/**
* Title: MD5加密 生成32位md5码
* Description: TestDemo
* @param inStr
* @return 返回32位md5码
* @throws Exception
*/
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();
}
/**
* Title: MD5加密
* Description: TestDemo
* @author lu
* @date 2016年6月23日 下午2:43:31
* @param inStr
* @return
*/
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();

}

/**
* Title: 加密解密算法 执行一次加密，两次解密
* Description: TestDemo
* @author lu
* @date 2016年6月23日 下午2:37:29
* @param inStr
* @return
*/
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"));
}
}

来源：https://blog.csdn.net/zhang150114/article/details/90411683