Java implementation of unsigned number conversion string complement md5 uuid random number examples

package com.hongyuan.test;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Random;
import java.util.UUID;


public class SundryTest {

 //Turns into an unsigned number
 public static Number toUnsignedNumber(Number num){
  if(num instanceof Byte){
   return (Byte)num & 0xff;
  }else if(num instanceof Short){
   return (Short)num & 0xffff;
  }else if(num instanceof Integer){
   return (Integer)num & 0xffffffffL;
  }else{
   return -1;
  }
 }
 //Left a filling
 public static String leftPad(String str,String pad,int len){
  String newStr=(str==null?"":str);
  while(newStr.length()<len){
   newStr=pad+newStr;
  }
  if(newStr.length()>len){
   newStr=newStr.substring(newStr.length()-len);
  }
  return newStr;
 }
 //Right up
 public static String rightPad(String str,String pad,int len){
  String newStr=(str==null?"":str);
  while(newStr.length()<len){
   newStr=newStr+pad;
  }
  if(newStr.length()>len){
   newStr=newStr.substring(0, len);
  }
  return newStr;
 }

 //md5
 public static String md5(String str){
  StringBuilder sb=new StringBuilder();
  try {
   MessageDigest digest = MessageDigest.getInstance("MD5");
   byte[] message=digest.digest(str.getBytes());
   for(int i=0;i<message.length;i++){
    sb.append(leftPad(           //Left a filling
        Integer.toHexString(      //Turned into a hexadecimal number & cake;
         (Integer)toUnsignedNumber(message[i])), //Turns into an unsigned number
       "0",2).toUpperCase());       //To uppercase
   }
  } catch (NoSuchAlgorithmException e) {
   throw new RuntimeException(" There is no md5 Service! ");
  }
  return sb.toString();
 }
 //UUID
 public static String uuid(){
  return UUID.randomUUID().toString().replaceAll("-","").toUpperCase();
 }

 //Random number (including min, excluding Max)
 public static int random(int min,int max){
  if(min<=max){
   Random random=new Random();
   return random.nextInt(max-min)+min;
  }else{
   throw new IllegalArgumentException(" Unable to handle an illegal number range! ");
  }
 }

 public static void main(String[] args){
  System.out.println("MD5(123456):"+md5("123456"));
  System.out.println("UUID:"+uuid());
  System.out.println(" Random number: "+random(1,100));
 }
}