为什么经常出现一样的随机数呢?
追答package com.test;
import java.util.HashSet;
import java.util.Random;
import java.util.Scanner;
import java.util.Set;
public class RandomTest {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println("请输入字符串:");
Scanner scan = new Scanner(System.in);
String source = scan.next();
int sourceLength = source.length();
int randomLength = 6;
if(sourceLength set =new HashSet();
for(int i=0;i= sourceLength || set.contains(randomNum)){
System.out.println("set存在随机数:"+randomNum);
continue;
}
i++;
set.add(randomNum);
System.out.println(randomNum);
result.append(source.charAt(randomNum));
}
System.out.println("随机的6个字符为:"+result);
}
}
这样就可以了。