通过java实现随机生成字符串并排序

package com.imooc.collection;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Random;

import javax.sound.midi.Synthesizer;

public class CollectionsTest {

public void testSort3(){
    List<String> stringList=new ArrayList<String>();
    Random random=new Random();
    String str;
    for(int i=0;i<10;i++){
        do{
        str=getRandomString(random.nextInt(10));
        }while(stringList.contains(str));
        stringList.add(str);
        System.out.println("成功添加字符串:"+str);
    }
    System.out.println("------排序前------");
    for (String string : stringList) {
        System.out.println("元素："+string);
    }
    Collections.sort(stringList);
    System.out.println("------排序后------");
    for (String string : stringList) {
        System.out.println("元素："+string);
    }
}

public static String getRandomString(int length) { //length表示生成字符串的长度
    String base = "abcdefghijklmnopqrstuvwxyz0123456789";   
    Random random = new Random();   
    StringBuffer sb = new StringBuffer();   
    for (int i = 0; i < length; i++) {   
        int number = random.nextInt(base.length());   
        sb.append(base.charAt(number));   
    }   
    return sb.toString();   
 }  

public static void main(String[] args) {
    // TODO Auto-generated method stub

    CollectionsTest ct=new CollectionsTest();
    ct.testSort3();
}

}