java第三季：随机字符串

package com.yjc;

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

public class CollectionsTest {

    public void sort1(){
        List<Integer> integerList=new ArrayList<Integer>();
        Random random=new Random();
        int k;
        for(int i=0;i<10;i++){
            do{
                k=random.nextInt(100);
            }while(integerList.contains(k));
            integerList.add(k);
            System.out.println("成功添加："+k);
        }
        System.out.println("---------------排序前--------------");
        for (Integer integer : integerList) {
            System.out.println("元素："+integer);
        }
        Collections.sort(integerList);
        System.out.println("---------------排序后--------------");
        for (Integer integer : integerList) {
            System.out.println("元素："+integer);
        }
    }

    public void sort2(){
        List<String> stringList=new ArrayList<String>();
        stringList.add("microsoft");
        stringList.add("google");
        stringList.add("lenovo");
        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 void sort3(){
        List<String> stringList=new ArrayList<String>();
        String s="1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
        for(int i=0;i<10;){
            StringBuffer sb=new StringBuffer();
            Random l=new Random();
            int k=l.nextInt(10);
            for(int j=0;j<k;j++){
                sb.append(s.charAt(l.nextInt(s.length()-1)));
            }
            if(stringList.contains(sb))
                continue;
            String newS=sb.toString();
            System.out.println("元素："+newS);
            stringList.add(newS);
            i++;
        }
        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 void main(String[] args) {
        // TODO 自动生成的方法存根
        CollectionsTest ct=new CollectionsTest();
//      ct.sort1();
//      ct.sort2();
        ct.sort3();
    }

}