随机长度字符串排序输出

package com.imooc.collection;

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

public class CollectionsTest {

//创建一个List
public List<String> rd = new ArrayList<String>();

/**
 * 创建一个能随机生成10个长度在10以内的字符串，然后通过collections.sort()进行排序并输出
 * @param args
 */
public void testRandom() {
    Random random = new Random();
    String str ="01234ABCmopqDEFGnKNO579PQRSTUVW6XYZabcdHIJefghijklrstLMwx8yz";

    for (int i = 0; i < 10; i++) {
        StringBuffer kString = new StringBuffer();

        int n = random.nextInt(10);
        for (int j = 0; j <= n; j++) {
            int startId = random.nextInt(str.length());
            kString.insert(j, str.charAt(startId)) ;
        }
        rd.add(kString.toString());
    }
}

/**
 * 遍历显示随机字符串
 * @param args
 */
public void testForEach(){
    for (String string : rd) {
        System.out.println("元素："+string);
    }
}

/**
 * 用collections。sort()排序
 * @param args
 */
public void testCollectionsSort(){
    System.out.println("---------排序后的结果-----------");
    Collections.sort(rd);
}

public static void main(String[] args) {
    // TODO Auto-generated method stub
    CollectionsTest ct = new CollectionsTest();
    ct.testRandom();
    ct.testForEach();
    ct.testCollectionsSort();
    ct.testForEach();

}

}