Java-集合框架-集合操作的工具类collections

package cn.burce.Collection;

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

//集合操作的工具类collections
//
public class collectionsDemo {

    public static void main(String[] args) {
        fun();
        fun1();
        fun2();
    }

    // Collections.sort()对list集合进行排序
    public static void fun() {
        List<String> list = new ArrayList<String>();
        list.add("abc1");
        list.add("abc3");
        list.add("abc2");
        list.add("abc4");
        System.out.println(list);
        Collections.sort(list);
        System.out.println(list);
    }

    // collections.binarysearch查找元素
    public static void fun1() {
        List<String> list = new ArrayList<String>();
        list.add("abc1");
        list.add("abc3");
        list.add("abc2");
        list.add("abc4");
        Collections.sort(list);// 二分查找时先进行升序排序
        int a = Collections.binarySearch(list, "abc2");
        System.out.println(a);
    }

    // collections.shuffle对元素随机排列
    public static void fun2() {
        List<String> list = new ArrayList<String>();
        list.add("abc1");
        list.add("abc3");
        list.add("abc2");
        list.add("abc4");
        Collections.sort(list);// 二分查找时先进行升序排序
        Collections.shuffle(list);
        System.out.println(list);
    }
}