java List的遍历和自定义排序

今天药忘吃喽~ 2021-09-23 02:18 415阅读 0赞

# 闲来无事，学习一下基础–List #

package com.crazzy.day01;
    
    import java.util.*;
    
    /** * Created by qqg on 2017/9/20. */
    public class ListDemo {
        public static void main(String[] args) {
            List<String>  list = new ArrayList<>();
            list.add("Hello ");
            list.add("World ,");
            list.add("I am crazzy!");
            System.out.println("第一种遍历方法：");
            for (String s : list){
                System.out.print(s);
            }
            System.out.println();
            System.out.println("第二种遍历方法：");
            Iterator<String> ite = list.iterator();
            while (ite.hasNext()){
                System.out.print(ite.next());
            }
            //默认的排序，按照String来排序
            Collections.sort(list);
            System.out.println();
            System.out.println("排序后的结果：");
            for(String s : list){
                System.out.println(s);
            }
            //自定义排序
            List<String> list2 = new ArrayList<>();
            list2.add("11");
            list2.add("0012");
            list2.add("10");
            list2.add("19");
            list2.add("5");
            System.out.println("list2 排序前为：");
            for(String s : list2){
                System.out.print(s+"\t");
            }
            System.out.println();
            System.out.println("按照整数大小排序后的结果：");
            MyCompartor mc = new MyCompartor();
            Collections.sort(list2,mc);
            for (String s : list2){
                System.out.print(s + "\t");
            }
        }
    }
    //自定义比较器
    class MyCompartor implements Comparator{
        @Override
        public int compare(Object o1, Object o2) {
            Integer a = Integer.parseInt((String)o1);
            Integer b = Integer.parseInt((String)o2);
            return a.compareTo(b);
        }
    }

## 运行结果： ##

![这里写图片描述][SouthEast]

[SouthEast]: /images/20210923/2f6d75d921bd4f04920aff917e59a5b8.png