Java集合

list

ArrayList

package TestFile.ArraryClass;

import javax.sound.midi.Soundbank;
import java.util.ArrayList;
import java.util.Collections;

public class arraysList {
    public static void main(String[] args) {
        ArrayList<Integer> cars = new ArrayList<Integer>();
        cars.add(10);
        cars.add(100);
        cars.add(59);
        cars.add(54);
        cars.add(35);
        cars.add(98);
        cars.add(108);
        for (int i : cars){
            System.out.println(i);
        }
        cars.remove(0);
        System.out.println("--------------------");
        System.out.println(cars.get(0));
        for (int i = 0; i < cars.size(); i++) {
            System.out.println(cars.get(i));
        }
        cars.set(0, 1000);
        System.out.println("----------------------");
        for (Integer car : cars) {
            System.out.println(car);
        }
        System.out.println("---------------------");
        Collections.sort(cars);
        for (Integer car : cars) {
            System.out.println(car);
        }

    }
}

LinkedList

package TestFile.ArraryClass;

import javax.sound.midi.Soundbank;
import javax.swing.text.html.HTMLDocument;
import java.util.LinkedList;

public class linkedListl {
    public static void main(String[] args) {
        LinkedList<Integer> llist = new LinkedList<Integer>();
        llist.add(10);
        llist.add(108);
        llist.add(59);
        llist.add(54);
        llist.add(35);
        llist.add(98);
        llist.add(1, 199);
        for (int i = 0; i < llist.size(); i++) {
            System.out.println(llist.get(i));
        }
        System.out.println("------------------");
        System.out.println(llist.getFirst());
        System.out.println(llist.getLast());
        System.out.println("-------------------");
        llist.removeFirst();
        llist.removeLast();
        for (Integer integer : llist) {
            System.out.println(integer);
        }
        
        llist.set(4, 10);
        
    }
}

map

最常用的就是HashMap();

HashMap

package TestFile.hashMapp;

import javax.sound.midi.Soundbank;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

public class Hashmapp {
    public static void main(String[] args){
        HashMap<Integer, String> hashMap = new HashMap<>();
        hashMap.put(1, "a");
        System.out.println(hashMap);
//        hashMap.put(1, "b");
//        System.out.println(hashMap);
        hashMap.put(2, "b");
        hashMap.put(3, "c");
        hashMap.put(4, "d");
        hashMap.put(5, "4");

        // 第一种遍历方式
        for (Integer i : hashMap.keySet()){
            System.out.println(i + ":" + hashMap.get(i));
        }
        System.out.println("-------------------------");
        // 第二种遍历方式，entrySet
        Iterator iter = hashMap.entrySet().iterator();
        while (iter.hasNext()){
            Map.Entry<Integer, String> entry = (Map.Entry) iter.next();
            int key = entry.getKey();
            String value = entry.getValue();
            System.out.println(key + ":" + value);

        }
    }
}