Map集合-LinkedHashMap

LinkedHashMap

package eight.map.linkedhashmap;

import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Set;

public class AbhievementTest {
    public static void main(String[] args) {
        Abhievement a1 = new   Abhievement("化学",93);
        Abhievement a2= new Abhievement("数学",98);
        Abhievement a3 = new Abhievement("生物",92);
        Abhievement a4 = new Abhievement("英语",97);
        Abhievement a5 = new Abhievement("物理",94);

        //LinkedHashMap 有序！！
        LinkedHashMap<Abhievement, Integer> ldm = new LinkedHashMap<>();
        ldm.put(a1,12);
        ldm.put(a2,22);
        ldm.put(a3,33);
        ldm.put(a4,66);
        ldm.put(a5,55);

        Set<Abhievement> ks = ldm.keySet();
        for (Abhievement i:ks){
            System.out.println(i);
        }
        

    }
}

package eight.map.linkedhashmap;

import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Set;

public class Course {
    public static void main(String[] args) {
        LinkedHashMap<String, String> lh = new LinkedHashMap<>();
        lh.put("yjs01","CoreJava");
        lh.put("yd03","Android");
        lh.put("dsj04","JavaWeb");

        lh.remove("yd03");//
        Set<Map.Entry<String, String>> en = lh.entrySet();//entrySet封装
        Iterator<Map.Entry<String, String>> it = en.iterator();//封装后使用迭代器遍历
        while(it.hasNext()){
            Map.Entry<String, String> nn = it.next();
            System.out.println(nn.getKey()+"---"+nn.getValue());
        }
    }
}