第五篇 集合与容器（五）

TreeMap

package com.zzp.demo;

import java.util.Map;
import java.util.TreeMap;

/**
 * 
 * 测试TreeMap
 * @author java
 *
 */
public class TestTreeMap {
    public static void main(String[] args) {
        Map<Integer,String> treeMap1 = new TreeMap<>();
        treeMap1.put(30, "aa");
        treeMap1.put(2, "bb");
        treeMap1.put(10, "cc");
        
        for(Integer key : treeMap1.keySet()){
            System.out.println(key + "---" +treeMap1.get(key));
        }
        
        Map<Emp,String> treeMap2 = new TreeMap<>();
        treeMap2.put(new Emp(100,"张三",1000), "张三真垃圾");
        treeMap2.put(new Emp(200,"李四",10000), "李四真棒棒");
        treeMap2.put(new Emp(150,"王五",100), "王五更垃圾");
        treeMap2.put(new Emp(50,"赵六",2000), "赵六也垃圾");
        treeMap2.put(new Emp(300,"钱七",2000), "钱七也垃圾");
        
        for(Emp key : treeMap2.keySet()){
            System.out.println(key +"----"+ treeMap2.get(key));
        }
    }
}

class Emp implements Comparable<Emp>{
    int id;
    String name;
    int salary;
    
    public Emp(int id, String name, int salary) {
        super();
        this.id = id;
        this.name = name;
        this.salary = salary;
    }
    
    @Override
    public int compareTo(Emp o) {
        //负数小于0，整数大于0，等于0
        if(this.salary > o.salary){
            return 1;
        }else if(this.salary < o.salary){
            return -1;
        }else{
            if(this.id > o.id){
                return 1;
            }else if(this.id < o.id){
                return -1;
            }else{
                return 0;
            }
        }
    }

    @Override
    public String toString() {
        // TODO Auto-generated method stub
        return "id:"+id+",name:"+name+",salary:"+salary;
    }
}