2020.02.25 HashMap集合

keyBean

 

package com.guoyun.bean;

import java.security.Key;

/**
 * ClassName:
 * Function:  ADD FUNCTION
 * Reason:   ADD REASON
 *
 * @author
 * @Date
 * @since Ver 1.1
 */
public class KeyBean {
    //编号
    public Integer  id;
    //名称
    public String name;

    @Override
    public int hashCode() {
        return id.hashCode();
    }

    @Override
    public boolean equals(Object obj) {
        if(this==obj){
            return true;
        }else if(obj instanceof KeyBean){
            KeyBean kb=(KeyBean)obj;
            if(id==kb.id){
                return true;
            }
        }
            return false;
    }
}
valueBean

package com.guoyun.bean;

/**
 * ClassName:
 * Function:  ADD FUNCTION
 * Reason:   ADD REASON
 *
 * @author
 * @Date
 * @since Ver 1.1
 */
public class ValueBean {
    public Integer id;
    public String name;
}
*************************************************************

package com.guoyun.view;

import com.guoyun.bean.KeyBean;
import com.guoyun.bean.ValueBean;

import java.io.Serializable;
import java.util.*;

/**
 * ClassName:
 * Function:  ADD FUNCTION
 * Reason:   ADD REASON
 *
 * @author
 * @Date
 * @since Ver 1.1
 */
public class MainView {
    public static void main(String[] args) {
        HashMap<String,String> map1=new HashMap<String,String>();
        AbstractMap<String,String> map2=new HashMap<String,String>();
        Map<String,String> map3=new HashMap<String,String>();
        Cloneable map4=new HashMap();
        Serializable map5=new HashMap();
        // 存值
        map3.put("1","Intention");
        map3.put("2","Changes");
        map3.put("3","By your side");
        //取值
//        System.out.println(map3.get("3"));
        //长度
//        System.out.println(map3.size());
        //遍历 循环迭代
         //一种是获取key 用key做迭代
        Set<String> set=map3.keySet();
        for (String i:set
             ) {
//            System.out.println(i+"\t"+map3.get(i));
        }
        //整体转换为set结构 实现迭代
        Set<Map.Entry<String,String>> set1=map3.entrySet();
        for (Iterator<Map.Entry<String, String>> iterator = set1.iterator(); iterator.hasNext(); ) {
            Map.Entry<String, String> next =  iterator.next();
//            System.out.println(next.getKey()+"\t"+next.getValue());
        }
        for (Map.Entry<String,String> entry:set1
             ) {
//            System.out.println(entry.getKey()+"\t"+entry.getValue());
        }
        //HashMap中的常用方法
        //清空集合
//        map3.clear();
        System.out.println(map3.containsKey("0"));
        System.out.println(map3.containsValue("Intention"));
        map3.isEmpty();
        //类似于addAll
//        map3.putAll();
//        map3.remove("2");
//        Set<Map.Entry<String, String>> entries = map3.entrySet();
//        for (Iterator<Map.Entry<String, String>> iterator = entries.iterator(); iterator.hasNext(); ) {
//            Map.Entry<String, String> next =  iterator.next();
//            System.out.println(next.getKey()+" "+next.getValue());
//
//        }
//        map3.replace("1","Yummy");

        map3.replace("1","Intention","gorgeous");
        Set<Map.Entry<String, String>> entries = map3.entrySet();
        for (Iterator<Map.Entry<String, String>> iterator = entries.iterator(); iterator.hasNext(); ) {
            Map.Entry<String, String> next =  iterator.next();
//            System.out.println(next.getKey()+" "+next.getValue());

        }
        Map<KeyBean, ValueBean> map6=new HashMap<>();
        KeyBean k1=new KeyBean();
        k1.id=1;
        k1.name="贵州省";
        ValueBean v1=new ValueBean();
        v1.id=11;
        v1.name="贵阳市";
        map6.put(k1,v1);
        KeyBean k2=new KeyBean();
        k2.id=2;
        k2.name="贵州省";
        ValueBean v2=new ValueBean();
        v2.id=22;
        v2.name="毕节市";
        map6.put(k2,v2);
        Set<Map.Entry<KeyBean,ValueBean>> set2=map6.entrySet();
        for (Iterator<Map.Entry<KeyBean, ValueBean>> iterator = set2.iterator(); iterator.hasNext(); ) {
            Map.Entry<KeyBean, ValueBean> next =  iterator.next();
            System.out.println(next.getKey().id+"\t"+next.getKey().name+"\t"+next.getValue().name);
        }
    }
}