put(Object key,Object value) // 添加
putAll(Collection c) // 添加
get(Object key) //根据键来获取对应的值
containsKey(Object key) // 是否包含key
containsValue(Object value) // 是否包含value
remove(Object key)  //删除key
values() //获取所有的values
isEmpty() //判断Map是否为空
entrySet() //
keySet()  //获取所有的key，返回的是Set

//创建HashMap
HashMap<String,String> hm1 = new HashMap<String,String>();
HashMap<String,String> hm2 = new HashMap<String,String>();

String [] key = {"name","age","tender"};
String [] value = {"zhangsan","16","men"};

//添加元素
//hm2
hm2.put("id","012");
hm2.put("describe", "zhangdelaohaokanle");

//hm1一个一个添加
for(int i = 0;i<3;i++){
    hm1.put(key[i], value[i]);
}
//hm1直接全添加
hm1.putAll(hm2);

//根据key获取值
String name = hm1.get("name");

//hm1是否包含value, key
boolean flag = hm1.containsValue("013");
boolean flag = hm1.containsKey("age");

//hm1删除并返回
String des = hm1.remove("describe")

//获取所有的values
Collection<String> li = hm1.values();

//获取所有的keys
Set<String> set = hm1.keySet();

package test;
import java.util.HashMap;
import java.util.Iterator;  
import java.util.ArrayList;
import java.util.Collection;
import java.util.Map.Entry;
import java.util.Set;
public class test6 {
 
    public static void main(String[] args) {
        HashMap<String,Integer> map =new HashMap<>();
        map.put("a", 1);
        map.put("b", 2);
        map.put("c", 3);
        map.put("d", 4);
         
//       Map map=new HashMap();               
//         map.put("a", "aaa");   
//         map.put("b", "bbb");   
//         map.put("c", "ccc");   
//         map.put("d", "ddd");   
         
        //hashMap遍历方法1
         Iterator<String> iterator = map.keySet().iterator();               
         while (iterator.hasNext()) {   
          Object key = iterator.next();   
          System.out.println("map.get(key) is :"+map.get(key));   
         }
          
         //遍历方法2
         Set<Map.Entry<String, Integer>> set=map.entrySet();
         Iterator<Map.Entry<String, Integer>> it=set.iterator();
         while(it.hasNext()){
          //System.out.println(list.get(0) ); 
             Map.Entry<String, Integer> e=it.next();
          System.out.println(e.getKey()+":"+e.getValue()); 
         }
          
          System.out.println(map.containsValue(1) ); 
          System.out.println(map.containsKey("a") ); 
          System.out.println(map.size() );
          System.out.println(map.remove("a") ); 
          System.out.println(map.size() ); 
          System.out.println(map.containsKey("a") ); 
          System.out.println(map.containsValue(1) ); 
           
          //ArrayList <Integer> list =(ArrayList<Integer>)map.values();     
          //上面会出现异常，因为map.values()返回的是一个Collection<Integer>对象，可用下面的方法解决
          ArrayList <Integer> list =new ArrayList<Integer>(map.values());   
          Iterator <Integer>ite=list.iterator();
          while(ite.hasNext()){
              //System.out.println(list.get(0) ); 
              System.out.println(ite.next() ); 
          }
          map.clear();
          System.out.println(map.isEmpty() ); 
           
    }
 
}