HashMap在编程题中的常用代码

package UML;
import java.util.Collection;
import java.util.HashMap; 
public class Test {
    public static void main(String[] args){
        HashMap<String,String>hm1=new HashMap<String,String>();
        HashMap<String,String>hm2=new HashMap<String,String>();
        String []key= {"name","age","tender"};
        String []value= {"JHY","23","man"};
        
        //put(Object key,Object value)在此映射中关联指定的Key-value
        //putAll(Collection c)在此映射中将指定的映射关系添加到被操作的映射中
        hm2.put("id","01");
        hm2.put("describe","是个神经病");
        for(int i=0;i<3;i++) {
            hm1.put(key[i],value[i]);
        }
        hm1.putAll(hm2);
        
        //get(Object key)根据key获取指定的value
        System.out.println(hm1.get("name"));
        //containsKey(Object key)检测该映射中是否存在指定key的映射，有则返回true；没有则返回false
        System.out.println(hm1.containsKey("id")+"    "+hm1.containsValue("013"));
        //remove(Object key)根据key的值删除指定的映射关系
        System.out.println(hm1.remove("describe"));
        //values()返回值的集合
        Collection<String>li=hm1.values();
        for(String string:li) {
            System.out.println(string+"  ");
        }
        //isEmpty()测试映射是否为空
        System.out.println("
"+hm1.isEmpty());
        for(String key1:hm1.keySet()) {
            System.out.println(key1+":"+hm1.get(key1));
        }
}}