关于map集合的遍历

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

public class Main {
    /**
     *
     * 关于map集合的遍历
     */
    public static void main(String[] args) {

        System.out.println("Hello World!");
      // function01();
        //function02();
        //function03();
        function04();

    }
    /**
     *第一种遍历map集合的方法
     *      通过map集合的keyset()方法来得到键的集合
     */

    public static void function01(){

          Map<Integer, String> map = new HashMap<>();
          map.put(1,"一");
          map.put(2,"二");
          map.put(3,"三");
          map.put(4,"四");
          map.put(5,"五");
          map.put(6,"六");

        Set<Integer> set = map.keySet();
        for(Integer in:set){
            System.out.println(in+":"+map.get(in));
        }

    }
    /**
     * 第二种方法：通过map的entryset（）
     */
    public static void function02(){
        Map map = new HashMap<Integer,String>();
        map.put(1,"一");
        map.put(2,"二");
        map.put(3,"三");
        map.put(4,"四");
        map.put(5,"五");
        map.put(6,"六");

       Set<Map.Entry<Integer,String>> set = map.entrySet();
       for(Map.Entry<Integer,String> entry:set){
           System.out.println("key键为："+entry.getKey()+"values为："+entry.getValue());
        }
    }

    /**
     * 第三种方法：使用iterator
     */
    public static void function03(){
        Map map = new HashMap<Integer,String>();
        map.put(1,"一");
        map.put(2,"二");
        map.put(3,"三");
        map.put(4,"四");
        map.put(5,"五");
        map.put(6,"六");
        Iterator<Map.Entry<Integer,String>> iterator = map.entrySet().iterator();
        while(iterator.hasNext()){
            Map.Entry<Integer, String> next =iterator.next();
            System.out.println("key为："+next.getKey()+"value为："+next.getValue());
        }
    }
    /**
     * 第四种方法：使用map的values（）方法：
     */
    public static void function04(){
        Map map = new HashMap<Integer,String>();
        map.put(1,"一");
        map.put(2,"二");
        map.put(3,"三");
        map.put(4,"四");
        map.put(5,"五");
        map.put(6,"六");
        for (Object  value : map.values()) {
            System.out.println("value为："+value);
        }
        ;
    }
}