map的遍历输出

// 创建集合对象
        HashMap<Teacher, String> hm = new HashMap<Teacher, String>();

        // 创建元素
        Teacher t1 = new Teacher("小明", 19);
        Teacher t2 = new Teacher("小刚", 15);
        Teacher    t3 = new Teacher("小强", 23);
      Teacher t4 = new Teacher("小周", 20);
        Teacher t5 = new Teacher("小明", 19);
        // 添加元素
        hm.put(t1, "001");
        hm.put(t2, "003");
        hm.put(t3, "002");
        hm.put(t4, "004");
        hm.put(t5, "005");

        // 遍历
        Set<Map.Entry<Teacher, String>> set = hm.entrySet();
        Iterator<Map.Entry<Teacher, String>> it = set.iterator();
        while (it.hasNext()) {
            Map.Entry<Teacher, String> me = it.next();
            Teacher key = me.getKey();
            String value = me.getValue();
            System.out.println(key.getName() + "***" + key.getAge() + "***"
                    + value);
        }

 

 

// 创建Map集合对象
        Map<String, String> hm = new HashMap<String, String>();

        // 创建元素并添加元素
        hm.put("it002", "hello");
        hm.put("it003", "world");
        hm.put("it001", "java");
        hm.put("it004", "itcast");
        hm.put("it002", "javaee");
        
        //System.out.println("get:"+hm.get("it003"));
        
        //获取所有键的集合
        Set<String> set = hm.keySet();
        Iterator<String> it = set.iterator();
        while(it.hasNext()){
            String key = it.next();
            System.out.println(key);
        }
        
        System.out.println("**************************************");
        Collection<String> coll = hm.values(); //返回的是Collection子类对象
        Iterator<String> it2 = coll.iterator();
        while(it2.hasNext()){
            String value = it2.next();
            System.out.println(value);
        }
        
        System.out.println("**************************************");
        //Map的遍历
        //获取所有键的集合
        Set<String> keySet = hm.keySet();
        Iterator<String> keyIt = keySet.iterator();
        //通过迭代器遍历键的集合，获取到每一个键值
        while(keyIt.hasNext()){
            //获取到每一个键
            String key = keyIt.next();
            //根据键获取对应的值
            String value = hm.get(key);
            System.out.println(key+":"+value);
        }
        
        System.out.println("**************************************");
        //Set<Map.Entry<K,V>> entrySet()
        //获取所有键值对的集合
        Set<Map.Entry<String,String>> entrySet = hm.entrySet();
        Iterator<Map.Entry<String,String>> entryIt = entrySet.iterator();
        //遍历键值对的集合，获取每一个键值对对象
        while(entryIt.hasNext()){
            Map.Entry<String,String> me = entryIt.next(); //返回的是实现了该接口的子类对象
            //获取键
            String key = me.getKey();
            //获取值
            String value=  me.getValue();
            System.out.println(key+":"+value);
        }