JSON知识总结- Gson（四）List和Map

1.List

 简单使用

@Test
	public void testList() {
		List list = new ArrayList();
		list.add("one");
		list.add(122);
		String json = gson.toJson(list);
		System.out.println("json->" + json);
		
		List list2 = gson.fromJson(json , List.class);
		for(Object each : list2) {
			System.out.println(each);
		}
		
	}

结果：

处理泛型：

       class Person {
		public int id;
		public String name;
		
		public Person(int _id , String _name) {
			this.id = _id;
			this.name = _name;
		}
		
		public String toString() {
			return "id->" + id + ",name->" + name;
		}
	}
	@Test
	public void testList2() {
		List<Person> persons = new ArrayList<Person>();
		persons.add(new Person(1 , "one"));
		persons.add(new Person(2 , "two"));
		
		String json = gson.toJson(persons);
		System.out.println("json->" + json);
		
		Type type = new TypeToken<List<Person>>() {}.getType(); 
		List<Person> anotherPersons = gson.fromJson(json , type);
		for(Person each : anotherPersons) {
			System.out.println(each);
		}
		
	}

结果：

2.Map

简单使用

@Test
	public void testMap() {
		Map map = new HashMap();
		map.put("one" , "路飞");
		map.put("two" , 999);
		
		String json = gson.toJson(map);
		System.out.println(json);
		
		Map map2 = gson.fromJson(json , Map.class);
		for(Object each : map2.entrySet()) {
			System.out.println(each);
		}
	}

结果显示：

使用泛型：

        @Test
	public void testMap2() {
		Map<String , Person> map = new HashMap<String , Person>();
		map.put("first" , new Person(1 , "路飞"));
		map.put("second", new Person(2 , "索隆"));
		
		String json = gson.toJson(map);
		System.out.println("json->" + json);
		
		Type type = new TypeToken<Map<String , Person>>() {}.getType(); 
		Map<String , Person> map2 = gson.fromJson(json , type);
		for(String key : map2.keySet()) {
			System.out.println(key + "->" + map2.get(key));
		}
		
	}