使用ObjectMapper进行序列化与反序列化

再使用springboot项目的时候，返回json格式数据给前端。或者手动的序列化一些数据，因为使用的是jackson。 如果使用的是FastJson直接使用就没这些事。

public static void main(String[] args) throws Exception{
		ObjectMapper objectMapper = new ObjectMapper();
		//序列化的时候序列对象的所有属性
		objectMapper.setSerializationInclusion(Include.ALWAYS);
		//取消时间的转化格式,默认是时间戳,可以取消,同时需要设置要表现的时间格式
		objectMapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
objectMapper.setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));	
		Person person = new Person(1, "zs", new Date());
		//这是最简单的一个例子,把一个对象转换为json字符串
		String personJson = objectMapper.writevalueAsString(person);
		System.out.println(personJson);
		
		//默认为true,会显示时间戳
		objectMapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, true);
		personJson = objectMapper.writevalueAsString(person);
		System.out.println(personJson);
	}

public static void main(String[] args) throws Exception{
		ObjectMapper objectMapper = new ObjectMapper();
		//序列化的时候序列对象的所有属性
		objectMapper.setSerializationInclusion(Include.ALWAYS);
		//反序列化的时候如果多了其他属性,不抛出异常
		objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
		
//		Person person = new Person(1, "zxc", new Date());
 
//		String personJson = objectMapper.writevalueAsString(person);
//		System.out.println(personJson);
		
		//注意,age属性是不存在在person对象中的
		String personStr = "{"id":1,"name":"zxc","age":"zxc"}";
		
		Person person = objectMapper.readValue(personStr, Person.class);
		System.out.println(person);
		
		//默认为true
		objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, true);
		person = objectMapper.readValue(personStr, Person.class);
		System.out.println(person);
		
	}

public static void main(String[] args) throws Exception{
		ObjectMapper objectMapper = new ObjectMapper();
		//序列化的时候序列对象的所有属性
		objectMapper.setSerializationInclusion(Include.NON_DEFAULT);
		
		Person person1 = new Person(1, "zxc", new Date());
		Person person2 = new Person(2, "ldh", new Date());
		
		List persons = new ArrayList<>();
		persons.add(person1);
		persons.add(person2);
		
		//先转换为json字符串
		String personStr = objectMapper.writevalueAsString(persons);
		
		//反序列化为List 集合,1需要通过 TypeReference 来具体传递值
		List persons2 = objectMapper.readValue(personStr, new TypeReference>() {});
		
		for(Person person : persons2) {
			System.out.println(person);
		}
		
		//2,通过 JavaType 来进行处理返回
		JavaType javaType = objectMapper.getTypeFactory().constructParametricType(List.class, Person.class);
		List persons3 = objectMapper.readValue(personStr, javaType);
		
		for(Person person : persons3) {
			System.out.println(person);
		}
	}