objectmapper用法

ObjectMapper是一个Java库，用于将JSON数据转换为Java对象或将Java对象转换为JSON数据。它提供了一种简单易用的方式来处理JSON数据，使得在Java应用程序中使用JSON数据变得更加方便。以下是ObjectMapper用法的一些示例：

1. 将JSON字符串转换为Java对象：

ObjectMapper objectMapper = new ObjectMapper();
String json = "{\"name\":\"John\", \"age\":30}";
Person person = objectMapper.readValue(json, Person.class);

2. 将Java对象转换为JSON字符串：

ObjectMapper objectMapper = new ObjectMapper();
Person person = new Person("John", 30);
String json = objectMapper.writeValueAsString(person);

3. 将JSON字符串转换为Java集合：

ObjectMapper objectMapper = new ObjectMapper();
String json = "[{\"name\":\"John\", \"age\":30}, {\"name\":\"Jane\", \"age\":25}]";
List<Person> persons = objectMapper.readValue(json, new TypeReference<List<Person>>(){});

4. 将Java集合转换为JSON字符串：

ObjectMapper objectMapper = new ObjectMapper();
List<Person> persons = Arrays.asList(new Person("John", 30), new Person("Jane", 25));
String json = objectMapper.writeValueAsString(persons);

5. 使用ObjectMapper配置：

ObjectMapper objectMapper = new ObjectMapper();
objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
// 禁止序列化null值
objectMapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);