注解

@JsonProperty

@JsonAlias

@JsonAlias 为反序列化期间接受的属性定义一个或多个备用名称，即将 JSON 数据设置为 Java 对象。但是在序列化时，即从 Java 对象获取 JSON 时，只使用实际的逻辑属性名而不是别名。

转换

Object —> Map

  1. ObjectMapper oMapper = new ObjectMapper();
  2. Student obj = new Student("ZhangSan",18);
  3. Map<String, Object> map = oMapper.convertValue(obj, Map.class);

Map —> Object

String —> List / Array

  1.     ObjectMapper mapper = new ObjectMapper();
  2.     String json = "[{\"name\":\"mkyong\", \"age\":37}, {\"name\":\"fong\", \"age\":38}]";
  4.     // 1. convert JSON array to Array objects
  5.     Person[] pp1 = mapper.readValue(json, Person[].class);
  7.     // 2. convert JSON array to List of objects
  8.     List<Person> ppl2 = Arrays.asList(mapper.readValue(json, Person[].class));
  1. Map<String, Object> convertJsonStringToMap(String json) throws IOException {
  2.     ObjectMapper mapper = new ObjectMapper();
  3.     TypeReference type = new TypeReference<Map<String, Object>>(){};
  4.     return mapper.readValue(json, type);
  5. }

List <—> ArrayNode

  1. List<MyClass> myObjects = Arrays.asList(mapper.readValue(json, MyClass[].class))
  3. ObjectMapper mapper = new ObjectMapper();
  4. List<Employee> e = new ArrayList<Employee>();
  5. ArrayNode array = mapper.valueToTree(e);
  9.       array.forEach(node -> {
  10.         try {
  11.           erModelProps.add(objectMapper.treeToValue(node, Employee.class));
  12.         } catch (JsonProcessingException e) {
  13.           throw new JeecgBootException("转换失败");
  14.         }
  15.       });

异常处理

解析json字符串失败，原因：Java 8 date/time type java.time.LocalDate not supported by default: add Module “com.fasterxml.jackson.datatype:jackson-datatype-jsr310”