接到一个需求，Java后台接到前台的请求后，要转为另一个格式存储，具体如下
前台的请求：
[{"id":"1","name":"张三"},{"id":"2","name":"李四"},{"id":"3","name":"王五"}]
转为另一个格式存到数据库：（不要问为什么，问就是历史原因，而且要保持这种顺序 0...0）
[{"id":"1","name":"张三"},{"name":"李四","id":"2"},{"name":"王五","id":"3"}]
首先解析前台的请求，新建一个PersonDto来映射请求的字段
@Data
public class PersonDto implements Serializable {
String id;
String name;
}
实现类：（省略main方法）
String request = "[{"id":"1","name":"张三"},{"id":"2","name":"李四"},{"id":"3","name":"王五"}]";
ObjectMapper mapper = new ObjectMapper();
List personDtoList = mapper.readValue(request, new TypeReference>() {});
for (PersonDto personDto : personDtoList) {
System.out.println("["personDto"] = " + personDto);
}
代码输出结果如下：
["personDto"] = PersonDto(id=1, name=张三) ["personDto"] = PersonDto(id=2, name=李四) ["personDto"] = PersonDto(id=3, name=王五)
但是问题来了：如果我直接输出，就达不到需求的结果
String response = mapper.writeValueAsString(personDtoList);
System.out.println("["response"] = " + response);
结果输出：
["response"] = [{"id":"1","name":"张三"},{"id":"2","name":"李四"},{"id":"3","name":"王五"}]
后面思考了一段时间，为啥不适用多态试一下呢？
创建ResponseDto类
@Data
public class ResponseDto implements Serializable {
}
创建子类（正序子类）
@EqualsAndHashCode(callSuper = true)
@Data
public class ResponseAscDto extends ResponseDto{
String id;
String name;
}
创建子类（逆序子类）
@EqualsAndHashCode(callSuper = true)
@Data
public class ResponseDescDto extends ResponseDto{
String name;
String id;
}
实现类：（省略main方法）
String request = "[{"id":"1","name":"张三"},{"id":"2","name":"李四"},{"id":"3","name":"王五"}]";
ObjectMapper mapper = new ObjectMapper();
List personDtoList = mapper.readValue(request, new TypeReference>() {});
List responseDtoList = new ArrayList<>();
//单独处理第一个，用正序ResponseAscDto来接收
PersonDto personDto = personDtoList.get(0);
ResponseDto responseDto = mapper.readValue(mapper.writeValueAsString(personDto), ResponseAscDto.class);
//添加到父类集合
responseDtoList.add(responseDto);
//处理后面几个，用逆序ResponseDescDto来接收
for (int i = 1; i < personDtoList.size(); i++) {
ResponseDto responseDescDto = mapper.readValue(mapper.writeValueAsString(personDto), ResponseDescDto.class);
//添加到父类集合
responseDtoList.add(responseDescDto);
}
//通过父类List集合一次性输出
String response = mapper.writeValueAsString(responseDtoList);
System.out.println("["response"] = " + response);
代码输出结果如下：
["response"] = [{"id":"1","name":"张三"},{"name":"张三","id":"1"},{"name":"张三","id":"1"}]
