Spring Rest Controller如何将JSON请求映射到两个独立Java对象

1. 使用Map<String, Object>接收请求体 #

直接用Map承接整个JSON结构，通过键名提取嵌套对象，还可以将嵌套Map转换为对应的实体类：

@RequestMapping(value = "/save", method = RequestMethod.POST)
public Instructor persistInstructorInformation(@RequestBody Map<String, Object> requestMap) {
    // 获取并处理customer数据
    Map<String, Object> customerMap = (Map<String, Object>) requestMap.get("customer");
    Integer customerId = (Integer) customerMap.get("id");
    String firstName = (String) customerMap.get("firstName");
    
    // 可选：将Map转为Customer实体类
    ObjectMapper mapper = new ObjectMapper();
    Customer customer = mapper.convertValue(customerMap, Customer.class);

    // 获取并处理student数据
    Map<String, Object> studentMap = (Map<String, Object>) requestMap.get("student");
    String studentId = (String) studentMap.get("id");
    Integer age = (Integer) studentMap.get("age");
    Student student = mapper.convertValue(studentMap, Student.class);

    // 后续业务逻辑
    ...
}

2. 使用Jackson的JsonNode接收请求体 #

借助Jackson的JsonNode类解析JSON结构，支持灵活的节点遍历和字段提取，无需提前定义Wrapper类：

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

@RequestMapping(value = "/save", method = RequestMethod.POST)
public Instructor persistInstructorInformation(@RequestBody JsonNode requestNode) {
    // 提取customer节点字段
    JsonNode customerNode = requestNode.get("customer");
    int customerId = customerNode.get("id").asInt();
    String firstName = customerNode.get("firstName").asText();
    String lastName = customerNode.get("lastName").asText();
    
    // 可选：将JsonNode转为Customer实体类
    ObjectMapper mapper = new ObjectMapper();
    Customer customer = mapper.treeToValue(customerNode, Customer.class);

    // 提取student节点字段
    JsonNode studentNode = requestNode.get("student");
    String studentId = studentNode.get("id").asText();
    String studentName = studentNode.get("name").asText();
    int age = studentNode.get("age").asInt();
    Student student = mapper.treeToValue(studentNode, Student.class);

    // 后续业务逻辑
    ...
}

这两种方式既不用定义包裹整个请求的Wrapper类，也比直接用Object类更便于操作请求数据。

内容的提问来源于stack exchange，提问作者Subhendu Das