原文网址：SpringBoot--通过JSON传递请求参数--方法/实例_IT利刃出鞘的博客-CSDN博客
简介
本文用示例介绍SpringMVC如何通过JSON格式传递入参。
JSON格式使用post方式来请求，即：对应的注解为：@PostMapping。
@PostMapping注解的方法可以接收1个@RequestBody标记的参数和多个没有@RequestBody标记的参数。
代码
Entity
User.java
-
package com.example.demo.entity;
-
-
import lombok.Data;
-
import java.util.List;
-
-
@Data
-
public
class
User {
-
private String name;
-
private Integer age;
-
private String[] password;
-
private List<Integer> scoreArray;
-
}
Account.java
-
package com.example.demo.entity;
-
-
import lombok.Data;
-
import java.io.Serializable;
-
-
@Data
-
public
class
Account
implements
Serializable {
-
private String phoneNum;
-
private String[] emails;
-
}
Controller
-
package com.example.demo.controller;
-
-
import com.example.demo.entity.User;
-
import org.springframework.web.bind.annotation.RestController;
-
import org.springframework.web.bind.annotation.RequestBody;
-
import org.springframework.web.bind.annotation.PostMapping;
-
import org.springframework.web.bind.annotation.RequestParam;
-
import org.springframework.web.bind.annotation.ResponseBody;
-
-
import java.util.Arrays;
-
import java.util.List;
-
-
@RequestMapping("/json")
-
@RestController
-
public
class
JsonController {
-
@PostMapping("/1")
-
public User
setUserNoAnnotation
(User user, List<String> password, Integer[] scoreArray) {
-
printUser(user);
-
return user;
-
}
-
-
@RequestMapping("/2")
-
public User
setUserAnnotation
(@RequestBody User user) {
-
printUser(user);
-
return user;
-
}
-
-
@RequestMapping("/3")
-
public User
setUserAnnotation1
(@RequestBody User user, @RequestParam List<String> password, Integer[] scoreArray) {
-
System.out.println(password);
-
if (scoreArray !=
null) {
-
System.out.println(Arrays.asList(scoreArray));
-
}
else {
-
System.out.println(
"scoreArray = null");
-
}
-
System.out.println();
-
printUser(user);
-
-
return user;
-
}
-
-
@RequestMapping("/4")
-
public User
setUserAnnotation2
(@RequestBody User user, @RequestBody List<String> password, @RequestBody Integer[] scoreArray) {
-
if (password !=
null) {
-
System.out.println(password);
-
}
else {
-
System.out.println(
"password = null");
-
}
-
-
if (scoreArray !=
null) {
-
System.out.println(Arrays.asList(scoreArray));
-
}
else {
-
System.out.println(
"scoreArray = null");
-
}
-
System.out.println();
-
printUser(user);
-
return user;
-
}
-
-
private
void
printUser
(User user){
-
System.out.println(
"name : " + user.getName());
-
System.out.println(
"password : " + Arrays.asList(user.getPassword()));
-
System.out.println(
"scoreArray : " + user.getScoreArray());
-
System.out.println(
"acount.phoneNum : " + user.getAccount().getPhoneNum());
-
System.out.println(
"account.emails : " + Arrays.asList(user.getAccount().getEmails()));
-
}
-
}
测试
为方便测试，我用了knife4j。
测试前提
json的body
-
{
-
"name":
"Jarvis",
-
"password": [
-
"ab",
-
"cd"
-
],
-
"scoreArray": [
-
99,
-
98
-
],
-
"account": {
-
"phoneNum":
"123",
-
"emails": [
-
"123@qq.com",
-
"456@163.com"
-
]
-
}
-
}
正确的用法
1个RequestBody
0个@RequestBody，多个无@RequestBody
1个@RequestBody，多个无@RequestBody
错误的用法（会报错）
多个@RequestBody
后端报错信息
2022-09-20 22:04:45.857 WARN 3340 --- [nio-8080-exec-1] .w.s.m.s.DefaultHandlerExceptionResolver : Resolved [org.springframework.http.converter.HttpMessageNotReadableException: I/O error while reading input message; nested exception is java.io.IOException: Stream closed]
错误原因
每个方法只能有一个@RequestBody。使用@RequestBody把请求转化为特定的Object（在最后会关闭相应的流），所以在同一个方法中第二次使用@RequestBody是没用的，因为流已经关闭。
You cannot use it this way as only one @RequestBody per method is allowed. Using @RequestBody Spring converts incoming request body into the specified object (what closes the stream representing body at the end) so attempting to use @RequestBody second time in the same method makes no sense as stream has been already closed.
不带@RequestBody参数类型是List
后端错误信息
-
2022-09-
20
23:
19:
11.044 ERROR
3340 --- [nio-
8080-exec-
2] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service()
for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.IllegalStateException: No primary or
default constructor found
for
interface
java.util.List] with root cause
-
-
java.lang.NoSuchMethodException: java.util.List.<init>()
-
at java.lang.Class.getConstructor0(Class.java:
3082) ~[na:
1.8
.0_201]
-
at java.lang.Class.getDeclaredConstructor(Class.java:
2178) ~[na:
1.8
.0_201]
-
...（其他信息）
错误原因
不支持非@RequstBody的参数是List类型。（数组类型可以）。
转载：https://blog.csdn.net/feiying0canglang/article/details/126955477
查看评论