SpringMVC（请求处理方法接收json参数）

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我是靠谱客的博主温暖蜡烛，最近开发中收集的这篇文章主要介绍SpringMVC（请求处理方法接收json参数），觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

SpringMVC的请求处理方法接收请求参数
1.请求处理方法接收json参数
1.1创建项目
1.2完善项目
1.3导入依赖

<!-- 配置开发SpringMVC所以来的jar包 -->
<!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-webmvc</artifactId>
  <version>5.1.5.RELEASE</version>
</dependency>
<!-- 配置ServletAPI依赖 -->
<!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
<dependency>
  <groupId>javax.servlet</groupId>
  <artifactId>javax.servlet-api</artifactId>
  <version>3.0.1</version>
  <scope>provided</scope>
</dependency>
<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-core -->
<dependency>
  <groupId>com.fasterxml.jackson.core</groupId>
  <artifactId>jackson-core</artifactId>
  <version>2.9.8</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind -->
<dependency>
  <groupId>com.fasterxml.jackson.core</groupId>
  <artifactId>jackson-databind</artifactId>
  <version>2.9.8</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-annotations -->
<dependency>
  <groupId>com.fasterxml.jackson.core</groupId>
  <artifactId>jackson-annotations</artifactId>
  <version>2.9.8</version>
</dependency>

1.4配置web.xml

<!DOCTYPE web-app PUBLIC
 "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
 "http://java.sun.com/dtd/web-app_2_3.dtd" >
<web-app>
  <display-name>Archetype Created Web Application</display-name>
  <servlet>
    <servlet-name>dispatcherServle</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>classpath:springmvc.xml</param-value>
    </init-param>
  </servlet>
  <servlet-mapping>
    <servlet-name>dispatcherServle</servlet-name>
    <url-pattern>*.do</url-pattern>
  </servlet-mapping>
</web-app>

1.5配置SpringMVC配置文件

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/mvc
       http://www.springframework.org/schema/mvc/spring-mvc.xsd
        http://www.springframework.org/schema/context
       http://www.springframework.org/schema/context/spring-context.xsd">
    <!--开启注解-->
    <mvc:annotation-driven></mvc:annotation-driven>
    <!--配置自动扫描包-->
    <context:component-scan base-package="com.wangxing.springmvc.controller"></context:component-scan>
</beans>

1.6创建HTML页面

<!DOCTYPE html>
<html lang="en">
	<head>
    <meta charset="UTF-8">
    <title>用户注册</title>
   </head>
<body>
    <table>
        <tr>
            <td colspan="2"><h1>用户注册</h1></td>
        </tr>
        <tr>
            <td>用户名:</td>
            <td><input id="username" type="text" name="username"/></td>
        </tr>
        <tr>
            <td>密码:</td>
            <td><input id="password" type="password" name="password"/></td>
        </tr>
        <tr>
            <td>年龄:</td>
            <td><input id="myage" type="text" name="myage"/></td>
        </tr>
        <tr>
            <td>地址:</td>
            <td><input id="myaddress" type="text" name="myaddress"/></td>
        </tr>
        <tr>
            <td colspan="2"><input id="but1" type="button" value="提交" /></td>
        </tr>
    </table>
</body>
</html>

1.7.在webapp文件夹中创建jquery文件，并将jquery-3.5.1.min.js复制进jquery文件。
重新加载一次jquery文件中的jquery-3.5.1.min.js文件

1.8 在html文件中导入jquery，并发送ajax请求

<script  src="jquery/jquery-3.5.1.min.js"></script>
<script>
    $(function () {
        $("#but1").click(function () {
            var username=$("#username").val();
            var password=$("#password").val();
            var myage=$("#myage").val();
            var myaddress=$("#myaddress").val();
            //组织成json数据[json对象]
            var params={"username":username,"password":password,"myage":myage,"myaddress":myaddress};
            //3.将上面组织好的json数据发送到控制器类的请求处理方法中接收处理
            $.ajax({
                //设置访问地址
                url:"http://localhost:8080/springmvc3/test1.do",
                //设置被发送的具体数据【json字符串】
                data:JSON.stringify(params),
                //设置请求提交方式
                type:"POST",
                //设置响应数据的类型是json
                datatype:"json",
                //设置请求的数据是json数据，绝对不可以省略
                contentType:"application/json",
                //设置请求发送成功以后的处理函数
                success:function(data){
                  alert(data);
                }
            });
        });
    });
</script>

注意:不能使用jquery的post方式发送ajax请求，因为jquery的post方式发送ajax请求时http协议的请求头中的contentType的属性值不是"application/json"，所以会出现“Failed to load resource: the server responded with a status of 415 (Unsupported Media Type)”错误。
1.9 创建被提交的json数据对应的java实体类
注意:java实体类的成员变量名称与被提交的json数据中的key值相同。
1.10创建控制器

package com.wangxing.springmvc.controller;
import com.wangxing.springmvc.bean.UserBean;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.servlet.ModelAndView;

@Controller
public class HelloController {
    @RequestMapping(value = "/test1.do",method = RequestMethod.POST)
    public void   testRequest(@RequestBody UserBean userBean){
        System.out.println("username=="+userBean.getUsername());
        System.out.println("password=="+userBean.getPassword());
        System.out.println("myage=="+userBean.getMyage());
        System.out.println("myaddress=="+userBean.getMyaddress());
    }
}

11.测试
http://localhost:8080/springmvc3/register.html

控制台输出

@RequestBody
@RequestBody注解接收来自请求体中的参数。
一般用于处理非 Content-Type: application/x-www-form-urlencoded编码格式的数据，比如：application/json、application/xml等类型的数据。
“Content-Type：application/json”使用注解@RequestBody可以将请求体里面所有的json数据传到后端，后端再进行解析，封装成java对象。
请求处理方法向浏览器页面返回json数据

package com.wangxing.springmvc.controller;

import com.wangxing.springmvc.bean.UserBean;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.servlet.ModelAndView;

@Controller
public class HelloController {
    @RequestMapping(value = "/test1.do")
    @ResponseBody
    public UserBean   testRequest(){
        UserBean user1=new UserBean();
        user1.setUsername("zhangsan");
    	user1.setPassword("000000");
    	user1.setMyage(23);
    	user1.setMyaddress("西安");
        return user1;
    }

@RequestMapping(value = "/test2.do")
@ResponseBody
public List<UserBean> testRequest2(){
    UserBean user1=new UserBean();
    user1.setUsername("zhangsan");
    user1.setPassword("000000");
    user1.setMyage(23);
    user1.setMyaddress("西安");
    UserBean user2=new UserBean();
    user2.setUsername("lisi");
    user2.setPassword("111111");
    user2.setMyage(24);
    user2.setMyaddress("北京");
    List<UserBean>  userBeanList=new ArrayList<UserBean>();
    userBeanList.add(user1);
    userBeanList.add(user2);
    return userBeanList;
	}
}

http://localhost:8080/springmvc3/test1.do

{"username":"zhangsan","password":"000000","myage":23,"myaddress":"西安"}

http://localhost:8080/springmvc3/test2.do
[{“username”:“zhangsan”,“password”:“000000”,“myage”:23,“myaddress”:“西安”},{“username”:“lisi”,“password”:“111111”,“myage”:24,“myaddress”:“北京”}]

@ResponseBody的作用其实是将java对象转为json格式的数据【json对象】。

Json对象与json字符串之间的转换
Json对象—》json字符串 JSON.stringify(json对象)
json字符串—》Json对象 eval("("+json字符串+")");
例如:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>用户注册</title>
    <script  src="jquery/jquery-3.5.1.min.js"></script>
    <script>
        $(function () {
            $("#but1").click(function () {
                //定义json对象
                var  jsonObj={id:1001,username:"zhangsan",age:23,address:"西安"};
                //alert(jsonObj); //[object Object]
                var jsonString=JSON.stringify(jsonObj);
                alert(jsonString); //{"id":1001,"username":"zhangsan","age":23,"address":"西安"}
            });
            $("#but2").click(function () {
                   //var jsonString="{"id":1001,"username":"zhangsan","age":23,"address":"西安"}";
                   var jsonString="{'id':1001,'username':'zhangsan','age':23,'address':'西安'}";
                   var jsonObj=eval("("+jsonString+")");
                   alert(jsonObj);  //[object Object]
            });
        });
    </script>
</head>
<body>
    <input id="but1" type="button" value="json对象转换成Json字符串" /><br>
    <input id="but2" type="button" value="Json字符串转换成json对象" />
</body>
</html>