spring-mvc 系列：获取请求参数（ServletAPI、形参、RequestParam、RequestHeader、CookieValue、POJO等方式）-526互联

一、通过 ServletAPI 获取
二、通过控制器方法的形参获取请求参数
三、@RequestParam
四、@RequestHeader
五、@CookieValue
六、通过 POJO 获取请求参数
七、解决获取请求参数的乱码问题
- 处理tomcat的乱码
- 处理post请求乱码

一、通过 ServletAPI 获取

将 HttpServletRequest 作为控制器方法的形参，此时 HttpServletRequest 类型的参数表示封装了当前请求的请求报文的对象

html

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
    <head>
        <meta charset="UTF-8" />
        <title>params</title>
        <style>
            a {
                display: block;
            }
        </style>
    </head>
    <body>
        <!--第一种写法-->
        <!--    <a th:href="@{/testServletParam?userName=admin&password=123456}">测试获取请求参->/testServletParam</a> -->
        <!--第二种写法-->
        <a th:href="@{/testServletParam(userName='admin',password=123456)}"
            >测试获取请求参数----->/testServletParam</a
        >
    </body>
</html>

java

package com.mcode.api.controller;

import com.mcode.api.bean.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;

/**
 * ClassName: ParamController
 * Package: com.mcode.api.controller
 * Description:
 *
 * @Author robin
 * @Create 2023/8/4 12:41
 * @Version 1.0
 */
@Controller
public class ParamController {

    @RequestMapping("/")
    public String index(){
        return "params";
    }

    @RequestMapping("/testServletParam")
    public String testServletParam(HttpServletRequest request){
        String userName = request.getParameter("userName");
        String password = request.getParameter("password");
        System.out.println("userName:"+userName+",password:"+password);
        return "success";
    }
}

二、通过控制器方法的形参获取请求参数

在控制器方法的形参位置，设置和请求参数同名的形参，当浏览器发送请求，匹配到请求映射时，在 DispatcherServlet 中就会将请求参数赋值给相应的形参

html

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
    <head>
        <meta charset="UTF-8" />
        <title>params</title>
        <style>
            a {
                display: block;
            }
        </style>
    </head>
    <body>
        <!--第一种写法-->
        <!--    <a th:href="@{/testServletParam?userName=admin&password=123456}">测试获取请求参->/testServletParam</a> -->
        <!--第二种写法-->
        <a th:href="@{/testServletParam(userName='admin',password=123456)}"
            >测试获取请求参数----->/testServletParam</a
        >

        <a th:href="@{/testParam(userName='admin',password=123456)}"
            >测试获取请求参数----->/testParam</a
        >
    </body>
</html>

java

package com.mcode.api.controller;

import com.mcode.api.bean.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;

/**
 * ClassName: ParamController
 * Package: com.mcode.api.controller
 * Description:
 *
 * @Author robin
 * @Create 2023/8/4 12:41
 * @Version 1.0
 */
@Controller
public class ParamController {

    @RequestMapping("/")
    public String index(){
        return "params";
    }

    @RequestMapping("/testServletParam")
    public String testServletParam(HttpServletRequest request){
        String userName = request.getParameter("userName");
        String password = request.getParameter("password");
        System.out.println("userName:"+userName+",password:"+password);
        return "success";
    }

    @RequestMapping("/testParam")
    public  String testParam(String userName, String password){
        System.out.println("userName:"+userName+",password:"+password);
        return "success";
    }
}

注：
若请求所传输的请求参数中有多个同名的请求参数，此时可以在控制器方法的形参中设置字符串
数组或者字符串类型的形参接收此请求参数
若使用字符串数组类型的形参，此参数的数组中包含了每一个数据
若使用字符串类型的形参，此参数的值为每个数据中间使用逗号拼接的结果

三、@RequestParam

@RequestParam 是将请求参数和控制器方法的形参创建映射关系
@RequestParam 注解一共有三个属性：

value：指定为形参赋值的请求参数的参数名

required：设置是否必须传输此请求参数，默认值为 true
若设置为 true 时，则当前请求必须传输 value 所指定的请求参数，若没有传输该请求参数，且没有设置

defaultValue 属性，则页面报错 400：Required String parameter 'xxx' is not present；若设置为 false，则当前请求不是必须传输 value 所指定的请求参数，若没有传输，则注解所标识的形参的值为 null

defaultValue：不管 required 属性值为 true 或 false，当 value 所指定的请求参数没有传输或传输的值为""时，则使用默认值为形参赋值

html

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>params</title>
    <style>
        a{
            display: block;
        }
    </style>
</head>
<body>
<!--第一种写法-->
<!--    <a th:href="@{/testServletParam?userName=admin&password=123456}">测试获取请求参->/testServletParam</a> -->
<!--第二种写法-->
<a th:href="@{/testServletParam(userName='admin',password=123456)}">测试获取请求参数----->/testServletParam</a>

<a th:href="@{/testParam(user_name='admin',password=123456)}">测试获取请求参数----->/testParam</a>
</body>
</html>

java

package com.mcode.api.controller;

import com.mcode.api.bean.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;

/**
 * ClassName: ParamController
 * Package: com.mcode.api.controller
 * Description:
 *
 * @Author robin
 * @Create 2023/8/4 12:41
 * @Version 1.0
 */
@Controller
public class ParamController {

    @RequestMapping("/")
    public String index(){
        return "params";
    }

    @RequestMapping("/testServletParam")
    public String testServletParam(HttpServletRequest request){
        String userName = request.getParameter("userName");
        String password = request.getParameter("password");
        System.out.println("userName:"+userName+",password:"+password);
        return "success";
    }

    @RequestMapping("/testParam")
    public  String testParam(String userName, String password){
        System.out.println("userName:"+userName+",password:"+password);
        return "success";
    }

    

    @RequestMapping("/testRequestParam")
    public  String testRequestParam(@RequestParam(value = "user_name",defaultValue = "admin",required = false) String userName, String password){
        System.out.println("userName:"+userName+",password:"+password);
        return "success";
    }
}

四、@RequestHeader

@RequestHeader 是将请求头信息和控制器方法的形参创建映射关系
@RequestHeader 注解一共有三个属性：value、required、defaultValue，用法同@RequestParam

html

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>params</title>
    <style>
        a{
            display: block;
        }
    </style>
</head>
<body>
<!--第一种写法-->
<!--    <a th:href="@{/testServletParam?userName=admin&password=123456}">测试获取请求参->/testServletParam</a> -->
<!--第二种写法-->
<a th:href="@{/testServletParam(userName='admin',password=123456)}">测试获取请求参数----->/testServletParam</a>

<a th:href="@{/testParam(userName='admin',password=123456)}">测试获取请求参数----->/testParam</a>

<a th:href="@{/testRequestParam(user_name='admin',password=123456)}">测试获取请求参数----->/testRequestParam</a>


<a th:href="@{/testRequestHeader}">测试获取请求参数----->/testRequestHeader</a>
</body>
</html>

java

package com.mcode.api.controller;

import com.mcode.api.bean.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;

/**
 * ClassName: ParamController
 * Package: com.mcode.api.controller
 * Description:
 *
 * @Author robin
 * @Create 2023/8/4 12:41
 * @Version 1.0
 */
@Controller
public class ParamController {

    @RequestMapping("/")
    public String index() {
        return "params";
    }

    @RequestMapping("/testServletParam")
    public String testServletParam(HttpServletRequest request) {
        String userName = request.getParameter("userName");
        String password = request.getParameter("password");
        System.out.println("userName:" + userName + ",password:" + password);
        return "success";
    }

    @RequestMapping("/testParam")
    public String testParam(String userName, String password) {
        System.out.println("userName:" + userName + ",password:" + password);
        return "success";
    }


    @RequestMapping("/testRequestParam")
    public String testRequestParam(@RequestParam(value = "user_name", defaultValue = "admin", required = false) String userName, String password) {
        System.out.println("userName:" + userName + ",password:" + password);
        return "success";
    }

    @RequestMapping("/testRequestHeader")
    public String testParam1(@RequestHeader("Host") String host) {
        System.out.println("host:" + host);
        return "success";
    }
}

五、@CookieValue

@RequestHeader 是将请求的Cookie和控制器方法的形参创建映射关系
@RequestHeader 注解一共有三个属性：value、required、defaultValue，用法同@RequestParam

html

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>params</title>
    <style>
        a{
            display: block;
        }
    </style>
</head>
<body>
<!--第一种写法-->
<!--    <a th:href="@{/testServletParam?userName=admin&password=123456}">测试获取请求参->/testServletParam</a> -->
<!--第二种写法-->
<a th:href="@{/testServletParam(userName='admin',password=123456)}">测试获取请求参数----->/testServletParam</a>

<a th:href="@{/testParam(userName='admin',password=123456)}">测试获取请求参数----->/testParam</a>

<a th:href="@{/testRequestParam(user_name='admin',password=123456)}">测试获取请求参数----->/testRequestParam</a>


<a th:href="@{/testRequestHeader}">测试获取请求参数----->/testRequestHeader</a>

<a th:href="@{/testCookieValue}">测试获取请求参数----->/testCookieValue</a>
</body>
</html>

java

package com.mcode.api.controller;

import com.mcode.api.bean.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;

/**
 * ClassName: ParamController
 * Package: com.mcode.api.controller
 * Description:
 *
 * @Author robin
 * @Create 2023/8/4 12:41
 * @Version 1.0
 */
@Controller
public class ParamController {

    @RequestMapping("/")
    public String index() {
        return "params";
    }

    @RequestMapping("/testServletParam")
    public String testServletParam(HttpServletRequest request) {
        String userName = request.getParameter("userName");
        String password = request.getParameter("password");
        System.out.println("userName:" + userName + ",password:" + password);
        return "success";
    }

    @RequestMapping("/testParam")
    public String testParam(String userName, String password) {
        System.out.println("userName:" + userName + ",password:" + password);
        return "success";
    }


    @RequestMapping("/testRequestParam")
    public String testRequestParam(@RequestParam(value = "user_name", defaultValue = "admin", required = false) String userName, String password) {
        System.out.println("userName:" + userName + ",password:" + password);
        return "success";
    }

    @RequestMapping("/testRequestHeader")
    public String testParam1(@RequestHeader("Host") String host) {
        System.out.println("host:" + host);
        return "success";
    }

    @RequestMapping("testCookieValue")
    public String testCookieValue(@CookieValue("JSESSIONID") String JSESSIONID) {
        System.out.println("JSESSIONID:" + JSESSIONID);
        return "success";
    }
}

六、通过 POJO 获取请求参数

可以在控制器方法的形参位置设置一个实体类类型的形参，此时若浏览器传输的请求参数的参数名和实体类中的属性名一致，那么请求参数就会为此属性赋值

html

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>params</title>
    <style>
        a{
            display: block;
        }
    </style>
</head>
<body>
<!--第一种写法-->
<!--    <a th:href="@{/testServletParam?userName=admin&password=123456}">测试获取请求参->/testServletParam</a> -->
<!--第二种写法-->
<a th:href="@{/testServletParam(userName='admin',password=123456)}">测试获取请求参数----->/testServletParam</a>

<a th:href="@{/testParam(userName='admin',password=123456)}">测试获取请求参数----->/testParam</a>

<a th:href="@{/testRequestParam(user_name='admin',password=123456)}">测试获取请求参数----->/testRequestParam</a>


<a th:href="@{/testRequestHeader}">测试获取请求参数----->/testRequestHeader</a>

<a th:href="@{/testCookieValue}">测试获取请求参数----->/testCookieValue</a>

<form th:action="@{/testBeanParam}" method="post">
    用户名：<input type="text" name="userName"><br>
    密码：<input type="password" name="password"><br>
    性别：<input type="radio" name="sex" value="男">男
    <input type="radio" name="sex" value="女">女 <br>
    年龄：<input type="text" name="age"><br>
    邮箱：<input type="text" name="email"><br>
    <input type="submit" value="测试获取请求参数----->/testBeanParam">
</form>
</body>
</html>

java

package com.mcode.api.controller;

import com.mcode.api.bean.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;

/**
 * ClassName: ParamController
 * Package: com.mcode.api.controller
 * Description:
 *
 * @Author robin
 * @Create 2023/8/4 12:41
 * @Version 1.0
 */
@Controller
public class ParamController {

    @RequestMapping("/")
    public String index() {
        return "params";
    }

    @RequestMapping("/testServletParam")
    public String testServletParam(HttpServletRequest request) {
        String userName = request.getParameter("userName");
        String password = request.getParameter("password");
        System.out.println("userName:" + userName + ",password:" + password);
        return "success";
    }

    @RequestMapping("/testParam")
    public String testParam(String userName, String password) {
        System.out.println("userName:" + userName + ",password:" + password);
        return "success";
    }


    @RequestMapping("/testRequestParam")
    public String testRequestParam(@RequestParam(value = "user_name", defaultValue = "admin", required = false) String userName, String password) {
        System.out.println("userName:" + userName + ",password:" + password);
        return "success";
    }

    @RequestMapping("/testRequestHeader")
    public String testParam1(@RequestHeader("Host") String host) {
        System.out.println("host:" + host);
        return "success";
    }

    @RequestMapping("testCookieValue")
    public String testCookieValue(@CookieValue("JSESSIONID") String JSESSIONID) {
        System.out.println("JSESSIONID:" + JSESSIONID);
        return "success";
    }


    @RequestMapping("/testBeanParam")
    public String testBeanParam(User user) {
        System.out.println(user.toString());
        return "success";
    }
}

java bean

package com.mcode.api.bean;

/**
 * ClassName: User
 * Package: com.mcode.api.bean
 * Description:
 *
 * @Author robin
 * @Create 2023/8/4 13:02
 * @Version 1.0
 */
public class User {
    private String userName;
    private String password;

    private String sex;

    private Integer age;

    private String email;

    public User() {
    }

    public User(String userName, String password, String sex, Integer age, String email) {
        this.userName = userName;
        this.password = password;
        this.sex = sex;
        this.age = age;
        this.email = email;
    }

    @Override
    public String toString() {
        return "User{" +
                "userName='" + userName + '\'' +
                ", password='" + password + '\'' +
                ", sex='" + sex + '\'' +
                ", age=" + age +
                ", email='" + email + '\'' +
                '}';
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }
}

七、解决获取请求参数的乱码问题

处理tomcat的乱码

一、Tomcat设置编码UTF-8

为了在Tomcat中确保正确的字符集编码，我们需要在以下几个方面进行设置：

1、在server.xml文件中，对Connector进行设置：

<Connector port="8080" URIEncoding="UTF-8">

其中URIEncoding属性被设置为UTF-8，确保请求URI以UTF-8进行解码。

2、对于静态文件，我们需要在web.xml文件中进行设置：

<mime-mapping>
    <extension>html</extension>
    <mime-type>text/html;charset=UTF-8</mime-type>
</mime-mapping>

这将确保静态HTML文件以UTF-8编码进行解码。

3、设置JSP页面的编码方式：

<%@ page contentType="text/html;charset=UTF-8" %>

这将确保JSP页面以UTF-8编码进行响应。

二、Tomcat编码设置UTF-8

如果我们需要进行全局的编码设置，可以在catalina.bat（Windows）或catalina.sh（Linux）文件中进行修改。我们需要添加以下参数：

set JAVA_OPTS=%JAVA_OPTS% -Dfile.encoding=UTF-8

这将确保Tomcat使用UTF-8编码。

三、Tomcat设置编码格式

我们可以在Tomcat的server.xml文件中配置字符集。我们需要设置两个属性：URIEncoding和useBodyEncodingForURI：

<Connector port="8080" URIEncoding="UTF-8" useBodyEncodingForURI="true">

其中URIEncoding被设置为UTF-8，useBodyEncodingForURI设置为true，确保请求和响应的编码一致。

四、Tomcat设置编码GBK

如果我们需要使用GBK编码，我们需要将server.xml文件中的属性URIEncoding修改为GBK：

<Connector port="8080" URIEncoding="GBK">

五、Tomcat设置编码设置

在IDEA中，我们可以在Run/Debug Configurations的VM options中添加以下参数：

-Dfile.encoding=UTF-8

这将确保Tomcat在IDEA中使用UTF-8编码。

六、Tomcat设置编码字符集

我们也可以在response中设置编码字符集，例如：

response.setCharacterEncoding("UTF-8");

这将确保响应以UTF-8编码进行。

七、IDEA设置Tomcat编码

在IDEA中我们可以通过设置配置文件来设置Tomcat的编码。我们需要修改TOMCAT_HOME/conf/logging.properties文件中的属性：

java.util.logging.ConsoleHandler.encoding = UTF-8

这将确保Tomcat日志以UTF-8编码进行输出。

八、Tomcat设置日志编码

我们可以在Tomcat的logging.properties文件中设置编码：

org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/].encoding=UTF-8

这将确保Tomcat的日志输出以UTF-8编码进行。

处理post请求乱码

解决获取请求参数的乱码问题，可以使用SpringMVC提供的编码过滤器CharacterEncodingFilter，但是必须在web.xml中进行注册

<!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>
   <!--配置springMVC的编码过滤器-->
    <filter>
        <filter-name>CharacterEncodingFilter</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
        <init-param>
            <param-name>forceEncoding</param-name>
            <param-value>true</param-value>
        </init-param>
    </filter>

    <filter-mapping>
        <filter-name>CharacterEncodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <servlet>
        <servlet-name>DispatcherServlet</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:spring-mvc.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>DispatcherServlet</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

</web-app>

注：SpringMVC中处理编码的过滤器一定要配置到其他过滤器之前，否则无效

requestheader requestparam cookievalue spring-mvc

requestheader hook js

requestparam requestbody