SpringMVC4-SpringMVC获取请求参数

通过ServletAPI获取（不常用）

通过控制器方法的形参获取请求参数

@RequestParam

@RequestHeader

@CookieValue

通过POJO获取请求参数

解决获取请求参数的乱码问题

test_param.html：

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head><meta charset="UTF-8"><title>测试请求参数</title>
</head>
<body>
<h1>测试请求参数</h1>
</body>
</html>

package com.qcby.mvc.controller;import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;@Controller
public class TestController {@RequestMapping("/param")public String param(){return "test_param";}}

启动：

通过ServletAPI获取（不常用）

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

package com.qcby.mvc.controller;import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;import javax.servlet.http.HttpServletRequest;@Controller
public class ParamController {@RequestMapping("/testServletAPI")//形参位置的request表示当前请求public String testServletAPI(HttpServletRequest request){String username = request.getParameter("username");String password = request.getParameter("password");System.out.println("username："+username+"，password："+password);return "success";}}

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head><meta charset="UTF-8"><title>测试请求参数</title>
</head>
<body>
<h1>测试请求参数</h1>
<a th:href="@{/testServletAPI(username='admin',password=123456)}">测试使用ServletAPI获取请求参数</a>
</body>
</html>

通过控制器方法的形参获取请求参数

package com.qcby.mvc.controller;import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;import javax.servlet.http.HttpServletRequest;@Controller
public class ParamController {@RequestMapping("/testParam")public String testParam(String username,String password){System.out.println("username："+username+"，password："+password);return "success";}
}

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head><meta charset="UTF-8"><title>测试请求参数</title>
</head>
<body>
<h1>测试请求参数</h1>
<a th:href="@{/testParam(username='admin',password=123456)}">测试使用控制器的形参获取请求参数</a>
</body>
</html>

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

字符串数组：

package com.qcby.mvc.controller;import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;import javax.servlet.http.HttpServletRequest;@Controller
public class ParamController {@RequestMapping("/testParam")public String testParam(String username,String password,String[] hobby){System.out.println("username："+username+"，password："+password+"，hobby："+ Arrays.toString(hobby));return "success";}
}

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head><meta charset="UTF-8"><title>测试请求参数</title>
</head>
<body>
<h1>测试请求参数</h1>
<form th:action="@{/testParam}" method="post">用户名：<input type="text" name="username"><br>密码：<input type="password" name="password"><br>爱好：<input type="checkbox" name="hobby" value="a">a<input type="checkbox" name="hobby" value="b">b<input type="checkbox" name="hobby" value="c">c<br><input type="submit" value="测试使用控制器的形参获取请求参数">
</form>
</body>
</html>

字符串：

package com.qcby.mvc.controller;import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;import javax.servlet.http.HttpServletRequest;@Controller
public class ParamController {@RequestMapping("/testParam")public String testParam(String username,String password,String hobby){System.out.println("username："+username+"，password："+password+"，hobby："+hobby);return "success";}
}

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head><meta charset="UTF-8"><title>测试请求参数</title>
</head>
<body>
<h1>测试请求参数</h1>
<form th:action="@{/testParam}" method="post">用户名：<input type="text" name="username"><br>密码：<input type="password" name="password"><br>爱好：<input type="checkbox" name="hobby" value="a">a<input type="checkbox" name="hobby" value="b">b<input type="checkbox" name="hobby" value="c">c<br><input type="submit" value="测试使用控制器的形参获取请求参数">
</form>
</body>
</html>

@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

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head><meta charset="UTF-8"><title>测试请求参数</title>
</head>
<body>
<h1>测试请求参数</h1>
<form th:action="@{/testParam}" method="post">用户名：<input type="text" name="user_name"><br>密码：<input type="password" name="password"><br>爱好：<input type="checkbox" name="hobby" value="a">a<input type="checkbox" name="hobby" value="b">b<input type="checkbox" name="hobby" value="c">c<br><input type="submit" value="测试使用控制器的形参获取请求参数">
</form>
</body>
</html>

package com.qcby.mvc.controller;import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;import javax.servlet.http.HttpServletRequest;
import java.util.Arrays;@Controller
public class ParamController {@RequestMapping("/testParam")public String testParam(@RequestParam("user_name") String username, String password, String[] hobby){System.out.println("username："+username+"，password："+password+"，hobby："+ Arrays.toString(hobby));return "success";}
}

@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

package com.qcby.mvc.controller;import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestHeader;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;import javax.servlet.http.HttpServletRequest;
import java.util.Arrays;@Controller
public class ParamController {@RequestMapping("/testParam")public String testParam(@RequestParam("user_name") String username, String password, String[] hobby,@RequestHeader("Host") String host){System.out.println("username："+username+"，password："+password+"，hobby："+ Arrays.toString(hobby));System.out.println("host:"+host);return "success";}
}

@CookieValue

@CookieValue是将cookie数据和控制器方法的形参创建映射关系

@CookieValue注解一共有三个属性：value、required、defaultValue，用法同@RequestParam

创建session：

package com.qcby.mvc.controller;import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.CookieValue;
import org.springframework.web.bind.annotation.RequestHeader;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import java.util.Arrays;@Controller
public class ParamController {@RequestMapping("/testServletAPI")//形参位置的request表示当前请求public String testServletAPI(HttpServletRequest request){HttpSession session = request.getSession();String username = request.getParameter("username");String password = request.getParameter("password");System.out.println("username："+username+"，password："+password);return "success";}@RequestMapping("/testParam")public String testParam(@RequestParam("user_name") String username, String password, String[] hobby,@RequestHeader("Host") String host,@CookieValue("JSESSIONID") String JSESSIONID){System.out.println("username："+username+"，password："+password+"，hobby："+ Arrays.toString(hobby));System.out.println("host:"+host);System.out.println("JSESSIONID:"+JSESSIONID);return "success";}
}

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

package com.qcby.mvc.bean;public class User {private Integer id;private String username;private String password;private Integer age;private String sex;private String email;public User() {}public User(Integer id, String username, String password, Integer age, String sex, String email) {this.id = id;this.username = username;this.password = password;this.age = age;this.sex = sex;this.email = email;}public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}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 Integer getAge() {return age;}public void setAge(Integer age) {this.age = age;}public String getSex() {return sex;}public void setSex(String sex) {this.sex = sex;}public String getEmail() {return email;}public void setEmail(String email) {this.email = email;}@Overridepublic String toString() {return "User{" +"id=" + id +", username='" + username + '\'' +", password='" + password + '\'' +", age=" + age +", sex='" + sex + '\'' +", email='" + email + '\'' +'}';}
}

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head><meta charset="UTF-8"><title>测试请求参数</title>
</head>
<body>
<h1>测试请求参数</h1>
<form th:action="@{/testpojo}" 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="使用实体类接收请求参数">
</form>
</body>
</html>

package com.qcby.mvc.controller;import com.qcby.mvc.bean.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.CookieValue;
import org.springframework.web.bind.annotation.RequestHeader;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import java.util.Arrays;@Controller
public class ParamController {@RequestMapping("/testpojo")public String testpojo(User user){System.out.println(user);return "success";}
}

解决获取请求参数的乱码问题

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

<!--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>forceResponseEncoding</param-name><param-value>true</param-value></init-param>
</filter>
<filter-mapping><filter-name>CharacterEncodingFilter</filter-name><url-pattern>/*</url-pattern>
</filter-mapping>

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