a、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
@RequestMapping("servletApi")
public String servletApi(HttpServletRequest request){
String username = request.getParameter("username");
String password = request.getParameter("password");
System.out.println("username:" + username + ",password:" + password);
return "success";
}
b、通过控制器方法的形参获取
在控制器方法的形参位置,设置和请求参数同名的参数,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
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
@RequestMapping("testParam")
public String testParam(String username,String password,String hobby){ System.out.println("username:" + username + ", password:" + password + ", hobby:" + hobby); return "success";
}
**控制台打印结果**:username:admin, password:123456, hobby:a,b,c
c、@RequestParam注解
@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fefaultValue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,则注解所标识记的形参的值为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
@RequestMapping("testRequestParam")
public String testRequestParam(@RequestParam(value = "username",required = false,defaultValue = "guo") String username, @RequestParam("password") String password, String hobby){ System.out.println("username:" + username + ", password:" + password + ", hobby:" + hobby);
return "success";
}
d、@RequestHeader注解
@RequestHeader是将请求头信息和控制器方法的形参创建映射关系
@RequestHeader注解一共三个属性,用法同@RequestParam
@RequestMapping("testRequestParam")public String testRequestParam(@RequestParam(value = "username",required = false,defaultValue = "guo") String username,@RequestParam("password") String password, String hobby, @RequestHeader(value = "host",required = false,defaultValue = "localhost:8080") String host){
System.out.println("username:" + username + ", password:" + password + ", hobby:" + hobby);
System.out.println("host:" + host); return "success";
}
e、@CookieValue注解
@CookieValue是将cookie数据和控制器方法的形参创建映射关系
@CookieValue注解一共三个注解,用法同@RequestParam
@RequestMapping("testRequestParam")public String testRequestParam(@RequestParam(value = "username",required = false,defaultValue = "guo") String username,@RequestParam("password") String password, String hobby, @RequestHeader(value = "host",required = false,defaultValue = "localhost:8080") String host, @CookieValue("JSESSIONID") String JSESSIONID){ System.out.println("username:" + username + ", password:" + password + ", hobby:" + hobby); System.out.println("host:" + host); System.out.println("JSESSIONID:" + JSESSIONID);
return "success";
}
f、通过请求实体类POJO(不一定是对象实体类)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
@RequestMapping("testBean")
public String testBean(User user){
System.out.println("user:" + user.toString()); return "success";
}
**控制台输出结果**: user:User{id='null', username='admin', password='123456', sex='??·', age=23, email='2990373448.@qq.com'}
note 项目启动加载顺序 : 监听器 --> 过滤器 -- > servlet
g、CharacterEncodingFilter处理请求参数乱码问题( 针对post请求乱码 需要在web.xml配置过滤器 ;针对get请求乱码 需要在tomcat的server.xml配置文件中修改uriEncoding参数为utf-8)
@RequestMapping("testBean")
public String testBean(User user){
System.out.println("user:" + user.toString());
return "success";
}
**控制台输出结果**: user:User{id='null', username='张三', password='123456', sex='男', age=23, email='2'}
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0">
<!-- 配置编码过滤器,解决post请求乱码问题 -->
<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>
<!-- 配置HiddenHttpMethodFilter -->
<filter>
<filter-name>HiddenHttpMethodFilter</filter-name>
<filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>HiddenHttpMethodFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<!-- 配置Spring的前端控制器,对浏览器发送的请求统一进行处理-->
<servlet>
<servlet-name>SpringMvc</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<!-- 配置SpringMVC配置文件的位置和名称 -->
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:SpringMvc.xml</param-value>
</init-param>
<!-- 将前端控制器DispatcherServlet的初始化时间提前到服务器启动时 -->
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>SpringMvc</servlet-name>
<!-- 设置SpringMvc的核心控制器所能处理的请求的请求路径
/所匹配的请求可以使/login或.html或.js或.css方式的请求路径
但是/不能匹配.jsp请求路径的请求 但/*能匹配所有请求-->
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>