SpringMVC获取前端数据的四种方法

在获取数据之前先说下注解，注解的功能大家都知道，不再多说，这里说下如何使用

 首先，我们需要在springmvc-servlet.xml文件中添加

<!--开启注解扫描功能-->
    <mvc:annotation-driven/>
    <!--定义注解扫描的包-->
    <context:component-scan base-package="com.jie.controller"/>

下面介绍获取前端数据的几种方法

1.req.getParameter()

这个和servlet中的使用一样

@RequestMapping("/login")
    public ModelAndView login(HttpServletRequest req, HttpServletResponse resp){
        String userName=req.getParameter("n");
        String userPwd=req.getParameter("p");
        UserService service=new UserService();
        boolean r=service.isLogin(userName,userPwd);
        ModelAndView mv=null;
        if (r) {
            System.out.println("登录成功！");
            mv=new ModelAndView("list");
            mv.addObject("msg","登录成功");
        }else {
            System.out.println("登录失败！");
            mv=new ModelAndView("index");
            mv.addObject("msg","登录失败");
        }
        return mv;
}

service类

package com.jie.service;

public class UserService {

    //登录
    public boolean isLogin(String userName,String userPwd){
        if (userName.equals("jie")&&userPwd.equals("123123"))
            return true;
        return false;
    }
}

user类

package com.jie.dao;

public class User {
    private int userId;
    private String userName;
    private String userPwd;

    public String getUserName() {
        return userName;
    }

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

    public String getUserPwd() {
        return userPwd;
    }

    public void setUserPwd(String userPwd) {
        this.userPwd = userPwd;
    }

    public int getUserId() {
        return userId;
    }

    public void setUserId(int userId) {
        this.userId = userId;
    }

    public User() {
    }

    public User(String userName, String userPwd) {
        this.userName = userName;
        this.userPwd = userPwd;
    }
}

前端的jsp页面直接使用el表达式接受数据就行，这里不再写

2.通过形参直接接收

 @RequestMapping("/login1")
    public ModelAndView login1(int userId,String userName,String userPwd){
        System.out.println(userId+"   "+userName+"  "+userPwd);
        return new ModelAndView("list");
    }

如果遇到前后端传值不同时使用@RequestParam()，例如：

 @RequestMapping("/login11")
    public ModelAndView login11(@RequestParam("id") int userId, String userName, String userPwd){
        System.out.println(userId+"   "+userName+"  "+userPwd);
        return new ModelAndView("list");
    }

3.通过对象接收

@RequestMapping("/login2")
    public ModelAndView login2(User user){
        ModelAndView mv=new ModelAndView("index");
        mv.addObject("user",user);
        return mv;
    }

4.地址栏传参 restful

@RequestMapping("/delete/{id}")
    public ModelAndView delete(@PathVariable("id") int userId){
        System.out.println(userId);
        return new ModelAndView("list");
    }

最后：解决中文乱码

在web.xml文件中配置过滤器

<!--filter过滤器  解决中文乱码问题-->
    <filter>
        <filter-name>characterEncoding</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>
    </filter>
    <filter-mapping>
        <filter-name>characterEncoding</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>