SpringMVC - springmvc支持的默认参数类型 - 《SSM学习笔记》

springmvc默认的参数类型

1）HttpServletRequest
2）HttpServletResponse
3）HttpSession
4）Model
5）Map
6）ModelMap
以上是不需要创建即可用(注意:Map,Model,ModelMap和request都是使用请求作用域进行数据传递.所以服务器端的跳转必须是请求转发)

接上一个项目(请求转发)

<%--
  Created by IntelliJ IDEA.
  User: Administrator
  Date: 2022/4/26
  Time: 11:55
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
...
<a href="${pageContext.request.contextPath}/four">4.重定向</a>
<br><br><br>
<a href="${pageContext.request.contextPath}/data">访问服务器，进行数据携带跳转</a>
</body>
</html>

package com.chentianyu.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.util.Map;

@Controller
public class DataAction {
    @RequestMapping("/data")
    public String data(HttpServletRequest request,
                       HttpServletResponse response,
                       HttpSession session,
                       Model model,
                       Map map,
                       ModelMap modelMap){
        //做一个数据传到main.jsp页面上

        return "main";//请求转发方式跳转
    }
}

做一个实体类Users

package com.chentianyu.pojo;

public class Users {
    private String name;
    private int age;

    public Users() {
    }

    public Users(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

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

    @Override
    public String toString() {
        return "Users{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}

再来做DataAction.java

package com.chentianyu.controller;

import com.chentianyu.pojo.Users;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.util.Map;

@Controller
public class DataAction {
    @RequestMapping("/data")
    public String data(HttpServletRequest request,
                       HttpServletResponse response,
                       HttpSession session,
                       Model model,
                       Map map,
                       ModelMap modelMap){
        //做一个数据传到main.jsp页面上
        Users users = new Users("张三",22);
        //传递数据
        request.setAttribute("requestUserZS",users);
        session.setAttribute("sessionUserZS",users);
        model.addAttribute("modelUserZS",users);
        map.put("mapUserZS",users);
        modelMap.addAttribute("modelMapUserZS",users);
        return "main";//请求转发方式跳转
    }
}

取出数据

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
    <%--
    request.setAttribute("requestUserZS",users);
    session.setAttribute("sessionUserZS",users);
    model.addAttribute("modelUserZS",users);
    map.put("mapUserZS",users);
    modelMap.addAttribute("modelMapUserZS",users);
    --%>
    <p>main...</p>
    <p>requestUserZS:${requestUserZS}</p>
    <p>sessionUserZS:${sessionUserZS}</p>
    <p>modelUserZS:${modelUserZS}</p>
    <p>mapUserZS:${mapUserZS}</p>
    <p>modelMapUserZS:${modelMapUserZS}</p>
</body>
</html>

上面的方法是通过一个@RequestMapping()和去转发数据得到的，我们直接通过index.jsp页面去跳转main.jsp页面也是可以的:

<a href="${pageContext.request.contextPath}/data?name=zar">访问服务器，进行数据携带跳转2</a>

<p>从index.jsp页传来的数据${param.name}</p><%--param是${}里的内置对象--$>

完全可以取到

从index.jsp页传来的数据zar

有个坑，不是转发跳而是**重定向跳**

@RequestMapping("/data")
public String data(HttpServletRequest request,
                   HttpServletResponse response,
                   HttpSession session,
                   Model model,
                   Map map,
                   ModelMap modelMap){
    //做一个数据传到main.jsp页面上
    Users users = new Users("张三",22);
    //传递数据
    request.setAttribute("requestUserZS",users);
    session.setAttribute("sessionUserZS",users);
    model.addAttribute("modelUserZS",users);
    map.put("mapUserZS",users);
    modelMap.addAttribute("modelMapUserZS",users);
    //return "main";//请求转发方式跳转
    return "redirect:/admin/main.jsp";
}

main...

requestUserZS:

sessionUserZS:Users{name='张三', age=22}

modelUserZS:

mapUserZS:

modelMapUserZS:

从index.jsp页传来的数据

发现数据都跳丢了