SpringMVC入门
SpringMVC的介绍
(1)springmvc 是什么?
Spring mvc属于表现层的框架,它是Spring框架的一部分
(2)springmvc 有什么用?
》接收请求,获取参数
》处理参数
》将结果响应给浏览器 如 重定向或者请求转发或者返回json
springmvc就是对Servlet的封装
(3)springmvc 属于spring FrameWork的一部分,就是一个模块
SpringMVC与Servlet的区别
Servlet作用在web层
SpringMVC也作用在web层但是MVC使用Handler来处理参数,还有前端控制器DispatcherServlet,springmvc就是对Servlet的封装
准备工作
pom.xlm
<!-- 3 servlet-->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>2.5</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jsp-api</artifactId>
<version>2.0</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>jstl</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<!-- spring mvc是对servlet的封装-->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>5.2.9.RELEASE</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
创建假数据
person对象
Personutil调用penson对象
public class Personutil {
public static List<Person> findAll(){
List<Person> list = new ArrayList<>();
list.add(new Person(1, "jack", "123456", "北京"));
list.add(new Person(2, "rose", "123456", "合肥"));
return list;
}
}
web.xml
地址通过web.xml找到dispatch
<web-app>
<display-name>Archetype Created Web Application</display-name>
<servlet>
<servlet-name>DispatcherServlet</servlet-name>
<!-- 2.找到前端控制器-->
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<!-- 3.每个框架都有属于自己的控制文件-->
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:springmvc.xml</param-value>
</init-param>
<!-- 4.让前端控制器去读,正整数,值越小,优先级越高(不加也会读)-->
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>DispatcherServlet</servlet-name>
<!-- 1. xxx.action 转给当前servlet-->
<url-pattern>*.action</url-pattern>
</servlet-mapping>
</web-app>
springmvc.xml
通过springmvc.xml找到xxxController ,在通过@RequestMapping(“地址”),来找到地址
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
<!--进行包扫描,创建controller层的对象 只要是指定的包与子包下面有@Controller的类
都要被创建对象,且加入ioc容器中-->
<context:component-scan base-package="com.zx.controller"/>
</beans>
PersonController
ModelAndView是spring提供的类,可以添加数据还有视图
1.modelAndView.addObject(“list”,list);相当于请求转发中的request.setAttribute(“list”,list);
2.modelAndView.setViewName(“jsp/list.jsp”);相当于请求转发中的 request.getDispatcher(“list.jsp”).forward(req,resp);
3. return maodelAndView:相当于forward(req,resp), 前端控制器拿到list,并且发给页面
package com.zx.controller;
import com.zx.domain.Person;
import com.zx.util.Personutil;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;
import javax.xml.ws.RequestWrapper;
import java.util.List;
@Controller
public class PersonController {
@RequestMapping("list.action")
public ModelAndView listPersons(){
//获取集合
List<Person> list=Personutil.findAll();
//转发到页面
/* 请求转发
request.setAttribute("list",list);
request.getDispatcher("list.jsp").forward(req,resp);
但是没有必要可以使用下面的进行请求转发
*/
ModelAndView modelAndView=new ModelAndView();
modelAndView.addObject("list",list);
modelAndView.setViewName("jsp/list.jsp");
return modelAndView;
//在页面上进行forEach循环
}
}
list.jsp
<%--
Created by IntelliJ IDEA.
User: 25863
Date: 2020/10/14
Time: 15:32
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" isELIgnored="false" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<table border="1px" width="100%">
<tr>
<td>编号 </td>
<td>用户名 </td>
<td>密码 </td>
<td>城市 </td>
<td>操作 </td>
</tr>
<c:forEach items="${list}" var="item">
<tr>
<td>${item.id}</td>
<td>${item.name}</td>
<td>${item.password}</td>
<td>${item.city}</td>
<td><a href="#">修改</a> </td>
</tr>
</c:forEach>
</body>
</html>