二十一、MVC的WEB框架（Spring MVC）

2022-05-24 01:50:42

一、基于注解方式配置

1、首先是修改IndexContoller控制器类

　　1.1、在类前面加上@Controller：表示这个类是一个控制器

　　1.2、在方法handleRequest前面加上@RequestMapping("/index")：表示路径/index会用射到该方法

　　1.3、不能让IndexController在实现Controller接口

IndexControlller.java具体实现如下：

package com.demo.controller;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequsetMapping;

import org.springframework.web.servlet.ModelAndView;

@Controller

public class IndexController{

    @RequestMapping("/index")

    public ModelAndView handleRequest(HttpServletRequest request,HttpServletResponse response) throws Exception{

        ModelAndView mav=new ModelAndView("index");

        mav.addObject("name","I love you");

        return mav;

    }

}

2、修改配置文件springmvc-servlet.xml

由于我们使用了注解方式实现，所以把之前的配置可以去掉，增加如下代码：

<!--表示从包controller下扫描所有注解@Controller的类-->

<context component-scan base-package="controller"/>

具体配置如下：

<?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-3.0.xsd

    http://www.springframework.org/schema/context

    http://www.springframework.org/schema/context/spring-context-3.0.xsd">

    <!--扫描包下面有注解@Controller的所有的类-->

    <context:component-scan base-package="controller" />

    <bean id="irViewResolver"

        class="org.springframework.web.servlet.view.InternalResourceViewResolver">

        <property name="prefix" value="/WEB-INF/page/" />

        <property name="suffix" value=".jsp" />

    </bean>

<!--注释掉之前基于xml方式的bean的配置-->

<!--     <bean id="simpleUrlHandlerMapping" -->

<!--         class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping"> -->

<!--         <property name="mappings"> -->

<!--             <props> -->

<!--                 <prop key="/index">indexController</prop> -->

<!--             </props> -->

<!--         </property> -->

<!--     </bean> -->

<!--     <bean id="indexController" class="controller.IndexController"></bean> -->

</beans>

二、Session的应用

Session在用户登录，一些特殊场合在页面间传递数据的时候会经常用到；

1、修改IndexController控制器类

为方法提供参数HttpSession session，这样可以在方法中使用session。新增一个check方法。

package com.demo.controller;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequsetMapping;

import org.springframework.web.servlet.ModelAndView;

@Controller

public class IndexController{

    @RequestMapping("/index")

    public ModelAndView handleRequest(HttpServletRequest request,HttpServletResponse response) throws Exception{

        ModelAndView mav=new ModelAndView("index");

        mav.addObject("name","I love you");

        return mav;

    }

    @RequestMapping("/check")

    publc ModelAndView check(HttpSession session){

        Integer i=(Integer)session.getAttribute("count");

        if(i==null){

            i=0;

        }

        else{

            i++

        }

        session.setAttribute("count",i);

        ModelAndView mav=new ModelAndView("check");

        return mav;

    }

}

2、新建一个check.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" isElIgnored="false"%>

session中记录的访问次数：${count}

三、SpringMVC的中文问题

在Spring MVC中处理中文问题和Filter处理中文问题是一样的。都是通过修改web.xml配置文件。

1、修改web.xml配置文件

<!--新增一个filter配置解决中文问题-->

<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>

</filter>

<!--指定映射-->

<filter-mapping>

    <filter-name>CharacterEncodingFilter</filter-name>

    <url-pattern>/*</url-pattern>

</filter-mapping>

具体配置web.xml如下：

<?xml version="1.0" encoding="UTF-8"?>

<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee"

    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee

http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">

    <servlet>

        <servlet-name>springmvc</servlet-name>

        <servlet-class>

            org.springframework.web.servlet.DispatcherServlet

        </servlet-class>

        <load-on-startup>1</load-on-startup>

    </servlet>

    <servlet-mapping>

        <servlet-name>springmvc</servlet-name>

        <url-pattern>/</url-pattern>

    </servlet-mapping>

    <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>

    </filter>

    <filter-mapping>

        <filter-name>CharacterEncodingFilter</filter-name>

        <url-pattern>/*</url-pattern>

    </filter-mapping>

</web-app>

2、jsp页面也要使用相同对应的编码方式

新增一个addProduct.jsp，设置字符集为UTF-8

<%@ page language="java" contentType="text/html; charset=UTF-8"

    pageEncoding="UTF-8" import="java.util.*" isELIgnored="false"%>

<form action="addProduct" method="post">

    产品名称 ：<input type="text" name="name" value=""><br />

    产品价格： <input type="text" name="price" value=""><br />

    <input type="submit" value="增加商品">

</form>

四、上传文件功能解决

修改web.xml配置文件，允许访问*.jpg等文件

1、在web.xml中新增一段

<!--表示允许访问jpg文件-->
<servlet-mapping>

    <servlet-name>default</servlet-name>

    <url-pattern>*.jpg</url-pattern>

</servlet-mapping>

<?xml version="1.0" encoding="UTF-8"?>

<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee"

    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee

http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">

        <!--因为配置springmvc的servlet使用的路径是"/"，导致静态资源无法访问，所以加上这一段，才能允许访问-->

    <servlet-mapping>

        <servlet-name>default</servlet-name>

        <url-pattern>*.jpg</url-pattern>

    </servlet-mapping>

    <servlet>

        <servlet-name>springmvc</servlet-name>

        <servlet-class>

            org.springframework.web.servlet.DispatcherServlet

        </servlet-class>

        <load-on-startup>1</load-on-startup>

    </servlet>

    <servlet-mapping>

        <servlet-name>springmvc</servlet-name>

        <url-pattern>/</url-pattern>

                <!--<url-pattern>/*.do</url-pattern>加上这个，可以不用配置，允许所有的 -->

    </servlet-mapping>

    <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>

    </filter>

    <filter-mapping>

        <filter-name>CharacterEncodingFilter</filter-name>

        <url-pattern>/*</url-pattern>

    </filter-mapping>

</web-app>

2、配置springmvc-servlet.xml

新增一段配置：

<bean id="multipartRevoler" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">

<?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-3.0.xsd

    http://www.springframework.org/schema/context

    http://www.springframework.org/schema/context/spring-context-3.0.xsd">

    <context:component-scan base-package="controller" />

    <bean id="irViewResolver"

        class="org.springframework.web.servlet.view.InternalResourceViewResolver">

        <property name="prefix" value="/WEB-INF/page/" />

        <property name="suffix" value=".jsp" />

    </bean>

    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"/>

</beans>

3、准备上传文件的jsp

新增一个upload.jsp文件

<%@ page language="java" contentType="text/html;charset=UTF-8" pageEncoding="UTF-8" import="java.util.*" isElIgnored="false" %>

<form action="uploadImage" method="post" enctype="multipart/form-data">

    选择图片：<input type="file" name="image" accept="image/*"/><br/>

    上传文件：<input type="submit" value="上传"/>

</form>

4、准备UploadedImageFile的实体类

package com.demo.pojo;

import org.springframework.web.multipart.MultipartFile;

publc class UploadedImageFile{

    MultipartFile image;//封装MultipartImage类型的属性image，用于接受页面的注入

    //image与jsp里的input的name属性值保持相同。

    public MultipartFile getImage(){

        return image;

    }

    public void setImge(MultipartFile image){

        this.image=image;

    }

}

5、上传控制器UploadController

新建一个控制器类

package com.demo.controller;

import java.io.File;

import java.io.IOException;

import javax.servlet.http.HttpServletRequest;

import org.apache.commons.lang.xwork.RandomStringUtils;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequsetMapping;

import org.springframework.web.servlet.ModelAndView;

import com.demo.pojo.UploadedImageFile;

@Controller

public class IndexController{

    @RequestMapping("/uploadImage")

    public ModelAndView upload(HttpServletRequest request,UploadedImageFile file) throws IOException,IllegalStateException{

        String name=RandomStringUtils.randomAlphanumeric(10);

        String newFileName=name+".jpg";

        File newFile=new File(request.getServletContext().getRealPath("/image"),newFileName);

        newFile.getParentFile().mkdirs();

        file.getImage().transferTo(newFile);

        ModelAndView mav=new ModelAndView("showUploadedFile");

        mav.addObject("imageName",newFileName);

        return mav;

    }

}

6、准备showUploaddFile.jsp显示图片的页面

<%@ page language="java" contentType="text/html;charset=UTF-8" pageEncoding="UTF-8" import="java.util.*" isElIgnored="false" %>

<img src="data:image/${imageName}"/>

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