二十一、MVC的WEB框架（Spring MVC）

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}"/>