Spring MVC上传文件

网页上传文件，首先需要了解MIME多媒体类型

http://www.w3school.com.cn/media/media_mimeref.asp

再看web.xml配置，巩固之前的知识

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
  <display-name>webtest</display-name>

  <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>
            /WEB-INF/config/applicationContext.xml
            /WEB-INF/config/codeifAction.xml
        </param-value>
    </context-param>

    <servlet>
        <servlet-name>dispatcherServlet</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>/WEB-INF/config/codeifAction.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <!-- 拦截所有以do结尾的请求 -->
    <servlet-mapping>
        <servlet-name>dispatcherServlet</servlet-name>
        <url-pattern>*.do</url-pattern>
    </servlet-mapping>

  <welcome-file-list>
    <welcome-file>index.do</welcome-file>
  </welcome-file-list>
</web-app>

接着是applicationContext.xml

<?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:p="http://www.springframework.org/schema/p"
    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"
    default-lazy-init="true">

    <!-- 启动Spring MVC的注解功能，完成请求和注解POJO的映射 -->
    <bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" lazy-init="false" />

    <!-- 另外最好还要加入DefaultAnnotationHandlerMapping，不然会被 XML或其它的映射覆盖！ -->
    <bean class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping" />

    <!-- 对模型视图名称的解析，即在模型视图名称添加前后缀 -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" p:prefix="/WEB-INF/jsp/" p:suffix=".jsp" />

    <!-- 支持上传文件 -->
    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"/>

</beans>

在spring中，文件被包装为multipart类型。

接着是controller

package com.codeif.action;

import java.io.File;
import java.util.Date;

import javax.servlet.http.HttpServletRequest;

import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.multipart.MultipartFile;

@Controller
public class UploadAction {

    @RequestMapping(value = "/upload.do")
    public String upload(@RequestParam(value = "file", required = false) MultipartFile file, HttpServletRequest request, ModelMap model) {

        System.out.println("开始");
        String path = request.getSession().getServletContext().getRealPath("upload");//获取网页根目录的upload目录的绝对路径
        String fileName = file.getOriginalFilename();  //从页面上传过来的文件名
//        String fileName = new Date().getTime()+".jpg";
        System.out.println(path);
        File targetFile = new File(path, fileName);
        if(!targetFile.exists()){
            targetFile.mkdirs();
        }

        //保存
        try {
            file.transferTo(targetFile);
        } catch (Exception e) {
            e.printStackTrace();
        }
        model.addAttribute("fileUrl", request.getContextPath()+"/upload/"+fileName);

        return "result";
    }

}

最后是网页表单类型：

<!DOCTYPE html>  
<html>  
<head>  
<meta charset="utf-8">  
<title>上传图片</title>  
</head>  
<body>  
<form action="upload.do" method="post" enctype="multipart/form-data">  
<input type="file" name="file" /> <input type="submit" value="Submit" /></form>  
</body>  
</html> 

注意这里的enctype="multipart/form-data"

这就是设置请求的mime的，默认为application/x-www-form-urlencoded，不能用于文件上传；只有使用了multipart/form-data，才能完整的传递文件数据，进行下面的操作.

这样就完成了文件上传

可用uploadify插件美化上传

注意，spring数据绑定中若出现了multipartFile，则不能绑定其他POJO对象，因为会在multipartFile中数据会干扰对象绑定，只能使用简单类型的数据。