Spring实现文件上传(示例代码)

在实际开发中，经常遇到要实现文件上传到服务器端的功能。Spring可以继承commons-fileupload插件来实现文件上传的功能。分为前端JSP编写和后台Controller的编写。

前期准备工作，首先要引入commons-fileupload这个jar包，pom.xml中的配置如下：


代码如下:

<!-- 实现文件上传，spring集成了这个功能 -->
<dependency>
 <groupId>commons-fileupload</groupId>
 <artifactId>commons-fileupload</artifactId>
 <version>1.2.2</version>
</dependency>

然后配置拦截器，在dispatcher-servlet.xml中添加


代码如下:

<!-- 实现文件上传，这样一旦某个Request是一个MultipartRequest，它就会首先被MultipartResolver处理，然后再转发相应的Controller -->
<bean id="multipartResolver"
 class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
 <!-- 设置上传文件的最大尺寸为1MB -->
 <property name="maxUploadSize">
  <value>1048576</value>
 </property>
</bean>

直接上代码：

1、前端JSP编写

upload.jsp


代码如下:

<%@ page language="java" pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
 <head>
  <script src="resources/js/jquery.js"></script>
 </head>
 <body>
  <form method="post" action="upload.do" enctype="multipart/form-data">
   <input type="file" name="file" />
   <input type="submit" />
  </form>
 </body>
</html>

2、后台UploadController编写


代码如下:

package nju.software.xkxt.web.controller;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.multipart.MultipartHttpServletRequest;

/**
 * @author typ
 *
 */
@Controller
public class UploadController {

/**
  * 进入下载界面
  *
  * @param request
  * @param response
  * @param model
  * @return
  * @throws IOException
  */
 @RequestMapping(value = "upload_enter.do", method = RequestMethod.GET)
 public String enter(HttpServletRequest request,
   HttpServletResponse response, ModelMap model) throws IOException {
  // 进入下载界面
  return "upload";

}

/**
  * 具体的实现下载功能
  *
  * @param request
  * @param response
  * @param model
  * @throws IOException
  */
 @RequestMapping(value = "upload.do", method = RequestMethod.POST)
 public void upload(HttpServletRequest request,
   HttpServletResponse response, ModelMap model) throws IOException {
  MultipartHttpServletRequest multipartRequest = (MultipartHttpServletRequest) request;
  // 得到上传的文件
  MultipartFile mFile = multipartRequest.getFile("file");
  // 得到上传服务器的路径
  String path = request.getSession().getServletContext()
    .getRealPath("/WEB-INF/upload/");
  // 得到上传的文件的文件名
  String filename = mFile.getOriginalFilename();
  InputStream inputStream = mFile.getInputStream();
  byte[] b = new byte[1048576];
  int length = inputStream.read(b);
  path += "\\" + filename;
  // 文件流写到服务器端
  FileOutputStream outputStream = new FileOutputStream(path);
  outputStream.write(b, 0, length);
  inputStream.close();
  outputStream.close();
 }
}

这样就很容易的实现了文件上传的功能。