SpringMVC实现上传和下载

package com.pk.web.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.multipart.MultipartHttpServletRequest;
import org.springframework.web.multipart.commons.CommonsMultipartResolver;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import java.io.*;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Iterator;

/**
 * Created by Administrator on 2014/9/5.
 */
@Controller
@RequestMapping("file")
public class UploadController {
	@RequestMapping("/upload.do")
	public String upload(HttpServletRequest request,HttpServletResponse response) throws IOException {
		CommonsMultipartResolver multipartResolver = new CommonsMultipartResolver(
				request.getSession().getServletContext());
		if (multipartResolver.isMultipart(request)) {
			MultipartHttpServletRequest multiRequest = (MultipartHttpServletRequest) request;

			Iterator<String> iter = multiRequest.getFileNames();
			while (iter.hasNext()) {
				MultipartFile file = multiRequest.getFile((String) iter.next());
				if (file != null) {
					String fileName = file.getOriginalFilename();

					String path1 = Thread.currentThread()
							.getContextClassLoader().getResource("").getPath()
							+ "download" + File.separator;

					//  下面的加的日期是为了防止上传的名字一样
					String path = path1
							+ new SimpleDateFormat("yyyyMMddHHmmss")
									.format(new Date()) + fileName;

					File localFile = new File(path);

					file.transferTo(localFile);
				}

			}

		}
		return "uploadSuccess";

	}
	@RequestMapping("/toUpload.do")
	public String toUpload() {
		return "upload";
	}

	@RequestMapping("/download")
	public void download(String fileName, HttpServletRequest request,HttpServletResponse response) {
		response.setCharacterEncoding("utf-8");
		response.setContentType("multipart/form-data");
		response.setHeader("Content-Disposition", "attachment;fileName="
				+ fileName);
		try {
			String path = Thread.currentThread().getContextClassLoader()
					.getResource("").getPath()
					+ "download";//这个download目录为啥建立在classes下的
			InputStream inputStream = new FileInputStream(new File(path
					+ File.separator + fileName));

			OutputStream os = response.getOutputStream();
			byte[] b = new byte[2048];
			int length;
			while ((length = inputStream.read(b)) > 0) {
				os.write(b, 0, length);
			}

			 // 这里主要关闭。
			os.close();

			inputStream.close();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
      
	}
}

    <!-- mvc注解驱动 -->

    <mvc:annotation-driven/>

    <!-- 扫描器已经有了上面这个mvc注解驱动的功能了，所有不需要了 -->

    <context:component-scan base-package="com.pk.web.controller" />

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

        <property name="defaultEncoding" value="utf-8" />

        <property name="maxUploadSize" value="104857600"/>

        <property name="maxInMemorySize" value="4096"/>

    </bean>

    <!-- 前缀+ viewName +后缀 -->

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

        <!-- webroot到某一指定的文件夹的路径 -->

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

      <!--  自己在你的 /WEB-INF/jsp下建立给jsp见面吧。或者该我上面的配置 -->

        <!-- 视图名称的后缀 -->

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

    </bean>

这里是html 点击下载

  <a href="file/download.do?fileName=map.txt">下载1 </a><br />

下面这里是上传代码

   <form action="file/upload.do" method="post" enctype="multipart/form-data">

            选择文件<input type="file" name="file">

            <input type="submit" value="上传">

        </form>

web.xml 配置文件

<servlet>

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

        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>

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

    </servlet>

    <filter>

        <filter-name>encodingFilter</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>

        <init-param>

            <param-name>forceEncoding</param-name>

            <param-value>true</param-value>

        </init-param>

    </filter>

    <filter-mapping>

        <filter-name>encodingFilter</filter-name>

        <url-pattern>/*</url-pattern>

    </filter-mapping>

    <servlet-mapping>

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

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

    </servlet-mapping>