Spring mvc文件上传与下载

package cn.happyangel2008.controller;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.text.SimpleDateFormat;

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

import org.apache.commons.fileupload.FileUpload;
import org.apache.commons.io.FileUtils;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.servlet.ModelAndView;


@Controller
public class FileController {

/*
* SpringMVC中的文件上传
* @第一步：由于SpringMVC使用的是commons-fileupload实现，故将其组件引入项目中
* @这里用到的是commons-fileupload-1.2.1.jar和commons-io-1.3.2.jar
* @第二步：spring-mvx中配置MultipartResolver处理器。可在此加入对上传文件的属性限制
* <bean id="multipartResolver"
* class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
* <!-- 设置上传文件的最大尺寸为10MB -->
* <property name="maxUploadSize">
* <value>10000000</value>
* </property>
* </bean>
* 第三步：在Controller的方法中添加MultipartFile参数。该参数用于接收表单中file组件的内容
*第四步：编写前台表单。注意enctype="multipart/form-data"以及<input type="file" name="****"/>
* 如果是单个文件 直接使用MultipartFile 即可
*/

@RequestMapping("/upload.html")
public ModelAndView upload(String name,
//上传多个文件
@RequestParam("file") MultipartFile[] file,
HttpServletRequest request) throws IllegalStateException,
IOException {
System.out.println("222");
//获取文件 存储位置
String realPath = request.getSession().getServletContext()
.getRealPath("/uploadFile");

File pathFile = new File(realPath);
System.out.println("路径"+realPath);

if (!pathFile.exists()) {
//文件夹不存 创建文件
pathFile.mkdirs();
}
for (MultipartFile f : file) {

System.out.println("文件类型："+f.getContentType());
System.out.println("文件名称："+f.getOriginalFilename());
System.out.println("文件大小:"+f.getSize());
System.out.println(".................................................");
//将文件copy上传到服务器
f.transferTo(new File(realPath + "/" + f.getOriginalFilename()));
//FileUtils.copy
}
//获取modelandview对象
ModelAndView view = new ModelAndView();
view.setViewName("redirect:index.jsp");
return view;
}


@RequestMapping("/download.html")
public String 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 = request.getSession().getServletContext().getRealPath
("uploadFile")+File.separator;
InputStream inputStream = new FileInputStream(new File(path
+ 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();
}
// 返回值要注意，要不然就出现下面这句错误！
//java+getOutputStream() has already been called for this response
return null;
}

}