SpringMVC 系列教程3-文件上传-CommonsMultipartResolver

CommonsMultipartResolverUploadController

package com.jege.spring.mvc;

import java.io.File;
import java.util.Iterator;

import javax.servlet.http.HttpServletRequest;

import org.springframework.stereotype.Controller;
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;
import org.springframework.web.multipart.commons.CommonsMultipartResolver;

@Controller
public class CommonsMultipartResolverUploadController{
  // http://localhost:8080/upload

  @RequestMapping(value = "/upload", method = RequestMethod.GET)
  public String uploadGet() {
    System.out.println("先以get的请求方式显示上传页面");
    return "upload";
  }

  int i = 0;// 简单改变上传文件的名字

  @RequestMapping(value = "/upload", method = RequestMethod.POST)
  public String uploadPost(HttpServletRequest request) throws Exception {
    System.out.println("在以post请求方式处理上传的请求");

    // 记录开始上传文件的时间
    long startTime = System.currentTimeMillis();

    String webapp = request.getServletContext().getRealPath("/upload");
    System.out.println("上传文件保存到服务器webapp的路径:" + webapp);

    // 存放文件的路径
    File deskFile = new File(webapp, "eclipse.zip");
    System.out.println("上传文件存放的最终路径：" + deskFile.getAbsolutePath());

    // 将当前上下文初始化给 CommonsMutipartResolver:配置上传文件解析器
    CommonsMultipartResolver multipartResolver = new CommonsMultipartResolver(request.getSession().getServletContext());
    // 检查form中是否有enctype="multipart/form-data"，便是是否有文件上传
    if (multipartResolver.isMultipart(request)) {
      // 将request变成多部件MultipartHttpServletRequest
      MultipartHttpServletRequest multiRequest = (MultipartHttpServletRequest) request;
      // 获取multiRequest 中全部的文件名
      Iterator<String> iter = multiRequest.getFileNames();
      // 遍历全部文件
      while (iter.hasNext()) {  
    MultipartFile file = multiRequest.getFile(iter.next());
    if (file != null) {// 处理上传
      file.transferTo(deskFile);
    }
      }
    }

    // 添加提示信息
    request.setAttribute("msg", "上传成功");

    // 记录结束上传文件的时间
    long endTime = System.currentTimeMillis();
    System.out.println("上传究竟用了多少时间：" + String.valueOf(endTime - startTime) + "ms");

    // 直接转发到upload.jsp
    return "upload";
  }

}

上传300MB文件耗时比较

• 使用CommonsMultipartResolver来保存上传的文件
  先以get的请求方式显示上传页面
  在以post请求方式处理上传的请求
  上传究竟用了多少时间：261ms
  第二次上传究竟用了多少时间：223ms
  第三次上传究竟用了多少时间：276ms

其余关联项目

• SpringMVC-文件上传-配置
  http://blog.csdn.net/je_ge/article/details/53725357
• SpringMVC-文件上传-MultipartFile
  http://blog.csdn.net/je_ge/article/details/53726147

源码地址

https://github.com/je-ge/spring

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