利用MultipartFile实现文件上传功能

在java中上传文件似乎总有点麻烦，没.net那么简单，记得最开始的时候用smartUpload实现文件上传，最近在工作中使用spring的MultipartFile实现文件上传，感觉挺简单，在这里和大家分享一下。

一.主要有两个java类,和一般的servlet放在一起即可.

1.FileUploadBean.java

package chb.demo.web;

import org.springframework.web.multipart.MultipartFile;


public class FileUploadBean {

  private MultipartFile file;

  public void setFile(MultipartFile file) {
    this.file = file;
  }

  public MultipartFile getFile() {
    return file;
  }
}

2.FileUploadController.java

package chb.demo.web;

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.validation.BindException;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.SimpleFormController;



public class FileUploadController extends SimpleFormController {
    
  protected ModelAndView onSubmit(
    HttpServletRequest request,
    HttpServletResponse response,
    Object command,
    BindException errors){
    
    try
    {
      // cast the bean
      FileUploadBean bean = (FileUploadBean) command;

      // let's see if there's content there
      MultipartFile file = bean.getFile();
  
      if (file == null) {
 throw new Exception("上传失败：文件为�空");  
      }
      if(file.getSize()>10000000)    
      {
 throw new Exception("上传失败：文件大小不能超过10M");      
      }
      //得到文件�名
      String filename=file.getOriginalFilename();    
      
      if(file.getSize()>0){ 
 try {
   SaveFileFromInputStream(file.getInputStream(),"D:/",filename);
 } catch (IOException e) {
   System.out.println(e.getMessage());
   return null;
 }
      }
      else{
 throw new Exception("上传失败：上传文件不能为�空");
      }
      // well, let's do nothing with the bean for now and return:
      try {
 return super.onSubmit(request, response, command, errors);
 
      } catch (Exception e) {
 System.out.println(e.getMessage());
 return null;
      }
    }
    catch(Exception ex)
    {
      System.out.println(ex.getMessage());
      return null;
    }
  }  
  
  
  public void SaveFileFromInputStream(InputStream stream,String path,String filename) throws IOException
  {   
    FileOutputStream fs=new FileOutputStream( path + "/"+ filename);
    byte[] buffer =new byte[1024*1024];
    int bytesum = 0;
    int byteread = 0; 
    while ((byteread=stream.read(buffer))!=-1)
    {
      bytesum+=byteread;
      fs.write(buffer,0,byteread);
      fs.flush();
    } 
    fs.close();
    stream.close();   
  }    
}

二.配置文件中如下配置:

1.web.xml,利用spring mvc模式,大家应该都很熟悉了

  
    chb
    org.springframework.web.servlet.DispatcherServlet
    1
  

  
    chb
    *.do
  

2.chb-servlet.xml,这里要配置映射,并可以设定最大可上传文件的大小

  
  
    
      action
    
    
      index
    
  
  
  
    
    
  
  

  
    
     
      fileUploadController
     
    
  
  
  
    
    
    
    
     
  

三.设定jsp页面

ok,现在就可以上传文件了,挺简单吧?这里我只列出了基本步骤,至于具体的操作(比如中文问题)可能就需要大家自己再完善完善了.

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持考高分网。