文件的上传

FileUploadServlet.java

package com.kaishengit.web;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
import java.util.UUID;

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

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

public class FileUploadServlet extends HttpServlet {

  private static final long serialVersionUID = 1L;


	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		response.sendRedirect("upload.jsp");
		
	}
	
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		//服务器端存放文件的文件夹
		File uploadFile=new File("C:/upload");
		//服务器端存放临时文件的文件夹
		File tempFile=new File("C:/temp");
		if(!uploadFile.exists()){
			uploadFile.mkdir();
		}
		
		if(!tempFile.exists()){
			tempFile.mkdir();
		}
		
		//ServletFileUpload.isMultipartContent(request)用来判断是否设置form表单的enctype属性(enctype="multipart/form-data")
		if(ServletFileUpload.isMultipartContent(request)){
			DiskFileItemFactory factory=new DiskFileItemFactory();
			//设置缓冲区
			factory.setSizeThreshold(1024*1024);
			//设置临时文件目录
			factory.setRepository(tempFile);
			
			ServletFileUpload servletFileUpload=new ServletFileUpload(factory);
			//设置最大上传文件体积
			servletFileUpload.setSizeMax(1024*1024*10);
			
			try {
				@SuppressWarnings("unchecked")
				//获得所有表单元素
				List<FileItem> itemList=servletFileUpload.parseRequest(request);
				for(FileItem item:itemList){
					//判断是不是一个普通的表单元素
					if(!item.isFormField()){
						//获取原始文件名
						String fileName=item.getName();
						//获取文件的类型
						//String typeName=item.getContentType();
						//获取文件的后缀名
						String extName=fileName.substring(fileName.lastIndexOf("."));
						//给上传的文件随机生成一个文件名
						fileName=UUID.randomUUID().toString()+extName;
						
						InputStream inputStream=item.getInputStream();
						BufferedInputStream bis=new BufferedInputStream(inputStream);
						BufferedOutputStream bos=new BufferedOutputStream(new FileOutputStream(new File(uploadFile, fileName)));
						byte[] buffer=new byte[4096];
						int len=-1;
						while((len=bis.read(buffer))!=-1){
							bos.write(buffer, 0, len);
						}
						bos.flush();
						bos.close();
						bis.close();
					}else{
						//获取普通表单的内容
						String desc=item.getString("UTF-8");
						System.out.println(desc);
					}
				}
				
			} catch (FileUploadException e) {
				throw new RuntimeException("请设置form表单的enctype属性");
			}
		}
	}

	

}