java上传文件图片

别忘记更换包名
注意需要下载两个包

apache官网下载即可
java页面

package com.jdbc.servlet;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;
import java.util.UUID;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
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.ProgressListener;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

public class Upload extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public Upload() {
        super();
        // TODO Auto-generated constructor stub
    }

	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
	    doPost(request, response);
	}
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 
		  String path=request.getServletContext().getRealPath("/WEB-INF/upload");
		  String temp=request.getServletContext().getRealPath("/WEB-INF/temp");
		 File file = new File(temp);
		 if(!file.exists()) {
			 file.mkdirs();
		 }
	   //创建一个工厂  可以设置很多上传文件的限制内容
		System.out.println(request.getServletContext().getRealPath("/WEB-INF/upload"));
		DiskFileItemFactory factory = new DiskFileItemFactory();
		factory.setSizeThreshold(100*1024);
		factory.setRepository(file);
	  //创建req请求的解析器  
		ServletFileUpload sfu = new  ServletFileUpload(factory);
	  //stu解析器 也可以设置很多上传文件的限制内容
		sfu.setFileSizeMax(20*1024*1024);//上传文件大小
		sfu.setHeaderEncoding("utf-8");  //上传编码
		sfu.setSizeMax(40*1024*1024);//同时上传文件总大小的最大值
		/*
		 * 上传监听器
		 */
		sfu.setProgressListener(new ProgressListener() {
			
			@Override
			public void update(long arg0, long arg1, int arg2) {
				// TODO Auto-generated method stub
				System.out.println("上传文件大小为:"+arg1+"已上传文件大小:"+arg0);
			}
		});
		 if(!ServletFileUpload.isMultipartContent(request)) {
			 System.out.println("无法上传");
			 return ;
		 }
		//解析器解析req请求 解析需要获取异常
	   try {
		List<FileItem> list=sfu.parseRequest(request);
		for(FileItem fileItem:list) {
			//fileItem表单项  普通/文件域
			   //isFormField()判断是不是普通表单项
			 if(fileItem.isFormField()) {
				 //正常
			String	     name=fileItem.getFieldName();
			String	 val=fileItem.getString();
			 }else {
				 //文件
				String filename = fileItem.getName();//获取文件的名称
				 if(filename==null ||filename.trim().equals("")) {
					 System.out.println("没有选择文件");
					 continue;
				 }
				filename=filename.substring(filename.lastIndexOf("\\")+1);
		       // System.out.println("文件名称："+filename);
				String fileex= filename.substring(filename.lastIndexOf("."));//文件后缀名
				//System.out.println(fileex);
				 fileItem.getContentType();//获取文件的类型
				 fileItem.getSize();//获取文件大小
				 InputStream in=fileItem.getInputStream();//获取文件
			     String saveFileName=makeFileName(filename); //生成保存文件名
			     String realSavePath=makePath(saveFileName,path);//生成保存路径
			    //第一种
			     try {
					fileItem.write(new File(realSavePath+"\\"+saveFileName));
				//	fileItem.delete();
				} catch (Exception e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			     //第二种
			     /*
			     FileOutputStream out = new FileOutputStream(realSavePath+"\\"+saveFileName);
			     byte[] buffer = new byte[1024];
			     int len=0;
			     while((len=in.read(buffer))>0) {
			    	  out.write(buffer,0,len);
			     }
			     in.close();
			     out.close();
			     */
			 }
		}
	} catch (FileUploadException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	}
	}

	private String makePath(String saveFileName,String path) {
		//
	  /*   生成新的文件
		int hashCoad=saveFileName.hashCode();
		int dir1=hashCode()&0xf;
		int dir2=hashCode()&0xf >> 4;
		String dir=path+"\\"+dir1+"\\"+dir2;
		*/
		Date dt = new Date();   
	    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");   
	   String datepath=sdf.format(dt);
	   String dir=path+File.separator+datepath;
		File file=new File(dir);
		if(!file.exists()) {
			file.mkdirs();
		}
		return dir;
	}

	private String makeFileName(String filename) {
		// TODO Auto-generated method stub
		return UUID.randomUUID().toString()+"_"+filename;
	}

}

jsp页面

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP 'upload.jsp' starting page</title>
    
	<meta http-equiv="pragma" content="no-cache">
	<meta http-equiv="cache-control" content="no-cache">
	<meta http-equiv="expires" content="0">    
	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
	<meta http-equiv="description" content="This is my page">
	<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->

  </head>
  
  <body>
     <form action="Upload" method="post" enctype="multipart/form-data">
         <input type="file" name="img">
        <input type="submit" value="上传">
     </form>
  </body>
</html>