别忘記更換包名
注意需要下載下傳兩個包

apache官網下載下傳即可
java頁面
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();
}
//建立一個工廠 可以設定很多上傳檔案的限制内容
System.out.println(request.getServletContext().getRealPath("/WEB-INF/upload"));
DiskFileItemFactory factory = new DiskFileItemFactory();
factory.setSizeThreshold(100*1024);
factory.setRepository(file);
//建立req請求的解析器
ServletFileUpload sfu = new ServletFileUpload(factory);
//stu解析器 也可以設定很多上傳檔案的限制内容
sfu.setFileSizeMax(20*1024*1024);//上傳檔案大小
sfu.setHeaderEncoding("utf-8"); //上傳編碼
sfu.setSizeMax(40*1024*1024);//同時上傳檔案總大小的最大值
/*
* 上傳監聽器
*/
sfu.setProgressListener(new ProgressListener() {
@Override
public void update(long arg0, long arg1, int arg2) {
// TODO Auto-generated method stub
System.out.println("上傳檔案大小為:"+arg1+"已上傳檔案大小:"+arg0);
}
});
if(!ServletFileUpload.isMultipartContent(request)) {
System.out.println("無法上傳");
return ;
}
//解析器解析req請求 解析需要擷取異常
try {
List<FileItem> list=sfu.parseRequest(request);
for(FileItem fileItem:list) {
//fileItem表單項 普通/檔案域
//isFormField()判斷是不是普通表單項
if(fileItem.isFormField()) {
//正常
String name=fileItem.getFieldName();
String val=fileItem.getString();
}else {
//檔案
String filename = fileItem.getName();//擷取檔案的名稱
if(filename==null ||filename.trim().equals("")) {
System.out.println("沒有選擇檔案");
continue;
}
filename=filename.substring(filename.lastIndexOf("\\")+1);
// System.out.println("檔案名稱:"+filename);
String fileex= filename.substring(filename.lastIndexOf("."));//檔案字尾名
//System.out.println(fileex);
fileItem.getContentType();//擷取檔案的類型
fileItem.getSize();//擷取檔案大小
InputStream in=fileItem.getInputStream();//擷取檔案
String saveFileName=makeFileName(filename); //生成儲存檔案名
String realSavePath=makePath(saveFileName,path);//生成儲存路徑
//第一種
try {
fileItem.write(new File(realSavePath+"\\"+saveFileName));
// fileItem.delete();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
//第二種
/*
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) {
//
/* 生成新的檔案
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頁面
<%@ 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%>" target="_blank" rel="external nofollow" >
<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" target="_blank" rel="external nofollow" >
-->
</head>
<body>
<form action="Upload" method="post" enctype="multipart/form-data">
<input type="file" name="img">
<input type="submit" value="上傳">
</form>
</body>
</html>