工具包：使用必須導入 commons-fileupload-1.2.1.jar 和 commons-io-1.4.jar（導入這個是因爲fileupload包依賴於它）
下載地址：http://download.csdn.net/detail/qqahanson/8260931
直接貼代碼了：
jsp頁面：
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<script type="text/javascript">
function add(){
var div = document.getElementById("addDiv");
div.innerHTML+="<div>上傳文件<input type='file' name='upload'/><input type='button' id='delbut' value='刪除' οnclick='del(this)' /><br></div>";
}
function del(obj){
//刪除這一行
var div = obj.parentNode;
div.parentNode.removeChild(div);
}
</script>
</head>
<body>
<form action="${pageContext.request.contextPath }/servlet/Update" method="post" enctype="multipart/form-data">
文件信息<input type="text" name="info"/>
<input type="button" id="but" value="加一個" οnclick="add()"/><br>
上傳文件<input type='file' name='upload'/><br>
<div id="addDiv"></div>
<input type="submit" value="上傳"/>
</form>
</body>
</html>處理上傳servlet
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.ProgressListener;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
public class Update extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//傳輸長度
int l = request.getIntHeader("Content-Length");
try {
String info = request.getParameter("info");
System.out.println(info);
// 創建工廠
DiskFileItemFactory factory = new DiskFileItemFactory();
//設置內存緩存上傳文件的大小 超出這個值就放入硬件緩存
factory.setSizeThreshold(1024 * 10);
//設置上傳文件在服務器緩存路徑
factory.setRepository(new File(this.getServletContext()
.getRealPath("/temp")));
final Long time = System.currentTimeMillis();
// 利用工廠創建上傳核心類
ServletFileUpload upload = new ServletFileUpload(factory);
//監聽器 可以用於做進度條等
upload.setProgressListener(new ProgressListener(){
//bytesRead：當前已經上傳完成的字節數
//contentLength：需要上傳的字節（總的字節數）
//items:當前上傳的內容在提交上來的表單中的位置，是第幾個
public void update(long bytesRead, long contentLength, int items) {
//
System.out.print("已經讀取到的字節數："+bytesRead+" 共有字節數："+contentLength+" 在表單中的位置："+items);
System.out.print(" 上傳進度"+(double)bytesRead/contentLength);
Long time2 = System.currentTimeMillis();
System.out.print(" 上傳速度爲(KB/s)"+bytesRead/(time2-time) );
System.out.print(" 大約剩餘時間："+(contentLength-bytesRead)/(bytesRead/(time2-time)));
System.out.println();
}
});
// upload.setFileSizeMax(1024*100);//單個上傳的最大值
// upload.setSizeMax(1024*1024);//總的最大值
//設置編碼 防止文件名亂碼
upload.setHeaderEncoding("utf-8");
// 利用核心類解析request
List<FileItem> list = upload.parseRequest(request);
if (upload.isMultipartContent(request)) {
// 遍歷集合，獲取所有的FIleItem
for (FileItem item : list) {
if (item.isFormField()) {// 如果當前的FileItem封裝到是一個普通的請求參數，則返回true
//獲取字段名
String name = item.getFieldName();
//取值
String value = item.getString("utf-8");
System.out.println(name + ":" + value);
} else {// 說明這個FileItem中保存是上傳的文件
String fileName = item.getName();// 獲取上傳文件的名稱
if(fileName == null ||fileName==""){
throw new RuntimeException("文件名不能爲空");
}
if(fileName.contains("\\")){
//fileName 獲得的是全文件名 包括路徑 應該只截取文件名字
fileName = fileName.substring(fileName.lastIndexOf("\\")+1);
}
InputStream in = item.getInputStream();// 獲取文件內容流
System.out.println("上傳文件：" + fileName);
//創建上傳目錄
String path = this.getServletContext().getRealPath(
"/update/"+request.getRemoteAddr());
new File(path).mkdirs();
//UUID.randomUUID() 生成唯一識別號 防止重複
FileOutputStream out = new FileOutputStream(path + "/"+ UUID.randomUUID().toString()+"_"+fileName);
// 將上傳的文件保存到指定位置
int i = 0;
while ((i = in.read()) != -1) {
out.write(i);
}
in.close();
out.close();
//刪除緩存文件
item.delete();
}
}
}else{
}
} catch (FileUploadException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}