java采用Apache FileUpload组件实现上传

可见：FileItemSteam（servletFileUpload.getItemIterator(httpServletRequest)）速度要快于FileItem(servletFileUpload.parseRequest(request))速度。且一般情况下，FileItemSteam不产生临时文件：

package cn.itcast.servlet;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.Scanner;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.fileupload.FileItemIterator;
import org.apache.commons.fileupload.FileItemStream;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.io.FileUtils;
/**
 * FileItemStream示例
 * @author <a href="mailto:wj@itcast.cn">王健</a>
 * @version 1.0 2012-3-15
 */
public class Upload3Servlet extends HttpServlet {
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
long start = System.currentTimeMillis();
String path = getServletContext().getRealPath("/imgs");
DiskFileItemFactory factory = new DiskFileItemFactory();
factory.setSizeThreshold(1024 * 8);// 设置8k的缓存空间
factory.setRepository(new File("d:/a"));
ServletFileUpload upload = new ServletFileUpload(factory);
upload.setHeaderEncoding("UTF-8");// 设置文件名处理中文编码
try {
FileItemIterator fii = upload.getItemIterator(request);// 使用遍历类
while (fii.hasNext()) {
FileItemStream fis = fii.next();
if (fis.isFormField()) {//FileItemStream同样使用OpenStream获取普通表单的值
InputStreamReader in = new InputStreamReader(fis.openStream(),"UTF-8");
Scanner sc = new Scanner(in);
StringBuffer sb = new StringBuffer();
if(sc.hasNextLine()){
sb.append(sc.nextLine());
}
System.err.println("Desc:"+sb.toString());
} else {
String fileName = fis.getName();
fileName = fileName
.substring(fileName.lastIndexOf("\\") + 1);
System.err.println("文件名为：" + fileName);
InputStream in = fis.openStream();
FileUtils.copyInputStreamToFile(in, new File(path+"/"+fileName));
}
}
} catch (FileUploadException e) {
e.printStackTrace();
}
long end = System.currentTimeMillis();
System.err.println("用时:"+(end-start));
}
}

　　

转自：

Apache FileUpload详细介绍

http://www.open-open.com/lib/view/open1338108871261.html