Flex+JavaServlet处理文件上传.doc

flex中的请求交由服务器中的servlet处理，在提交的URL中需要包括servlet名，然后在服务器中的web.xml中配置对该URL的mapping。java上传文件程序步骤：首先对request和response设置编码格式，以免产生中文乱码，特别是request，一旦有乱码，后台根本就识别不了了，更别说处理。创建一个工厂对象（DiskFileItemFactory类），用于对磁盘的写入。再根据这个工厂对象创建一个上传对象。该上传对象会根据request来解析文件，生成一个List，在就是对该List进行循环处理，通过List中对象的write方法将数据写入磁盘。操作结束。/ Check that we have a file upload request 判断是否是文件上传请求boolean isMultipart = ServletFileUpload.isMultipartContent(request);The simplest usage scenario of uploading is the following:1. Uploaded items should be retained in memory as long as they are reasonably small.2. Larger items should be written to a temporary file on disk.3. Very large upload requests should not be permitted.4. The built-in defaults for the maximum size of an item to be retained in memory, the maximum permitted size of an upload request, and the location of temporary files are acceptable.Flex负责前台界面，Java则负责前台传递过来的请求（即文件上传请求）。这里只是一个简单的例子，供大家入门用哈。有关Flex和Java servlet方面的知识这里就不列出来了，没有整理，大家自己找资料吧。前提：要从网上下载这两个jar包，commons-fileupload-1.2.jar和commons-io-1.4.jar。然后在MyEclipse中配置Build Path，将这两个包包含进去。直接贴代码吧：Flex代码，upload.mxml:Java Servlet代码，FileUploaded.java：package fileupload;import java.io.File;import java.io.IOException;import java.io.PrintWriter;import java.util.Iterator;import java.util.List;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import mons.fileupload.FileItem;import mons.fileupload.FileUploadException;import mons.fileupload.disk.DiskFileItemFactory;import mons.fileupload.servlet.ServletFileUpload;/* * Processes requests for both HTTP GET and POST methods. * * * author huahua */public class FileUploaded extends HttpServlet private String uploadPath = E:; / 定义文件的上传路径private int MAXFILESIZE = 100 * 1024 * 1024; / 限制文件的上传大小public FileUploaded() super();public void destroy() super.destroy();/ 主处理protected void processRequest(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException System.out.println(Access !);request.setCharacterEncoding(utf-8);response.setContentType(text/html;charset=UTF-8);PrintWriter out = response.getWriter();/ 保存文件到服务器中 |Create a factory for disk-based file itemsDiskFileItemFactory factory = new DiskFileItemFactory();factory.setSizeThreshold(4096); / 超出这个大小放磁盘，否则放在内存中ServletFileUpload upload = new ServletFileUpload(factory); / Create a new file upload handlerupload.setSizeMax(MAXFILESIZE);try List fileItems = upload.parseRequest(request); / Parse the request,have a List of file items that you need to processIterator iter = fileItems.iterator();while (iter.hasNext() FileItem item = (FileItem) iter.next();/ 如果item.isFormField为true,则代表简单域，否则为file域。Field有2种，一种是简单域，一种是file域。if (!item.isFormField() / 获得文件名，包括文件的扩展名String name = item.getName();System.out.println(name);try / factory.setRepository(new File(path);可以设置临时目录item.write(new File(uploadPath + name); / 写入磁盘。 catch (Exception e) e.printStackTrace(); catch (FileUploadException e) e.printStackTrace();System.out.println(e.getMessage() + 结束);/* * Handles the HTTP GET method. * * param request * servlet请求 * param response * servlet响应 */ 如果是GET请求，则调用doGet方法。protected void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException processRequest(request, response);/* * Handles the HTTP POST method. * * param request * servlet请求 * param response * servlet响应 */ 如果是POST请求，则调用doPost方法protected void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException processRequest(request, response);/* * Returns a short description of the servlet. */public String getServletInfo() return ServletName: FileUploaded. extends: HttpServlet.;