有关FileUpload组件的使用和调试的经验
类别: JAVA教程 
在通过使用FileUpload组件上传的过程中，通过自己的调试，总结如下：1）使用之前的准备，我用的是commons-fileupload-1.1-dev.jar和commons-io-1.1-dev.jar。 解释一下：尽管有的资料解释是commons-fileupload-1.0-beta.jar和commons-beanutils.jar，通过调试的结果 显示并不是需要commons-beanutils.jar文件，而是由于在parseRequest(request)的类有关继承于DiskFileItem类。而他有private org.apache.commons.io.output.DeferredFileOutputStream dfos。这样的就必须使用到commons-io-1.1-dev.jar。因此需要导入该包。否则就出classNotFound：.DeferredFileOutputStream的错误。
2）由于涉及文件，就涉及到文件系统。然而在java或应用服务器中对于文件系统的访问，就有一定的安全策略。 需要将下列权限添加到您应用程序服务器的安全策略文件中：permission java.io.FilePermission "<<ALL FILES>>", "read,write,delete";具体是添加到../bea/weblogic81 erver/lib/weblogic.policy中的.否则会可能出如下异常错误： org.apache.commons.fileupload.FileUploadException:java.lang.reflect.InvocationTargetExceptionatorg.apache.commons.fileupload.FileUpload.createItem(FileUpload.java:615)atorg.apache.commons.fileupload.FileUpload.parseRequest(FileUpload.java:474)atorg.apache.commons.fileupload.FileUpload.parseRequest(FileUpload.java:355)....
3）对于不同的服务器，在调试的过程中会出各种不一样的结果。这个与具体的服务器有关。
4）由于FileUpload在不断的更新版本，它的很多方法已经不推荐使用了（这与该组件的不断的改进有关）。通过对最新的帮助文档和网上的资料写了一个标准的程序如下：fileUpload文件：import java.io.IOException;import java.io.PrintWriter;
import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;
import org.apache.commons.fileupload.*;import java.util.*;import java.util.regex.*;import java.io.*;import org.apache.commons.fileupload.servlet.*;import org.apache.commons.fileupload.disk.DiskFileItemFactory;
/* * 创建日期 2005-4-10 * * TODO 要更改此生成的文件的模板，请转至 * 窗口 － 首选项 － Java － 代码样式 － 代码模板 */
/** * @author gaolong1 * * TODO 要更改此生成的类型注释的模板，请转至 * 窗口 － 首选项 － Java － 代码样式 － 代码模板 */public class FileUpload extends HttpServlet {
/** * Destruction of the servlet. <br> */ private String uploadPath = "D://addnetFile//"; // 用于存放上传文件的目录 private File tempPath =new File("D://addnetFile//tmp//"); // 用于存放临时文件的目录 public void destroy() { super.destroy(); // Just puts "destroy" string in log // Put your code here }
/** * The doPost method of the servlet. <br> * * This method is called when a form has its tag value method equals to post. * * @param request the request send by the client to the server * @param response the response send by the server to the client * @throws ServletException if an error occurred * @throws IOException if an error occurred */ public void doPost(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException{ res.setContentType( "text/html; charset=GB2312"); PrintWriter out=res.getWriter(); System.out.println(req.getContentLength()); System.out.println(req.getContentType()); DiskFileItemFactory factory = new DiskFileItemFactory(); // maximum size that will be stored in memory factory.setSizeThreshold(4096); // the location for saving data that is larger than getSizeThreshold() factory.setRepository(new File("d://File//addnetFile//temp"));
ServletFileUpload upload = new ServletFileUpload(factory); // maximum size before a FileUploadException will be thrown upload.setSizeMax(1000000); try{ List fileItems = upload.parseRequest(req); // assume we know there are two files. The first file is a small // text file, the second is unknown and is written to a file on // the server Iterator iter = fileItems.iterator();
// 正则匹配，过滤路径取文件名 String regExp=".+////(.+)$";
// 过滤掉的文件类型 String[] errorType={".exe",".com",".cgi",".asp"}; Pattern p = Pattern.compile(regExp); while (iter.hasNext()) { FileItem item = (FileItem)iter.next(); //忽略其他不是文件域的所有表单信息 if (!item.isFormField()) { String name = item.getName(); long size = item.getSize(); if((name==null||name.equals("")) && size==0) continue; Matcher m = p.matcher(name); boolean result = m.find(); if (result){ for (int temp=0;temp<errorType.length;temp++){ if (m.group(1).endsWith(errorType[temp])){ throw new IOException(name+": wrong type"); } } try{
// 保存上传的文件到指定的目录
// 在下文中上传文件至数据库时，将对这里改写 item.write(new File("d://" + m.group(1)));
out.print(name+" "+size+"<br>"); } catch(Exception e){ out.println(e); }
} else { throw new IOException("fail to upload"); } } } } catch (IOException e){ out.println(e); } catch (FileUploadException e){ out.println(e); }
// 保存上传的文件到指定的目录
// 在下文中上传文件至数据库时，将对这里改写
}
/** * Initialization of the servlet. <br> * * @throws ServletException if an error occure */ public void init() throws ServletException { // Put your code here }
}对应的请求文件：
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html> <head> <title>index.html</title>
<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="./servlet/FileUpload" method="post" enctype="multipart/form-data" name="form1"> <input type="file" name="file"> <input type="submit" name="Submit" value="upload"></form> <form action="./servlet/HelloWord" method="post"> <input type="submit"/> </form> <form name="uploadform" method="POST" action="./servlet/FileUpload" ENCTYPE="multipart/form-data">
<table border="1" width="450" cellpadding="4" cellspacing="2" bordercolor="#9BD7FF">
<tr><td width="100%" colspan="2">
文件1：<input name="x" size="40" type="file">
</td></tr>
<tr><td width="100%" colspan="2">
文件2：<input name="y" size="40" type="file">
</td></tr>
<tr><td width="100%" colspan="2">
文件3：<input name="z" size="40" type="file">
</td></tr>
</table>
<br/><br/>
<table>
<tr><td align="center"><input name="upload" type="submit" value="开始上传"/></td></tr>
</table>
</form>
</body></html>注：该代码由部分来自网上！
