FileUpload的使用案例

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1、www.apache.org下载commons fileupload 和 commons io

2、创建jsp并附上如下代码

<%@ page language="java" contentType="text/html; charset=GB18030"

    pageEncoding="GB18030"%>

<%

String strId = request.getParameter("id");

int id = 0;

if(strId == null && strId.trim().equals("")){

	out.println("你选择的商品有错！");

	return;

}

id = Integer.parseInt(strId);

%>

<!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="../FileUpload" method="post" enctype="multipart/form-data" name="form1">

   <input type="hidden" name="id" value="<%=id %>">

  <input type="file" name="file">

  <input type="submit" name="Submit" value="upload">

</form>

<br>

<br>

    <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>

3、直接在项目下创建servlet并附上如下代码

package com.cuijun.shopping.servlet;

import java.io.IOException;

import java.io.PrintWriter;

import javax.servlet.ServletConfig;

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;

public class FileUpload extends HttpServlet {

	String uploadPath = "";

    @Override

	public void init(ServletConfig config) throws ServletException {

    	uploadPath = config.getInitParameter("uploadPath");

	}

	int id = -1;

	public void destroy() {

		super.destroy(); // Just puts "destroy" string in log

		// Put your code here

	}

	public void doPost(HttpServletRequest req, HttpServletResponse res)

			throws ServletException, IOException {

		res.setContentType("text/html; charset=GB18030");

		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:\\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()){

					if(item.getFieldName().equals("id")){

						id = Integer.parseInt(item.getString());

					}

				}

				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)));

							item.write(new File(uploadPath + id + ".jpg"));

							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

	}

}

4、注意代码中的路径问题。千万小心。

	1、路径中\\代表\。不要写成//。

	2、路径后面不要忘记添加\\。

5、接受id。

	1、先定义int id = -1;

	2、判断接受的域是正常域if (item.isFormField()){

					if(item.getFieldName().equals("id")){

						id = Integer.parse(item.getString());

					}

				}

	3、把上传的文件写到内存item.write(new File(uploadPath + id + ".jpg"));

6、修改WEB-INF下的配置文件

	1、添加<init-param>

			<param-name>uploadPath</param-name>

			<param-value>D:\\web\\Shopping\\WebContent\\image\\product\\</param-value>

		</init-param>

	2、在servlet中重写init方法String uploadPath = "";

    @Override

	public void init(ServletConfig config) throws ServletException {

    	uploadPath = config.getInitParameter("uploadPath");

	}

7、Over！
巴特西

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