FileUpload的使用案例
文件上传
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！
