web Servlet中如何使用上传组件FileUpload
在web开发中要实现上传功能，就要用到上传组件FileUpload
FileUpload下载链接地址：http://archive.apache.org/dist/commons/fileupload/binaries/
Commons IO下载链接地址：http://commons.apache.org/proper/commons-io/
上传的服务器：
import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
public class FileUpload extends HttpServlet {
int id = -1;
//String uploadPath2="";
private static final long serialVersionUID = 1L;
// location to store file uploaded
private static final String UPLOAD_DIRECTORY = "upload";
// private static final String UPLOAD_DIRECTORY = "images\\product\\";
// upload settings
private static final int MEMORY_THRESHOLD = 1024 * 1024 * 3; // 3MB
private static final int MAX_FILE_SIZE = 1024 * 1024 * 40; // 40MB
private static final int MAX_REQUEST_SIZE = 1024 * 1024 * 50; // 50MB
@Override
/*public void init(ServletConfig config) throws ServletException
{
uploadPath2 = config.getInitParameter("uploadfilepath");
}
*/
/**
* Upon receiving file upload submission, parses the request to read
* upload data and saves the file on disk.
*/
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
// checks if the request actually contains upload file
if (!ServletFileUpload.isMultipartContent(request)) {
// if not, we stop here
PrintWriter writer = response.getWriter();
writer.println("Error: Form must has enctype=multipart/form-data.");
writer.flush();
return;
}
// configures upload settings
DiskFileItemFactory factory = new DiskFileItemFactory();
// sets memory threshold - beyond which files are stored in disk
factory.setSizeThreshold(MEMORY_THRESHOLD);
// sets temporary location to store files
factory.setRepository(new File(System.getProperty("java.io.tmpdir")));
ServletFileUpload upload = new ServletFileUpload(factory);
// sets maximum size of upload file
upload.setFileSizeMax(MAX_FILE_SIZE);
// sets maximum size of request (include file + form data)
upload.setSizeMax(MAX_REQUEST_SIZE);
// constructs the directory path to store upload file
// this path is relative to application's directory
String uploadPath = getServletContext().getRealPath("")
+ File.separator + UPLOAD_DIRECTORY;
// creates the directory if it does not exist
File uploadDir = new File(uploadPath);
if (!uploadDir.exists()) {
uploadDir.mkdir();
}
try {
// parses the request's content to extract file data
@SuppressWarnings("unchecked")
List<FileItem> formItems = upload.parseRequest(request);
if (formItems != null && formItems.size() > 0) {
// iterates over form's fields
for (FileItem item : formItems)
{
/**自己写的代码*/
if(item.isFormField())
{
if(item.getFieldName().equals("id"))
{
id = Integer.parseInt(item.getString());
//System.out.println(id);
}
}
// processes only fields that are not form fields
if (!item.isFormField()) {
File storeFile = new File("F:\\svnTest\\webTest\\project\\Shopping2\\WebRoot\\images\\product\\"+ id + ".jpg");
// saves the file on disk
item.write(storeFile);
request.setAttribute("message",
"Upload has been done successfully!");
}
}
}
} catch (Exception ex) {
request.setAttribute("message",
"There was an error: " + ex.getMessage());
}
// redirects client to message page
getServletContext().getRequestDispatcher("/admin/message.jsp").forward(
request, response);
}
}
ProductUpload.jsp(上传的客户端)
<%@ page language="java" contentType="text/html; charset=GB18030" import="com.zhaoming.shopping.*, java.util.*"
pageEncoding="GB18030"%>
<%
int id = Integer.parseInt(request.getParameter("id"));
%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>File Upload Demo</title>
</head>
<body>
<center>
<form method="post" action="../servlet/FileUpload" enctype="multipart/form-data">
<input type="hidden" name="id" value=<%=id %>>
Select file to upload:
<input type="file" name="uploadFile" />
<br/><br/>
<input type="submit" value="Upload" />
</form>
</center>
</body>
</html>
message.jsp(显示上传成功)
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Upload Result</title>
</head>
<body>
<center>
<h2>${message}</h2>
</center>
</body>
</html>
web.xml
?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<servlet>
<description>This is the description of my J2EE component</description>
<display-name>This is the display name of my J2EE component</display-name>
<servlet-name>FileUpload</servlet-name>
<servlet-class>com.zhaoming.shopping.servlet.FileUpload</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>FileUpload</servlet-name>
<url-pattern>/servlet/FileUpload</url-pattern>
</servlet-mapping>
