JSP上传文件失败 [英] JSP upload File failed
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问题描述
我将使用Servlet构建一个简单的jspfile来处理上传文件。在执行时，它显示以下消息
I am going to build up a simple jspfile to handle upload files using Servlet. When it comes to the execution, it shows the following message
demo Fail: org.apache.catalina.connector.RequestFacade cannot
be cast to org.apache.tomcat.util.http.fileupload.RequestContext
<你能告诉我如何将HTTP请求转换为RequestContext吗？
Would you please tell me how to convert the HTTP request to RequestContext ?
以下是我的jsp首页代码
The below is my code for jsp front-page
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!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=ISO-8859-1">
<title>Insert title Test Upload</title>
</head>
<body>
<form action="uploadFile" method="post" enctype="multipart/form-data">
<input type="file" name="file" />
<input type="submit" />
</form>
</body>
</html>
以下是我的Servlet代码
The below is my code for the Servlet
import java.io.*;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLEncoder;
import java.sql.*;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.List;
import javax.servlet.*;
import javax.servlet.http.*;
import org.apache.tomcat.util.http.fileupload.FileItem;
import org.apache.tomcat.util.http.fileupload.FileItemFactory;
import org.apache.tomcat.util.http.fileupload.FileUploadException;
import org.apache.tomcat.util.http.fileupload.RequestContext;
import org.apache.tomcat.util.http.fileupload.disk.DiskFileItemFactory;
import org.apache.tomcat.util.http.fileupload.servlet.ServletFileUpload;
/**
* Servlet implementation class getLogin
*/
public class uploadFile extends HttpServlet {
private static final long serialVersionUID = 17864986468494864L;
// location to store file uploaded
private static final String UPLOAD_DIRECTORY = "upload";
// upload settings
public uploadFile() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
//doPost(request, response);
//throw new ServletException("GET method used with " + getClass( ).getName( )+": POST method required.");
request.getRequestDispatcher("/WEB-INF/upload.jsp").forward(request, response);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
System.out.println("demo");
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 temporary location to store files
factory.setRepository(new File(System.getProperty("java.io.tmpdir")));
ServletFileUpload upload = new ServletFileUpload(factory);
// 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
System.out.println(uploadPath);
List<FileItem> formItems = upload.parseRequest((RequestContext)request);
if (formItems != null && formItems.size() > 0) {
// iterates over form's fields
for (FileItem item : formItems) {
// processes only fields that are not form fields
if (!item.isFormField()) {
String fileName = new File(item.getName()).getName();
String filePath = uploadPath + File.separator + fileName;
File storeFile = new File(filePath);
// C:\tomcat\apache-tomcat-7.0.40\webapps\data\
// saves the file on disk
item.write(storeFile);
request.setAttribute("message","Upload has been done successfully!");
System.out.println("demo Success");
}
}
}
} catch (Exception ex) {
request.setAttribute("message","There was an error: " + ex.getMessage());
System.out.println("demo Fail: " + ex.getMessage() );
}
}
}
推荐答案
当您使用enctype = multipart / form-data从表单获取参数而不使用标准
This error attemp on Tomcat 7 and Servlet 3.0 when you are getting parameters from a Form with enctype=multipart/form-data without using standard
@WebServlet("/yourPattern")
@MultipartConfig
public class UploadFile extends HttpServlet { //...
然后使用Part对象
Part filePart = request.getPart("file"); // Retrieves <input type="file" name="file">
InputStream filecontent = filePart.getInputStream();
而不是
List<FileItem> formItems = upload.parseRequest((RequestContext)request);
if (formItems != null && formItems.size() > 0) {
// iterates over form's fields
for (FileItem item : formItems) {
if (!item.isFormField()) { //...
请参阅此其他帖子以获取更多信息信息。
See this other post for further information.
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