使用servlet和html在服务器上的上传文件中找不到符号getServletContext（）错误(cannot find symbol getServletContext() error in

使用servlet和html在服务器上的上传文件中找不到符号getServletContext（）错误(cannot find symbol getServletContext() error in upload file on server using servlet and html)

使用带有HTML表单的servlet在服务器上上传txt文件，但它显示以下错误：

cannot find symbol filePath = getServletContext().getInitParameter("file-upload");

Jar文件添加：

commons-fileupload-1.3.jar, commons-io-2.4.jar, servlet-api-3.0.jar

使用NetBeansIDE和web.xml中设置的参数，路径为“C：\ apache-tomcat-7.0.40 \ webapps \ ROOT \ WEB-INF”

<context-param> <description>destination storing uploaded file</description> <param-name>file-upload</param-name> <param-value> C:\apache-tomcat-7.0.40\webapps\data\ </param-value> </context-param>

尝试了以下代码：FileUpload3

package fileupload3; import java.io.*; import java.util.*; import javax.servlet.*; 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.FileItem; import org.apache.commons.fileupload.FileUploadException; import org.apache.commons.fileupload.disk.DiskFileItemFactory; import org.apache.commons.fileupload.servlet.ServletFileUpload; import org.apache.commons.io.output.*; public class FileUpload3 { private boolean isMultipart; private String filePath; private int maxFileSize = 50 * 1024; private int maxMemSize = 4 * 1024; private File file ; public void init() { // Showing cannot find symbol getServletContext() error here filePath = getServletContext().getInitParameter("file-upload"); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, java.io.IOException { isMultipart = ServletFileUpload.isMultipartContent(request); response.setContentType("text/html"); java.io.PrintWriter out = response.getWriter( ); if( !isMultipart ){ out.println("<html>"); out.println("<head>"); out.println("<title>Servlet upload</title>"); out.println("</head>"); out.println("<body>"); out.println("<p>No file uploaded</p>"); out.println("</body>"); out.println("</html>"); return; } DiskFileItemFactory factory = new DiskFileItemFactory(); // maximum size that will be stored in memory factory.setSizeThreshold(maxMemSize); // Location to save data that is larger than maxMemSize. factory.setRepository(new File("c:\\temp")); // Create a new file upload handler ServletFileUpload upload = new ServletFileUpload(factory); // maximum file size to be uploaded. upload.setSizeMax( maxFileSize ); try{ // Parse the request to get file items. List fileItems = upload.parseRequest(request); // Process the uploaded file items Iterator i = fileItems.iterator(); out.println("<html>"); out.println("<head>"); out.println("<title>Servlet upload</title>"); out.println("</head>"); out.println("<body>"); while ( i.hasNext () ) { FileItem fi = (FileItem)i.next(); if ( !fi.isFormField () ) { // Get the uploaded file parameters String fieldName = fi.getFieldName(); String fileName = fi.getName(); String contentType = fi.getContentType(); boolean isInMemory = fi.isInMemory(); long sizeInBytes = fi.getSize(); // Write the file if( fileName.lastIndexOf("\\") >= 0 ){ file = new File( filePath + fileName.substring( fileName.lastIndexOf("\\"))) ; }else{ file = new File( filePath + fileName.substring(fileName.lastIndexOf("\\")+1)) ; } fi.write( file ) ; out.println("Uploaded Filename: " + fileName + "<br>"); } } out.println("</body>"); out.println("</html>"); }catch(Exception ex) { System.out.println(ex); } } public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, java.io.IOException { throw new ServletException("GET method used with " + getClass( ).getName( )+": POST method required."); } }

HTML表单：newhtml1.html

<html> <head> <title>HTML Form</title> </head> <body> <h3>File Upload:</h3> Select a file to upload: <br /> <form action="FileUpload3" method="post" enctype="multipart/form-data"> <input type="file" name="file" /> <br /> <input type="submit" value="Upload File" /> </form> </body> </html>

Uploading a txt file on server using servlets with HTML form, but it is showing the following error:

cannot find symbol filePath = getServletContext().getInitParameter("file-upload");

Jar files added:

commons-fileupload-1.3.jar, commons-io-2.4.jar, servlet-api-3.0.jar

Using NetBeansIDE and parameters set in web.xml with path "C:\apache-tomcat-7.0.40\webapps\ROOT\WEB-INF"

<context-param> <description>destination storing uploaded file</description> <param-name>file-upload</param-name> <param-value> C:\apache-tomcat-7.0.40\webapps\data\ </param-value> </context-param>

Tried the following code:FileUpload3

package fileupload3; import java.io.*; import java.util.*; import javax.servlet.*; 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.FileItem; import org.apache.commons.fileupload.FileUploadException; import org.apache.commons.fileupload.disk.DiskFileItemFactory; import org.apache.commons.fileupload.servlet.ServletFileUpload; import org.apache.commons.io.output.*; public class FileUpload3 { private boolean isMultipart; private String filePath; private int maxFileSize = 50 * 1024; private int maxMemSize = 4 * 1024; private File file ; public void init() { // Showing cannot find symbol getServletContext() error here filePath = getServletContext().getInitParameter("file-upload"); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, java.io.IOException { isMultipart = ServletFileUpload.isMultipartContent(request); response.setContentType("text/html"); java.io.PrintWriter out = response.getWriter( ); if( !isMultipart ){ out.println("<html>"); out.println("<head>"); out.println("<title>Servlet upload</title>"); out.println("</head>"); out.println("<body>"); out.println("<p>No file uploaded</p>"); out.println("</body>"); out.println("</html>"); return; } DiskFileItemFactory factory = new DiskFileItemFactory(); // maximum size that will be stored in memory factory.setSizeThreshold(maxMemSize); // Location to save data that is larger than maxMemSize. factory.setRepository(new File("c:\\temp")); // Create a new file upload handler ServletFileUpload upload = new ServletFileUpload(factory); // maximum file size to be uploaded. upload.setSizeMax( maxFileSize ); try{ // Parse the request to get file items. List fileItems = upload.parseRequest(request); // Process the uploaded file items Iterator i = fileItems.iterator(); out.println("<html>"); out.println("<head>"); out.println("<title>Servlet upload</title>"); out.println("</head>"); out.println("<body>"); while ( i.hasNext () ) { FileItem fi = (FileItem)i.next(); if ( !fi.isFormField () ) { // Get the uploaded file parameters String fieldName = fi.getFieldName(); String fileName = fi.getName(); String contentType = fi.getContentType(); boolean isInMemory = fi.isInMemory(); long sizeInBytes = fi.getSize(); // Write the file if( fileName.lastIndexOf("\\") >= 0 ){ file = new File( filePath + fileName.substring( fileName.lastIndexOf("\\"))) ; }else{ file = new File( filePath + fileName.substring(fileName.lastIndexOf("\\")+1)) ; } fi.write( file ) ; out.println("Uploaded Filename: " + fileName + "<br>"); } } out.println("</body>"); out.println("</html>"); }catch(Exception ex) { System.out.println(ex); } } public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, java.io.IOException { throw new ServletException("GET method used with " + getClass( ).getName( )+": POST method required."); } }

HTML Form: newhtml1.html

<html> <head> <title>HTML Form</title> </head> <body> <h3>File Upload:</h3> Select a file to upload: <br /> <form action="FileUpload3" method="post" enctype="multipart/form-data"> <input type="file" name="file" /> <br /> <input type="submit" value="Upload File" /> </form> </body> </html>