commons fileupload(Apache)
Question
I am getting null pointer exception here:
List fileItems = upload.parseRequest(req);
That happens if the number of line in the file is greater the 2000 approx, as I could upload the file of lines above 1000. Someone please help me out. The form is below.
<form name="fos_picks" id="fos_picks" action="<%=path%>/fos_upld" method="post" enctype="multipart/form-data" >
<br/><br/><br/><br/>
<p align="center">
<input type="file" name="file" size="50" /><br/>
<br/>
<input type="submit" class="buttons" value="Upload File" />
</p>
</form>
Upload controller code...
package file_proc;
import DBConn.DBConn;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.sql.PreparedStatement;
import java.util.Iterator;
import java.util.List;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
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;
@WebServlet(name="file_upld", urlPatterns = {"/file_upld"})
public class file_upld extends HttpServlet {
private boolean isMultipart;
private String filePath;
private int maxFileSize = 50 * 1024;
private int maxMemSize = 10 * 1024;
private File file ;
/* public void init( ){
// Get the file location where it would be stored.
filePath =
getServletContext().getInitParameter("file-upload");
}*/
@Override
public void doPost(HttpServletRequest req, HttpServletResponse res)throws ServletException, java.io.IOException {
// Check that we have a file upload request
java.io.PrintWriter out = res.getWriter( );
// out.println("entered");
isMultipart = ServletFileUpload.isMultipartContent(req);
res.setContentType("text/html");
if( !isMultipart ){
out.println("!multipart");
System.out.println("here");
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 );
ServletContext servletContext = getServletContext();
String path = servletContext.getRealPath("/");
BufferedReader br=null;
String fileName="";
DBConn db = new DBConn();
try{
// Parse the request to get file items.
System.out.println("here1"+req);
List fileItems = upload.parseRequest(req);
// Process the uploaded file items
Iterator i = fileItems.iterator();
/* out.println("<html>");
out.println("<head>");
out.println("<title>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();
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( "c:/Temp/" +
fileName.substring( fileName.lastIndexOf("\\"))) ;
}else{
file = new File( "c:/Temp/"+
fileName.substring(fileName.lastIndexOf("\\")+1)) ;
}
if(!file.exists())
{
File fold=new File(file.getParent());
fold.mkdirs();
}
fi.write( file ) ;
System.out.println("Uploaded Filename: " + fileName + "<br>");
}
}
}catch(Exception ce)
{
out.println("<font size='30' color='red'>Error Code 016</font>");
//out.println("Exception1: "+ce);
}
//read uploaded file and insert into table********************************************
// String newline = System.getProperty("line.separator");
// File file = new File(path+"//"+fileName);
// file.createNewFile();
try{
if(file.isFile())
{
br = new BufferedReader(new FileReader(file));
String str="";
String temp[]=null;
file.canWrite();
file.canRead();
file.setWritable(true);
db.conn.setAutoCommit(false);
while((str=br.readLine())!=null)
{
temp=str.split(" ");
// PreparedStatement ps = db.conn.prepareStatement("INSERT INTO file_proc VALUES(?,?,?,?,?,?,?,?,?,STR_TO_DATE(?,'%m/%d/%Y'))");
PreparedStatement ps = db.conn.prepareStatement("INSERT INTO file_proc(run_date,zone,location,bank,file_type,num_rec,ex_sett_date,ex_stat_date) "
+ "VALUES(STR_TO_DATE(?,'%m/%d/%Y'),?,?,?,?,?,STR_TO_DATE(?,'%m/%d/%Y'),STR_TO_DATE(?,'%m/%d/%Y'))");
ps.setString(1,temp[0]);
ps.setString(2,temp[1]);
ps.setString(3,temp[2]);
ps.setString(4,temp[3]);
ps.setString(5,temp[4]);
ps.setInt(6,Integer.parseInt(temp[5]));
ps.setString(7,temp[6]);
ps.setString(8,temp[7]);
ps.executeUpdate();
ps.close();
}
db.conn.commit();
db.conn.setAutoCommit(true);
db.conn.close();
br.close();
file.delete();
// RequestDispatcher rd = req.getRequestDispatcher("./status/status.jsp");
// rd.forward(req, res);
out.print("success");
// out.println("</html>");
}
else
{
out.println(file+" is not a file");
}
}catch(Exception ex) {
out.println("file name= "+fileName);
// out.println("DBEX= "+ex );
out.println("<font size='30' color='red'>Error Code 017 - Recommended date format = m/d/yyyy.</font>");
out.println("<font size='30' color='red'>Check the column order</font>"+ex);
//file.delete();
// RequestDispatcher rd = req.getRequestDispatcher("./status/error.jsp");
// rd.forward(req, res);
}finally{
try{
db.conn.close();
br.close();
}catch(Exception e){}
}
}
@Override
public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, java.io.IOException {
doPost(request, response);
}
}
** * * Here is form * ** * **
<form name="file_proc" id="file_proc" method = "post" action="../file_upld" enctype="multipart/form-data">
<br/><br/><br/><br/>
<p align="center">
<input type="file" id="file" name="file" size="50" /><br/>
<br/>
<input type="submit" class="buttons" value="Upload File" />br/><br/><br/>
</p>
</form>
Upload controller code...
package file_proc;
import DBConn.DBConn;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.sql.PreparedStatement;
import java.util.Iterator;
import java.util.List;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
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;
@WebServlet(name="file_upld", urlPatterns = {"/file_upld"})
public class file_upld extends HttpServlet {
private boolean isMultipart;
private String filePath;
private int maxFileSize = 50 * 1024;
private int maxMemSize = 10 * 1024;
private File file ;
/* public void init( ){
// Get the file location where it would be stored.
filePath =
getServletContext().getInitParameter("file-upload");
}*/
@Override
public void doPost(HttpServletRequest req, HttpServletResponse res)throws ServletException, java.io.IOException {
// Check that we have a file upload request
java.io.PrintWriter out = res.getWriter( );
// out.println("entered");
isMultipart = ServletFileUpload.isMultipartContent(req);
res.setContentType("text/html");
if( !isMultipart ){
out.println("!multipart");
System.out.println("here");
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 );
ServletContext servletContext = getServletContext();
String path = servletContext.getRealPath("/");
BufferedReader br=null;
String fileName="";
DBConn db = new DBConn();
try{
// Parse the request to get file items.
System.out.println("here1"+req);
List fileItems = upload.parseRequest(req);
// Process the uploaded file items
Iterator i = fileItems.iterator();
/* out.println("<html>");
out.println("<head>");
out.println("<title>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();
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( "c:/Temp/" +
fileName.substring( fileName.lastIndexOf("\\"))) ;
}else{
file = new File( "c:/Temp/"+
fileName.substring(fileName.lastIndexOf("\\")+1)) ;
}
if(!file.exists())
{
File fold=new File(file.getParent());
fold.mkdirs();
}
fi.write( file ) ;
System.out.println("Uploaded Filename: " + fileName + "<br>");
}
}
}catch(Exception ce)
{
out.println("<font size='30' color='red'>Error Code 016</font>");
//out.println("Exception1: "+ce);
}
//read uploaded file and insert into table********************************************
// String newline = System.getProperty("line.separator");
// File file = new File(path+"//"+fileName);
// file.createNewFile();
try{
if(file.isFile())
{
br = new BufferedReader(new FileReader(file));
String str="";
String temp[]=null;
file.canWrite();
file.canRead();
file.setWritable(true);
db.conn.setAutoCommit(false);
while((str=br.readLine())!=null)
{
temp=str.split(" ");
// PreparedStatement ps = db.conn.prepareStatement("INSERT INTO file_proc VALUES(?,?,?,?,?,?,?,?,?,STR_TO_DATE(?,'%m/%d/%Y'))");
PreparedStatement ps = db.conn.prepareStatement("INSERT INTO file_proc(run_date,zone,location,bank,file_type,num_rec,ex_sett_date,ex_stat_date) "
+ "VALUES(STR_TO_DATE(?,'%m/%d/%Y'),?,?,?,?,?,STR_TO_DATE(?,'%m/%d/%Y'),STR_TO_DATE(?,'%m/%d/%Y'))");
ps.setString(1,temp[0]);
ps.setString(2,temp[1]);
ps.setString(3,temp[2]);
ps.setString(4,temp[3]);
ps.setString(5,temp[4]);
ps.setInt(6,Integer.parseInt(temp[5]));
ps.setString(7,temp[6]);
ps.setString(8,temp[7]);
ps.executeUpdate();
ps.close();
}
db.conn.commit();
db.conn.setAutoCommit(true);
db.conn.close();
br.close();
file.delete();
// RequestDispatcher rd = req.getRequestDispatcher("./status/status.jsp");
// rd.forward(req, res);
out.print("success");
// out.println("</html>");
}
else
{
out.println(file+" is not a file");
}
}catch(Exception ex) {
out.println("file name= "+fileName);
// out.println("DBEX= "+ex );
out.println("<font size='30' color='red'>Error Code 017 - Recommended date format = m/d/yyyy.</font>");
out.println("<font size='30' color='red'>Check the column order</font>"+ex);
//file.delete();
// RequestDispatcher rd = req.getRequestDispatcher("./status/error.jsp");
// rd.forward(req, res);
}finally{
try{
db.conn.close();
br.close();
}catch(Exception e){}
}
}
@Override
public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, java.io.IOException {
doPost(request, response);
}
}
** * * Here is form * ** * **
<form name="file_proc" id="file_proc" method = "post" action="../file_upld" enctype="multipart/form-data">
<br/><br/><br/><br/>
<p align="center">
<input type="file" id="file" name="file" size="50" /><br/>
<br/>
<input type="submit" class="buttons" value="Upload File" />br/><br/><br/>
</p>
</form>
here is the log4j stuff, it shows the error at filter.java, which i am not using in the current servlet.
[ERROR] 29:05(file_upld.java:doPost:172) failed!
java.lang.NullPointerException at file_proc.file_upld.doPost(file_upld.java:120) at javax.servlet.http.HttpServlet.service(HttpServlet.java:641) at javax.servlet.http.HttpServlet.service(HttpServlet.java:722) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) at filter.filter.doFilter(filter.java:16) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:225) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168) at org.apache.ca talina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98) at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407) at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:999) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:565) at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:307) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603) at java.lang.Thread.run(Thread.java:722)
Here goes the filter.javapackage filter;
import java.io.IOException;
import javax.servlet.*;
import javax.servlet.http.HttpServletResponse;
public class filter implements Filter{
private FilterConfig config=null;
@Override
public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException
{
HttpServletResponse hsr = (HttpServletResponse) res;
hsr.setHeader("Cache-Control", "no-cache, no-store, must-revalidate"); // HTTP 1.1.
hsr.setHeader("Pragma", "no-cache"); // HTTP 1.0.
hsr.setDateHeader("Expires", 0); // Proxies.
chain.doFilter(req, res);
}
@Override
public void destroy() { }
@Override
public void init(FilterConfig config) {
this.config = config;
}
}
1 answers
solution1
3 ACCPTED 2012-10-11 19:53:42
Your concrete problem is caused by bad exception handling and tight-coupling view with the controller.
After filtering noise from your code, it goes roughly like:
File file = null;
try {
// ...
file = new File(...);
// ...
} catch (Exception e) {
out.println("...");
}
try {
if (file.isFile())
// ...
} else {
// ...
}
} catch (Exception e) {
out.println("...");
}
The NullPointerException is been thrown at the line with the if (file.isFile()) block. This thus means that the first try block threw an exception, hereby leaving the file as null .
The cause of the problem is two-fold:
- The first
tryblock is not returning from the servlet method on exception, but incorrectly continuing the code flow. - The second
tryblock is not checking beforehand if thefileis notnull.
Your concrete problem is however much bigger. You're completely swallowing exceptions and printing irrelevant HTML code instead of throwing them through and/or logging the exceptions.
Replace your catch blocks as follows:
} catch (Exception e) {
throw new ServletException(e);
}
By default, this way the exception will be logged and be displayed in its full glory, complete with the stacktrace, in a HTTP 500 error page. The stacktrace gives you a wealth of information to understand the problem and fix it.
Unrelated to the concrete problem, there are many other conceptual and design mistakes in the code, but they are so far not directly related to the concrete problem. I would however recommend to take a pause and go through some sane Servlet books/tutorials/resources. This code seems to be just cobbled together based on snippets found in Google instead of being well thought out written. The first step would be understanding how servlets actually work: How do servlets work? Instantiation, sessions, shared variables and multithreading
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