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Java FileNotFoundException Too many open files

I am trying to create an automatic backup script in Java. I am not very good at Java, although it is complicated.

Here is my code:

package javatest;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

public class Main {   
 public static void main(String[] args) throws Exception {
      String path = "/mnt/192.168.1.89";
      String destFile = "/home/scott/backup.zip";

      zip(path,destFile);
 }

 private static void zip(String src, String destFile) throws Exception
 {
     FileOutputStream fileWriter = new FileOutputStream(destFile);
     ZipOutputStream zip = new ZipOutputStream(fileWriter);

     addFolderToZip("", src, zip);

     zip.flush();
     zip.close();
 }

 private static void addFolderToZip(String path, String srcFolder, ZipOutputStream zip) throws Exception
 {
       File folder = new File(srcFolder);

       for (String filename : folder.list())
       {
            if (path.equals("")) {
                 addFileToZip(folder.getName(), srcFolder + "/" + filename, zip);
            } else {
                 addFileToZip(path + "/" + folder.getName(), srcFolder + "/" + filename, zip);
            }
       }
 }

 private static void addFileToZip(String path, String srcFile, ZipOutputStream zip) throws Exception
 {
     File folder = new File(srcFile);

     if (folder.isDirectory()) {
          addFolderToZip(path,srcFile,zip);
     } else {
          byte[] buf = new byte[1024];

          int len;

          FileInputStream in = new FileInputStream(srcFile);

          zip.putNextEntry(new ZipEntry(path + "/" + folder.getName()));

          while((len = in.read(buf)) > 0)
          {
               zip.write(buf,0,len);
          }
     }
 }
}

And here is the exception:

Exception in thread "main" java.io.FileNotFoundException: FILENAME (Too many open files)
    at java.io.FileInputStream.open(Native Method)
    at java.io.FileInputStream.<init>(FileInputStream.java:106)
    at java.io.FileInputStream.<init>(FileInputStream.java:66)
    at javatest.Main.addFileToZip(Main.java:53)
    at javatest.Main.addFolderToZip(Main.java:37)
    at javatest.Main.addFileToZip(Main.java:47)
    at javatest.Main.addFolderToZip(Main.java:37)
    at javatest.Main.addFileToZip(Main.java:47)
    at javatest.Main.addFolderToZip(Main.java:37)
    at javatest.Main.addFileToZip(Main.java:47)
    at javatest.Main.addFolderToZip(Main.java:37)
    at javatest.Main.addFileToZip(Main.java:47)
    at javatest.Main.addFolderToZip(Main.java:37)
    at javatest.Main.addFileToZip(Main.java:47)
    at javatest.Main.addFolderToZip(Main.java:37)
    at javatest.Main.addFileToZip(Main.java:47)
    at javatest.Main.addFolderToZip(Main.java:37)
    at javatest.Main.addFileToZip(Main.java:47)
    at javatest.Main.addFolderToZip(Main.java:35)
    at javatest.Main.zip(Main.java:22)
    at javatest.Main.main(Main.java:14)
Java Result: 1
+3
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4 answers

Make sure close()both of you :

  • ZipOutputStream (which you rightfully did), and
  • FileInputStream

There are a lot of open connections in your threads right now.

in addFolderToZip(), close FileInputStreamat the end like this:

try {
    in.close();
} catch (IOException e) {
    //Log exception
}
+1
source

Close these threads. Best practice is to do this in try-finally blocks like this (finally, blocks almost always execute when the try block exits

private static void zip(String src, String destFile) throws Exception
 {
   FileOutputStream fileWriter=null;
   ZipOutputStream zip = null;
   try{
     fileWriter = new FileOutputStream(destFile)
     zip = new ZipOutputStream(fileWriter);

     addFolderToZip("", src, zip);

     zip.flush();
   }finally{
     if(zip!=null)zip.close();//close also does a flush
     if(fileWriter!=null)fileWriter.close();
   }
 }

private static void addFileToZip(String path, String srcFile, ZipOutputStream zip) throws Exception
 {
     File folder = new File(srcFile);

     if (folder.isDirectory()) {
          addFolderToZip(path,srcFile,zip);
     } else {
          byte[] buf = new byte[1024];

          int len;

          FileInputStream in = null;
          try{
              in = new FileInputStream(srcFile);
              zip.putNextEntry(new ZipEntry(path + "/" + folder.getName()));

              while((len = in.read(buf)) > 0)
              {
                   zip.write(buf,0,len);
              }
          }finally{if(in!=null)in.close()}//<<--ensure in is closed you forgot this in the example code
     }
 }
+1
source 
FileInputStream in = new FileInputStream(srcFile);

zip.putNextEntry(new ZipEntry(path + "/" + folder.getName()));
while((len = in.read(buf)) > 0)
{
    zip.write(buf,0,len);
}
in.close(); //You have to close file !

,

0

addFileToZip, in.close() else, . , , .

0
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