Close file using java

Close a File in Java

Classes for input and output operations can be found in the java.io package . This package contains input and output streams for reading and writing data to files.

We’ll use the close() method to flush out the stream after executing any file operations.

Use the close() Method to Close a File in Java

The BufferedWriter class is utilized in the following program. This class allows you to efficiently write arrays, strings, and characters into a character-output stream.

We also employ the FileWriter class, designed for writing streams of characters, and the BufferedWriter class.

A file path is represented by an instance of the File class file. An abstract pathname is constructed from the specified pathname string.

The BufferedWriter ’s write() method saves some text to the file. The newLine() method adds a /n as a line separator.

The majority of streams don’t need to be closed after being used. When the source is an Input/Output Channel, it is recommended to close the stream.

We should invoke the close() method before terminating the program or executing any file operations. We might lose some data if we don’t.

As a result, to close the stream and keep the data secure, the close() method is utilized.

Streams include a method called BaseStream.close() , which implements Autoclosable . Almost all stream instances don’t need to be closed because they’re supported by collections, which are arrays that don’t need any additional resource management.

The stream should be closed if the source is an IO channel.

The contents of the file are shown below before conducting the write operation.

import java.io.BufferedWriter; import java.io.File; import java.io.FileWriter;  public class CloseFile   public static void main(String[] args) throws Exception   File file = new File("/Users/John/Temp/demo1.txt");  if (file.exists())   BufferedWriter bufferWriter = new BufferedWriter(new FileWriter(file, true));  bufferWriter.write("New Text");  bufferWriter.newLine();  bufferWriter.close();  >  > > 

After performing the write operation, the file’s contents changed.

Rupam Saini is an android developer, who also works sometimes as a web developer., He likes to read books and write about various things.

Related Article — Java File

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How to close a text file using java

Question: I am using java Runtime.exec() method to execute bat file,in bat file i have write code that execute jar. If you want do this, you must know exactly what application it is every case and you must do it differently for each different OS: Solution 3: It depends on what is the default application that opens txt file.

How to close a text file using java

If i have opened a text file using Desktop API in java and i want to close it again only using the code? I have opened it like this

Desktop d=Desktop.getDesktop(); try < d.open(new File("C:/Users/home/Desktop/123.txt")); >catch (IOException e) < // TODO Auto-generated catch block e.printStackTrace(); >Thread.sleep(2000); 

Now i want to close it?how will i do it,what code do i have to Write,Since there is no method in the Desktop API of the java

The Desktop#open() tells the OS to use its file type mappings to select and launch the appropriate application for a given file. Unless that application itself provides an API by which you can control it, you cannot close it. The desktop API does not retain a connection to the application that gets launched.

In any case, since the Java API does not return the process ID of the launched application, it is going to be problematic to even find the process.

Launches the associated application to open the file.

If the specified file is a directory, the file manager of the current platform is launched to open it.

This means you can’t close the file from the Desktop class. This is a related question you might want to look at. If you are worried about closing files like you would with streams, you are fine (since this isn’t a stream where you need to save work).

If you want to still close the file, you would need to go thru the list of processes (how to do that for Windows) and some how identify which process is the application you just opened the file with, then close that with OS commands.

Also, the issue with doing something like this is:

Runtime.getRuntime().exec("taskkill /IM notepad.exe"); 

It will only work on a Windows platform (check this out). If you want do this, you must know exactly what application it is every case and you must do it differently for each different OS:

It depends on what is the default application that opens txt file . Generally in windows its notepad. If that is the case you could try

Desktop d=Desktop.getDesktop(); try < d.open(new File("test.txt")); Thread.sleep(5000); Runtime.getRuntime().exec("taskkill /IM notepad.exe"); >catch (IOException e) < e.printStackTrace(); >catch (InterruptedException e)

The problem with this is it closes all open notepad instances 🙁

Java — open and close files, I am learning the basics of reading from text files. I have code that works fine if everything is in the main method. However, for this exercise I am …

Opening an existing file in Java and closing it

Is it possible to open a file a in java append data and close numerous times. For example:

 //---- psuedocode //class variable declaration FileWriter writer1 = new FileWriter(filename); fn1: writer.append(data - title); fn2: while(incomingdata == true)

The problem lies in the while loop. The file is closed and cant be opened again. Any one can help me in this?

The answers that advise against closing and re-opening the file each time are quite correct.

However, if you absolutely have to do this (and it’s not clear to me that you do), then you can create a new FileWriter each time. Pass true as the second argument when you construct a FileWriter, to get one that appends to the file instead of replacing it. Like

FileWriter writer1 = new FileWriter(filename, true); 

Once a stream has been closed, further write() or flush() invocations will cause an IOException to be thrown. Closing a previously- closed stream , however, has no effect.

 while(incomingdata == true) < writer.write(data) >writer.close() 

You don’t need to flush each time. as calling close() will first flush data before closing the stream.

Updated for

The file that i created has to be saved. For which im supposed to close it so the timestamp is updated. Thats when the file is synced live.

while(incomingdata == true) < writer.append(data); writer.flush(); >writer.close(); 

I don’t recommend trying to close your file and then reopening it again. Opening a file is an expensive operation and the fewer times you do this, the better it is for your code to run quickly.

Open it once, and close the file once you’re done writing to it. This would be outside your loop.

Once that the file is closed you will need to re-open it. Calling writer.flush() should flush the stream. So basically, you will then remove writer.close() from within the while loop. This will allow you to close the file once that you will have finished with it.

So you have two options, either remove writer.close() from within the while loop or else create a new FileWriter instance at the beginning of your loop.

Opening an existing file in Java and closing it, So basically, you will then remove writer.close () from within the while loop. This will allow you to close the file once that you will have finished …

How to close running process using java?

I am using Java Runtime.exec() method to execute bat file,in bat file i have write code that execute jar.This jar contain thread class that pooling infinite time the rabbitmq queue,if message are found then perform operation on that,mean the process will run infinite. i want to **** this process using java code,also i want know that can this method are able to execute shall script on Linux Os.

 **Used java code** String myCMD = "cmd.exe /C start c:\\elasticmgmtservice.bat"; Runtime rt = Runtime.getRuntime(); Process proc = rt.exec(myCMD); **used batch file** cd c: cd ElasticMgmtService\ java -jar ElasticIndexManagementService.jar config\ElasticIndexManagementService.xml 

please help me to solve the problem.

Runtime.exec(. ) returns Process object which consists following methods

• destroy()
• exitValue()
• getErrorStream()
• getInputStream()
• getOutputStream()
• waitFor()

you can call destroy() which kills the subprocess. The subprocess represented by this Process object is forcibly terminated. or you can **** by passing taskkill /PID in Runtime.exec(. ) or **** -9

Runtime rt = Runtime.getRuntime(); rt.exec("taskkill " +); 

Runtime rt = Runtime.getRuntime(); rt.exec("kill -9 " +); 

Runtime.exec() returns a Process object, which is an handler for the process the exec method has created. To **** this process, you have to call Process.destroy();

Java.io.FileOutputStream.close() Method, Description The java.io.FileOutputStream.close () closes this file output stream and releases any system resources associated with this stream. Declaration …

Java code for closing a file that is open in java(TM) platform SE binary

I have java code in my application for deleting a file i.e nameOffile.delete(). As I try to delete the file I get an error: The action can not be completed because the file is open in Java (TM) Platform SE binary. Close the file and try again. I tried deleting the file without the application but I still get the same problem. Please help me solve thes error.

You were probably opening the file first to read/write its content?
There you probably forgot to close the stream. Therefore you are not able to delete it.

Writer out = new OutputStreamWriter(new FileOutputStream(fileName), fEncoding); try < out.write("some text here"); >finally < out.close(); >// write code to delete the file 

To solve this problem open task manager and close java then you’ll be able to delete the file

Exit the batch file after running using java, Here is the solution that works: to close command window after executing the commands from the batch (.bat) file you need to add «exit» …

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