Java Create File If Not Exists

last modified July 6, 2020

In Java create file tutorial, we show how to create a file in Java. We create files with built-in classes including File, FileOutputStream, andFiles. We also use two third-party libraries: Apache Commons IO and Google Guava.

A computer file is a computer resource for recording data discretely in a computer storage device.

The tutorials shows five ways to create a file in Java. The examples create empty files.

Java creating file with File

The File'screateNewFile() method creates a new, empty file named by the pathname if a file with this name does not yet exist.

Java Create File If Not Exists Append

JavaCreateFileEx.java

The example presented might be simple however it shows the behaviour of the exists method of File class. Basically we have used the returned value of the exists method before reading the file. If the file exists, Scanner class is used to read the file and print the contents line by line. If the file does not exists, a message 'File does. In my function I want to read a text file. If file does not exists it will be created. I want to use relative path so if i have.jar, file will be created in the exact same dir. Create BufferedWriter from FileWriter: 11.36.3. Read Input From User and Write to File: 11.36.4. Write to file using a BufferedWriter: 11.36.5. Use a BufferedReader and a BufferedWriter to copy a text file, inverting the case of letters in the process: 11.36.6. Writing to a File: If the file does not exist, it is automatically created.

The createNewFile() returns true if the named file doesnot exist and was successfully created; false if the named file already exists.

Java creating file with FileOutputStream

In the second example, we create a new, empty file with FileOutputStream.

The file is created when FileOutputStream object is instantiated.If the file already exists, it is overridden.

FileNotFoundException is thrown if the file exists but is a directory rather than a regular file, does not exist but cannot be created, or cannot be opened for any other reason.

Java creating file with Files

Java 7 introduced Files, which consists exclusively of static methods that operate on files, directories, or other types of files. Its createFile()method creates a new and empty file, failing if the file already exists.

JavaCreateFileEx3.java

The example creates a new, empty file with Files.

A Path object is created. It is used to locate a file in a file system.

The new file is created with Files.createFile(). Diskcatalogmaker 7 9 0 cm.

FileAlreadyExistsException is thrown if the file already exists.

Java creating file with Apache Commons IO

Mega samples vol 85 download free. The next example creates a file with Apache Commons IO library.

For the project we need the commons-io dependency.

Java Create File If Not Exists Filewriter

How to open options in excel mac. The new file is created with FileUtils.touch() method.

Java creating file with Google Guava

In the following example, we create a new file with Google Guavalibrary.

For the project we need the guava dependency.

JavaCreateFileEx5.java

The new file is created with Files.touch(). It acceptsa File as a parameter.

In this tutorial, we have shown several ways how to create a file in Java. We have used built-in toolsand third-party libraries.

List all Java tutorials.

Java Conditions and If Statements

Java supports the usual logical conditions from mathematics:

• Less than: a < b
• Less than or equal to: a <= b
• Greater than: a > b
• Greater than or equal to: a >= b
• Equal to a b
• Not Equal to: a != b

You can use these conditions to perform different actions for different decisions.

Java has the following conditional statements:

• Use if to specify a block of code to be executed, if a specified condition is true
• Use else to specify a block of code to be executed, if the same condition is false
• Use else if to specify a new condition to test, if the first condition is false
• Use switch to specify many alternative blocks of code to be executed

The if Statement

Use the if statement to specify a block of Java code to be executed if a condition is true.

Note that if is in lowercase letters. Uppercase letters (If or IF) will generate an error.

In the example below, we test two values to find out if 20 is greater than 18. If the condition is true, print some text:

We can also test variables:

Example

Java Create A File If Not Exists

Example explained

In the example above we use two variables, x and y, to test whether x is greater than y (using the > operator). As x is 20, and y is 18, and we know that 20 is greater than 18, we print to the screen that 'x is greater than y'.

The else Statement

Templates for keynote 6 0 9 pdf. Use the else statement to specify a block of code to be executed if the condition is false.

Java Create File If Not Exists Automatically

Syntax

Example explained

In the example above, time (20) is greater than 18, so the condition is false. Because of this, we move on to the else condition and print to the screen 'Good evening'. If the time was less than 18, the program would print 'Good day'.

The else if Statement

Use the else if statement to specify a new condition if the first condition is false.

Syntax

Example explained

In the example above, time (22) is greater than 10, so the first condition is false. The next condition, in the else if statement, is also false, so we move on to the else condition since condition1 and condition2 is both false - and print to the screen 'Good evening'.

However, if the time was 14, our program would print 'Good day.'

Short Hand If.Else (Ternary Operator)

There is also a short-hand if else, which is known as the ternary operator because it consists of three operands. It can be used to replace multiple lines of code with a single line. It is often used to replace simple if else statements:

Syntax

Instead of writing:

You can simply write:

Example

HowToDoInJava / Java / I/O / Java Create New File

Creating a new file in Java is a very easy task. In this Java tutorial, we will list down different ways to create a new file.

Read More: Create a read only file in Java

1. Create file with java.nio.file.Files

Files.write() is best way to create a new file in Java and it should be your preferred approach in future if you are not already using it.

Macgo blu ray player pro 3 2 22. This method writes lines of text to the created file. Each line is a char sequence and is written to the file in sequence with each line terminated by the platform's line separator.

Method Syntax

Example 1: Check if a file already exist in Java

LinkOption.NOFOLLOW_LINKS indicates that the application should not follow symbolic links in the file system to determine if the path exists.

Example 2: Create a new file or append to an existing file

Use StandardOpenOption to indicate if a new file has to be created or not.

Example 3: Create a new file with default options

If we do not specify any options parameter then by default, CREATE, TRUNCATE_EXISTING, and WRITE options are use.

It does the following things:

• Opens the file for write if exist
• Creates the file if the file doesn't exist
• Opens the file for writing
• Deletes all the file content
• Write the new content into the file

2. Create new file with java.io.File class

Use File.createNewFile() method to create new file. This method returns a boolean value –

• true if the file is created successfully.
• false if the file already exists or the operation failed for some reason.

Please note that this method will only create a file, and does not write any content into the file.

Java example to create a new create file if not exist

To write the content into the created file, use FileWriter class.

3. Create new file with FileOutputStream

FileOutputStream.write() method automatically creates a new file and write content to it.

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