Force create file java
The conversion of a pathname string to or from an abstract pathname is inherently system-dependent. When an abstract pathname is converted into a pathname string, each name is separated from the next by a single copy of the default separator character. The default name-separator character is defined by the system property file.separator , and is made available in the public static fields separator and separatorChar of this class. When a pathname string is converted into an abstract pathname, the names within it may be separated by the default name-separator character or by any other name-separator character that is supported by the underlying system.
A pathname, whether abstract or in string form, may be either absolute or relative. An absolute pathname is complete in that no other information is required in order to locate the file that it denotes. A relative pathname, in contrast, must be interpreted in terms of information taken from some other pathname. By default the classes in the java.io package always resolve relative pathnames against the current user directory. This directory is named by the system property user.dir , and is typically the directory in which the Java virtual machine was invoked.
The parent of an abstract pathname may be obtained by invoking the getParent() method of this class and consists of the pathname’s prefix and each name in the pathname’s name sequence except for the last. Each directory’s absolute pathname is an ancestor of any File object with an absolute abstract pathname which begins with the directory’s absolute pathname. For example, the directory denoted by the abstract pathname «/usr» is an ancestor of the directory denoted by the pathname «/usr/local/bin» .
- For UNIX platforms, the prefix of an absolute pathname is always «/» . Relative pathnames have no prefix. The abstract pathname denoting the root directory has the prefix «/» and an empty name sequence.
- For Microsoft Windows platforms, the prefix of a pathname that contains a drive specifier consists of the drive letter followed by «:» and possibly followed by «\\» if the pathname is absolute. The prefix of a UNC pathname is «\\\\» ; the hostname and the share name are the first two names in the name sequence. A relative pathname that does not specify a drive has no prefix.
Instances of this class may or may not denote an actual file-system object such as a file or a directory. If it does denote such an object then that object resides in a partition. A partition is an operating system-specific portion of storage for a file system. A single storage device (e.g. a physical disk-drive, flash memory, CD-ROM) may contain multiple partitions. The object, if any, will reside on the partition named by some ancestor of the absolute form of this pathname.
A file system may implement restrictions to certain operations on the actual file-system object, such as reading, writing, and executing. These restrictions are collectively known as access permissions. The file system may have multiple sets of access permissions on a single object. For example, one set may apply to the object’s owner, and another may apply to all other users. The access permissions on an object may cause some methods in this class to fail.
Instances of the File class are immutable; that is, once created, the abstract pathname represented by a File object will never change.
Interoperability with java.nio.file package
The java.nio.file package defines interfaces and classes for the Java virtual machine to access files, file attributes, and file systems. This API may be used to overcome many of the limitations of the java.io.File class. The toPath method may be used to obtain a Path that uses the abstract path represented by a File object to locate a file. The resulting Path may be used with the Files class to provide more efficient and extensive access to additional file operations, file attributes, and I/O exceptions to help diagnose errors when an operation on a file fails.
Java – Create a File
The Kubernetes ecosystem is huge and quite complex, so it’s easy to forget about costs when trying out all of the exciting tools.
To avoid overspending on your Kubernetes cluster, definitely have a look at the free K8s cost monitoring tool from the automation platform CAST AI. You can view your costs in real time, allocate them, calculate burn rates for projects, spot anomalies or spikes, and get insightful reports you can share with your team.
Connect your cluster and start monitoring your K8s costs right away:
We rely on other people’s code in our own work. Every day.
It might be the language you’re writing in, the framework you’re building on, or some esoteric piece of software that does one thing so well you never found the need to implement it yourself.
The problem is, of course, when things fall apart in production — debugging the implementation of a 3rd party library you have no intimate knowledge of is, to say the least, tricky.
Lightrun is a new kind of debugger.
It’s one geared specifically towards real-life production environments. Using Lightrun, you can drill down into running applications, including 3rd party dependencies, with real-time logs, snapshots, and metrics.
Learn more in this quick, 5-minute Lightrun tutorial:
Slow MySQL query performance is all too common. Of course it is. A good way to go is, naturally, a dedicated profiler that actually understands the ins and outs of MySQL.
The Jet Profiler was built for MySQL only, so it can do things like real-time query performance, focus on most used tables or most frequent queries, quickly identify performance issues and basically help you optimize your queries.
Critically, it has very minimal impact on your server’s performance, with most of the profiling work done separately — so it needs no server changes, agents or separate services.
Basically, you install the desktop application, connect to your MySQL server, hit the record button, and you’ll have results within minutes:
DbSchema is a super-flexible database designer, which can take you from designing the DB with your team all the way to safely deploying the schema.
The way it does all of that is by using a design model, a database-independent image of the schema, which can be shared in a team using GIT and compared or deployed on to any database.
And, of course, it can be heavily visual, allowing you to interact with the database using diagrams, visually compose queries, explore the data, generate random data, import data or build HTML5 database reports.
The Kubernetes ecosystem is huge and quite complex, so it’s easy to forget about costs when trying out all of the exciting tools.
To avoid overspending on your Kubernetes cluster, definitely have a look at the free K8s cost monitoring tool from the automation platform CAST AI. You can view your costs in real time, allocate them, calculate burn rates for projects, spot anomalies or spikes, and get insightful reports you can share with your team.
Connect your cluster and start monitoring your K8s costs right away:
We’re looking for a new Java technical editor to help review new articles for the site.
1. Overview
In this quick tutorial, we’re going to learn how to create a new File in Java – first using the Files and Path classes from NIO, then the Java File and FileOutputStream classes, Google Guava, and finally the Apache Commons IO library.
This article is part of the “Java – Back to Basic” series here on Baeldung.
2. Setup
In the examples, we’ll define a constant for the file name:
private final String FILE_NAME = "src/test/resources/fileToCreate.txt";And we’ll also add a clean-up step to make sure that the file doesn’t already exist before each test, and to delete it after each test runs:
@AfterEach @BeforeEach public void cleanUpFiles()
3. Using NIO Files.createFile()
Let’s start by using the Files.createFile() method from the Java NIO package:
@Test public void givenUsingNio_whenCreatingFile_thenCorrect() throws IOException
As you can see the code is still very simple; we’re now using the new Path interface instead of the old File.
One thing to note here is that the new API makes good use of exceptions. If the file already exists, we no longer have to check a return code. Instead, we’ll get a FileAlreadyExistsException:
java.nio.file.FileAlreadyExistsException: 4. Using File.createNewFile()
Let's now look at how we can do the same using the java.io.File class:
@Test public void givenUsingFile_whenCreatingFile_thenCorrect() throws IOException
Note that the file must not exist for this operation to succeed. If the file does exist, then the createNewFile() operation will return false.
5. Using FileOutputStream
Another way to create a new file is to use the java.io.FileOutputStream:
@Test public void givenUsingFileOutputStream_whenCreatingFile_thenCorrect() throws IOException < try(FileOutputStream fileOutputStream = new FileOutputStream(FILE_NAME))< >>In this case, a new file is created when we instantiate the FileOutputStream object. If a file with a given name already exists, it will be overwritten. If, however, the existing file is a directory or a new file cannot be created for any reason, then we'll get a FileNotFoundException.
Additionally, note we used a try-with-resources statement – to be sure that a stream is properly closed.
6. Using Guava
The Guava solution for creating a new file is a quick one-liner as well:
@Test public void givenUsingGuava_whenCreatingFile_thenCorrect() throws IOException
7. Using Apache Commons IO
The Apache Commons library provides the FileUtils.touch() method which implements the same behavior as the “touch” utility in Linux.
Therefore it creates a new empty file or even a file and the full path to it in a file system:
@Test public void givenUsingCommonsIo_whenCreatingFile_thenCorrect() throws IOException
Note that this behaves slightly differently than the previous examples: if the file already exists, the operation doesn't fail, it simply doesn't do anything.
And there we have it – 4 quick ways to create a new file in Java.
8. Conclusion
In this article, we looked at different solutions for creating a file in Java. We used classes that are part of the JDK and external libraries.
The code for the examples is available over on GitHub.
Slow MySQL query performance is all too common. Of course it is. A good way to go is, naturally, a dedicated profiler that actually understands the ins and outs of MySQL.
The Jet Profiler was built for MySQL only, so it can do things like real-time query performance, focus on most used tables or most frequent queries, quickly identify performance issues and basically help you optimize your queries.
Critically, it has very minimal impact on your server's performance, with most of the profiling work done separately - so it needs no server changes, agents or separate services.
Basically, you install the desktop application, connect to your MySQL server, hit the record button, and you'll have results within minutes: