How to unzip a zip file in Java
This article shows how to use ZipInputStream and zip4j library to unzip a zip file in Java. To unzip a file manually, remember to add validation for the zip slip…
How to create Zip file in Java
This article shows a few examples to zip a single file and a whole directory (including sub-files and subdirectories): (1) Zip a file – java.util.zip, (2) Zip a file –…
Java – Convert File to Hex
This article shows how to convert a file into a hexadecimal (hex) representative format. The idea is to read the file into an InputStream and uses String.format(%X) to convert each…
Java – How to save byte[] to a file
This article shows a few ways to save a byte into a file. For JDK 1.7 and above, the NIO Files.write is the simplest solution to save byte to a…
Java – How to convert File to byte[]
In Java, we can use Files.readAllBytes(path) to convert a File object into a byte. Before Java 7, we can initiate a new byte with a predefined size (same with the…
How to check if a file exists in Java
In Java, we can use Files.exists(path) to test whether a file exists. The path can be a file or a directory. It is better to combine with !Files.isDirectory(path) to ensure…
Java – Count number of lines in a file
This article shows few Java examples to get the total number of lines in a file. The steps are similar: (1) Open the file, (2) Read line by line, and…
How to get file size in Java
In Java, we can use Files.size(path) to get the size of a file in bytes. This example uses NIO Files.size(path) to print the size of an image file (140 kb).…
How to get file creation date in Java
In Java (@since 1.7), we can use the NIO Files.readAttributes to get all the file metadata, including the file creation date. We also can use the same code to get…
How to rename or move a file in Java
In Java, we can use the NIO Files.move(source, target) to rename or move a file. The Apache FileUtils.moveFile uses a "copy and delete" mechanism to rename or move a file.…