How to get file size in Java [duplicate]

Answer 1

Use the length() method in the File class. From the javadocs:

Returns the length of the file denoted by this abstract pathname. The return value is unspecified if this pathname denotes a directory.

UPDATED Nowadays we should use the Files.size() method:

Paths path = Paths.get("/path/to/file");
long size = Files.size(path);

For the second part of the question, straight from File's javadocs:

• getUsableSpace() Returns the number of bytes available to this virtual machine on the partition named by this abstract pathname

• getTotalSpace() Returns the size of the partition named by this abstract pathname

• getFreeSpace() Returns the number of unallocated bytes in the partition named by this abstract path name

Answer 2

Try this:

long length = f.length();

Answer 3

Did a quick google. Seems that to find the file size you do this,

long size = f.length();

The differences between the three methods you posted can be found here

getFreeSpace() and getTotalSpace() are pretty self explanatory, getUsableSpace() seems to be the space that the JVM can use, which in most cases will be the same as the amount of free space.