Java IO.pdf - Nguyen Dang Binh

public int hashCode()
public boolean equals(Object o)
public String toString()
Java I/O
In Java 2, the File class implements the java.lang.Comparable interface so that two
pathnames may be compared to each other. This requires these two compareTo() methods:
public int compareTo(File pathname) // Java 2
public int compareTo(Object o) // Java 2
For example:
File f1 = new File("readme.txt");
File f2 = new File("README.TXT");
int result = f1.compareTo(f2);
This method returns a number less than zero if f1 is less than f2, zero if they're the same, and
a positive number if f1 is greater than f2. The comparison is made against the path fields of
f1 and f2. The algorithm used for comparison is more or less alphabetical. On caseinsensitive
platforms like Windows and the Mac, case is not considered. For instance, the
previous result would be zero on the Mac or Windows but positive on Unix.
12.3.7 Working with Directories
A File object can represent a directory as easily as a file. Most of the File methods, like
getName(), canWrite(), and getPath(), behave exactly the same for a directory as they do
for a file. However, there are a couple of methods in the File class that behave differently
when they operate on directories than they do when operating on ordinary files.
The delete() method only works on empty directories. If a directory contains even one file,
it can't be easily deleted. If you attempt to delete a nonempty directory, delete() fails and
returns false. No exception is thrown.
The renameTo() method works on both empty and nonempty directories. However—whether
a directory is empty or not—renameTo() can only rename it, not move it to a different
directory. If you attempt to move a directory into another directory, renameTo() fails and
returns false. No exception is thrown.
The File class also has several methods that just work with directories, not with regular files.
12.3.7.1 Creating directories
To create a file, you open a FileOutputStream to it (Java 1.0 and 1.1) or call
createNewFile() (Java 2). This doesn't work for directories, though. For that purpose, the
File class has a mkdir() method:
public boolean mkdir()
The mkdir() method attempts to create a directory with the path specified in the path field. If
the directory is created, the method returns true. For example:
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