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| package com.util;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.ByteArrayInputStream;
import java.io.CharArrayReader;
import java.io.Closeable;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.util.ArrayList;
import java.util.List;
public class Util {
private static final String LINE_SEPARATOR = System.getProperty("line.separator");
// Constructors -------------------------------------------------------------------------------
private Util() {
// Utility class, hide constructor.
}
// Writers ------------------------------------------------------------------------------------
/**
* Write byte array to file. If file already exists, it will be overwritten.
* @param file The file where the given byte array have to be written to.
* @param bytes The byte array which have to be written to the given file.
* @throws IOException If writing file fails.
*/
public static void write(File file, byte[] bytes) throws IOException {
write(file, new ByteArrayInputStream(bytes), false);
}
/**
* Write byte array to file with option to append to file or not. If not, then any existing
* file will be overwritten.
* @param file The file where the given byte array have to be written to.
* @param bytes The byte array which have to be written to the given file.
* @param append Append to file?
* @throws IOException If writing file fails.
*/
public static void write(File file, byte[] bytes, boolean append) throws IOException {
write(file, new ByteArrayInputStream(bytes), append);
}
/**
* Write byte inputstream to file. If file already exists, it will be overwritten.It's highly
* recommended to feed the inputstream as BufferedInputStream or ByteArrayInputStream as those
* are been automatically buffered.
* @param file The file where the given byte inputstream have to be written to.
* @param input The byte inputstream which have to be written to the given file.
* @throws IOException If writing file fails.
*/
public static void write(File file, InputStream input) throws IOException {
write(file, input, false);
}
/**
* Write byte inputstream to file with option to append to file or not. If not, then any
* existing file will be overwritten. It's highly recommended to feed the inputstream as
* BufferedInputStream or ByteArrayInputStream as those are been automatically buffered.
* @param file The file where the given byte inputstream have to be written to.
* @param input The byte inputstream which have to be written to the given file.
* @param append Append to file?
* @throws IOException If writing file fails.
*/
public static void write(File file, InputStream input, boolean append) throws IOException {
mkdirs(file);
BufferedOutputStream output = null;
try {
output = new BufferedOutputStream(new FileOutputStream(file, append));
int data = -1;
while ((data = input.read()) != -1) {
output.write(data);
}
} finally {
close(input, file);
close(output, file);
}
}
/**
* Write character array to file. If file already exists, it will be overwritten.
* @param file The file where the given character array have to be written to.
* @param chars The character array which have to be written to the given file.
* @throws IOException If writing file fails.
*/
public static void write(File file, char[] chars) throws IOException {
write(file, new CharArrayReader(chars), false);
}
/**
* Write character array to file with option to append to file or not. If not, then any
* existing file will be overwritten.
* @param file The file where the given character array have to be written to.
* @param chars The character array which have to be written to the given file.
* @param append Append to file?
* @throws IOException If writing file fails.
*/
public static void write(File file, char[] chars, boolean append) throws IOException {
write(file, new CharArrayReader(chars), append);
}
/**
* Write string value to file. If file already exists, it will be overwritten.
* @param file The file where the given string value have to be written to.
* @param string The string value which have to be written to the given file.
* @throws IOException If writing file fails.
*/
public static void write(File file, String string) throws IOException {
write(file, new CharArrayReader(string.toCharArray()), false);
}
/**
* Write string value to file with option to append to file or not. If not, then any existing
* file will be overwritten.
* @param file The file where the given string value have to be written to.
* @param string The string value which have to be written to the given file.
* @param append Append to file?
* @throws IOException If writing file fails.
*/
public static void write(File file, String string, boolean append) throws IOException {
write(file, new CharArrayReader(string.toCharArray()), append);
}
/**
* Write character reader to file. If file already exists, it will be overwritten. It's highly
* recommended to feed the reader as BufferedReader or CharArrayReader as those are been
* automatically buffered.
* @param file The file where the given character reader have to be written to.
* @param reader The character reader which have to be written to the given file.
* @throws IOException If writing file fails.
*/
public static void write(File file, Reader reader) throws IOException {
write(file, reader, false);
}
/**
* Write character reader to file with option to append to file or not. If not, then any
* existing file will be overwritten. It's highly recommended to feed the reader as
* BufferedReader or CharArrayReader as those are been automatically buffered.
* @param file The file where the given character reader have to be written to.
* @param reader The character reader which have to be written to the given file.
* @param append Append to file?
* @throws IOException If writing file fails.
*/
public static void write(File file, Reader reader, boolean append) throws IOException {
mkdirs(file);
BufferedWriter writer = null;
try {
writer = new BufferedWriter(new FileWriter(file, append));
int data = -1;
while ((data = reader.read()) != -1) {
writer.write(data);
}
} finally {
close(reader, file);
close(writer, file);
}
}
/**
* Write list of String records to file. If file already exists, it will be overwritten.
* @param file The file where the given character reader have to be written to.
* @param records The list of String records which have to be written to the given file.
* @throws IOException If writing file fails.
*/
public static void write(File file, List<String> records) throws IOException {
write(file, records, false);
}
/**
* Write list of String records to file with option to append to file or not. If not, then any
* existing file will be overwritten.
* @param file The file where the given character reader have to be written to.
* @param records The list of String records which have to be written to the given file.
* @param append Append to file?
* @throws IOException If writing file fails.
*/
public static void write(File file, List<String> records, boolean append) throws IOException {
mkdirs(file);
BufferedWriter writer = null;
try {
writer = new BufferedWriter(new FileWriter(file, append));
for (String record : records) {
writer.write(record);
writer.write(LINE_SEPARATOR);
}
} finally {
close(writer, file);
}
}
// Readers ------------------------------------------------------------------------------------
/**
* Read byte array from file. Take care with big files, this would be memory hogging, rather
* use readStream() instead.
* @param file The file to read the byte array from.
* @return The byte array with the file contents.
* @throws IOException If reading file fails.
*/
public static byte[] readBytes(File file) throws IOException {
BufferedInputStream stream = (BufferedInputStream) readStream(file);
byte[] bytes = new byte[stream.available()];
stream.read(bytes);
return bytes;
}
/**
* Read byte stream from file.
* @param file The file to read the byte stream from.
* @return The byte stream with the file contents (actually: BufferedInputStream).
* @throws IOException If reading file fails.
*/
public static InputStream readStream(File file) throws IOException {
return new BufferedInputStream(new FileInputStream(file));
}
/**
* Read character array from file. Take care with big files, this would be memory hogging,
* rather use readReader() instead.
* @param file The file to read the character array from.
* @return The character array with the file contents.
* @throws IOException If reading file fails.
*/
public static char[] readChars(File file) throws IOException {
BufferedReader reader = (BufferedReader) readReader(file);
char[] chars = new char[(int) file.length()];
reader.read(chars);
return chars;
}
/**
* Read string value from file. Take care with big files, this would be memory hogging, rather
* use readReader() instead.
* @param file The file to read the string value from.
* @return The string value with the file contents.
* @throws IOException If reading file fails.
*/
public static String readString(File file) throws IOException {
return new String(readChars(file));
}
/**
* Read character reader from file.
* @param file The file to read the character reader from.
* @return The character reader with the file contents (actually: BufferedReader).
* @throws IOException If reading file fails.
*/
public static Reader readReader(File file) throws IOException {
return new BufferedReader(new FileReader(file));
}
/**
* Read list of String records from file.
* @param file The file to read the character writer from.
* @return A list of String records which represents lines of the file contents.
* @throws IOException If reading file fails.
*/
public static List<String> readRecords(File file) throws IOException {
BufferedReader reader = (BufferedReader) readReader(file);
List<String> records = new ArrayList<String>();
String record = null;
try {
while ((record = reader.readLine()) != null) {
records.add(record);
}
} finally {
close(reader, file);
}
return records;
}
// Copiers ------------------------------------------------------------------------------------
/**
* Copy file. Any existing file at the destination will be overwritten.
* @param source The file to read the contents from.
* @param destination The file to write the contents to.
* @throws IOException If copying file fails.
*/
public static void copy(File source, File destination) throws IOException {
copy(source, destination, true);
}
/**
* Copy file with the option to overwrite any existing file at the destination.
* @param source The file to read the contents from.
* @param destination The file to write the contents to.
* @param overwrite Set whether to overwrite any existing file at the destination.
* @throws IOException If the destination file already exists while <tt>overwrite</tt> is set
* to false, or if copying file fails.
*/
public static void copy(File source, File destination, boolean overwrite) throws IOException {
if (destination.exists() && !overwrite) {
throw new IOException(
"Copying file " + source.getPath() + " to " + destination.getPath() + " failed."
+ " The destination file already exists.");
}
mkdirs(destination);
BufferedInputStream input = null;
BufferedOutputStream output = null;
try {
input = new BufferedInputStream(new FileInputStream(source));
output = new BufferedOutputStream(new FileOutputStream(destination));
int data = -1;
while ((data = input.read()) != -1) {
output.write(data);
}
} finally {
close(input, source);
close(output, destination);
}
}
// Movers -------------------------------------------------------------------------------------
/**
* Move (rename) file. Any existing file at the destination will be overwritten.
* @param source The file to be moved.
* @param destination The new destination of the file.
* @throws IOException If moving file fails.
*/
public static void move(File source, File destination) throws IOException {
move(source, destination, true);
}
/**
* Move (rename) file with the option to overwrite any existing file at the destination.
* @param source The file to be moved.
* @param destination The new destination of the file.
* @param overwrite Set whether to overwrite any existing file at the destination.
* @throws IOException If the destination file already exists while <tt>overwrite</tt> is set
* to false, or if moving file fails.
*/
public static void move(File source, File destination, boolean overwrite) throws IOException {
if (destination.exists()) {
if (overwrite) {
destination.delete();
} else {
throw new IOException(
"Moving file " + source.getPath() + " to " + destination.getPath() + " failed."
+ " The destination file already exists.");
}
}
mkdirs(destination);
if (!source.renameTo(destination)) {
throw new IOException(
"Moving file " + source.getPath() + " to " + destination.getPath() + " failed.");
}
}
// Filenames ----------------------------------------------------------------------------------
/**
* Trim the eventual file path from the given file name. Anything before the last occurred "/"
* and "\" will be trimmed, including the slash.
* @param fileName The file name to trim the file path from.
* @return The file name with the file path trimmed.
*/
public static String trimFilePath(String fileName) {
return fileName
.substring(fileName.lastIndexOf("/") + 1)
.substring(fileName.lastIndexOf("\\") + 1);
}
/**
* Generate unique file based on the given path and name. If the file exists, then it will
* add "[i]" to the file name as long as the file exists. The value of i can be between
* 0 and 2147483647 (the value of Integer.MAX_VALUE).
* @param filePath The path of the unique file.
* @param fileName The name of the unique file.
* @return The unique file.
* @throws IOException If unique file cannot be generated, this can be caused if all file
* names are already in use. You may consider another filename instead.
*/
public static File uniqueFile(File filePath, String fileName) throws IOException {
File file = new File(filePath, fileName);
if (file.exists()) {
// Split filename and add braces, e.g. "name.ext" --> "name[", "].ext".
String prefix;
String suffix;
int dotIndex = fileName.lastIndexOf(".");
if (dotIndex > -1) {
prefix = fileName.substring(0, dotIndex) + "[";
suffix = "]" + fileName.substring(dotIndex);
} else {
prefix = fileName + "[";
suffix = "]";
}
int count = 0;
// Add counter to filename as long as file exists.
while (file.exists()) {
if (count < 0) { // int++ restarts at -2147483648 after 2147483647.
throw new IOException("No unique filename available for " + fileName
+ " in path " + filePath.getPath() + ".");
}
// Glue counter between prefix and suffix, e.g. "name[" + count + "].ext".
file = new File(filePath, prefix + (count++) + suffix);
}
}
return file;
}
// Helpers ------------------------------------------------------------------------------------
/**
* Check and create missing parent directories for the given file.
* @param file The file to check and create the missing parent directories for.
* @throws IOException If the given file is actually not a file or if creating parent
* directories fails.
*/
private static void mkdirs(File file) throws IOException {
if (file.exists() && !file.isFile()) {
throw new IOException("File " + file.getPath() + " is actually not a file.");
}
File parentFile = file.getParentFile();
if (!parentFile.exists() && !parentFile.mkdirs()) {
throw new IOException("Creating directories " + parentFile.getPath() + " failed.");
}
}
/**
* Close the given I/O resource of the given file.
* @param resource The I/O resource to be closed.
* @param file The I/O resource's subject.
*/
private static void close(Closeable resource, File file) {
if (resource != null) {
try {
resource.close();
} catch (IOException e) {
String message = "Closing file " + file.getPath() + " failed.";
// Do your thing with the exception and the message. Print it, log it or mail it.
System.err.println(message);
e.printStackTrace();
}
}
}
} |
