Java tutorial
//package com.java2s; /* * This file is part of OpenVPN-Settings. * * Copyright 2009-2012 Friedrich Schuffelhut * * OpenVPN-Settings is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * OpenVPN-Settings is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with OpenVPN-Settings. If not, see <http://www.gnu.org/licenses/>. * * Report bugs or new features at: http://code.google.com/p/android-openvpn-settings/ * Contact the author at: android.openvpn@schaeuffelhut.de */ import java.io.CharArrayWriter; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.OutputStream; import java.io.OutputStreamWriter; import java.io.Reader; import java.io.Writer; public class Main { /** * The default buffer size to use for * {@link #copyLarge(InputStream, OutputStream)} * and * {@link #copyLarge(Reader, Writer)} */ private static final int DEFAULT_BUFFER_SIZE = 1024 * 4; /** * Get the contents of an <code>InputStream</code> as a character array * using the default character encoding of the platform. * <p> * This method buffers the input internally, so there is no need to use a * <code>BufferedInputStream</code>. * * @param is the <code>InputStream</code> to read from * @return the requested character array * @throws NullPointerException if the input is null * @throws IOException if an I/O error occurs * @since Commons IO 1.1 */ public static char[] toCharArray(InputStream is) throws IOException { CharArrayWriter output = new CharArrayWriter(); copy(is, output); return output.toCharArray(); } /** * Get the contents of an <code>InputStream</code> as a character array * using the specified character encoding. * <p> * Character encoding names can be found at * <a href="http://www.iana.org/assignments/character-sets">IANA</a>. * <p> * This method buffers the input internally, so there is no need to use a * <code>BufferedInputStream</code>. * * @param is the <code>InputStream</code> to read from * @param encoding the encoding to use, null means platform default * @return the requested character array * @throws NullPointerException if the input is null * @throws IOException if an I/O error occurs * @since Commons IO 1.1 */ public static char[] toCharArray(InputStream is, String encoding) throws IOException { CharArrayWriter output = new CharArrayWriter(); copy(is, output, encoding); return output.toCharArray(); } /** * Get the contents of a <code>Reader</code> as a character array. * <p> * This method buffers the input internally, so there is no need to use a * <code>BufferedReader</code>. * * @param input the <code>Reader</code> to read from * @return the requested character array * @throws NullPointerException if the input is null * @throws IOException if an I/O error occurs * @since Commons IO 1.1 */ public static char[] toCharArray(Reader input) throws IOException { CharArrayWriter sw = new CharArrayWriter(); copy(input, sw); return sw.toCharArray(); } /** * Copy bytes from an <code>InputStream</code> to an * <code>OutputStream</code>. * <p> * This method buffers the input internally, so there is no need to use a * <code>BufferedInputStream</code>. * <p> * Large streams (over 2GB) will return a bytes copied value of * <code>-1</code> after the copy has completed since the correct * number of bytes cannot be returned as an int. For large streams * use the <code>copyLarge(InputStream, OutputStream)</code> method. * * @param input the <code>InputStream</code> to read from * @param output the <code>OutputStream</code> to write to * @return the number of bytes copied, or -1 if > Integer.MAX_VALUE * @throws NullPointerException if the input or output is null * @throws IOException if an I/O error occurs * @since Commons IO 1.1 */ public static int copy(InputStream input, OutputStream output) throws IOException { long count = copyLarge(input, output); if (count > Integer.MAX_VALUE) { return -1; } return (int) count; } /** * Copy bytes from an <code>InputStream</code> to chars on a * <code>Writer</code> using the default character encoding of the platform. * <p> * This method buffers the input internally, so there is no need to use a * <code>BufferedInputStream</code>. * <p> * This method uses {@link InputStreamReader}. * * @param input the <code>InputStream</code> to read from * @param output the <code>Writer</code> to write to * @throws NullPointerException if the input or output is null * @throws IOException if an I/O error occurs * @since Commons IO 1.1 */ public static void copy(InputStream input, Writer output) throws IOException { InputStreamReader in = new InputStreamReader(input); copy(in, output); } /** * Copy bytes from an <code>InputStream</code> to chars on a * <code>Writer</code> using the specified character encoding. * <p> * This method buffers the input internally, so there is no need to use a * <code>BufferedInputStream</code>. * <p> * Character encoding names can be found at * <a href="http://www.iana.org/assignments/character-sets">IANA</a>. * <p> * This method uses {@link InputStreamReader}. * * @param input the <code>InputStream</code> to read from * @param output the <code>Writer</code> to write to * @param encoding the encoding to use, null means platform default * @throws NullPointerException if the input or output is null * @throws IOException if an I/O error occurs * @since Commons IO 1.1 */ public static void copy(InputStream input, Writer output, String encoding) throws IOException { if (encoding == null) { copy(input, output); } else { InputStreamReader in = new InputStreamReader(input, encoding); copy(in, output); } } /** * Copy chars from a <code>Reader</code> to a <code>Writer</code>. * <p> * This method buffers the input internally, so there is no need to use a * <code>BufferedReader</code>. * <p> * Large streams (over 2GB) will return a chars copied value of * <code>-1</code> after the copy has completed since the correct * number of chars cannot be returned as an int. For large streams * use the <code>copyLarge(Reader, Writer)</code> method. * * @param input the <code>Reader</code> to read from * @param output the <code>Writer</code> to write to * @return the number of characters copied, or -1 if > Integer.MAX_VALUE * @throws NullPointerException if the input or output is null * @throws IOException if an I/O error occurs * @since Commons IO 1.1 */ public static int copy(Reader input, Writer output) throws IOException { long count = copyLarge(input, output); if (count > Integer.MAX_VALUE) { return -1; } return (int) count; } /** * Copy chars from a <code>Reader</code> to bytes on an * <code>OutputStream</code> using the default character encoding of the * platform, and calling flush. * <p> * This method buffers the input internally, so there is no need to use a * <code>BufferedReader</code>. * <p> * Due to the implementation of OutputStreamWriter, this method performs a * flush. * <p> * This method uses {@link OutputStreamWriter}. * * @param input the <code>Reader</code> to read from * @param output the <code>OutputStream</code> to write to * @throws NullPointerException if the input or output is null * @throws IOException if an I/O error occurs * @since Commons IO 1.1 */ public static void copy(Reader input, OutputStream output) throws IOException { OutputStreamWriter out = new OutputStreamWriter(output); copy(input, out); // XXX Unless anyone is planning on rewriting OutputStreamWriter, we // have to flush here. out.flush(); } /** * Copy chars from a <code>Reader</code> to bytes on an * <code>OutputStream</code> using the specified character encoding, and * calling flush. * <p> * This method buffers the input internally, so there is no need to use a * <code>BufferedReader</code>. * <p> * Character encoding names can be found at * <a href="http://www.iana.org/assignments/character-sets">IANA</a>. * <p> * Due to the implementation of OutputStreamWriter, this method performs a * flush. * <p> * This method uses {@link OutputStreamWriter}. * * @param input the <code>Reader</code> to read from * @param output the <code>OutputStream</code> to write to * @param encoding the encoding to use, null means platform default * @throws NullPointerException if the input or output is null * @throws IOException if an I/O error occurs * @since Commons IO 1.1 */ public static void copy(Reader input, OutputStream output, String encoding) throws IOException { if (encoding == null) { copy(input, output); } else { OutputStreamWriter out = new OutputStreamWriter(output, encoding); copy(input, out); // XXX Unless anyone is planning on rewriting OutputStreamWriter, // we have to flush here. out.flush(); } } /** * Copy bytes from a large (over 2GB) <code>InputStream</code> to an * <code>OutputStream</code>. * <p> * This method buffers the input internally, so there is no need to use a * <code>BufferedInputStream</code>. * * @param input the <code>InputStream</code> to read from * @param output the <code>OutputStream</code> to write to * @return the number of bytes copied * @throws NullPointerException if the input or output is null * @throws IOException if an I/O error occurs * @since Commons IO 1.3 */ public static long copyLarge(InputStream input, OutputStream output) throws IOException { byte[] buffer = new byte[DEFAULT_BUFFER_SIZE]; long count = 0; int n = 0; while (-1 != (n = input.read(buffer))) { output.write(buffer, 0, n); count += n; } return count; } /** * Copy chars from a large (over 2GB) <code>Reader</code> to a <code>Writer</code>. * <p> * This method buffers the input internally, so there is no need to use a * <code>BufferedReader</code>. * * @param input the <code>Reader</code> to read from * @param output the <code>Writer</code> to write to * @return the number of characters copied * @throws NullPointerException if the input or output is null * @throws IOException if an I/O error occurs * @since Commons IO 1.3 */ public static long copyLarge(Reader input, Writer output) throws IOException { char[] buffer = new char[DEFAULT_BUFFER_SIZE]; long count = 0; int n = 0; while (-1 != (n = input.read(buffer))) { output.write(buffer, 0, n); count += n; } return count; } /** * Read characters from an input character stream. * This implementation guarantees that it will read as many characters * as possible before giving up; this may not always be the case for * subclasses of {@link Reader}. * * @param input where to read input from * @param buffer destination * @param offset inital offset into buffer * @param length length to read, must be >= 0 * @return actual length read; may be less than requested if EOF was reached * @throws IOException if a read error occurs */ public static int read(Reader input, char[] buffer, int offset, int length) throws IOException { if (length < 0) { throw new IllegalArgumentException("Length must not be negative: " + length); } int remaining = length; while (remaining > 0) { int location = (length - remaining); int count = input.read(buffer, location, remaining); if (-1 == count) { // EOF break; } remaining -= count; } return length - remaining; } /** * Read characters from an input character stream. * This implementation guarantees that it will read as many characters * as possible before giving up; this may not always be the case for * subclasses of {@link Reader}. * * @param input where to read input from * @param buffer destination * @return actual length read; may be less than requested if EOF was reached * @throws IOException if a read error occurs */ public static int read(Reader input, char[] buffer) throws IOException { return read(input, buffer, 0, buffer.length); } /** * Read bytes from an input stream. * This implementation guarantees that it will read as many bytes * as possible before giving up; this may not always be the case for * subclasses of {@link InputStream}. * * @param input where to read input from * @param buffer destination * @param offset inital offset into buffer * @param length length to read, must be >= 0 * @return actual length read; may be less than requested if EOF was reached * @throws IOException if a read error occurs */ public static int read(InputStream input, byte[] buffer, int offset, int length) throws IOException { if (length < 0) { throw new IllegalArgumentException("Length must not be negative: " + length); } int remaining = length; while (remaining > 0) { int location = (length - remaining); int count = input.read(buffer, location, remaining); if (-1 == count) { // EOF break; } remaining -= count; } return length - remaining; } /** * Read bytes from an input stream. * This implementation guarantees that it will read as many bytes * as possible before giving up; this may not always be the case for * subclasses of {@link InputStream}. * * @param input where to read input from * @param buffer destination * @return actual length read; may be less than requested if EOF was reached * @throws IOException if a read error occurs */ public static int read(InputStream input, byte[] buffer) throws IOException { return read(input, buffer, 0, buffer.length); } /** * Writes bytes from a <code>byte[]</code> to an <code>OutputStream</code>. * * @param data the byte array to write, do not modify during output, * null ignored * @param output the <code>OutputStream</code> to write to * @throws NullPointerException if output is null * @throws IOException if an I/O error occurs * @since Commons IO 1.1 */ public static void write(byte[] data, OutputStream output) throws IOException { if (data != null) { output.write(data); } } /** * Writes bytes from a <code>byte[]</code> to chars on a <code>Writer</code> * using the default character encoding of the platform. * <p> * This method uses {@link String#String(byte[])}. * * @param data the byte array to write, do not modify during output, * null ignored * @param output the <code>Writer</code> to write to * @throws NullPointerException if output is null * @throws IOException if an I/O error occurs * @since Commons IO 1.1 */ public static void write(byte[] data, Writer output) throws IOException { if (data != null) { output.write(new String(data)); } } /** * Writes bytes from a <code>byte[]</code> to chars on a <code>Writer</code> * using the specified character encoding. * <p> * Character encoding names can be found at * <a href="http://www.iana.org/assignments/character-sets">IANA</a>. * <p> * This method uses {@link String#String(byte[], String)}. * * @param data the byte array to write, do not modify during output, * null ignored * @param output the <code>Writer</code> to write to * @param encoding the encoding to use, null means platform default * @throws NullPointerException if output is null * @throws IOException if an I/O error occurs * @since Commons IO 1.1 */ public static void write(byte[] data, Writer output, String encoding) throws IOException { if (data != null) { if (encoding == null) { write(data, output); } else { output.write(new String(data, encoding)); } } } /** * Writes chars from a <code>char[]</code> to a <code>Writer</code> * using the default character encoding of the platform. * * @param data the char array to write, do not modify during output, * null ignored * @param output the <code>Writer</code> to write to * @throws NullPointerException if output is null * @throws IOException if an I/O error occurs * @since Commons IO 1.1 */ public static void write(char[] data, Writer output) throws IOException { if (data != null) { output.write(data); } } /** * Writes chars from a <code>char[]</code> to bytes on an * <code>OutputStream</code>. * <p> * This method uses {@link String#String(char[])} and * {@link String#getBytes()}. * * @param data the char array to write, do not modify during output, * null ignored * @param output the <code>OutputStream</code> to write to * @throws NullPointerException if output is null * @throws IOException if an I/O error occurs * @since Commons IO 1.1 */ public static void write(char[] data, OutputStream output) throws IOException { if (data != null) { output.write(new String(data).getBytes()); } } /** * Writes chars from a <code>char[]</code> to bytes on an * <code>OutputStream</code> using the specified character encoding. * <p> * Character encoding names can be found at * <a href="http://www.iana.org/assignments/character-sets">IANA</a>. * <p> * This method uses {@link String#String(char[])} and * {@link String#getBytes(String)}. * * @param data the char array to write, do not modify during output, * null ignored * @param output the <code>OutputStream</code> to write to * @param encoding the encoding to use, null means platform default * @throws NullPointerException if output is null * @throws IOException if an I/O error occurs * @since Commons IO 1.1 */ public static void write(char[] data, OutputStream output, String encoding) throws IOException { if (data != null) { if (encoding == null) { write(data, output); } else { output.write(new String(data).getBytes(encoding)); } } } /** * Writes chars from a <code>CharSequence</code> to a <code>Writer</code>. * * @param data the <code>CharSequence</code> to write, null ignored * @param output the <code>Writer</code> to write to * @throws NullPointerException if output is null * @throws IOException if an I/O error occurs * @since Commons IO 2.0 */ public static void write(CharSequence data, Writer output) throws IOException { if (data != null) { write(data.toString(), output); } } /** * Writes chars from a <code>CharSequence</code> to bytes on an * <code>OutputStream</code> using the default character encoding of the * platform. * <p> * This method uses {@link String#getBytes()}. * * @param data the <code>CharSequence</code> to write, null ignored * @param output the <code>OutputStream</code> to write to * @throws NullPointerException if output is null * @throws IOException if an I/O error occurs * @since Commons IO 2.0 */ public static void write(CharSequence data, OutputStream output) throws IOException { if (data != null) { write(data.toString(), output); } } /** * Writes chars from a <code>CharSequence</code> to bytes on an * <code>OutputStream</code> using the specified character encoding. * <p> * Character encoding names can be found at * <a href="http://www.iana.org/assignments/character-sets">IANA</a>. * <p> * This method uses {@link String#getBytes(String)}. * * @param data the <code>CharSequence</code> to write, null ignored * @param output the <code>OutputStream</code> to write to * @param encoding the encoding to use, null means platform default * @throws NullPointerException if output is null * @throws IOException if an I/O error occurs * @since Commons IO 2.0 */ public static void write(CharSequence data, OutputStream output, String encoding) throws IOException { if (data != null) { write(data.toString(), output, encoding); } } /** * Writes chars from a <code>String</code> to a <code>Writer</code>. * * @param data the <code>String</code> to write, null ignored * @param output the <code>Writer</code> to write to * @throws NullPointerException if output is null * @throws IOException if an I/O error occurs * @since Commons IO 1.1 */ public static void write(String data, Writer output) throws IOException { if (data != null) { output.write(data); } } /** * Writes chars from a <code>String</code> to bytes on an * <code>OutputStream</code> using the default character encoding of the * platform. * <p> * This method uses {@link String#getBytes()}. * * @param data the <code>String</code> to write, null ignored * @param output the <code>OutputStream</code> to write to * @throws NullPointerException if output is null * @throws IOException if an I/O error occurs * @since Commons IO 1.1 */ public static void write(String data, OutputStream output) throws IOException { if (data != null) { output.write(data.getBytes()); } } /** * Writes chars from a <code>String</code> to bytes on an * <code>OutputStream</code> using the specified character encoding. * <p> * Character encoding names can be found at * <a href="http://www.iana.org/assignments/character-sets">IANA</a>. * <p> * This method uses {@link String#getBytes(String)}. * * @param data the <code>String</code> to write, null ignored * @param output the <code>OutputStream</code> to write to * @param encoding the encoding to use, null means platform default * @throws NullPointerException if output is null * @throws IOException if an I/O error occurs * @since Commons IO 1.1 */ public static void write(String data, OutputStream output, String encoding) throws IOException { if (data != null) { if (encoding == null) { write(data, output); } else { output.write(data.getBytes(encoding)); } } } /** * Writes chars from a <code>StringBuffer</code> to a <code>Writer</code>. * * @param data the <code>StringBuffer</code> to write, null ignored * @param output the <code>Writer</code> to write to * @throws NullPointerException if output is null * @throws IOException if an I/O error occurs * @since Commons IO 1.1 * @deprecated replaced by write(CharSequence, Writer) */ @Deprecated public static void write(StringBuffer data, Writer output) throws IOException { if (data != null) { output.write(data.toString()); } } /** * Writes chars from a <code>StringBuffer</code> to bytes on an * <code>OutputStream</code> using the default character encoding of the * platform. * <p> * This method uses {@link String#getBytes()}. * * @param data the <code>StringBuffer</code> to write, null ignored * @param output the <code>OutputStream</code> to write to * @throws NullPointerException if output is null * @throws IOException if an I/O error occurs * @since Commons IO 1.1 * @deprecated replaced by write(CharSequence, OutputStream) */ @Deprecated public static void write(StringBuffer data, OutputStream output) throws IOException { if (data != null) { output.write(data.toString().getBytes()); } } /** * Writes chars from a <code>StringBuffer</code> to bytes on an * <code>OutputStream</code> using the specified character encoding. * <p> * Character encoding names can be found at * <a href="http://www.iana.org/assignments/character-sets">IANA</a>. * <p> * This method uses {@link String#getBytes(String)}. * * @param data the <code>StringBuffer</code> to write, null ignored * @param output the <code>OutputStream</code> to write to * @param encoding the encoding to use, null means platform default * @throws NullPointerException if output is null * @throws IOException if an I/O error occurs * @since Commons IO 1.1 * @deprecated replaced by write(CharSequence, OutputStream, String) */ @Deprecated public static void write(StringBuffer data, OutputStream output, String encoding) throws IOException { if (data != null) { if (encoding == null) { write(data, output); } else { output.write(data.toString().getBytes(encoding)); } } } }