Java by API/java.nio/CharBuffer
Содержание
- 1 CharBuffer: allocate(int capacity)
- 2 CharBuffer: array()
- 3 CharBuffer: arrayOffset()
- 4 CharBuffer: capacity()
- 5 CharBuffer: flip()
- 6 CharBuffer: get()
- 7 CharBuffer: hasArray()
- 8 CharBuffer: hasRemaining()
- 9 CharBuffer: limit()
- 10 CharBuffer: limit(int newLimit)
- 11 CharBuffer: position()
- 12 CharBuffer: put(char c)
- 13 CharBuffer: put(String str)
- 14 CharBuffer: slice()
- 15 CharBuffer: subSequence(int start, int end)
- 16 CharBuffer: wrap(char[] array, int offset, int length)
- 17 CharBuffer: wrap(CharSequence csq)
CharBuffer: allocate(int capacity)
import java.nio.CharBuffer;
public class Main {
public static void main(String[] argv) throws Exception {
CharBuffer cb = CharBuffer.allocate(100);
cb.put("This is a test String");
cb.flip();
System.out.println("hasArray() = " + cb.hasArray());
char[] carray = cb.array();
System.out.print("array=");
for (int i = 0; i < carray.length; i++) {
System.out.print(carray[i]);
}
}
}
CharBuffer: array()
import java.nio.CharBuffer;
public class Main {
public static void main(String[] argv) throws Exception {
CharBuffer cb = CharBuffer.allocate(100);
cb.put("This is a test String");
cb.flip();
System.out.println("hasArray() = " + cb.hasArray());
char[] carray = cb.array();
System.out.print("array=");
for (int i = 0; i < carray.length; i++) {
System.out.print(carray[i]);
}
}
}
CharBuffer: arrayOffset()
import java.nio.CharBuffer;
public class Main {
public static void main(String[] argv) throws Exception {
CharBuffer buffer = CharBuffer.allocate(8);
buffer.position(3).limit(5);
CharBuffer sliceBuffer = buffer.slice();
println(buffer);
println(sliceBuffer);
char[] myBuffer = new char[100];
CharBuffer cb = CharBuffer.wrap(myBuffer);
cb.position(12).limit(21);
CharBuffer sliced = cb.slice();
println(cb);
println(sliced);
}
private static void println(CharBuffer cb) {
System.out.println("pos=" + cb.position() + ", limit=" + cb.limit() + ", capacity="
+ cb.capacity() + ", arrayOffset=" + cb.arrayOffset());
}
}
CharBuffer: capacity()
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
public class MainClass {
public static void main(String[] args) {
File aFile = new File("afile.txt");
FileOutputStream outputFile = null;
try {
outputFile = new FileOutputStream(aFile, true);
System.out.println("File stream created successfully.");
} catch (FileNotFoundException e) {
e.printStackTrace(System.err);
}
ByteBuffer buf = ByteBuffer.allocate(1024);
System.out.println("\nByte buffer:");
System.out.printf("position = %2d Limit = %4d capacity = %4d%n", buf.position(), buf.limit(),
buf.capacity());
// Create a view buffer
CharBuffer charBuf = buf.asCharBuffer();
System.out.println("Char view buffer:");
System.out.printf("position = %2d Limit = %4d capacity = %4d%n", charBuf.position(), charBuf
.limit(), charBuf.capacity());
try {
outputFile.close(); // Close the O/P stream & the channel
} catch (IOException e) {
e.printStackTrace(System.err);
}
}
}
CharBuffer: flip()
import java.nio.CharBuffer;
/**
* Buffer fill/drain example. This code uses the simplest means of filling and
* draining a buffer: one element at a time.
*/
public class Main {
public static void main(String[] argv) throws Exception {
CharBuffer buffer = CharBuffer.allocate(100);
String string = "asdf";
for (int i = 0; i < string.length(); i++) {
buffer.put(string.charAt(i));
}
buffer.flip();
drainBuffer(buffer);
buffer.clear();
}
private static void drainBuffer(CharBuffer buffer) {
while (buffer.hasRemaining()) {
System.out.print(buffer.get());
}
System.out.println("");
}
}
CharBuffer: get()
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
public class Main {
private static void symmetricScramble(CharBuffer buffer) {
while (buffer.hasRemaining()) {
buffer.mark();
char c1 = buffer.get();
char c2 = buffer.get();
buffer.reset();
buffer.put(c2).put(c1);
}
}
public static void main(String[] args) {
char[] data = "UsingBuffers".toCharArray();
ByteBuffer bb = ByteBuffer.allocate(data.length * 2);
CharBuffer cb = bb.asCharBuffer();
cb.put(data);
System.out.println(cb.rewind());
symmetricScramble(cb);
System.out.println(cb.rewind());
symmetricScramble(cb);
System.out.println(cb.rewind());
}
}
CharBuffer: hasArray()
import java.nio.CharBuffer;
public class Main {
public static void main(String[] argv) throws Exception {
CharBuffer cb = CharBuffer.allocate(100);
cb.put("This is a test String");
cb.flip();
System.out.println("hasArray() = " + cb.hasArray());
char[] carray = cb.array();
System.out.print("array=");
for (int i = 0; i < carray.length; i++) {
System.out.print(carray[i]);
}
}
}
CharBuffer: hasRemaining()
import java.nio.CharBuffer;
/**
* Buffer fill/drain example. This code uses the simplest means of filling and
* draining a buffer: one element at a time.
*/
public class Main {
public static void main(String[] argv) throws Exception {
CharBuffer buffer = CharBuffer.allocate(100);
String string = "asdf";
for (int i = 0; i < string.length(); i++) {
buffer.put(string.charAt(i));
}
buffer.flip();
drainBuffer(buffer);
buffer.clear();
}
private static void drainBuffer(CharBuffer buffer) {
while (buffer.hasRemaining()) {
System.out.print(buffer.get());
}
System.out.println("");
}
}
CharBuffer: limit()
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
public class MainClass {
public static void main(String[] args) {
File aFile = new File("afile.txt");
FileOutputStream outputFile = null;
try {
outputFile = new FileOutputStream(aFile, true);
System.out.println("File stream created successfully.");
} catch (FileNotFoundException e) {
e.printStackTrace(System.err);
}
ByteBuffer buf = ByteBuffer.allocate(1024);
System.out.println("\nByte buffer:");
System.out.printf("position = %2d Limit = %4d capacity = %4d%n", buf.position(), buf.limit(),
buf.capacity());
// Create a view buffer
CharBuffer charBuf = buf.asCharBuffer();
System.out.println("Char view buffer:");
System.out.printf("position = %2d Limit = %4d capacity = %4d%n", charBuf.position(), charBuf
.limit(), charBuf.capacity());
try {
outputFile.close(); // Close the O/P stream & the channel
} catch (IOException e) {
e.printStackTrace(System.err);
}
}
}
CharBuffer: limit(int newLimit)
import java.nio.CharBuffer;
public class Main {
public static void main(String[] argv) throws Exception {
CharBuffer buffer = CharBuffer.allocate(8);
buffer.position(3).limit(5);
CharBuffer sliceBuffer = buffer.slice();
println(buffer);
println(sliceBuffer);
char[] myBuffer = new char[100];
CharBuffer cb = CharBuffer.wrap(myBuffer);
cb.position(12).limit(21);
CharBuffer sliced = cb.slice();
println(cb);
println(sliced);
}
private static void println(CharBuffer cb) {
System.out.println("pos=" + cb.position() + ", limit=" + cb.limit() + ", capacity="
+ cb.capacity() + ", arrayOffset=" + cb.arrayOffset());
}
}
CharBuffer: position()
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
public class MainClass {
public static void main(String[] args) {
File aFile = new File("afile.txt");
FileOutputStream outputFile = null;
try {
outputFile = new FileOutputStream(aFile, true);
System.out.println("File stream created successfully.");
} catch (FileNotFoundException e) {
e.printStackTrace(System.err);
}
ByteBuffer buf = ByteBuffer.allocate(1024);
System.out.println("\nByte buffer:");
System.out.printf("position = %2d Limit = %4d capacity = %4d%n", buf.position(), buf.limit(),
buf.capacity());
// Create a view buffer
CharBuffer charBuf = buf.asCharBuffer();
System.out.println("Char view buffer:");
System.out.printf("position = %2d Limit = %4d capacity = %4d%n", charBuf.position(), charBuf
.limit(), charBuf.capacity());
try {
outputFile.close(); // Close the O/P stream & the channel
} catch (IOException e) {
e.printStackTrace(System.err);
}
}
}
CharBuffer: put(char c)
import java.nio.CharBuffer;
public class Main {
public static void main(String[] args) {
CharBuffer cb1 = CharBuffer.allocate(5), cb2 = CharBuffer.allocate(5);
cb1.put("B").put("u").put("f").put("f").put("A");
cb2.put("B").put("u").put("f").put("f").put("B");
cb1.rewind();
cb2.rewind();
System.out.println(cb1.limit(4).equals(cb2.limit(4)));
}
}
CharBuffer: put(String str)
/*
* Output:
*/
import java.io.File;
import java.io.FileOutputStream;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
public class MainClass {
public static void main(String[] args) {
try {
File aFile = new File("test.txt");
FileOutputStream outputFile = null;
outputFile = new FileOutputStream(aFile, true);
FileChannel outChannel = outputFile.getChannel();
ByteBuffer buf = ByteBuffer.allocate(200);
buf.putInt(10).asCharBuffer().put("www.jexp.ru");
buf.position(10).flip();
outChannel.write(buf);
buf.clear();
outputFile.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
CharBuffer: slice()
import java.nio.CharBuffer;
public class Main {
public static void main(String[] argv) throws Exception {
CharBuffer buffer = CharBuffer.allocate(8);
buffer.position(3).limit(5);
CharBuffer sliceBuffer = buffer.slice();
println(buffer);
println(sliceBuffer);
char[] myBuffer = new char[100];
CharBuffer cb = CharBuffer.wrap(myBuffer);
cb.position(12).limit(21);
CharBuffer sliced = cb.slice();
println(cb);
println(sliced);
}
private static void println(CharBuffer cb) {
System.out.println("pos=" + cb.position() + ", limit=" + cb.limit() + ", capacity="
+ cb.capacity() + ", arrayOffset=" + cb.arrayOffset());
}
}
CharBuffer: subSequence(int start, int end)
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
public class Main {
public static void main(String[] argv) throws Exception {
ByteBuffer buf = ByteBuffer.allocate(100);
CharBuffer cbuf = buf.asCharBuffer();
cbuf.put("a string");
int start = 2; // start is relative to cbuf"s current position
int end = 5;
CharSequence sub = cbuf.subSequence(start, end); // str
}
}
CharBuffer: wrap(char[] array, int offset, int length)
import java.nio.CharBuffer;
public class Main {
public static void main(String[] argv) throws Exception {
char[] chars = new char[60];
CharBuffer cb = CharBuffer.wrap(chars, 12, 42);
println(cb);
cb.put("This is a test String");
cb.flip();
println(cb);
cb.clear();
cb.put("Foobar");
println(cb);
for (int i = 0; i < 20; i++) {
System.out.println("[" + i + "] = " + chars[i]);
}
}
private static void println(CharBuffer cb) {
System.out.println("pos=" + cb.position() + ", limit=" + cb.limit() + ", capacity="
+ cb.capacity() + ", arrayOffset=" + cb.arrayOffset());
}
}
CharBuffer: wrap(CharSequence csq)
import java.nio.CharBuffer;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.nio.charset.Charset;
import java.nio.charset.CharsetEncoder;
public class MainClass {
public static void main(String[] args) throws Exception{
CharsetEncoder encoder = Charset.forName("US-ASCII").newEncoder();
ServerSocketChannel server = ServerSocketChannel.open();
server.socket().bind(new java.net.InetSocketAddress(8000));
for (;;) { // This server runs forever
SocketChannel client = server.accept();
String response = new java.util.Date().toString() + "\r\n";
client.write(encoder.encode(CharBuffer.wrap(response)));
client.close();
}
}
}
