60 lines
1.9 KiB
Java
60 lines
1.9 KiB
Java
// newio/BufferToText.java
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// (c)2016 MindView LLC: see Copyright.txt
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// We make no guarantees that this code is fit for any purpose.
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// Visit http://mindviewinc.com/Books/OnJava/ for more book information.
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// Converting text to and from ByteBuffers
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import java.nio.*;
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import java.nio.channels.*;
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import java.nio.charset.*;
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import java.io.*;
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public class BufferToText {
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private static final int BSIZE = 1024;
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public static void main(String[] args) throws Exception {
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FileChannel fc =
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new FileOutputStream("data2.txt").getChannel();
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fc.write(ByteBuffer.wrap("Some text".getBytes()));
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fc.close();
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fc = new FileInputStream("data2.txt").getChannel();
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ByteBuffer buff = ByteBuffer.allocate(BSIZE);
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fc.read(buff);
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buff.flip();
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// Doesn't work:
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System.out.println(buff.asCharBuffer());
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// Decode using this system's default Charset:
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buff.rewind();
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String encoding = System.getProperty("file.encoding");
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System.out.println("Decoded using " + encoding + ": "
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+ Charset.forName(encoding).decode(buff));
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// Or, we could encode with something that prints:
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fc = new FileOutputStream("data2.txt").getChannel();
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fc.write(ByteBuffer.wrap(
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"Some text".getBytes("UTF-16BE")));
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fc.close();
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// Now try reading again:
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fc = new FileInputStream("data2.txt").getChannel();
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buff.clear();
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fc.read(buff);
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buff.flip();
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System.out.println(buff.asCharBuffer());
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// Use a CharBuffer to write through:
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fc = new FileOutputStream("data2.txt").getChannel();
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buff = ByteBuffer.allocate(24); // More than needed
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buff.asCharBuffer().put("Some text");
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fc.write(buff);
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fc.close();
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// Read and display:
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fc = new FileInputStream("data2.txt").getChannel();
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buff.clear();
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fc.read(buff);
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buff.flip();
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System.out.println(buff.asCharBuffer());
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}
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}
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/* Output:
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????
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Decoded using Cp1252: Some text
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Some text
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Some textNULNULNUL
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*/
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