Java Byte Array to String by Charset getPrefixWithMaxBytes(String string, int maxBytes, Charset charSet)

Description

Returns the prefix of string which takes up a maximum of maxBytes.

License

Open Source License

Exception

Parameter	Description
CharacterCodingException	an exception

Declaration

static String getPrefixWithMaxBytes(String string, int maxBytes, Charset charSet)
        throws CharacterCodingException 

Method Source Code

//package com.java2s;
/*//from   ww w. j  a  va2 s .  c o m
 * This program 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.
 *
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 */

import java.io.UnsupportedEncodingException;

import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.CharacterCodingException;
import java.nio.charset.Charset;
import java.nio.charset.CharsetEncoder;
import java.nio.charset.CoderResult;

public class Main {
    /**
     * Returns the prefix of <code>string</code> which takes up a maximum
     * of <code>maxBytes</code>.
     * @throws CharacterCodingException 
     */
    static String getPrefixWithMaxBytes(String string, int maxBytes, Charset charSet)
            throws CharacterCodingException {
        try {
            return new String(getMaxBytes(string, maxBytes, charSet), charSet.name());
        } catch (UnsupportedEncodingException uee) {
            throw new RuntimeException("Could not recreate string", uee);
        }
    }

    /**
     * Returns the first <code>maxBytes</code> of <code>string</code> encoded 
     * using the encoder of <code>charSet</code>
     * @param string whose prefix bytes to return
     * @param maxBytes the maximum number of bytes to return
     * @param charSet the char set used for encoding the characters into bytes
     * @return the array of bytes of length <= maxBytes
     * @throws CharacterCodingException if the char set's encoder could not
     * handle the characters in the string
     */
    static byte[] getMaxBytes(String string, int maxBytes, Charset charSet) throws CharacterCodingException {
        byte[] bytes = new byte[maxBytes];
        ByteBuffer out = ByteBuffer.wrap(bytes);
        CharBuffer in = CharBuffer.wrap(string.toCharArray());
        CharsetEncoder encoder = charSet.newEncoder();
        CoderResult cr = encoder.encode(in, out, true);
        encoder.flush(out);
        if (cr.isError()) {
            cr.throwException();
        }
        byte[] result = new byte[out.position()];
        System.arraycopy(bytes, 0, result, 0, result.length);
        return result;
    }
}

Related

1. getBytesUnchecked(String string, String charsetName)
2. getChars(byte[] data, String charset)
3. getContentAsString(byte[] content, Charset charset)
4. getMaxBytes(String string, int maxBytes, Charset charSet)
5. getNumberOfBytesPerCharacter(final String charsetName)
6. getRowId(final byte[] rowId, final Charset charset, final boolean base64encodeValues)
7. getString(@Nonnull byte[] b, @Nonnegative int bufferSize, @Nonnegative int offset, @Nonnull Charset charset)
8. getString(byte[] bytes, String charset)
9. getString(byte[] bytesIn, Charset cs)