java-classic-code/serializer/StringSerializer.java

package com.sdyc.ndmp.protobuf.serializer;

import java.nio.charset.Charset;

/**
 * <pre>
 *
 * Created by IntelliJ IDEA.
 * User: ZhenQin
 * Date: 13-10-8
 * Time: 上午9:57
 * To change this template use File | Settings | File Templates.
 *
 * </pre>
 *
 * @author ZhenQin
 */
public class StringSerializer implements Serializer<String> {

    private static final long serialVersionUID = 1L;
    /**
     * 默认支持的编码类型
     */
    private Charset charset = Charset.forName("UTF-8");


    /**
     * 默认是UTF-8的数据编码类型
     */
    public StringSerializer() {

    }


    /**
     * 自己指定数据编码类型
     * @param charset
     */
    public StringSerializer(Charset charset) {
        this.charset = charset;
    }


    /**
     * 自己指定数据编码类型
     * @param charset
     */
    public StringSerializer(String charset) {
        this.charset = Charset.forName(charset);
    }

    /**
     * Serialize the given object to binary data.
     *
     * @param s object to serialize
     * @return the equivalent binary data
     */
    @Override
    public byte[] serialize(String s) {
        return s.getBytes(charset);
    }




    public String deserialize(byte[] bytes, int offset, int length) {
        return new String(bytes, offset, length, charset);
    }



    /**
     * Deserialize an object from the given binary data.
     *
     * @param bytes object binary representation
     * @return the equivalent object instance
     */
    @Override
    public String deserialize(byte[] bytes) {
        return new String(bytes, charset);
    }


    public Charset getCharset() {
        return charset;
    }

    public void setCharset(Charset charset) {
        this.charset = charset;
    }

    /**
     * 把非字符串化的字符串转换成 String
     * @param bytes
     * @return
     */
    public static String toString(byte[] bytes) {
        StringBuffer strBuf = new StringBuffer();

        for (int i = 0; i < bytes.length; i++) {
            strBuf.append((char) (((bytes[i] >> 4) & 0xF) + ((int) 'a')));
            strBuf.append((char) (((bytes[i]) & 0xF) + ((int) 'a')));
        }

        return strBuf.toString();
    }


    /**
     * 把非字符串化的字符串转换成 byte
     * @param str
     * @return
     */
    public static byte[] toBytes(String str) {
        byte[] bytes = new byte[str.length() / 2];
        for (int i = 0; i < str.length(); i += 2) {
            char c = str.charAt(i);
            bytes[i / 2] = (byte) ((c - 'a') << 4);
            c = str.charAt(i + 1);
            bytes[i / 2] += (c - 'a');
        }
        return bytes;
    }
}