java enUnicode and deUnicode

参考网上程序，写一个 中文 --> unicode 以及 unicode -->中文的程序
代码

package com.tomsun.dms.user.utils;

import java.security.SecureRandom;

import org.apache.log4j.Logger;

public class Helper {

	private static final Logger LOGGER = Logger.getLogger(Helper.class);

	private static final SecureRandom SECURE_RANDOM = new SecureRandom();

	private static final String KEYS = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789@#%";

	private static final int KEYS_LENGTH = KEYS.length();

	private static final char[] hexDigit = { '0', '1', '2', '3', '4', '5', '6',
			'7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };

	public static void main(String[] args) throws Exception {   
        String Chinese_characters ="软件股份春节加班费 a a a.xls";   
        String enUnicode = toUnicode(Chinese_characters,true);
        System.out.println("enUnicode2="+enUnicode); 
           
        String deUnicode = deUnicode(enUnicode);   
        System.out.println("deUnicode2="+deUnicode);   
    } 
	private static char toHex(int nibble) {
		return hexDigit[(nibble & 0xF)];
	}

	/**
	 * 将字符串编码成 Unicode 。
	 * 
	 * @param theString
	 *            待转换成Unicode编码的字符串。
	 * @param escapeSpace
	 *            是否忽略空格。
	 * @return 返回转换后Unicode编码的字符串。
	 */
	public static String toUnicode(String theString, boolean escapeSpace) {
		int len = theString.length();
		int bufLen = len * 2;
		if (bufLen < 0) {
			bufLen = Integer.MAX_VALUE;
		}
		StringBuffer outBuffer = new StringBuffer(bufLen);
		for (int x = 0; x < len; x++) {
			char aChar = theString.charAt(x);
			// Handle common case first, selecting largest block that
			// avoids the specials below
			if ((aChar > 61) && (aChar < 127)) {
				if (aChar == '\\') {
					outBuffer.append('\\');
					outBuffer.append('\\');
					continue;
				}
				outBuffer.append(aChar);
				continue;
			}
			switch (aChar) {
			case ' ':
				if (x == 0 || escapeSpace)
					outBuffer.append('\\');
				outBuffer.append(' ');
				break;
			case '\t':
				outBuffer.append('\\');
				outBuffer.append('t');
				break;
			case '\n':
				outBuffer.append('\\');
				outBuffer.append('n');
				break;
			case '\r':
				outBuffer.append('\\');
				outBuffer.append('r');
				break;
			case '\f':
				outBuffer.append('\\');
				outBuffer.append('f');
				break;
			case '=': // Fall through
			case ':': // Fall through
			case '#': // Fall through
			case '!':
				outBuffer.append('\\');
				outBuffer.append(aChar);
				break;
			default:
				if ((aChar < 0x0020) || (aChar > 0x007e)) {
					outBuffer.append('\\');
					outBuffer.append('u');
					outBuffer.append(toHex((aChar >> 12) & 0xF));
					outBuffer.append(toHex((aChar >> 8) & 0xF));
					outBuffer.append(toHex((aChar >> 4) & 0xF));
					outBuffer.append(toHex(aChar & 0xF));
				} else {
					outBuffer.append(aChar);
				}
			}
		}
		return outBuffer.toString();
	}

	/*
	 * Converts encoded uxxxx to unicode chars and changes special saved chars
	 * to their original forms
	 */
	public static String deUnicode(String enUnicode) {

		char[] in = enUnicode.toCharArray();
		int off = 0;
		int len = enUnicode.length();
		char[] convtBuf = new char[0];
		if (convtBuf.length < len) {
			int newLen = len * 2;
			if (newLen < 0) {
				newLen = Integer.MAX_VALUE;
			}
			convtBuf = new char[newLen];
		}
		char aChar;
		char[] out = convtBuf;
		int outLen = 0;
		int end = off + len;

		while (off < end) {
			aChar = in[off++];
			if (aChar == '\\') {
				aChar = in[off++];
				if (aChar == 'u') {
					// Read the xxxx
					int value = 0;
					for (int i = 0; i < 4; i++) {
						aChar = in[off++];
						switch (aChar) {
						case '0':
						case '1':
						case '2':
						case '3':
						case '4':
						case '5':
						case '6':
						case '7':
						case '8':
						case '9':
							value = (value << 4) + aChar - '0';
							break;
						case 'a':
						case 'b':
						case 'c':
						case 'd':
						case 'e':
						case 'f':
							value = (value << 4) + 10 + aChar - 'a';
							break;
						case 'A':
						case 'B':
						case 'C':
						case 'D':
						case 'E':
						case 'F':
							value = (value << 4) + 10 + aChar - 'A';
							break;
						default:
							throw new IllegalArgumentException(
									"Malformed \\uxxxx encoding.");
						}
					}
					out[outLen++] = (char) value;
				} else {
					if (aChar == 't')
						aChar = '\t';
					else if (aChar == 'r')
						aChar = '\r';
					else if (aChar == 'n')
						aChar = '\n';
					else if (aChar == 'f')
						aChar = '\f';
					out[outLen++] = aChar;
				}
			} else {
				out[outLen++] = (char) aChar;
			}
		}
		return new String(out, 0, outLen);
	}

	/**
	 * Create random string.
	 * 
	 * @param max
	 * @return
	 */
	public static String createRandomString(final int max) {
		StringBuffer sb = new StringBuffer(max);
		int idx;
		int range = max * KEYS_LENGTH;
		for (int i = 0; i < max; i++) {
			idx = SECURE_RANDOM.nextInt(range) % KEYS_LENGTH;
			sb.append(KEYS.charAt(idx));
		}
		return sb.toString();
	}

}