[0001]来自jdk自带的方法，进行String与Unicode互转

前言：试过很多字符串转unicode或者unicode转字符串，但是都不完美，当要转换的字符中有干扰符号的话，如：空格，斜线等等，就转换有问题。这个是jdk里面的，测试相当的完美，大家可以单独封装一个类中，来调用，以后乱码神马的都

是浮云了，呵呵！

 

1.整理后代码（main方法中为调用方法）：

package com.test;

/**
 * unicode 中文（或者其它语言）互转，算法来自JDK1.6 src
 * 
 * @author 整理 By why
 */
public class Unicode {

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

	/**
	 * Convert a nibble to a hex character
	 * @param nibble the nibble to convert.
	 */
	private static char toHex(int nibble) {
		return hexDigit[(nibble & 0xF)];
	}
	
	/**
	 * Unicode 与 String 换转
	 * @param String theString 要转换的字符串
	 * @param boolean escapeSpace 忽略空
	 * @param escapeUnicode escapeUnicode 忽略Unicode （true:string转unicode false:unicode转string）
	 * */
	private static String saveConvert(String theString, boolean escapeSpace,
			boolean escapeUnicode) {
		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)) & escapeUnicode) {
					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();
	}

	public static void main(String[] args) {
		String str = "0.123 ABCabc ~&*《》<>,，。./ ☆★○◎◇◆※ 日本語／にほんご Nihongo";
		String unicode = "0.123 abcabc ~&*\u300a\u300b<>,\uff0c\u3002./ \u2606\u2605\u25cb\u25ce\u25c7\u25c6\u203b \u65e5\u672c\u8a9e\uff0f\u306b\u307b\u3093\u3054 nihongo";
		System.out.println("原始字符串：" + str);
		System.out.println("==============================================================================");
		System.out.println("unicode转string：" + saveConvert(unicode, false, false));
		System.out.println("string转unicode：" + saveConvert(str, false, true).toLowerCase());// .toLowerCase() 方法将字符串转换为小写
	}

}

 2.说明：

这个方法也是我Google了半天看到的一篇博文，

然后自己做的整理http://hi.baidu.com/k_boy/blog/item/a30c568247b5b7a10cf4d25a.html 

博文内容

[tips]使用Java将中文字符转换成Unicode编码

2007年10月18日 星期四 上午 11:47

这两天操作XML使用到了Jdom，在创建XML文件并输出到硬盘的时候遇到一个中文编码的问题：Jdom默认输出的XML编码是UTF-8，但是文档中如果出现中文字符那么该中文字符就会变成乱码，造成XML文件无法被正确解析。

UTF-8应该是可以用来表示中文的吧？我不知道这是不是Jdom的一个BUG（Jdom 1.0，beta了10次的产物哦！）。我google了一下，大家解决这个问题的办法无非是把Jdom的输出字符集改为GBK或者GB2312，但是这 样就会有一些副作用，如果在没有特定字符集（GBK或者GB2312）的操作系统上不是依然不能正确解析吗？一个比较好的解决办法是先把中文转换成 Unicode编码在直接输出，程序解析XML后的时候再把Unicode编码转回中文就没有问题了。

于是我查看了JDK的文档，截至Java 5好像都没有做类似转换的类可以直接使用，但是我发现一个类 java.util.Properties，它的源代码里有两个私有（private）方法 loadConvert (char[] in, int off, int len, char[] convtBuf) 和 saveConvert(String theString, boolean escapeSpace) 其实就是做特殊字符和Unicode编码字符间转换的，我把它们提取出来，单独包装到一个类里就可以使用了。

下面是我包装的类 CharacterSetToolkit

/*
* CharacterSetToolkit.java
*
* Created on 2006年10月27日, 下午2:06
*
* To change this template, choose Tools | Template Manager
* and open the template in the editor.
*/

package mobi.chenwei.lang;

/**
* 进行字符操作的工具类
* @author Chen Wei
* @email [e-mail]
*/
public class CharacterSetToolkit {
    
     /** Creates a new instance of CharacterSetToolkit */
     public CharacterSetToolkit() {
     }
    
     private static final char[] hexDigit = {
         '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'
     };
    
     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();
     }
    
     /**
      * 从 Unicode 码转换成编码前的特殊字符串。
      * @param in Unicode编码的字符数组。
      * @param off 转换的起始偏移量。
      * @param len 转换的字符长度。
      * @param convtBuf 转换的缓存字符数组。
      * @return 完成转换，返回编码前的特殊字符串。
      */
     public String fromUnicode(char[] in, int off, int len, char[] convtBuf) {
         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);
     }
}