changecharset.java

本代码以J2SE 5.0为开发环境

package book.string;

import java.io.UnsupportedEncodingException;

/**
 * 转换字符串的编码
 */
public class ChangeCharset {
	/**	7位ASCII字符，也叫作ISO646-US、Unicode字符集的基本拉丁块	*/
	public static final String US_ASCII = "US-ASCII";
	/**	ISO 拉丁字母表 No.1，也叫作 ISO-LATIN-1	*/
	public static final String ISO_8859_1 = "ISO-8859-1";
	/**	8 位 UCS 转换格式	*/
	public static final String UTF_8 = "UTF-8";
	/**	16 位 UCS 转换格式，Big Endian（最低地址存放高位字节）字节顺序	*/
	public static final String UTF_16BE = "UTF-16BE";
	/**	16 位 UCS 转换格式，Little-endian（最高地址存放低位字节）字节顺序	*/
	public static final String UTF_16LE = "UTF-16LE";
	/**	16 位 UCS 转换格式，字节顺序由可选的字节顺序标记来标识	*/
	public static final String UTF_16 = "UTF-16";
	/**	中文超大字符集	*/
	public static final String GBK = "GBK";

	/**
	 * 将字符编码转换成US-ASCII码
	 */
	public String toASCII(String str) throws UnsupportedEncodingException{
		return this.changeCharset(str, US_ASCII);
	}
	/**
	 * 将字符编码转换成ISO-8859-1码
	 */
	public String toISO_8859_1(String str) throws UnsupportedEncodingException{
		return this.changeCharset(str, ISO_8859_1);
	}
	/**
	 * 将字符编码转换成UTF-8码
	 */
	public String toUTF_8(String str) throws UnsupportedEncodingException{
		return this.changeCharset(str, UTF_8);
	}
	/**
	 * 将字符编码转换成UTF-16BE码
	 */
	public String toUTF_16BE(String str) throws UnsupportedEncodingException{
		return this.changeCharset(str, UTF_16BE);
	}
	/**
	 * 将字符编码转换成UTF-16LE码
	 */
	public String toUTF_16LE(String str) throws UnsupportedEncodingException{
		return this.changeCharset(str, UTF_16LE);
	}
	/**
	 * 将字符编码转换成UTF-16码
	 */
	public String toUTF_16(String str) throws UnsupportedEncodingException{
		return this.changeCharset(str, UTF_16);
	}
	/**
	 * 将字符编码转换成GBK码
	 */
	public String toGBK(String str) throws UnsupportedEncodingException{
		return this.changeCharset(str, GBK);
	}
	
	/**
	 * 字符串编码转换的实现方法
	 * @param str		待转换编码的字符串
	 * @param newCharset	目标编码
	 * @return
	 * @throws UnsupportedEncodingException
	 */
	public String changeCharset(String str, String newCharset)
			throws UnsupportedEncodingException {
		if (str != null) {
			//用默认字符编码解码字符串。
			byte[] bs = str.getBytes();
			//用新的字符编码生成字符串
			return new String(bs, newCharset);
		}
		return null;
	}
	/**
	 * 字符串编码转换的实现方法
	 * @param str		待转换编码的字符串
	 * @param oldCharset	原编码
	 * @param newCharset	目标编码
	 * @return
	 * @throws UnsupportedEncodingException
	 */
	public String changeCharset(String str, String oldCharset, String newCharset)
			throws UnsupportedEncodingException {
		if (str != null) {
			//用旧的字符编码解码字符串。解码可能会出现异常。
			byte[] bs = str.getBytes(oldCharset);
			//用新的字符编码生成字符串
			return new String(bs, newCharset);
		}
		return null;
	}

	public static void main(String[] args) throws UnsupportedEncodingException {
		ChangeCharset test = new ChangeCharset();
		String str = "This is a 中文的 String!";
		System.out.println("str: " + str);
		String gbk = test.toGBK(str);
		System.out.println("转换成GBK码: " + gbk);
		System.out.println();
		String ascii = test.toASCII(str);
		System.out.println("转换成US-ASCII码: " + ascii);
		gbk = test.changeCharset(ascii,ChangeCharset.US_ASCII, ChangeCharset.GBK);
		System.out.println("再把ASCII码的字符串转换成GBK码: " + gbk);
		System.out.println();
		String iso88591 = test.toISO_8859_1(str);
		System.out.println("转换成ISO-8859-1码: " + iso88591);
		gbk = test.changeCharset(iso88591,ChangeCharset.ISO_8859_1, ChangeCharset.GBK);
		System.out.println("再把ISO-8859-1码的字符串转换成GBK码: " + gbk);
		System.out.println();
		String utf8 = test.toUTF_8(str);
		System.out.println("转换成UTF-8码: " + utf8);
		gbk = test.changeCharset(utf8,ChangeCharset.UTF_8, ChangeCharset.GBK);
		System.out.println("再把UTF-8码的字符串转换成GBK码: " + gbk);
		System.out.println();
		String utf16be = test.toUTF_16BE(str);
		System.out.println("转换成UTF-16BE码:" + utf16be);
		gbk = test.changeCharset(utf16be,ChangeCharset.UTF_16BE, ChangeCharset.GBK);
		System.out.println("再把UTF-16BE码的字符串转换成GBK码: " + gbk);
		System.out.println();
		String utf16le = test.toUTF_16LE(str);
		System.out.println("转换成UTF-16LE码:" + utf16le);
		gbk = test.changeCharset(utf16le,ChangeCharset.UTF_16LE, ChangeCharset.GBK);
		System.out.println("再把UTF-16LE码的字符串转换成GBK码: " + gbk);
		System.out.println();
		String utf16 = test.toUTF_16(str);
		System.out.println("转换成UTF-16码:" + utf16);
		gbk = test.changeCharset(utf16,ChangeCharset.UTF_16LE, ChangeCharset.GBK);
		System.out.println("再把UTF-16码的字符串转换成GBK码: " + gbk);
		String s = new String("中文".getBytes("UTF-8"),"UTF-8");
		System.out.println(s);
	}
}