java 字符串编码转换

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 static String toASCII(String str) throws UnsupportedEncodingException{
	  return changeCharset(str, US_ASCII);
	 }
	 /**
	  * 将字符编码转换成ISO-8859-1码
	  */
	 public static String toISO_8859_1(String str) throws UnsupportedEncodingException{
	  return changeCharset(str, ISO_8859_1);
	 }
	 /**
	  * 将字符编码转换成UTF-8码
	  */
	 public static String toUTF_8(String str) throws UnsupportedEncodingException{
	  return changeCharset(str, UTF_8);
	 }
	 /**
	  * 将字符编码转换成UTF-16BE码
	  */
	 public static String toUTF_16BE(String str) throws UnsupportedEncodingException{
	  return changeCharset(str, UTF_16BE);
	 }
	 /**
	  * 将字符编码转换成UTF-16LE码
	  */
	 public static String toUTF_16LE(String str) throws UnsupportedEncodingException{
	  return changeCharset(str, UTF_16LE);
	 }
	 /**
	  * 将字符编码转换成UTF-16码
	  */
	 public static String toUTF_16(String str) throws UnsupportedEncodingException{
	  return changeCharset(str, UTF_16);
	 }
	 /**
	  * 将字符编码转换成GBK码
	  */
	 public static String toGBK(String str) throws UnsupportedEncodingException{
	  return 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 static 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 static 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;
	 }
	 
	 /**
	  * 判断字符串编码
	  *
	  * make by Administrator on 2014-6-9 上午10:48:24
	  * @param str
	  * @return
	  */
	 public static String getEncoding(String str) {      
	       String encode = "GB2312";      
	       try {      
	           if (str.equals(new String(str.getBytes(encode), encode))) {      
	                String s = encode;      
	               return s;      
	            }      
	        } catch (Exception exception) {      
	        }      
	        encode = "ISO-8859-1";      
	       try {      
	           if (str.equals(new String(str.getBytes(encode), encode))) {      
	                String s1 = encode;      
	               return s1;      
	            }      
	        } catch (Exception exception1) {      
	        }      
	        encode = "UTF-8";      
	       try {      
	           if (str.equals(new String(str.getBytes(encode), encode))) {      
	                String s2 = encode;      
	               return s2;      
	            }      
	        } catch (Exception exception2) {      
	        }      
	        encode = "GBK";      
	       try {      
	           if (str.equals(new String(str.getBytes(encode), encode))) {      
	                String s3 = encode;      
	               return s3;      
	            }      
	        } catch (Exception exception3) {      
	        }      
	       return "";      
	    }  

	 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);
	 }
	}