java各种字符串编码转换

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。
正在装载数据…… 
   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);
 }
}