java万能字符转换

不多说，代码中有详细的注释

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);
     }
}