package com.zuidaima.util;

import java.io.UnsupportedEncodingException;

/**
 * 轉換字串的編碼
 */
public class ChangeCharset {
/** 7位ASCII字元，也叫作ISO646-US、Unicode字符集的基本拉丁塊 */
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 轉換格式 */
public static final String UTF_8 = "UTF-8";

/** 16 位 UCS 轉換格式，Big Endian（最低地址存放高位位元組）位元組順序 */
public static final String UTF_16BE = "UTF-16BE";

/** 16 位 UCS 轉換格式，Little-endian（最高地址存放低位位元組）位元組順序 */
public static final String UTF_16LE = "UTF-16LE";

/** 16 位 UCS 轉換格式，位元組順序由可選的位元組順序標記來標識 */
 

public static final String UTF_16 = "UTF-16";

/** 中文超大字符集 */
public static final String GBK = "GBK";

/**
 * 將字元編碼轉換成US-ASCII碼
 */
public String toASCII(String str) throws UnsupportedEncodingException {
return this.changeCharset(str, US_ASCII);
}

/**
 * 將字元編碼轉換成ISO-8859-1碼
 */
public String toISO_8859_1(String str) throws
 
 UnsupportedEncodingException {
return this.changeCharset(str, ISO_8859_1);
}

/**
 * 將字元編碼轉換成UTF-8碼
 */
public String toUTF_8(String str) throws UnsupportedEncodingException {
return this.changeCharset(str, UTF_8);
}

/**
 * 將字元編碼轉換成UTF-16BE碼
 */
public String toUTF_16BE(String str) throws UnsupportedEncodingException {
return this.changeCharset(str, UTF_16BE);
}

/**
 * 將字元編碼轉換成UTF-16LE碼
 */
public String toUTF_16LE(String str) throws UnsupportedEncodingException {
return this.changeCharset(str, UTF_16LE);
}

/**
 * 將字元編碼轉換成UTF-16碼
 */
public String toUTF_16(String str) throws UnsupportedEncodingException {
return this.changeCharset(str, UTF_16);
}

/**
 * 將字元編碼轉換成GBK碼
 */
public String toGBK(String str) throws UnsupportedEncodingException {
return this.changeCharset(str, GBK);
}

/**
 * 字串編碼轉換的實現方法
 * 
 * @param str
 *            待轉換編碼的字串
 * @param newCharset
 *            目標編碼
 * @return
 * @throws UnsupportedEncodingException
 */
public String changeCharset(String str, String newCharset)
throws UnsupportedEncodingException {
if (str != null) {
// 用預設字元編碼解碼字串。
byte[] bs = str.getBytes();
// 用新的字元編碼生成字串
return new String(bs, newCharset);
}
return null;
}

/**
 * 字串編碼轉換的實現方法
 * 
 * @param str
 *            待轉換編碼的字串
 * @param oldCharset
 *            原編碼
 * @param newCharset
 *            目標編碼
 * @return
 * @throws UnsupportedEncodingException
 */
public String changeCharset(String str, String oldCharset, String newCharset)
throws UnsupportedEncodingException {
if (str != null) {
// 用舊的字元編碼解碼字串。解碼可能會出現異常。
byte[] bs = str.getBytes(oldCharset);
// 用新的字元編碼生成字串
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("轉換成GBK碼: " + gbk);
System.out.println();
String ascii = test.toASCII(str);
System.out.println("轉換成US-ASCII碼: " + ascii);
gbk = test.changeCharset(ascii, ChangeCharset.US_ASCII,
ChangeCharset.GBK);
System.out.println("再把ASCII碼的字串轉換成GBK碼: " + gbk);
System.out.println();
String iso88591 = test.toISO_8859_1(str);
System.out.println("轉換成ISO-8859-1碼: " + iso88591);
gbk = test.changeCharset(iso88591, ChangeCharset.ISO_8859_1,
ChangeCharset.GBK);
System.out.println("再把ISO-8859-1碼的字串轉換成GBK碼: " + gbk);
System.out.println();
String utf8 = test.toUTF_8(str);
System.out.println("轉換成UTF-8碼: " + utf8);
gbk = test.changeCharset(utf8, ChangeCharset.UTF_8, ChangeCharset.GBK);
System.out.println("再把UTF-8碼的字串轉換成GBK碼: " + gbk);
System.out.println();
String utf16be = test.toUTF_16BE(str);
System.out.println("轉換成UTF-16BE碼:" + utf16be);
gbk = test.changeCharset(utf16be, ChangeCharset.UTF_16BE,
ChangeCharset.GBK);
System.out.println("再把UTF-16BE碼的字串轉換成GBK碼: " + gbk);
System.out.println();
String utf16le = test.toUTF_16LE(str);
System.out.println("轉換成UTF-16LE碼:" + utf16le);
gbk = test.changeCharset(utf16le, ChangeCharset.UTF_16LE,
ChangeCharset.GBK);
System.out.println("再把UTF-16LE碼的字串轉換成GBK碼: " + gbk);
System.out.println();
String utf16 = test.toUTF_16(str);
System.out.println("轉換成UTF-16碼:" + utf16);
gbk = test.changeCharset(utf16, ChangeCharset.UTF_16LE,
ChangeCharset.GBK);
System.out.println("再把UTF-16碼的字串轉換成GBK碼: " + gbk);
String s = new String("中文".getBytes("UTF-8"), "UTF-8");
System.out.println(s);
}
}