Java 编码转换_java 判断文件编码

package encoding;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.nio.charset.Charset;
import java.nio.charset.CharsetEncoder;
import java.util.Hashtable;
/**
 * @author jianbo_you
 * @date 2008-09-25
 * 作用： 繁简体BIG5等编码的转换
 * 说明： 注释有点英文
 * */
public class EnCoding {
    
    protected Hashtable s2thash, t2shash;
    private int unsupportedStrategy;
    public final static int DELETE = 0;
    public final static int HTMLESC = 1;
    public final static int UNIESC = 2;
    public final static int QUESTIONMARK = 3;
    public final static int TOTAL = 4;
    public static int GB2312        = 0;
    public static int GBK           = 1;
    public static int GB18030       = 2;
    public static int HZ            = 3;
    public static int BIG5          = 4;
    public static int CNS11643      = 5;
    public static int UTF8          = 6;
    public static int UTF8T         = 7;
    public static int UTF8S         = 8;
    public static int UNICODE       = 9;
    public static int UNICODET      = 10;
    public static int UNICODES      = 11;
    public static int ISO2022CN     = 12;
    public static int ISO2022CN_CNS = 13;
    public static int ISO2022CN_GB  = 14;
    public static int EUC_KR        = 15;
    public static int CP949         = 16;
    public static int ISO2022KR     = 17;
    public static int JOHAB         = 18;
    public static int SJIS          = 19;
    public static int EUC_JP        = 20;
    public static int ISO2022JP     = 21;
    
    public static int ASCII         = 22;
    public static int OTHER         = 23;
    public static int TOTALTYPES    = 24;
    public final static int SIMP = 0;
    public final static int TRAD = 1;
    // Names of the encodings as understood by Java
    public static String[] javaname;
    // Names of the encodings for human viewing
    public static String[] nicename;
    // Names of charsets as used in charset parameter of HTML Meta tag
    public static String[] htmlname;
    public EnCoding()
    {
        unsupportedStrategy = UNIESC;
        String dataline;
        
        //Initialize and load in the simplified/traditional character hashses
        s2thash = new Hashtable();
        t2shash = new Hashtable();
        
        try {
            InputStream pydata = getClass().getResourceAsStream("hcutf8.txt");
            BufferedReader in = new BufferedReader(new InputStreamReader(pydata, "UTF8"));
            while ((dataline = in.readLine()) != null) {
                // Skip empty and commented lines
                if (dataline.length() == 0 || dataline.charAt(0) == '#') {
                    continue;
                }
                // Simplified to Traditional, (one to many, but pick only one)
                s2thash.put(dataline.substring(0,1), dataline.substring(1,2));
                // Traditional to Simplified, (many to one)
                for (int i = 1; i < dataline.length(); i++) {
                    t2shash.put(dataline.substring(i,i+1), dataline.substring(0,1));
                }
            }
        }
        catch (Exception e) {
            System.err.println(e);
        }
        
        javaname = new String[TOTALTYPES];
        nicename = new String[TOTALTYPES];
        htmlname = new String[TOTALTYPES];
        // Assign encoding names
        javaname[GB2312] = "GB2312";
        javaname[GBK] = "GBK";
        javaname[GB18030] = "GB18030";
        javaname[HZ] = "ASCII";  // What to put here?  Sun doesn't support HZ
        javaname[ISO2022CN_GB] = "ISO2022CN_GB";
        javaname[BIG5] = "BIG5";
        javaname[CNS11643] = "EUC-TW";
        javaname[ISO2022CN_CNS] = "ISO2022CN_CNS";
        javaname[ISO2022CN] = "ISO2022CN";
        javaname[UTF8] = "UTF8";
        javaname[UTF8T] = "UTF8";
        javaname[UTF8S] = "UTF8";
        javaname[UNICODE] = "Unicode";
        javaname[UNICODET] = "Unicode";
        javaname[UNICODES] = "Unicode";
        javaname[EUC_KR] = "EUC_KR";
        javaname[CP949] = "MS949";
        javaname[ISO2022KR] = "ISO2022KR";
        javaname[JOHAB] = "Johab";
        javaname[SJIS] = "SJIS";
        javaname[EUC_JP] = "EUC_JP";
        javaname[ISO2022JP] = "ISO2022JP";
        javaname[ASCII] = "ASCII";
        javaname[OTHER] = "ISO8859_1";
        // Assign encoding names
        htmlname[GB2312] = "GB2312";
        htmlname[GBK] = "GBK";
        htmlname[GB18030] = "GB18030";
        htmlname[HZ] = "HZ-GB-2312";  
        htmlname[ISO2022CN_GB] = "ISO-2022-CN-EXT";
        htmlname[BIG5] = "BIG5";
        htmlname[CNS11643] = "EUC-TW";
        htmlname[ISO2022CN_CNS] = "ISO-2022-CN-EXT";
        htmlname[ISO2022CN] = "ISO-2022-CN";
        htmlname[UTF8] = "UTF-8";
        htmlname[UTF8T] = "UTF-8";
        htmlname[UTF8S] = "UTF-8";
        htmlname[UNICODE] = "UTF-16";
        htmlname[UNICODET] = "UTF-16";
        htmlname[UNICODES] = "UTF-16";
        htmlname[EUC_KR] = "EUC-KR";
        htmlname[CP949] = "x-windows-949";
        htmlname[ISO2022KR] = "ISO-2022-KR";
        htmlname[JOHAB] = "x-Johab";
        htmlname[SJIS] = "Shift_JIS";
        htmlname[EUC_JP] = "EUC-JP";
        htmlname[ISO2022JP] = "ISO-2022-JP";
        htmlname[ASCII] = "ASCII";
        htmlname[OTHER] = "ISO8859-1";
        // Assign Human readable names
        nicename[GB2312] = "GB-2312";
        nicename[GBK] = "GBK";
        nicename[GB18030] = "GB18030";
        nicename[HZ] = "HZ";
        nicename[ISO2022CN_GB] = "ISO2022CN-GB";
        nicename[BIG5] = "Big5";
        nicename[CNS11643] = "CNS11643";
        nicename[ISO2022CN_CNS] = "ISO2022CN-CNS";
        nicename[ISO2022CN] = "ISO2022 CN";
        nicename[UTF8] = "UTF-8";
        nicename[UTF8T] = "UTF-8 (Trad)";
        nicename[UTF8S] = "UTF-8 (Simp)";
        nicename[UNICODE] = "Unicode";
        nicename[UNICODET] = "Unicode (Trad)";
        nicename[UNICODES] = "Unicode (Simp)";
        nicename[EUC_KR] = "EUC-KR";
        nicename[CP949] = "CP949";
        nicename[ISO2022KR] = "ISO 2022 KR";
        nicename[JOHAB] = "Johab";
        nicename[SJIS] = "Shift-JIS";
        nicename[EUC_JP] = "EUC-JP";
        nicename[ISO2022JP] = "ISO 2022 JP";
        nicename[ASCII] = "ASCII";
        nicename[OTHER] = "OTHER";
    }
    public static void main(String[] args) 
    {
        EnCoding encoding = new EnCoding();
        StringBuffer sb = new StringBuffer();
        sb.append(" 你們大家還好嗎？");
        System.out.println("转换前：         "+sb.toString());
        //转换成GB2312
        encoding.convertStringBuffer(sb, BIG5, GB2312);
        System.out.println("转换后：         "+sb.toString());
    }
    /**
     * 字符串转换
     * @param dataline         转换的字符串
     * @param source_encoding  原字符串编码
     * @param target_encoding  转换后的编码
     */
    public void convertStringBuffer(StringBuffer dataline, int source_encoding, int target_encoding) {
        int lineindex;
        String currchar;
        char charvalue;
        if (source_encoding == HZ) {//如果原字符串编码是HK
            hz2gbStringBuffer(dataline);
        } 
        for (lineindex = 0; lineindex < dataline.length(); lineindex++) {//循环转换字符串每个字符的编码
            charvalue = dataline.charAt(lineindex);
            currchar = "" + charvalue;
            if (((int)charvalue == 0xfeff || (int)charvalue == 0xfffe) &&
                    (target_encoding != UNICODE && target_encoding != UNICODES && target_encoding != UNICODET && 
                            target_encoding != UTF8 && target_encoding != UTF8S && target_encoding != UTF8T)) {
                dataline.deleteCharAt(lineindex);
                continue;
            }
            if ((source_encoding == GB2312 || source_encoding == GBK || source_encoding == ISO2022CN_GB ||
                    source_encoding == HZ || source_encoding == GB18030 ||
                    source_encoding == UNICODE || source_encoding == UNICODES || source_encoding == UTF8 ||
                    source_encoding == UTF8S) 
                    &&
                    (target_encoding == BIG5 || target_encoding == CNS11643 || target_encoding == UNICODET ||
                            target_encoding == UTF8T ||
                            target_encoding == ISO2022CN_CNS)) {
                if (s2thash.containsKey(currchar) == true) {
                    dataline.replace(lineindex, lineindex+1, (String)s2thash.get(currchar));
                } 
            } else if ((source_encoding == BIG5 || source_encoding == CNS11643 || 
                    source_encoding == UNICODET ||
                    source_encoding == UTF8 || source_encoding == UTF8T ||
                    source_encoding == ISO2022CN_CNS || source_encoding == GBK || 
                    source_encoding == GB18030 || source_encoding == UNICODE) 
                    &&
                    (target_encoding == GB2312 || target_encoding == UNICODES || 
                            target_encoding == ISO2022CN_GB ||
                            target_encoding == UTF8S || target_encoding == HZ)) {
                if (t2shash.containsKey(currchar) == true) {
                    dataline.replace(lineindex, lineindex+1, (String)t2shash.get(currchar));
                } 
            }
        }
        if (target_encoding == HZ) {
            // Convert to look like HZ
            gb2hzStringBuffer(dataline);
        }
        Charset charset = Charset.forName(javaname[target_encoding]);
        CharsetEncoder encoder = charset.newEncoder();
        for (int i = 0; i < dataline.length(); i++) {
            if (encoder.canEncode(dataline.subSequence(i, i+1)) == false) {
                // Replace or delete
                // Delete
                if (unsupportedStrategy == DELETE) {
                    dataline.deleteCharAt(i);
                    i--;
                } else if (unsupportedStrategy == HTMLESC) {
                    // HTML Escape NNNN;
                    dataline.replace(i, i+1, "" + Integer.toHexString((int)dataline.charAt(i)) + ";");
                } else if (unsupportedStrategy == UNIESC) {
                    // Unicode Escape //uNNNN
                    dataline.replace(i, i+1, "//u" + Integer.toHexString((int)dataline.charAt(i)));
                } else if (unsupportedStrategy == QUESTIONMARK) {
                    // Unicode Escape //uNNNN
                    dataline.replace(i, i+1, "?");
                }
            }
        }
    }
    /**
     * 将传入的字符串参数编码由HZ转换为GB2312
     * @param hzstring
     * @return
     */
    public String hz2gb(String hzstring) {
        StringBuffer gbstring = new StringBuffer(hzstring);
        hz2gbStringBuffer(gbstring);
        return gbstring.toString();
    }
    /**
     * 将传入的StringBuffer参数编码由HZ转换为GB2312
     * @param hzstring
     * @return
     */
    public void hz2gbStringBuffer(StringBuffer hzstring) {
        //byte[] hzbytes; // = new byte[2];
        byte[] gbchar = new byte[2];
        int i = 0;
        //StringBuffer gbstring = new StringBuffer("");
        // Convert to look like equivalent Unicode of GB
        for (i = 0; i < hzstring.length(); i++) {
            if (hzstring.charAt(i) == '~') {
                if (hzstring.charAt(i+1) == '{') {
                    hzstring.delete(i, i+2);
                    while (i < hzstring.length()) {
                        if (hzstring.charAt(i) == '~' && hzstring.charAt(i+1) == '}') {
                            hzstring.delete(i, i+2);
                            i--;
                            break;
                        } else if (hzstring.charAt(i) == '/r' || hzstring.charAt(i) == '/n') {
                            break;
                        }
                        gbchar[0] = (byte)(hzstring.charAt(i) + 0x80);
                        gbchar[1] = (byte)(hzstring.charAt(i+1) + 0x80);
                        try {
                            hzstring.replace(i, i+2, new String(gbchar, "GB2312"));
                        }  catch (Exception usee) { System.err.println(usee.toString()); } 
                        i++;
                    }
                } else if (hzstring.charAt(i+1) == '~') { // ~~ becomes ~
                    hzstring.replace(i, i+2, "~");
                } 
            } 
        }
    }
    /**
     * 将传入的字符串参数编码由GB2312转换为HZ
     * @param gbstring
     * @return
     */
    public String gb2hz(String gbstring) {
        StringBuffer hzbuffer = new StringBuffer(gbstring);
        gb2hzStringBuffer(hzbuffer);
        return hzbuffer.toString();
    }
    /**
     * 将传入的StringBuffer参数编码由GB2312转换为HZ
     * @param gbstring
     * @return
     */
    public void gb2hzStringBuffer(StringBuffer gbstring) {
        byte[] gbbytes = new byte[2];
        int i;
        boolean terminated = false;
        for (i = 0; i < gbstring.length(); i++) {
            if ((int)gbstring.charAt(i) > 0x7f) {
                gbstring.insert(i, "~{");
                terminated = false;
                while (i < gbstring.length()) {
                    if (gbstring.charAt(i) == '/r' || gbstring.charAt(i) == '/n') {
                        gbstring.insert(i, "~}");
                        i+=2;
                        terminated = true;
                        break;
                    } else if ((int)gbstring.charAt(i) <= 0x7f) {
                        gbstring.insert(i, "~}");
                        i+=2;
                        terminated = true;
                        break;
                    }
                    try {
                        gbbytes = gbstring.substring(i, i+1).getBytes("GB2312");
                    } 
                    catch (UnsupportedEncodingException uee) { System.out.println(uee); }
                    gbstring.delete(i, i+1);
                    gbstring.insert(i, (char)(gbbytes[0] + 256 - 0x80));
                    gbstring.insert(i+1, (char)(gbbytes[1] + 256 - 0x80));
                    i+=2;   
                }
                if (terminated == false) {
                    gbstring.insert(i, "~}");
                    i+=2;
                }
            } else {
                if (gbstring.charAt(i) == '~') {
                    gbstring.replace(i, i+1, "~~");
                    i++;
                } 
            }
        }
    }
}