get File Charset - Java File Path IO

Java examples for File Path IO:Text File

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Description

get File Charset

Demo Code

/**/*from   w  w w. jav  a2 s.  c o  m*/
 * baiweigang.cn 
 * Copyright (c) 1984-2014 All Rights Reserved.
 */
//package com.java2s;
import java.io.BufferedInputStream;

import java.io.File;
import java.io.FileInputStream;

import java.io.IOException;

public class Main {

    public static String getCharset(String pathName) {
        File file = new File(pathName);
        if (!file.exists()) {
            return "";
        }
        String charset = "GBK";
        byte[] first3Bytes = new byte[3];
        BufferedInputStream bis = null;
        try {
            boolean checked = false;
            bis = new BufferedInputStream(new FileInputStream(file));
            bis.mark(0);
            int read = bis.read(first3Bytes, 0, 3);
            if (read == -1)
                return charset;
            if (first3Bytes[0] == (byte) 0xFF
                    && first3Bytes[1] == (byte) 0xFE) {
                charset = "UTF-16LE";
                checked = true;
            } else if (first3Bytes[0] == (byte) 0xFE
                    && first3Bytes[1] == (byte) 0xFF) {
                charset = "UTF-16BE";
                checked = true;
            } else if (first3Bytes[0] == (byte) 0xEF
                    && first3Bytes[1] == (byte) 0xBB
                    && first3Bytes[2] == (byte) 0xBF) {
                charset = "UTF-8";
                checked = true;
            }
            bis.reset();
            if (!checked) {
                //    int len = 0;   
                //                int loc = 0;
                while ((read = bis.read()) != -1) {
                    //                    loc++;
                    if (read >= 0xF0)
                        break;
                    if (0x80 <= read && read <= 0xBF) // BF?GBK   
                        break;
                    if (0xC0 <= read && read <= 0xDF) {
                        read = bis.read();
                        if (0x80 <= read && read <= 0xBF) // ? (0xC0 - 0xDF) (0x80   
                                                          // - 0xBF),GB   
                            continue;
                        else
                            break;
                    } else if (0xE0 <= read && read <= 0xEF) {//    
                        read = bis.read();
                        if (0x80 <= read && read <= 0xBF) {
                            read = bis.read();
                            if (0x80 <= read && read <= 0xBF) {
                                charset = "UTF-8";
                                break;
                            } else
                                break;
                        } else
                            break;
                    }
                }
                //System.out.println( loc + " " + Integer.toHexString( read ) );   
            }

            bis.close();
        } catch (Exception e) {
            //            e.printStackTrace();
        } finally {
            try {
                bis.close();
            } catch (IOException e) {
            }
        }

        return charset;
    }
}

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