package org.shefron.fc.utfwithbom;import java.io.FileInputStream;import java.io.IOException;import java.io.InputStream;import java.io.PushbackInputStream;public class UTFFileHandler {	/**	 *	 * @param file the filePath	 * @return the FileInputStream	 * @throws Exception	 */	public static InputStream getInputStream(String file) throws Exception{		FileInputStream fis = null;		try{			fis = new FileInputStream(file);		}catch(Exception e){			System.out.println(e.getMessage());			throw new Exception("IO Stream Error!");		}		return fis;	}	/**	 *	 * @param file the filePath	 * @param enc  the default encoding	 * @return the UTFFileHandler.UnicodeInputStream	 * @throws Exception	 */	public static InputStream getInputStreamWithoutBom(String file,String enc) throws Exception{		UnicodeInputStream stream = null;		try{			FileInputStream fis = new FileInputStream(file);			stream = new UnicodeInputStream(fis,null);			System.out.println("encoding:"+stream.getEncoding() );		}catch(Exception e){			System.out.println(e.getMessage());			throw new Exception("IO Stream Error!");		}		return stream;	}	/**	 * This inputstream will recognize unicode BOM marks and will skip bytes if	 * getEncoding() method is called before any of the read(...) methods.	 *	 * Usage pattern: String enc = "ISO-8859-1"; // or NULL to use systemdefault	 * FileInputStream fis = new FileInputStream(file); UnicodeInputStream uin = new	 * UnicodeInputStream(fis, enc); enc = uin.getEncoding(); // check and skip	 * possible BOM bytes InputStreamReader in; if (enc == null) in = new	 * InputStreamReader(uin); else in = new InputStreamReader(uin, enc);	 */	public static class UnicodeInputStream extends InputStream {	    PushbackInputStream internalIn;	    boolean isInited = false;	    String defaultEnc;	    String encoding;	    private static final int BOM_SIZE = 4;	    public UnicodeInputStream(InputStream in, String defaultEnc) {	        internalIn = new PushbackInputStream(in, BOM_SIZE);	        this.defaultEnc = defaultEnc;	    }	    public String getDefaultEncoding() {	        return defaultEnc;	    }	    public String getEncoding() {	        if (!isInited) {	            try {	                init();	            } catch (IOException ex) {	                IllegalStateException ise = new IllegalStateException(	                        "Init method failed.");	                ise.initCause(ise);	                throw ise;	            }	        }	        return encoding;	    }	    /**	     * Read-ahead four bytes and check for BOM marks. Extra bytes are unread	     * back to the stream, only BOM bytes are skipped.	     */	    protected void init() throws IOException {	        if (isInited)	            return;	        byte bom[] = new byte[BOM_SIZE];	        int n, unread;	        n = internalIn.read(bom, 0, bom.length);	        if ((bom[0] == (byte) 0x00) && (bom[1] == (byte) 0x00)	                && (bom[2] == (byte) 0xFE) && (bom[3] == (byte) 0xFF)) {	            encoding = "UTF-32BE";	            unread = n - 4;	        } else if ((bom[0] == (byte) 0xFF) && (bom[1] == (byte) 0xFE)	                && (bom[2] == (byte) 0x00) && (bom[3] == (byte) 0x00)) {	            encoding = "UTF-32LE";	            unread = n - 4;	        } else if ((bom[0] == (byte) 0xEF) && (bom[1] == (byte) 0xBB)	                && (bom[2] == (byte) 0xBF)) {	            encoding = "UTF-8";	            unread = n - 3;	        } else if ((bom[0] == (byte) 0xFE) && (bom[1] == (byte) 0xFF)) {	            encoding = "UTF-16BE";	            unread = n - 2;	        } else if ((bom[0] == (byte) 0xFF) && (bom[1] == (byte) 0xFE)) {	            encoding = "UTF-16LE";	            unread = n - 2;	        } else {	            // Unicode BOM mark not found, unread all bytes	            encoding = defaultEnc;	            unread = n;	        }	        // System.out.println("read=" + n + ", unread=" + unread);	        if (unread > 0)	            internalIn.unread(bom, (n - unread), unread);	        isInited = true;	    }	    public void close() throws IOException {	        // init();//	        isInited = true;	        internalIn.close();	    }	    public int read() throws IOException {	        // init();//	        isInited = true;	        return internalIn.read();	    }	}}

java UTF-8 和 UTF-8 without BOM工具处理类