获取文件的编码

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;


import org.mozilla.intl.chardet.nsDetector;
import org.mozilla.intl.chardet.nsICharsetDetectionObserver;


/**
 * 
* @Description  获取文件的编码  
*
 */
public class FileCharsetDetector  {


private boolean found = false;


/**
* 如果完全匹配某个字符集检测算法, 则该属性保存该字符集的名称. 否则(如二进制文件)其值就为默认值 null, 这时应当查询属性 
*/
private String encoding = null;


/*public static void main(String[] argv) throws Exception {
FileCharsetDetector fileCharset = new FileCharsetDetector();
File file = new File("E://onlineDoc//新建文本文档.txt");
System.out.println(fileCharset.guestFileEncoding(file));
if (argv.length != 1 && argv.length != 2) {


System.out
.println("Usage: FileCharsetDetector <path> [<languageHint>]");


System.out.println("");
System.out.println("Where <path> is d:/demo.txt");
System.out.println("For optional <languageHint>. Use following...");
System.out.println(" 1 => Japanese");
System.out.println(" 2 => Chinese");
System.out.println(" 3 => Simplified Chinese");
System.out.println(" 4 => Traditional Chinese");
System.out.println(" 5 => Korean");
System.out.println(" 6 => Dont know (default)");


return;
} else {
String encoding = null;
if (argv.length == 2) {
encoding = new FileCharsetDetector().guestFileEncoding(argv[0],
Integer.valueOf(argv[1]));
} else {
encoding = new FileCharsetDetector().guestFileEncoding(argv[0]);
}
System.out.println("文件编码:" + encoding);
}
}*/


/**
* 传入一个文件(File)对象，检查文件编码
* 
* @param file
*            File对象实例
* @return 文件编码，若无，则返回null
* @throws FileNotFoundException
* @throws IOException
*/
public String guestFileEncoding(File file) throws FileNotFoundException,
IOException {
return geestFileEncoding(file, new nsDetector());
}


/**
* 获取文件的编码
* 
* @param file
*            File对象实例
* @param languageHint
*            语言提示区域代码 eg：1 : Japanese; 2 : Chinese; 3 : Simplified Chinese;
*            4 : Traditional Chinese; 5 : Korean; 6 : Dont know (default)
* @return 文件编码，eg：UTF-8,GBK,GB2312形式，若无，则返回null
* @throws FileNotFoundException
* @throws IOException
*/
public String guestFileEncoding(File file, int languageHint)
throws FileNotFoundException, IOException {
return geestFileEncoding(file, new nsDetector(languageHint));
}


/**
* 获取文件的编码
* 
* @param path
*            文件路径
* @return 文件编码，eg：UTF-8,GBK,GB2312形式，若无，则返回null
* @throws FileNotFoundException
* @throws IOException
*/
public String guestFileEncoding(String path) throws FileNotFoundException,
IOException {
return guestFileEncoding(new File(path));
}


/**
* 获取文件的编码
* 
* @param path
*            文件路径
* @param languageHint
*            语言提示区域代码 eg：1 : Japanese; 2 : Chinese; 3 : Simplified Chinese;
*            4 : Traditional Chinese; 5 : Korean; 6 : Dont know (default)
* @return
* @throws FileNotFoundException
* @throws IOException
*/
public String guestFileEncoding(String path, int languageHint)
throws FileNotFoundException, IOException {
return guestFileEncoding(new File(path), languageHint);
}


/**
* 获取文件的编码
* 
* @param file
* @param det
* @return
* @throws FileNotFoundException
* @throws IOException
*/
private String geestFileEncoding(File file, nsDetector det)
throws FileNotFoundException, IOException {
// Set an observer...
// The Notify() will be called when a matching charset is found.
det.Init(new nsICharsetDetectionObserver() {
public void Notify(String charset) {
found = true;
encoding = charset;
}
});


BufferedInputStream imp = new BufferedInputStream(new FileInputStream(
file));


byte[] buf = new byte[1024];
int len;
boolean done = false;
boolean isAscii = true;


while ((len = imp.read(buf, 0, buf.length)) != -1) {
// Check if the stream is only ascii.
if (isAscii)
isAscii = det.isAscii(buf, len);


// DoIt if non-ascii and not done yet.
if (!isAscii && !done)
done = det.DoIt(buf, len, false);
}
det.DataEnd();


if (isAscii) {
encoding = "ASCII";
found = true;
}


if (!found) {
String prob[] = det.getProbableCharsets();
if (prob.length > 0) {
// 在没有发现情况下，则取第一个可能的编码
encoding = prob[0];
} else {
return null;
}
}
return encoding;
}
}