//判断文件编码
CodepageDetectorProxy detector = CodepageDetectorProxy.getInstance();
detector.add(new ParsingDetector(false));
detector.add(JChardetFacade.getInstance());
detector.add(ASCIIDetector.getInstance());
detector.add(UnicodeDetector.getInstance());
java.nio.charset.Charset charset = null;
try {
    charset = detector.detectCodepage(sourseFile.toURL());
} catch (Exception ex) {
    ex.printStackTrace();
}
if (charset != null) {
    chartsetName=charset.name();
} else {
    chartsetName="UTF-8";
}
//读入文本文件
BufferedReader in = new BufferedReader(new InputStreamReader(new FileInputStream(fileName),chartsetName));
while (in.ready()) {
    str = in.readLine().trim();
    if (str.trim().equals("")) {
        break;
    }
    HashMap map=new HashMap();
    //解析
    String sno = str.substring(0, 16).trim();
    .....
    //放入map
    backMap.put(sno, myObj);
}

Obj objTmp=backMap.get(sno1);