src/com/chenlb/mmseg4j/Dictionary.java
private synchronized void addLastTime(File wordsFile) {
		if(wordsFile != null) {
			wordsLastTime.put(wordsFile, wordsFile.lastModified());
		}
	}
private synchronized void addLastTime(File wordsFile) {
		if(wordsFile != null) {
			wordsLastTime.put(wordsFile, wordsFile.lastModified());
		}
	}
把 wordsFile 文件的最后更新时间加记录下来.
@param wordsFile 非 null