e391. writing log records to a log file.txt

这里面包含了一百多个JAVA源文件

To make a logger write log records to a file, you need to add a file handler to the logger. 
    try {
        // Create a file handler that write log record to a file called my.log
        FileHandler handler = new FileHandler("my.log");
    
        // Add to the desired logger
        Logger logger = Logger.getLogger("com.mycompany");
        logger.addHandler(handler);
    } catch (IOException e) {
    }

By default, a file handler overwrites the contents of the log file each time it is created. This example creates a file handler that appends. 
    try {
        // Create an appending file handler
        boolean append = true;
        FileHandler handler = new FileHandler("my.log", append);
    
        // Add to the desired logger
        Logger logger = Logger.getLogger("com.mycompany");
        logger.addHandler(handler);
    } catch (IOException e) {
    }