java中的记录器和FileHandler

我想在文件中打印日期和时间，而不是在屏幕上

String fileName =  NameEnter.getText(); 
Logger logger = Logger.getLogger("puzzleNumberGame.securityScreen");  
FileHandler fh = new FileHandler(fileName);
logger.addHandler(fh);
logger.setLevel(Level.ALL);
SimpleFormatter formatter = new SimpleFormatter();
fh.setFormatter(formatter);
logger.log(Level.WARNING,"My first log");

这是我的代码：

String fileName =  NameEnter.getText(); 
Logger logger = Logger.getLogger("puzzleNumberGame.securityScreen");  
FileHandler fh = new FileHandler(fileName);
logger.addHandler(fh);
logger.setLevel(Level.ALL);
SimpleFormatter formatter = new SimpleFormatter();
fh.setFormatter(formatter);
logger.log(Level.WARNING,"My first log");

我用这个

String fileName =  NameEnter.getText(); 
Logger logger = Logger.getLogger("puzzleNumberGame.securityScreen");  
FileHandler fh = new FileHandler(fileName);
logger.addHandler(fh);
logger.setLevel(Level.ALL);
SimpleFormatter formatter = new SimpleFormatter();
fh.setFormatter(formatter);
logger.log(Level.WARNING,"My first log");

// handlers = java.util.logging.ConsoleHandler;

但它不起作用

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谢谢大家：）

在类中包含一个静态定义，如下所示

String fileName =  NameEnter.getText(); 
Logger logger = Logger.getLogger("puzzleNumberGame.securityScreen");  
FileHandler fh = new FileHandler(fileName);
logger.addHandler(fh);
logger.setLevel(Level.ALL);
SimpleFormatter formatter = new SimpleFormatter();
fh.setFormatter(formatter);
logger.log(Level.WARNING,"My first log");

private final static Logger LOGGER = Logger.getLogger("nescent");

然后设置记录器，如下所示

String fileName =  NameEnter.getText(); 
Logger logger = Logger.getLogger("puzzleNumberGame.securityScreen");  
FileHandler fh = new FileHandler(fileName);
logger.addHandler(fh);
logger.setLevel(Level.ALL);
SimpleFormatter formatter = new SimpleFormatter();
fh.setFormatter(formatter);
logger.log(Level.WARNING,"My first log");

    private static void setupLogger(){
    LOGGER.setLevel(Level.ALL);
    try {
            FileHandler fhandler = new FileHandler("Logfile.txt");
            SimpleFormatter sformatter = new SimpleFormatter();
            fhandler.setFormatter(sformatter);
            LOGGER.addHandler(fhandler);

    } catch (IOException ex) {
        LOGGER.log(Level.SEVERE, ex.getMessage(), ex);
    } catch (SecurityException ex) {
        LOGGER.log(Level.SEVERE, ex.getMessage(), ex);
    }
}

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以下是我的看法：在try{}块中，为FileHandler和SimpleFormatter对象提供实例化。要将数据记录到文件中，Logger类的方法必须在try块之外。代码如下：

String fileName =  NameEnter.getText(); 
Logger logger = Logger.getLogger("puzzleNumberGame.securityScreen");  
FileHandler fh = new FileHandler(fileName);
logger.addHandler(fh);
logger.setLevel(Level.ALL);
SimpleFormatter formatter = new SimpleFormatter();
fh.setFormatter(formatter);
logger.log(Level.WARNING,"My first log");

公共静态void setupLogger（）{

String fileName =  NameEnter.getText(); 
Logger logger = Logger.getLogger("puzzleNumberGame.securityScreen");  
FileHandler fh = new FileHandler(fileName);
logger.addHandler(fh);
logger.setLevel(Level.ALL);
SimpleFormatter formatter = new SimpleFormatter();
fh.setFormatter(formatter);
logger.log(Level.WARNING,"My first log");

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什么不起作用？您看到了什么结果？您收到了错误消息吗？我认为您最好在自己从头开始之前获得一个日志库。我认为，但它是在文件和屏幕中打印的，我不想在屏幕中打印