我需要以编程方式启用某些JDK7内部类的日志记录。
这是我在初始化应用程序时所做的:
httpLogger = Logger.getLogger("sun.net.www.protocol.http.HttpURLConnection");
httpLogger.setLevel(Level.FINEST);
其中
httpLogger是强引用(为了避免记录器被垃圾回收)。我还将ConsoleHandler的级别设置为ALL。但是我无法获得任何输出。如果我通过记录配置文件来做到这一点，它将按预期工作。
我可能是错的，但是我认为这与我不了解Java 7中引入的
PlatformLogger有关，该文件-afaik-现在已用于所有JDK内部日志记录。或者也许我只是不懂J.U.L.足够好。我猜测如果这样做，它会起作用:
httpLogger = PlatformLogger.getLogger("sun.net.www.protocol.http.HttpURLConnection");
httpLogger.setLevel(Level.FINEST);
但是
PlatformLogger类在我不能引用的包中。什么是
PlatformLogger？这是JavaDoc:
Platform logger provides an API for the JRE components to log
messages. This enables the runtime components to eliminate the
static dependency of the logging facility and also defers the
java.util.logging initialization until it is enabled.
In addition, the PlatformLogger API can be used if the logging
module does not exist.
If the logging facility is not enabled, the platform loggers
will output log messages per the default logging configuration
(see below). In this implementation, it does not log the
the stack frame information issuing the log message.
When the logging facility is enabled (at startup or runtime),
the java.util.logging.Logger will be created for each platform
logger and all log messages will be forwarded to the Logger
to handle.
Logging facility is "enabled" when one of the following
conditions is met:
1) a system property "java.util.logging.config.class" or
"java.util.logging.config.file" is set
2) java.util.logging.LogManager or java.util.logging.Logger
is referenced that will trigger the logging initialization.
Default logging configuration:
global logging level = INFO
handlers = java.util.logging.ConsoleHandler
java.util.logging.ConsoleHandler.level = INFO
java.util.logging.ConsoleHandler.formatter = java.util.logging.SimpleFormatter
Limitation:
<JAVA_HOME>/lib/logging.properties is the system-wide logging
configuration defined in the specification and read in the
default case to configure any java.util.logging.Logger instances.
Platform loggers will not detect if <JAVA_HOME>/lib/logging.properties
is modified. In other words, unless the java.util.logging API
is used at runtime or the logging system properties is set,
the platform loggers will use the default setting described above.
The platform loggers are designed for JDK developers use and
this limitation can be workaround with setting
-Djava.util.logging.config.file system property.
@since 1.7
最佳答案
我的解决方案出现在一个小型自定义小部件演示程序的开头:
// Log all focus messages.
final Logger rootLogger = Logger.getLogger("");
rootLogger.setLevel(Level.ALL);
final ConsoleHandler consoleHandler = new ConsoleHandler();
consoleHandler.setLevel(Level.ALL);
// Because there are a lot of focus messages, make them
// a little easier to read by logging only the message.
consoleHandler.setFormatter(new Formatter() {
@Override
public String format(LogRecord record) {
return "FOCUS: " + record.getMessage() + '\n';
}
});
final Logger logger = Logger.getLogger("java.awt.focus.Component");
logger.setLevel(Level.ALL);
logger.setUseParentHandlers(false);
logger.addHandler(consoleHandler);
我不清楚我为什么需要获取然后将rootLogger级别设置为ALL，但这就是我所需要的。