Package java.util.logging

提供Java ^TM 2平台核心日志记录工具的类和接口。

See: 描述

接口摘要

接口	描述
Filter	可以使用过滤器对超出记录级别提供的控制范围内的记录进行细粒度控制。
LoggingMXBean	记录设备的管理界面。

类摘要

类	描述
ConsoleHandler	这个 Handler将日志记录发布到 System.err 。
ErrorManager	ErrorManager对象可以附加到处理程序来处理在记录期间在处理程序中发生的任何错误。
FileHandler	简单的文件记录 Handler 。
Formatter	格式化程序提供对LogRecords进行格式化的支持。
Handler	一个 Handler对象从 Logger采用日志消息和出口他们。
Level	Level类定义了一组可用于控制日志输出的标准日志记录级别。
Logger	Logger对象用于记录特定系统或应用程序组件的消息。
LoggingPermission	当SecurityManager运行的代码调用其中一个日志控件方法（如Logger.setLevel）时，SecurityManager将检查该权限。
LogManager	有一个全局LogManager对象用于维护关于日志记录器和日志服务的一组共享状态。
LogRecord	LogRecord对象用于在日志框架和各个日志处理程序之间传递日志请求。
MemoryHandler	Handler缓存在内存中的循环缓冲区中的请求。
SimpleFormatter	以人类可读格式打印 LogRecord的简要摘要。
SocketHandler	简单网络记录 Handler 。
StreamHandler	基于流的日志记录 Handler 。
XMLFormatter	将LogRecord格式化为标准XML格式。

Package java.util.logging Description

Provides the classes and interfaces of the Java^TM 2 platform's core logging facilities. The central goal of the logging APIs is to support maintaining and servicing software at customer sites.

There are four main target uses of the logs:

1. Problem diagnosis by end users and system administrators. This consists of simple logging of common problems that can be fixed or tracked locally, such as running out of resources, security failures, and simple configuration errors.
2. Problem diagnosis by field service engineers. The logging information used by field service engineers may be considerably more complex and verbose than that required by system administrators. Typically such information will require extra logging within particular subsystems.
3. Problem diagnosis by the development organization. When a problem occurs in the field, it may be necessary to return the captured logging information to the original development team for diagnosis. This logging information may be extremely detailed and fairly inscrutable. Such information might include detailed tracing on the internal execution of particular subsystems.
4. Problem diagnosis by developers. The Logging APIs may also be used to help debug an application under development. This may include logging information generated by the target application as well as logging information generated by lower-level libraries. Note however that while this use is perfectly reasonable, the logging APIs are not intended to replace the normal debugging and profiling tools that may already exist in the development environment.

The key elements of this package include:

• Logger: The main entity on which applications make logging calls. A Logger object is used to log messages for a specific system or application component.
• LogRecord: Used to pass logging requests between the logging framework and individual log handlers.
• Handler: Exports LogRecord objects to a variety of destinations including memory, output streams, consoles, files, and sockets. A variety of Handler subclasses exist for this purpose. Additional Handlers may be developed by third parties and delivered on top of the core platform.
• Level: Defines a set of standard logging levels that can be used to control logging output. Programs can be configured to output logging for some levels while ignoring output for others.
• Filter: Provides fine-grained control over what gets logged, beyond the control provided by log levels. The logging APIs support a general-purpose filter mechanism that allows application code to attach arbitrary filters to control logging output.
• Formatter: Provides support for formatting LogRecord objects. This package includes two formatters, SimpleFormatter and XMLFormatter, for formatting log records in plain text or XML respectively. As with Handlers, additional Formatters may be developed by third parties.

The Logging APIs offer both static and dynamic configuration control. Static control enables field service staff to set up a particular configuration and then re-launch the application with the new logging settings. Dynamic control allows for updates to the logging configuration within a currently running program. The APIs also allow for logging to be enabled or disabled for different functional areas of the system. For example, a field service engineer might be interested in tracing all AWT events, but might have no interest in socket events or memory management.

Null Pointers

In general, unless otherwise noted in the javadoc, methods and constructors will throw NullPointerException if passed a null argument. The one broad exception to this rule is that the logging convenience methods in the Logger class (the config, entering, exiting, fine, finer, finest, log, logp, logrb, severe, throwing, and warning methods) will accept null values for all arguments except for the initial Level argument (if any).

Related Documentation

For an overview of control flow, please refer to the Java Logging Overview.

从以下版本开始：

1.4