<\/span><\/h1>\n\n\n\n\u6253\u5370\u4fe1\u606f\uff1a<\/p>\n\n\n\n
import java.util.logging.Logger;\n\npublic class MyClass {\n private static final Logger LOGGER = Logger.getLogger(MyClass.class.getName());\n\n public static void main(String[] args) {\n System.out.println(\"main method starts\");\n LOGGER.info(\"in MyClass\");\n }\n}\n<\/code><\/pre>\n\n\n\n<\/span>JUL\u7684workflow<\/span><\/h1>\n\n\n\n![\"\"](\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/logging.png\")
<\/figure>\n\n\n\n- Logger
A named entity to which user application sends messages.<\/li> - Handler
A specific handler is typically tied to a specific logging destination. A destination is where final formatted messages are sent. A handler can apply any additional logic, e.g. to improve performance.
Examples: ConsoleHandler, FileHandler, SocketHandler, user defined ones.<\/li> - Level
Used by Logger\/Handler. To discard messages if the Level of a given message is less than the Level associated with the Logger\/Handler.<\/li> - Filter
Used by Logger\/Handler. It can filter message which cannot be filtered based on Levels. A dynamic\/programmatic way to filter messages.<\/li> - Formatter
To display messages in a specific format.
Examples: SimpleFormatter, XMLFormatter or user defined ones<\/li> - Resource Bundle
A Logger may have a ResourceBundle associated with it. It is used to map raw message strings with localized message strings.<\/li><\/ul>\n\n\n\nLogger\u7684\u5c42\u6b21\u7ed3\u6784\uff1a
root Logger(“”)
Logger1 > “com.logicbig”
Logger2 > “com.logicbig.MyClass2” > parent namespace= “com.logicbig”
Logger3 > “com.logicbig.MyClass3” > parent namespace= “com.logicbig”<\/p>\n\n\n\n
\u63a8\u8350\u4f7f\u7528\u5e26\u6709\u5305\u540d\u4fe1\u606f\u7684\u7c7b\u540d\u4f5c\u4e3aLogger\u7684\u540d\u5b57\u3002<\/p>\n\n\n\n
\u914d\u7f6e\u65e5\u5fd7\u7684\u5c5e\u6027\uff1a<\/p>\n\n\n\n
- \u7528JVM\u5c5e\u6027\u6307\u5b9aConfig class\uff1a
java.util.logging.config.class=com.logicbig.example.MyConfigClass<\/code>
Java\u4f1a\u5728\u542f\u52a8\u65f6\u8f7d\u5165MyConfigClass\u3002\u6b64\u7c7b\u7684\u6784\u9020\u51fd\u6570\u53ef\u4ee5\u4f7f\u7528\u4e0b\u9762\u7684\u65b9\u6cd5\u521d\u59cb\u5316\u65e5\u5fd7\u5c5e\u6027\uff1a<\/li><\/ol>\n\n\n\nLogManager.getLogManager().readConfiguration(InputStream);\n<\/code><\/pre>\n\n\n\n\u5728\u8fd9\u4e2a\u7528\u4e8e\u521d\u59cb\u5316\u65e5\u5fd7\u5c5e\u6027\u7684\u7c7b\u91cc\uff0c\u4e5f\u53ef\u4ee5\u8bbe\u7f6e\u5404\u79cdlogger\uff1a<\/p>\n\n\n\n
Logger mainLogger = Logger.getLogger(\"com.logicbig.example\");\nmainLogger.setLevel(Level.FINEST);\nmainLogger.addHandler(....);\n .... \n<\/code><\/pre>\n\n\n\n- \u7528JVM\u5c5e\u6027\u6307\u5b9a\u914d\u7f6e\u6587\u4ef6\uff1a
java.util.logging.config.file=D:\\myApp\\logging.properties<\/code>\u3002<\/li>- \u9ed8\u8ba4\u7684\u65e5\u5fd7\u5c5e\u6027\u6587\u4ef6(
C:\\java\\jdk1.8.0_111\\jre\\lib\\logging.properties<\/code>)\uff1a<\/li><\/ol>\n\n\n\n############################################################\n# \tDefault Logging Configuration File\n#\n# You can use a different file by specifying a filename\n# with the java.util.logging.config.file system property.\n# For example java -Djava.util.logging.config.file=myfile\n############################################################\n\n############################################################\n# \tGlobal properties\n############################################################\n\n# \"handlers\" specifies a comma separated list of log Handler\n# classes. These handlers will be installed during VM startup.\n# Note that these classes must be on the system classpath.\n# By default we only configure a ConsoleHandler, which will only\n# show messages at the INFO and above levels.\nhandlers= java.util.logging.ConsoleHandler\n\n# To also add the FileHandler, use the following line instead.\n#handlers= java.util.logging.FileHandler, java.util.logging.ConsoleHandler\n\n# Default global logging level.\n# This specifies which kinds of events are logged across\n# all loggers. For any given facility this global level\n# can be overriden by a facility specific level\n# Note that the ConsoleHandler also has a separate level\n# setting to limit messages printed to the console.\n.level= INFO\n\n############################################################\n# Handler specific properties.\n# Describes specific configuration info for Handlers.\n############################################################\n\n# default file output is in user's home directory.\njava.util.logging.FileHandler.pattern = %h\/java%u.log\njava.util.logging.FileHandler.limit = 50000\njava.util.logging.FileHandler.count = 1\njava.util.logging.FileHandler.formatter = java.util.logging.XMLFormatter\n\n# Limit the message that are printed on the console to INFO and above.\njava.util.logging.ConsoleHandler.level = INFO\njava.util.logging.ConsoleHandler.formatter = java.util.logging.SimpleFormatter\n\n# Example to customize the SimpleFormatter output format\n# to print one-line log message like this:\n# <level>: <log message> [<date\/time>]\n#\n# java.util.logging.SimpleFormatter.format=%4$s: %5$s [%1$tc]%n\n\n############################################################\n# Facility specific properties.\n# Provides extra control for each logger.\n############################################################\n\n# For example, set the com.xyz.foo logger to only log SEVERE\n# messages:\ncom.xyz.foo.level = SEVERE\n<\/code><\/pre>\n\n\n\n<\/span>\u5728\u7a0b\u5e8f\u4e2d\u914d\u7f6e\u65e5\u5fd7\u5c5e\u6027\u7684\u51e0\u79cd\u65b9\u6cd5<\/span><\/h1>\n\n\n\n\u6309\u7167\u7edd\u5bf9\u8def\u5f84\u8bfb\u53d6\u914d\u7f6e\u6587\u4ef6<\/p>\n\n\n\n
public class MyClass {\n\n private static Logger LOGGER;\n\n static {\n System.setProperty(\"java.util.logging.config.file\",\n \"d:\\\\test-app\\\\logging.properties\");\n \/\/must initialize loggers after setting above property<\/em>\n LOGGER = Logger.getLogger(MyClass.class.getName());\n }\n\n public static void main(String[] args) {\n System.out.println(\"-- main method starts --\");\n LOGGER.info(\"an info msg\");\n LOGGER.warning(\"a warning msg\");\n LOGGER.severe(\"a severe msg\");\n }\n}\n<\/code><\/pre>\n\n\n\n\u6309\u7167classpath\u8bfb\u53d6\u914d\u7f6e\u6587\u4ef6<\/p>\n\n\n\n
public class MyClass2 {\n\n private static Logger LOGGER;\n\n static {\n String path = MyClass2.class.getClassLoader()\n .getResource(\"logging.properties\")\n .getFile();\n System.setProperty(\"java.util.logging.config.file\", path);\n LOGGER = Logger.getLogger(MyClass2.class.getName());\n }\n\n public static void main(String[] args) {\n System.out.println(\"-- main method starts --\");\n LOGGER.info(\"an info msg\");\n LOGGER.warning(\"a warning msg\");\n LOGGER.severe(\"a severe msg\");\n }\n}\n<\/code><\/pre>\n\n\n\n\u4f7f\u7528LogManager#readConfiguration()\u8bfb\u53d6\u914d\u7f6e\u6587\u4ef6<\/p>\n\n\n\n
public class MyClass3 {\n private static Logger LOGGER;\n\n static {\n InputStream stream = MyClass3.class.getClassLoader().\n getResourceAsStream(\"logging.properties\");\n try {\n LogManager.getLogManager().readConfiguration(stream);\n } catch (IOException e) {\n e.printStackTrace();\n }\n LOGGER = Logger.getLogger(MyClass3.class.getName());\n }\n\n public static void main(String[] args) {\n System.out.println(\"-- main method starts --\");\n LOGGER.info(\"an info msg\");\n LOGGER.warning(\"a warning msg\");\n LOGGER.severe(\"a severe msg\");\n }\n}\n<\/code><\/pre>\n\n\n\n<\/span>\u8bbe\u7f6e\u65e5\u5fd7\u683c\u5f0f<\/span><\/h1>\n\n\n\n\u5728\u4f7f\u7528SimpleFormatter\u8bbe\u7f6e\u65e5\u5fd7\u8f93\u51fa\u683c\u5f0f\u65f6\uff0c\u9ed8\u8ba4\u8c03\u7528\u4ee5\u4e0b\u65b9\u6cd5\u8f93\u51fa\u65e5\u5fd7\uff1a
String.format(format, date, source, logger, level, message, thrown);<\/code><\/p>\n\n\n\n\u5b9a\u4e49\u81ea\u5df1\u7684\u8f93\u51fa\u683c\u5f0f\u6709\u4ee5\u4e0b\u51e0\u79cd\u65b9\u6cd5\uff1a<\/p>\n\n\n\n
\u4f7f\u7528logging.properties
src\/main\/resources\/logging.propertis:<\/p>\n\n\n\n
handlers= java.util.logging.ConsoleHandler\n .level= INFO\n java.util.logging.ConsoleHandler.level = INFO\n java.util.logging.ConsoleHandler.formatter = java.util.logging.SimpleFormatter\n java.util.logging.SimpleFormatter.format=[%1$tF %1$tT] [%4$-7s] %5$s %n\n<\/code><\/pre>\n\n\n\npublic class MyClass {\n private static Logger LOGGER = null;\n\n static {\n InputStream stream = MyClass.class.getClassLoader().\n getResourceAsStream(\"logging.properties\");\n try {\n LogManager.getLogManager().readConfiguration(stream);\n LOGGER= Logger.getLogger(MyClass.class.getName());\n\n } catch (IOException e) {\n e.printStackTrace();\n }\n }\n\n public static void main(String[] args) {\n System.out.println(\"-- main method starts --\");\n LOGGER.info(\"in MyClass\");\n LOGGER.warning(\"a test warning\");\n }\n}\n<\/code><\/pre>\n\n\n\n\u4f7f\u7528system property<\/p>\n\n\n\n
public class MyClass2 {\n private static Logger LOGGER = null;\n\n static {\n System.setProperty(\"java.util.logging.SimpleFormatter.format\",\n \"[%1$tF %1$tT] [%4$-7s] %5$s %n\");\n LOGGER = Logger.getLogger(MyClass2.class.getName());\n }\n\n public static void main(String[] args) {\n System.out.println(\"-- main method starts --\");\n LOGGER.info(\"in MyClass2\");\n LOGGER.warning(\"a test warning\");\n }\n}\n<\/code><\/pre>\n\n\n\n\u901a\u8fc7\u7f16\u7a0b\u6307\u5b9a<\/p>\n\n\n\n
package com.logicbig.example;\n\nimport java.util.Date;\nimport java.util.logging.ConsoleHandler;\nimport java.util.logging.LogRecord;\nimport java.util.logging.Logger;\nimport java.util.logging.SimpleFormatter;\n\npublic class MyClass3 {\n private static Logger LOGGER = null;\n\n static {\n Logger mainLogger = Logger.getLogger(\"com.logicbig\");\n mainLogger.setUseParentHandlers(false);\n ConsoleHandler handler = new ConsoleHandler();\n handler.setFormatter(new SimpleFormatter() {\n private static final String format = \"[%1$tF %1$tT] [%2$-7s] %3$s %n\";\n\n @Override\n public synchronized String format(LogRecord lr) {\n return String.format(format,\n new Date(lr.getMillis()),\n lr.getLevel().getLocalizedName(),\n lr.getMessage()\n );\n }\n });\n mainLogger.addHandler(handler);\n LOGGER = Logger.getLogger(MyClass3.class.getName());\n }\n\n public static void main(String[] args) {\n System.out.println(\"-- main method starts --\");\n LOGGER.info(\"in MyClass3\");\n LOGGER.warning(\"a test warning\");\n }\n}\n<\/code><\/pre>\n\n\n\n<\/span>\u8bbe\u7f6e\u65e5\u5fd7\u7ea7\u522b<\/span><\/h1>\n\n\n\napi\uff1aLogger#setLevel()\u548cHandler#setLevel()<\/p>\n\n\n\n
\u5728\u7a0b\u5e8f\u4e2d\u8bbe\u7f6e\u65e5\u5fd7\u7ea7\u522b<\/p>\n\n\n\n
public class LogLevelExample {\n private static Logger log = Logger.getLogger(LogLevelExample.class.getName());\n\n static {\n System.setProperty(\"java.util.logging.SimpleFormatter.format\",\n \"[%1$tF %1$tT %1$tL] [%4$-7s] %5$s %n\");\n }\n\n public static void main(String[] args) throws Exception {\n setLevel(Level.ALL);\n Set<Level> levels = getAllLevels();\n int i = 1;\n for (Level level : levels) {\n log.log(level, level.getName() + \" - \" + (i++));\n }\n }\n\n public static void setLevel(Level targetLevel) {\n Logger root = Logger.getLogger(\"\");\n root.setLevel(targetLevel);\n for (Handler handler : root.getHandlers()) {\n handler.setLevel(targetLevel);\n }\n System.out.println(\"level set: \" + targetLevel.getName());\n }\n\n public static Set<Level> getAllLevels() throws IllegalAccessException {\n Class<Level> levelClass = Level.class;\n\n Set<Level> allLevels = new TreeSet<>(\n Comparator.comparingInt(Level::intValue));\n\n for (Field field : levelClass.getDeclaredFields()) {\n if (field.getType() == Level.class) {\n allLevels.add((Level) field.get(null));\n }\n }\n return allLevels;\n }\n}\n\n<\/code><\/pre>\n\n\n\n\u5728\u914d\u7f6e\u6587\u4ef6\u4e2d\u8bbe\u7f6e\u65e5\u5fd7\u7ea7\u522b<\/p>\n\n\n\n
src\/main\/resources\/logging.properties<\/p>\n\n\n\n
handlers= java.util.logging.ConsoleHandler\n.level= FINEST\njava.util.logging.ConsoleHandler.level = FINEST\njava.util.logging.ConsoleHandler.formatter = java.util.logging.SimpleFormatter\njava.util.logging.SimpleFormatter.format=[%1$tF %1$tT] [%4$-7s] %5$s %n\n<\/code><\/pre>\n\n\n\npublic class LogLevelPropertiesExample {\n private static Logger log;\n\n static {\n String path = LogLevelPropertiesExample.class\n .getClassLoader()\n .getResource(\"logging.properties\")\n .getFile();\n System.setProperty(\"java.util.logging.config.file\", path);\n log = Logger.getLogger(LogLevelPropertiesExample.class.getName());\n }\n\n public static void main(String[] args) throws Exception {\n Set<Level> levels = getAllLevels();\n int i = 1;\n for (Level level : levels) {\n log.log(level, level.getName() + \" - \" + (i++));\n }\n }\n .............\n}\n<\/code><\/pre>\n\n\n\n<\/span>Java Util Logging\uff0c\u81ea\u5b9a\u4e49\u5982\u4f55\u5904\u7406log\u4fe1\u606f<\/span><\/h1>\n\n\n\n\u901a\u8fc7\u81ea\u5b9a\u4e49\u4e00\u4e2aLog Handler\uff0c\u53ef\u4ee5\u7531\u5f00\u53d1\u8005\u81ea\u884c\u51b3\u5b9a\u5982\u4f55\u5904\u7406\u6765\u81ealogger\u7684\u65e5\u5fd7\u6d88\u606f\u3002<\/p>\n\n\n\n
\u81ea\u5b9a\u4e49handler<\/p>\n\n\n\n
package com.logicbig.example;\n\nimport java.util.logging.Handler;\nimport java.util.logging.LogRecord;\n\npublic class MyLogHandler extends Handler {\n\n @Override\n public void publish(LogRecord record) {\n StringBuilder sb = new StringBuilder();\n sb.append(record.getMillis())\n .append(\" - \")\n .append(record.getSourceClassName())\n .append(\"#\")\n .append(record.getSourceMethodName())\n .append(\" - \")\n .append(record.getMessage());\n System.out.println(sb.toString());\n }\n\n @Override\n public void flush() {\n }\n\n @Override\n public void close() throws SecurityException {\n }\n}\n<\/code><\/pre>\n\n\n\n\u751f\u6210\u65e5\u5fd7\u6d88\u606f<\/p>\n\n\n\n
package com.logicbig.example;\n\nimport java.util.logging.Logger;\n\npublic class AppClass {\n private static final Logger LOGGER = Logger.getLogger(AppClass.class.getName());\n\n public void doSomething(){\n LOGGER.info(\"in AppClass\");\n }\n}\n<\/code><\/pre>\n\n\n\n\u6ce8\u518chandler<\/p>\n\n\n\n
package com.logicbig.example;\n\nimport java.util.logging.Handler;\nimport java.util.logging.LogManager;\nimport java.util.logging.Logger;\n\npublic class ExampleMain {\n\n public static void main(String[] args) {\n \/\/reset() will remove all default handlers<\/em>\n LogManager.getLogManager().reset();\n Logger rootLogger = LogManager.getLogManager().getLogger(\"\");\n\n rootLogger.addHandler(new MyLogHandler());\n AppClass appClass = new AppClass();\n appClass.doSomething();\n rootLogger.info(\"some message\");\n }\n}<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"Java\u81ea\u5e26\u7684log\u5de5\u5177\u3002 \u5165\u95e8 \u6253\u5370\u4fe1\u606f\uff1a JUL\u7684workflow LoggerA named entity to which user application sends messages. H...<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[10],"tags":[87],"class_list":["post-860","post","type-post","status-publish","format-standard","hentry","category-10","tag-java"],"_links":{"self":[{"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/posts\/860","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=860"}],"version-history":[{"count":1,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/posts\/860\/revisions"}],"predecessor-version":[{"id":862,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/posts\/860\/revisions\/862"}],"wp:attachment":[{"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=860"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=860"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=860"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}