最近有需求要將context信息寫入文件,以備後續數據分析。本想直接同步寫入文件了事,但是logback針對日誌的輸出性能尤佳,且爲異步寫入。既然logback封裝如此完美,何不直接使用?
動態創建Logger及其appender。代碼如下:
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import ch.qos.logback.classic.Level;
import ch.qos.logback.classic.LoggerContext;
import ch.qos.logback.classic.encoder.PatternLayoutEncoder;
import ch.qos.logback.classic.spi.ILoggingEvent;
import ch.qos.logback.core.rolling.RollingFileAppender;
import ch.qos.logback.core.rolling.TimeBasedRollingPolicy;
Logger logger = LoggerFactory.getLogger(loggerName);
LoggerContext loggerContext = (LoggerContext) LoggerFactory.getILoggerFactory();
ch.qos.logback.classic.Logger newLogger = (ch.qos.logback.classic.Logger)logger;
//Remove all previously added appenders from this logger instance.
newLogger.detachAndStopAllAppenders();
//define appender
RollingFileAppender<ILoggingEvent> appender = new RollingFileAppender<ILoggingEvent>();
//policy
TimeBasedRollingPolicy<ILoggingEvent> policy = new TimeBasedRollingPolicy<ILoggingEvent>();
policy.setContext(loggerContext);
policy.setMaxHistory(5);
policy.setFileNamePattern("/home/lionbule/%d{yyyy-MM-dd}.log");
policy.setParent(appender);
policy.start();
//encoder
PatternLayoutEncoder encoder = new PatternLayoutEncoder();
encoder.setContext(loggerContext);
encoder.setPattern("%message%n");
encoder.start();
//start appender
appender.setRollingPolicy(policy);
appender.setContext(loggerContext);
appender.setEncoder(encoder);
appender.setPrudent(true); //support that multiple JVMs can safely write to the same file.
appender.start();
newLogger.addAppender(appender);
//setup level
newLogger.setLevel(Level.WARN);
//remove the appenders that inherited 'ROOT'.
newLogger.setAdditive(false);
上述代碼爲草稿,具體使用細節,則根據自己的需求調整。
要點總結:
1. 成功創建appender的關鍵在於,要實例化一個appender,然後set policy/encoder/&others...
最後再start appender。
並且在創建policy時,一定要記住set當前實例化的appender。
具體步驟看上述demo。