Many java applications need to be deployed on linux servers. If our java program uses system.out.println() to print logs on the linux server, the following steps are required.
1. The java program needs to configure the log4j log file and define the console output
log4j.rootLogger=INFO, console, rolling
log4j.appender.console=org.apache.log4j.ConsoleAppender
log4j.appender.console.layout=org.apache.log4j.PatternLayout
log4j.appender.console.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} [T=%t] [%c %M at
%L]-[%p] %m%n
log4j.appender.rolling=org.apache.log4j.RollingFileAppender
log4j.appender.rolling.layout=org.apache.log4j.PatternLayout
log4j.appender.rolling.MaxFileSize=100MB
log4j.appender.rolling.MaxBackupIndex=10
log4j.appender.rolling.File=./log/FtpProxyMonitor.log
log4j.appender.rolling.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} [T=%t] [%c %M at
%L]-[%p] %m%n
Among them, org.apache.log4j.ConsoleAppender is to configure console output. If log4j is not configured, it will report an error not found
2. When the application is deployed, there needs to be a startup command line
2.1 Not applicable to nohup startup
${JAVA_HOME}/bin/java -Xms64m -Xmx64m -Duser.timezone=GMT+8 -cp ${JARS} ${APP_NAME} 10.255.242.30 21 admin Cmcba PLOG
If so the system log will be printed at the top of the screen when the program starts. But we usually direct the console output to the run.out file
${JAVA_HOME}/bin/java -Xms64m -Xmx64m -Duser.timezone=GMT+8 -cp ${JARS} ${APP_NAME} 10.255.242.30 21 admin Cmcba PLOG >run.out
2.2 Start with nohup background operation
nohup ${JAVA_HOME}/bin/java -Xms64m -Xmx64m -Duser.timezone=GMT+8 -cp ${JARS} ${APP_NAME} 10.255.242.30 21 admin Cmcba PLOG &
In this way, the console output will be output to the nohup.out file by default.
If the definition points to the run.out file, the console output will be output to the run.out file, not to the nohup.out file
nohup ${JAVA_HOME}/bin/java -Xms64m -Xmx64m -Duser.timezone=GMT+8 -cp ${JARS} ${APP_NAME} 10.255.242.30 21 admin Cmcba PLOG >run.out &
3. If we don't want to print console output, we can turn off console output and error output
nohup ${JAVA_HOME}/bin/java -Xms64m -Xmx64m -Duser.timezone=GMT+8 -cp ${JARS} ${APP_NAME} 10.255.242.30 21 admin Cmcba PLOG >/dev/null 2>&1 &
This way the system output will no longer be printed.