Use slf4j instead of Apache common-logging to write logsApache common-logging is a widely used Java log facade library. I have always used it to write logs with log4j. Apache common-logging uses the dynamic search mechanism to automatically find the logstore in use when the program is running. Apache common-logging always works well. It wasn't working until recently when I wrote the osgi plug-in. The reason is that Apache common-logging uses classloader to search for and load the underlying logstore. In osgi, different plug-ins use their own classloader. Classloader of a thread has different execution capabilities when executing different plug-ins. This mechanism of osgi ensures that the plug-ins are independent from each other, but does make Apache common-logging unable to work! The solution is to use the new logstore slf4j. The slf4j library is similar to Apache common-logging. However, he binds the real log library statically during compilation. When using slf4j, if you need to use a log implementation, You must select the correct set of slf4j jar packages. This is indeed a little troublesome, but it is finally possible to develop logs in osgi. In fact, this is not a hassle.
The process of using the commonlog interface and actually implemented by slf4j and log4j1. Use it as usual in the project
ImportOrg. Apache. commons. Logging. log;
ImportOrg. Apache. commons. Logging. logfactory; write logs. 2. Use the log4j. properties file under SRC for configuration. 3, use all jar files: 1) log4j-1.2.15.jar this is the log4j library. Slf4j does not change the underlying implementation library. 2) slf4j-api-1.5.2.jar this is the slf4j library. 3) slf4j-log4j12-1.5.2.jar this includes the log4j adapter and the underlying implementation of static binding log4j. 4) jcl-over-slf4j-1.5.2.jar this provides the commons-logging interface, and the use of common-Loggin interfaces, the underlying is determined by slf4j which implementation mechanism. Here, we need to use the log4j native library, but do not need the commons-logging native library. OK. Copy the preceding four jar packages to lib and import them to the project. As before, you can continue to use Apache common-logging to write logs. If you prefer to use the slf4j portal class or non-log4j log implementation library. You just need to throw the required jar package into your project like above!
