Logback用法和打印列表

Question

我开始使用logback,我想知道是否有更好的方法来做某事.我有这个代码:

public class ClassA {
    private List<String> l;
    private Logger logger;

    public ClassA(){
        this.logger = LoggerFactory.getLogger(this.getClass().getName());
    }
....
    public List<String> method() {
        this.logger.debug("method()");
        List<String> names;

        try {
            names = otherClass.getNames();
        } catch (Exception e) {
            String msg = "Error getting names";
            this.logger.error(msg);
            throw new ClassAexception(msg, e);
        }

        this.logger.debug("names: {}", xxxxx);
        return names;
}

到目前为止我有些疑惑:

• 每个班级都有一个this.logger = LoggerFactory.getLogger(this.getClass().getName());创建记录器.
• 每个方法都有一个this.logger.debug("method()");知道何时调用方法的方法.

这看起来不太好.有办法解决吗？

另外,我想在此行的.log中打印一个列表: this.logger.debug("names: {}", xxxxx);

xxxxx应替换为打印列表的东西.一个匿名的课程？

谢谢阅读!

Answer 1

使用AspectJ和log4j可以使用它.使用ajc编译器而不是javac编译代码,然后使用java可执行文件正常运行.

您需要在类路径上包含aspectjrt.jar和log4j.jar.

import org.aspectj.lang.*;
import org.apache.log4j.*;

public aspect TraceMethodCalls {
    Logger logger = Logger.getLogger("trace");

    TraceMethodCalls() {
        logger.setLevel(Level.ALL);
    }

    pointcut traceMethods()
        //give me all method calls of every class with every visibility
        : (execution(* *.*(..))
        //give me also constructor calls
        || execution(*.new(..)))
        //stop recursion don't get method calls in this aspect class itself
        && !within(TraceMethodCalls);

    //advice before: do something before method is really executed
    before() : traceMethods() {
        if (logger.isEnabledFor(Level.INFO)) {
            //get info about captured method and log it
            Signature sig = thisJoinPointStaticPart.getSignature();
            logger.log(Level.INFO,
                        "Entering ["
                        + sig.getDeclaringType().getName() + "."
                        + sig.getName() + "]");
        }
    }
}

查看AspectJ文档,了解如何更改TraceMethodCalls调用.

// e.g. just caputre public method calls
// change this
: (execution(* *.*(..))
// to this
: (execution(public * *.*(..))

关于

另外,我想在此行的.log中打印一个列表: this.logger.debug("names: {}", xxxxx);

默认情况下,slf4j/logback支持这一点.做就是了

logger.debug("names: {}", names);

例如

List<String> list = new ArrayList<String>();
list.add("Test1"); list.add("Test2"); list.add("Test3");
logger.debug("names: {}", list);

//produces
//xx::xx.xxx [main] DEBUG [classname] - names: [Test1, Test2, Test3]

或者你想要一些特别不同的东西？