scala - 如何强制解释器显示完整的堆栈跟踪？

Question

有什么方法可以强制 Scala 解释器(通过 SBT 启动)打印完整的堆栈跟踪。默认显示少于 10 行:

scala> new CacheMonitoringClient
javax.management.InstanceNotFoundException: com.bea:Name=DomainRuntimeService,Type=weblogic.management.beanservers.domainrun
time.DomainRuntimeServiceMBean
        at weblogic.rjvm.ResponseImpl.unmarshalReturn(ResponseImpl.java:195)
        at weblogic.rmi.internal.BasicRemoteRef.invoke(BasicRemoteRef.java:224)
        at javax.management.remote.rmi.RMIConnectionImpl_921_WLStub.getAttribute(Unknown Source)
        at weblogic.management.remote.common.RMIConnectionWrapper$11.run(ClientProviderBase.java:498)
        at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:363)
        at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:147)
        at weblogic.security.Security.runAs(Security.java:61)
        at weblogic.management.remote.common.RMIConnectionWrapper.getAttribute(ClientProviderBas...

作为解决方法，我正在使用 try { new CacheMonitoringClient } catch { case ex => ex.printStackTrace}(显式包装引发我感兴趣的异常的调用)，但是真的很丑……

Answer 1

如果您只需要一件事，请使用 lastException:

scala> 1 / 0
java.lang.ArithmeticException: / by zero
    at .<init>(<console>:12)
    at .<clinit>(<console>)
    at RequestResult$.<init>(<console>:9)
    at RequestResult$.<clinit>(<console>)
    at RequestResult$scala_repl_result(<console>)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at scala.tools.nsc.Interpreter$Request$$anonfun$loadAndRun$1$$anonfun$apply$18.apply(Interpreter.scala:981)
    at scala.tools.nsc.Interpreter$Request$$anonfun$loadAndRun$1$$anonfun$apply$18.apply(Interpreter.scala:981)
    at scala.util.control.Exception$Catch.apply(Exception.scala:79)
    at scal...
scala> lastException.printStackTrace
java.lang.ArithmeticException: / by zero
    at line101$object$$iw$$iw$$iw$$iw$$iw$$iw$.<init>(<console>:12)
    at line101$object$$iw$$iw$$iw$$iw$$iw$$iw$.<clinit>(<console>)
    at RequestResult$line101$object$.<init>(<console>:9)
    at RequestResult$line101$object$.<clinit>(<console>)
    at RequestResult$line101$object.scala_repl_result(<console>)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at scala.tools.nsc.Interpreter$Request$$anonfun$loadAndRun$1$$anonfun$apply$18.apply(Interpreter.scala:981)
    at scala.tools.nsc.Interpreter$Request$$anonfun$loadAndRun$1$$anonfun$apply$18.apply(Interpreter.scala:981)
    at scala.util.control.Exception$Catch.apply(Exception.scala:79)
    at scala.tools.nsc.Interpreter$Request$$anonfun$loadAndRun$1.apply(Interpreter.scala:980)
    at scala.tools.nsc.Interpreter$Request$$anonfun$loadAndRun$1.apply(Interpreter.scala:980)
    at scala.util.control.Exception$Catch.apply(Exception.scala:79)
    at scala.tools.nsc.Interpreter$Request.loadAndRun(Interpreter.scala:979)
    at scala.tools.nsc.Interpreter.loadAndRunReq$1(Interpreter.scala:578)
    at scala.tools.nsc.Interpreter.interpret(Interpreter.scala:597)
    at scala.tools.nsc.Interpreter.interpret(Interpreter.scala:575)
    at scala.tools.nsc.InterpreterLoop.reallyInterpret$1(InterpreterLoop.scala:471)
    at scala.tools.nsc.InterpreterLoop.interpretStartingWith(InterpreterLoop.scala:514)
    at scala.tools.nsc.InterpreterLoop.command(InterpreterLoop.scala:361)
    at scala.tools.nsc.InterpreterLoop.processLine$1(InterpreterLoop.scala:242)
    at scala.tools.nsc.InterpreterLoop.repl(InterpreterLoop.scala:248)
    at scala.tools.nsc.InterpreterLoop.main(InterpreterLoop.scala:558)
    at scala.tools.nsc.MainGenericRunner$.main(MainGenericRunner.scala:72)
    at scala.tools.nsc.MainGenericRunner.main(MainGenericRunner.scala)

或者将 settings.maxPrintString 设置为 0，尽管这也会改变正常结果的打印方式。

scala> settings.maxPrintString = 0

scala> 1 /0
java.lang.ArithmeticException: / by zero
    at .<init>(<console>:12)
    at .<clinit>(<console>)
    at RequestResult$.<init>(<console>:9)
    at RequestResult$.<clinit>(<console>)
    at RequestResult$scala_repl_result(<console>)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at scala.tools.nsc.Interpreter$Request$$anonfun$loadAndRun$1$$anonfun$apply$18.apply(Interpreter.scala:981)
    at scala.tools.nsc.Interpreter$Request$$anonfun$loadAndRun$1$$anonfun$apply$18.apply(Interpreter.scala:981)
    at scala.util.control.Exception$Catch.apply(Exception.scala:79)
    at scala.tools.nsc.Interpreter$Request$$anonfun$loadAndRun$1.apply(Interpreter.scala:980)
    at scala.tools.nsc.Interpreter$Request$$anonfun$loadAndRun$1.apply(Interpreter.scala:980)
    at scala.util.control.Exception$Catch.apply(Exception.scala:79)
    at scala.tools.nsc.Interpreter$Request.loadAndRun(Interpreter.scala:979)
    at scala.tools.nsc.Interpreter.loadAndRunReq$1(Interpreter.scala:578)
    at scala.tools.nsc.Interpreter.interpret(Interpreter.scala:597)
    at scala.tools.nsc.Interpreter.interpret(Interpreter.scala:575)
    at scala.tools.nsc.InterpreterLoop.reallyInterpret$1(InterpreterLoop.scala:471)
    at scala.tools.nsc.InterpreterLoop.interpretStartingWith(InterpreterLoop.scala:514)
    at scala.tools.nsc.InterpreterLoop.command(InterpreterLoop.scala:361)
    at scala.tools.nsc.InterpreterLoop.processLine$1(InterpreterLoop.scala:242)
    at scala.tools.nsc.InterpreterLoop.repl(InterpreterLoop.scala:248)
    at scala.tools.nsc.InterpreterLoop.main(InterpreterLoop.scala:558)
    at scala.tools.nsc.MainGenericRunner$.main(MainGenericRunner.scala:72)
    at scala.tools.nsc.MainGenericRunner.main(MainGenericRunner.scala)