java log日志常见误区

<>原因分析

很多程序员会无意间可能会这样打日志
logger.error(e); logger.error(e.getMessage); logger.error("错误信息：" + e);
看下logger.error代码就知道error有2个重载方法
public void error(String msg); public void error(String msg, Throwable t);
上面的代码只有一个参数，因此都会被认为是调用第一种方法，这样造成的结果就是e将会被自动转成String类型，从而丢失的许多错误信息、堆栈信息。

<>错误示例

如下堆栈等信息基本上全丢失了，即不知道哪个方法调用了service产生的错误，也不知道错误的原因，更不知道代码抛出异常的行数。生产一旦出现问题，根本无从排起，总不能打开电脑debug吧？就像医生问病人哪里不舒服，病人答浑身不舒服，我要是医生当场我就想打人
logger.error("第x部分出错 " + e); 05:10:05.920 [startQuartz_Worker-8] ERROR com.cmx.
demo.data.outter.TestService - 第1部分错误
<>正确示例

而正确的日志，我们即可以知道发生错误的原因，抛出异常的行数，同时也能获悉堆栈调用的关系，这样排查生产问题才有解决的可能性。医生还是问病人哪里不舒服，病人答我因为某某原因，导致左下方腰酸，这下清楚多了
logger.error("第x部分出错", e); 05:10:05.920 [startQuartz_Worker-8] ERROR com.cmx.
demo.data.outter.TestService - 当前文件名：DMDXXX.csv 第x部分出错 com.cmx.common.exception.
AppException: 第x部分出错 at com.cmx.demo.data.outter.TestService.execAnalyze(
TestService.java:169) ~[TestService.class:?] at com.cmx.demo.data.outter.
TestService.execAnalyze(TestService.java:81) [TestService.class:?] at com.cmx.
demo.data.outter.TestService$$FastClassBySpringCGLIB$$4538247f.invoke(<generated
>) [TestService.class:?] at org.springframework.cglib.proxy.MethodProxy.invoke(
MethodProxy.java:204) [spring-core-4.3.24.RELEASE.jar:4.3.24.RELEASE] at org.
springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.
invokeJoinpoint(CglibAopProxy.java:736) [spring-aop-4.3.24.RELEASE.jar:4.3.24.
RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed
(ReflectiveMethodInvocation.java:157) [spring-aop-4.3.24.RELEASE.jar:4.3.24.
RELEASE] at org.springframework.transaction.interceptor.TransactionInterceptor$
1.proceedWithInvocation(TransactionInterceptor.java:99) [spring-tx-4.3.24.
RELEASE.jar:4.3.24.RELEASE] at org.springframework.transaction.interceptor.
TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:
283) [spring-tx-4.3.24.RELEASE.jar:4.3.24.RELEASE] at org.springframework.
transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.
java:96) [spring-tx-4.3.24.RELEASE.jar:4.3.24.RELEASE] at org.springframework.
aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java
:179) [spring-aop-4.3.24.RELEASE.jar:4.3.24.RELEASE] at org.springframework.aop.
framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:
671) [spring-aop-4.3.24.RELEASE.jar:4.3.24.RELEASE] at com.cmx.demo.data.outter.
TestService$$EnhancerBySpringCGLIB$$24bd9037.execAnalyze(<generated>) [
TestService.class:?] at com.cmx.demo.data.outter.job.CyberAnalyzeJob.invoke(
CyberAnalyzeJob.java:29) [CyberAnalyzeJob.class:?] at com.cmx.common.job.BaseJob
.execJob(BaseJob.java:57) [BaseJob.class:?] at sun.reflect.
GeneratedMethodAccessor142.invoke(Unknown Source) ~[?:?] at sun.reflect.
DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:
1.8.0_60] at java.lang.reflect.Method.invoke(Method.java:497) ~[?:1.8.0_60] at
org.springframework.util.MethodInvoker.invoke(MethodInvoker.java:265) [spring-
core-4.3.24.RELEASE.jar:4.3.24.RELEASE] at org.springframework.scheduling.quartz
.MethodInvokingJobDetailFactoryBean$MethodInvokingJob.executeInternal(
MethodInvokingJobDetailFactoryBean.java:257) [spring-context-support-4.3.24.
RELEASE.jar:4.3.24.RELEASE] at org.springframework.scheduling.quartz.
QuartzJobBean.execute(QuartzJobBean.java:75) [spring-context-support-4.3.24.
RELEASE.jar:4.3.24.RELEASE] at org.quartz.core.JobRunShell.run(JobRunShell.java:
202) [quartz-2.2.3.jar:?] at org.quartz.simpl.SimpleThreadPool$WorkerThread.run(
SimpleThreadPool.java:573) [quartz-2.2.3.jar:?] Caused by: java.io.
FileNotFoundException: File D:\xxx\DMDXXX.csv does not exist. at com.csvreader.
CsvReader.<init>(Unknown Source) ~[javacsv.jar:?] at com.cmx.demo.data.outter.
TestService.execAnalyze(TestService.java:157) ~[TestService.class:?] ... 21 more

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