实践测试

在单元测试中写入以下方法:
testMain()主方法,
out()里面嵌套了两层try catch
异常代码写在内层try中

示例一：

    @Testpublic void testMain(){out();log.info("后续处理业务");}public void out(){//外层trytry {System.out.println("外层输出");//内层trytry {int i = 2/0; //异常代码}catch (Exception e){log.error("内层异常",e);}}catch (Exception e){log.error("外层异常",e);}}

日志信息：
在这里插入图片描述

外层输出
20:38:27.172 [main] ERROR com.eshore.paas.ops.serv.secondalert.secondAlertTest - 内层异常
java.lang.ArithmeticException: / by zeroat com.eshore.paas.ops.serv.secondalert.secondAlertTest.out(secondAlertTest.java:52)at com.eshore.paas.ops.serv.secondalert.secondAlertTest.testMain(secondAlertTest.java:42)at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)at java.lang.reflect.Method.invoke(Method.java:498)at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)at org.junit.runners.ParentRunner.run(ParentRunner.java:363)at org.junit.runner.JUnitCore.run(JUnitCore.java:137)at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:69)at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:221)at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:54)
20:38:27.179 [main] INFO com.eshore.paas.ops.serv.secondalert.secondAlertTest - 后续处理业务

可以看到,内层try中的异常由内层catch处理了，外层catch并未处理，主方法后续业务逻辑并未受到影响，可正常执行.

示例二：

内层try catch中添加throw new RuntimeException("内层抛出异常",e)将异常抛出

    @Testpublic void testMain(){out();log.info("后续处理业务");}public void out(){//外层trytry {System.out.println("外层输出");//内层trytry {int i = 2/0;}catch (Exception e){log.error("内层异常",e);//向外抛出异常throw new RuntimeException("抛出异常",e);}}catch (Exception e){log.error("外层异常",e);}}

日志信息:
在这里插入图片描述

外层输出
20:47:15.890 [main] ERROR com.eshore.paas.ops.serv.secondalert.secondAlertTest - 内层异常
java.lang.ArithmeticException: / by zeroat com.eshore.paas.ops.serv.secondalert.secondAlertTest.out(secondAlertTest.java:52)at com.eshore.paas.ops.serv.secondalert.secondAlertTest.testMain(secondAlertTest.java:42)at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)at java.lang.reflect.Method.invoke(Method.java:498)at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)at org.junit.runners.ParentRunner.run(ParentRunner.java:363)at org.junit.runner.JUnitCore.run(JUnitCore.java:137)at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:69)at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:221)at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:54)
20:47:15.894 [main] ERROR com.eshore.paas.ops.serv.secondalert.secondAlertTest - 外层异常
java.lang.RuntimeException: 内层抛出异常at com.eshore.paas.ops.serv.secondalert.secondAlertTest.out(secondAlertTest.java:55)at com.eshore.paas.ops.serv.secondalert.secondAlertTest.testMain(secondAlertTest.java:42)at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)at java.lang.reflect.Method.invoke(Method.java:498)at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)at org.junit.runners.ParentRunner.run(ParentRunner.java:363)at org.junit.runner.JUnitCore.run(JUnitCore.java:137)at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:69)at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:221)at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:54)
Caused by: java.lang.ArithmeticException: / by zeroat com.eshore.paas.ops.serv.secondalert.secondAlertTest.out(secondAlertTest.java:52)... 23 common frames omitted
20:47:15.894 [main] INFO com.eshore.paas.ops.serv.secondalert.secondAlertTest - 后续处理业务

内层try catch向外抛出异常以后，外层try catch捕获了异常，并打印日志。主方法中后续处理业务逻辑正常执行。

示例三：

在外层try catch中再次将异常抛出throw new RuntimeException("外层抛出异常",e);

    @Testpublic void testMain(){out();log.info("后续处理业务");}public void out(){//外层trytry {System.out.println("外层输出");//内层trytry {int i = 2/0;}catch (Exception e){log.error("内层异常",e);throw new RuntimeException("内层抛出异常",e);}}catch (Exception e){log.error("外层异常",e);//向外抛出异常throw new RuntimeException("外层抛出异常",e);}}

日志信息：
在这里插入图片描述

可以看到，程序运行错误。
因为out()方法外层try catch抛出异常以后，主方法并未进行处理导致的

改进:
在主方法中，对out()添加一层try catch进行异常处理:

    @Testpublic void testMain(){//添加异常处理try {out();}catch (Exception e){log.info("处理out()方法异常",e);}log.info("后续处理业务");}public void out(){//外层trytry {System.out.println("外层输出");//内层trytry {int i = 2/0;}catch (Exception e){log.error("内层异常",e);throw new RuntimeException("内层抛出异常",e);}}catch (Exception e){log.error("外层异常",e);throw new RuntimeException("外层抛出异常",e);}}

此时可以看到主方法处理异常以后，可以正常向下执行.
在这里插入图片描述

示例四

如果out()方法中的异常代码不在try 代码块中，且主方法也没有对out()方法进行异常捕获处理会怎样?
代码：

    @Testpublic void testMain(){out();log.info("后续处理业务");}public void out(){//添加异常代码，不在try 代码块中int j = 3/0;//外层trytry {System.out.println("外层输出");//内层trytry {int i = 2/0;}catch (Exception e){log.error("内层异常",e);throw new RuntimeException("内层抛出异常",e);}}catch (Exception e){log.error("外层异常",e);throw new RuntimeException("外层抛出异常",e);}}

日志:
在这里插入图片描述
程序直接报错

那么该如何处理?
在out()的上层方法即主方法中,对out()进行异常处理

    @Testpublic void testMain(){//对out()进行异常处理try {out();}catch (Exception e){log.info("处理out()方法异常",e);}log.info("后续处理业务");}public void out(){int j = 3/0;//外层trytry {System.out.println("外层输出");//内层trytry {int i = 2/0;}catch (Exception e){log.error("内层异常",e);throw new RuntimeException("内层抛出异常",e);}}catch (Exception e){log.error("外层异常",e);throw new RuntimeException("外层抛出异常",e);}}

日志信息:
在这里插入图片描述
可以看出程序正常执行.