• Java 异常中 e.getMessage() 和 e.toString() e.printStackTrace()的区别

            Java 异常中 e.getMessage() 和 e.toString() e.printStackTrace()的区别

    一、概述

            在java异常体系中，要打印异常信息，可以通过：e.getMessage() 、 e.toString() e.printStackTrace() 等方法打印出 一些 异常信息。已知的是这些方法都可以打印异常信息，但是这些方法打印的异常信息 都不相同，那么问题来啦： 这些方法打印异常信息的区别是？日常开发工作中，该用哪个方法打印异常信息呢？

    二、代码理解

            1、 Junit 单元测试 --- 模拟异常信息输出

    1. @Test
    2. public void test(){
    3.     int num = 0 ;
    4.     try {
    5.         int  i = 3/num ;
    6.     } catch (Exception e) {
    7.         System.out.println(" e.printStackTrace() ==== start");
    8.         e.printStackTrace();
    9.         System.out.println(" e.printStackTrace() ==== end ");
    10.         System.out.println();
    11.  
    12.         System.out.println(" e.getMessage() ==== start");
    13.         System.out.println(e.getMessage());
    14.         System.out.println(" e.getMessage() ==== end");
    15.  
    16.         System.out.println();
    17.         System.out.println(" e.toString() ==== start");
    18.         System.out.println(e.toString());
    19.         System.out.println(" e.toString() ==== end");
    20.  
    21.         System.out.println();
    22.         System.out.println(" e.getExceptionToString() ==== start");
    23.         System.out.println(Exceptions.getExceptionToString(e));
    24.         System.out.println(" e.getExceptionToString() ==== end");
    25.     }
    26. }

            1.1、输出结果如下：

    1. e.printStackTrace() ==== start
    2. java.lang.ArithmeticException: / by zero
    3. 	at com.runcode.springboottourist.test.ExpTest2.test(ExpTest2.java:22)
    4. 	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    5. 	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    6. 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    7. 	at java.lang.reflect.Method.invoke(Method.java:498)
    8. 	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
    9. 	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    10. 	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
    11. 	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    12. 	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    13. 	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
    14. 	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
    15. 	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    16. 	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    17. 	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    18. 	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    19. 	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    20. 	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    21. 	at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
    22. 	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:69)
    23. 	at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
    24. 	at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:235)
    25. 	at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:54)
    26.  e.printStackTrace() ==== end 
    27.  
    28.  e.getMessage() ==== start
    29. / by zero
    30.  e.getMessage() ==== end
    31.  
    32.  e.toString() ==== start
    33. java.lang.ArithmeticException: / by zero
    34.  e.toString() ==== end
    35.  
    36.  e.getExceptionToString() ==== start
    37. java.lang.ArithmeticException: / by zero
    38. 	at com.runcode.springboottourist.test.ExpTest2.test(ExpTest2.java:22)
    39. 	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    40. 	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    41. 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    42. 	at java.lang.reflect.Method.invoke(Method.java:498)
    43. 	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
    44. 	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    45. 	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
    46. 	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    47. 	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    48. 	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
    49. 	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
    50. 	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    51. 	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    52. 	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    53. 	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    54. 	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    55. 	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    56. 	at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
    57. 	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:69)
    58. 	at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
    59. 	at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:235)
    60. 	at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:54)
    61.  
    62.  e.getExceptionToString() ==== end

            1.2、结果分析 ：

    • e.printStackTrace(): 打印完整的异常堆栈信息
    • e.getMessage(): 打印 异常的原因
    • e.toString(): 打印 异常类型 和 异常的原因
    • e.getExceptionToString(): 打印完整的异常堆栈信息

            2、web 环境下 --- 模拟异常信息输出

    1. @RequestMapping("/exp")
    2. @ResponseBody
    3. public String exp(String key){
    4.     int num = 0 ;
    5.     try {
    6.         int  i = 3/num ;
    7.     } catch (Exception e) {
    8.         System.out.println(" e.printStackTrace() ==== start");
    9.         e.printStackTrace();
    10.         System.out.println(" e.printStackTrace() ==== end ");
    11.  
    12.         System.out.println();
    13.         System.out.println(" e.getMessage() ==== start");
    14.         System.out.println(e.getMessage());
    15.         System.out.println(" e.getMessage() ==== end");
    16.  
    17.         System.out.println();
    18.         System.out.println(" e.toString() ==== start");
    19.         System.out.println(e.toString());
    20.         System.out.println(" e.toString() ==== end");
    21.  
    22.         System.out.println();
    23.         System.out.println(" e.getExceptionToString() ==== start");
    24.         System.out.println(Exceptions.getExceptionToString(e));
    25.         System.out.println(" e.getExceptionToString() ==== end");
    26.     }
    27.     return "success";
    28. }

            2.1、输出结果如下：

    1. e.printStackTrace() ==== start
    2.  e.printStackTrace() ==== end 
    3.  
    4.  e.getMessage() ==== start
    5. / by zero
    6.  e.getMessage() ==== end
    7.  
    8.  e.toString() ==== start
    9. java.lang.ArithmeticException: / by zero
    10.  e.toString() ==== end
    11.  
    12.  e.getExceptionToString() ==== start
    13. java.lang.ArithmeticException: / by zero
    14. 	at com.runcode.springboottourist.ExpController.exp(ExpController.java:54)
    15. 	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    16. 	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    17. 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    18. 	at java.lang.reflect.Method.invoke(Method.java:498)
    19. 	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:189)
    20. 	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138)
    21. 	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102)
    22. 	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895)
    23. 	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:800)
    24. 	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
    25. 	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1038)
    26. 	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:942)
    27. 	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1005)
    28. 	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:897)
    29. 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:634)
    30. 	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:882)
    31. 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
    32. 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
    33. 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    34. 	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
    35. 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    36. 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    37. 	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)
    38. 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    39. 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    40. 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    41. 	at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:92)
    42. 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    43. 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    44. 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    45. 	at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93)
    46. 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    47. 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    48. 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    49. 	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200)
    50. 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    51. 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    52. 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    53. 	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)
    54. 	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    55. 	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490)
    56. 	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
    57. 	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
    58. 	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
    59. 	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
    60. 	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408)
    61. 	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    62. 	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:834)
    63. 	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1417)
    64. 	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    65. 	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    66. 	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    67. 	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    68. 	at java.lang.Thread.run(Thread.java:748)
    69.  
    70.  e.getExceptionToString() ==== end
    71. java.lang.ArithmeticException: / by zero
    72. 	at com.runcode.springboottourist.ExpController.exp(ExpController.java:54)
    73. 	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    74. 	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    75. 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    76. 	at java.lang.reflect.Method.invoke(Method.java:498)
    77. 	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:189)
    78. 	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138)
    79. 	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102)
    80. 	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895)
    81. 	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:800)
    82. 	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
    83. 	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1038)
    84. 	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:942)
    85. 	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1005)
    86. 	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:897)
    87. 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:634)
    88. 	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:882)
    89. 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
    90. 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
    91. 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    92. 	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
    93. 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    94. 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    95. 	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)
    96. 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    97. 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    98. 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    99. 	at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:92)
    100. 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    101. 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    102. 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    103. 	at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93)
    104. 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    105. 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    106. 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    107. 	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200)
    108. 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    109. 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    110. 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    111. 	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)
    112. 	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    113. 	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490)
    114. 	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
    115. 	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
    116. 	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
    117. 	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
    118. 	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408)
    119. 	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    120. 	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:834)
    121. 	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1417)
    122. 	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    123. 	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    124. 	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    125. 	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    126. 	at java.lang.Thread.run(Thread.java:748)

    2.2、结果分析：

    • e.printStackTrace(): 打印完整的异常堆栈信息 （在e.getExceptionToString 后面） e.getMessage(): 打印 异常的原因
    • e.toString(): 打印 异常类型 和 异常的原因
    • e.getExceptionToString(): 打印完整的异常堆栈信息

    三、总结

            1、Exceptions.getExceptionToString(e) 方法，参考这里：java中将异常Exception转化为String字符串输出_HaHa_Sir的博客-CSDN博客

            2、e.getMessage() 和 e.toString() 方法： 打印的异常信息太少，没有具体的堆栈信息，不利于问题的定位处理， 不建议使用！

            3、e.printStackTrace() 和 Exceptions.getExceptionToString(e) 方法：都可以打印完整的异常堆栈信息； 二者的区别是： e.printStackTrace() 在遇到大量并发访问 且 出现异常时，会发生：内存被占满的情况，导致服务挂掉，不可用 ...

            4、日常开发中，会使用 log.error 来打印异常信息，下面比较几种 log.error 打印异常信息的区别：

    1. @RequestMapping("/log")
    2. @ResponseBody
    3. public String log(String key){
    4.     int num = 0 ;
    5.     try {
    6.         int  i = 3/num ;
    7.     } catch (Exception e) {
    8.  
    9.         System.out.println(" log.error(\"exp failure \"+ e) ==== start");
    10.         log.error("exp failure "+ e);
    11.         System.out.println(" log.error(\"exp failure \"+ e) ==== end");
    12.         System.out.println();
    13.  
    14.         System.out.println(" log.error(\"exp failure {}\"+ e) ==== start");
    15.         log.error("exp failure {}" + e);
    16.         System.out.println(" log.error(\"exp failure {}\"+ e) ==== end");
    17.         System.out.println();
    18.  
    19.         System.out.println(" log.error(\"exp failure {}\", e) ==== start");
    20.         log.error("exp failure {}" , e);
    21.         System.out.println(" log.error(\"exp failure {}\" ,e) ==== end");
    22.         System.out.println();
    23.  
    24.         System.out.println(" log.error(\"exp failure {}\", getExceptionToString) ==== start");
    25.         log.error("exp failure {}" , Exceptions.getExceptionToString(e));
    26.         System.out.println(" log.error(\"exp failure {}\" ,getExceptionToString) ==== end");
    27.     }
    28.     return "success";
    29. }

            4.1、输出结果：

    1、 log.error("exp failure "+ e) ==== start

    2022-09-20 16:48:51.783 ERROR 34220 --- [nio-8080-exec-8] c.r.springboottourist.ExpController : exp failure java.lang.ArithmeticException: / by zero

    log.error("exp failure "+ e) ==== end

    2、 log.error("exp failure {}"+ e) ==== start

    2022-09-20 16:48:51.783 ERROR 34220 --- [nio-8080-exec-8] c.r.springboottourist.ExpController : exp failure {}java.lang.ArithmeticException: / by zero

    log.error("exp failure {}"+ e) ==== end

    3、 log.error("exp failure {}", e) ==== start

    2022-09-20 16:48:51.784 ERROR 34220 --- [nio-8080-exec-8] c.r.springboottourist.ExpController : exp failure {}

    java.lang.ArithmeticException: / by zero

    -- 省略异常堆栈信息

    log.error("exp failure {}" ,e) ==== end

    4、 log.error("exp failure {}", getExceptionToString) ==== start

    2022-09-20 16:48:51.785 ERROR 34220 --- [nio-8080-exec-8] c.r.springboottourist.ExpController : exp failure java.lang.ArithmeticException: / by zero

    -- 省略异常堆栈信息

    log.error("exp failure {}" ,getExceptionToString) ==== end

    4.2、结果分析：

    • 1、2 两种情况：都是属于拼接字符串，实际调用的是 e.toString() 方法
    • 3 ：使用了占位符输出日志，打印了完整的堆栈信息， 但是 占位符 貌似没被识别到。
    • 4 ：使用了占位符输出日志，打印了完整的堆栈信息， 将异常对象转换为字符串后， 占位符 被识别到。

            5、日常开发工作中，该用哪个方法打印异常信息呢：

    1. 1.异常对象转换为字符串：
    2. String errMsg = Exceptions.getExceptionToString(e);
    3.  
    4. 2. 日志输出：
    5. log.error("exp failure : {}",errMsg);

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  • 原文地址：https://blog.csdn.net/HaHa_Sir/article/details/127104212