Arthas 使用 watch 命令观察返回值、抛出异常、入参
Arthas Java 诊断工具 About 11,509 words案例代码
package com.example.arthas.controller;
@Slf4j
@RestController
public class Test111Controller {
@Value("${config.maxConn}")
private Integer maxConn;
@GetMapping("/test1")
public Result test1(@RequestParam String key) throws InterruptedException {
log.info("test1111111111111#{}", key);
if ("ccc".equals(key)) {
throw new RuntimeException("custom exception");
}
if ("bbb".equals(key)) {
Thread.sleep(1000);
}
key = "ddd";
List<String> list = (List<String>) CollectionUtils.arrayToList(new String[]{"aaa", "bbb", "ccc", key});
return Result.builder().msg("success#" + maxConn).data(list).build();
}
}
@Data
@Builder
@NoArgsConstructor
@AllArgsConstructor
public class Result {
private int code;
private String msg;
private Object data;
}
watch 命令
默认观察方法退出后入参、类成员变量、返回值的情况。
watch 全路径类名 方法名
-x
:指定输出结果的属性遍历深度,默认为1
。
可以看到Result
中的data
字段其实List
集合,因为设置的遍历深度为2
,所以只输出到Result
的data
(List
)的成员变量。
-n
:限定捕捉次数,-n 1
表示捕捉到一次就停止捕捉。
location=AtExit
:表示观察的是退出后的参数情况。
watch com.example.arthas.controller.Test111Controller test1 -x 2 -n 1
输出:
curl http://127.0.0.1:8080/test1?key=aaa
[arthas@23612]$ watch com.example.arthas.controller.Test111Controller test1 -x 2 -n 1
Press Q or Ctrl+C to abort.
Affect(class count: 1 , method count: 1) cost in 22 ms, listenerId: 1
method=com.example.arthas.controller.Test111Controller.test1 location=AtExit
ts=2021-02-12 09:45:08; [cost=3.303678ms] result=@ArrayList[
@Object[][
@String[ddd],
],
@Test111Controller[
log=@Logger[Logger[com.example.arthas.controller.Test111Controller]],
maxConn=@Integer[100],
],
@Result[
code=@Integer[0],
msg=@String[success#100],
data=@ArrayList[isEmpty=false;size=4],
],
]
Command execution times exceed limit: 1, so command will exit. You can set it with -n option.
watch 观察指定入参和返回值
添加ognl
表达式:"{params,returnObj}"
。
watch com.example.arthas.controller.Test111Controller test1 "{params,returnObj}" -x 3
输出:
curl http://127.0.0.1:8080/test1?key=aaa
[arthas@23612]$ watch com.example.arthas.controller.Test111Controller test1 "{params,returnObj}" -x 3
Press Q or Ctrl+C to abort.
Affect(class count: 1 , method count: 1) cost in 29 ms, listenerId: 2
method=com.example.arthas.controller.Test111Controller.test1 location=AtExit
ts=2021-02-12 09:52:55; [cost=2.012585ms] result=@ArrayList[
@Object[][
@String[ddd],
],
@Result[
code=@Integer[0],
msg=@String[success#100],
data=@ArrayList[
@String[aaa],
@String[bbb],
@String[ccc],
@String[ddd],
],
],
]
watch 观察进入方法前和退出方法后
-b
:观察进入方法前参数的情况。
-s
:观察退出方法后参数的情况。
可以看到location=AtEnter
和location=AtExit
watch com.example.arthas.controller.Test111Controller test1 "{params,returnObj}" -x 3 -b -s
输出:
curl http://127.0.0.1:8080/test1?key=aaa
[arthas@24280]$ watch com.example.arthas.controller.Test111Controller test1 "{params,returnObj}" -x 3 -b -s
Press Q or Ctrl+C to abort.
Affect(class count: 1 , method count: 1) cost in 70 ms, listenerId: 3
method=com.example.arthas.controller.Test111Controller.test1 location=AtEnter
ts=2021-02-12 10:09:46; [cost=0.849065ms] result=@ArrayList[
@Object[][
@String[aaa],
],
null,
]
method=com.example.arthas.controller.Test111Controller.test1 location=AtExit
ts=2021-02-12 10:09:46; [cost=5.237757880806502E9ms] result=@ArrayList[
@Object[][
@String[ddd],
],
@Result[
code=@Integer[0],
msg=@String[success#100],
data=@ArrayList[
@String[aaa],
@String[bbb],
@String[ccc],
@String[ddd],
],
],
]
watch 观察发生异常
添加ognl
表达式:"{params,throwExp}"
。
-e
:观察方法异常之后参数及异常情况。
watch com.example.arthas.controller.Test111Controller test1 "{params,throwExp}" -x 3 -e
输出:
curl http://127.0.0.1:8080/test1?key=ccc
[arthas@24076]$ watch com.example.arthas.controller.Test111Controller test1 "{params,throwExp}" -x 3 -e
Press Q or Ctrl+C to abort.
Affect(class count: 1 , method count: 1) cost in 67 ms, listenerId: 4
method=com.example.arthas.controller.Test111Controller.test1 location=AtExceptionExit
ts=2021-02-12 10:55:47; [cost=0.505599ms] result=@ArrayList[
@Object[][
@String[ccc],
],
java.lang.RuntimeException: custom exception
at com.example.arthas.controller.Test111Controller.test1(Test111Controller.java:24)
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.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:197)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:141)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:106)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:894)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1060)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:962)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:626)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:733)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:888)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1597)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:748)
,
]
watch 观察耗时超过 1000 毫秒的情况
#cost>1000
:按耗时大于1000
毫秒进行过滤。
注意:添加-b
参数表示耗时计算只统计到入参阶段就结束了,往往都被过滤掉了。
watch com.example.arthas.controller.Test111Controller test1 "{params,returnObj}" "#cost>1000" -x 3
输出:
curl http://127.0.0.1:8080/test1?key=bbb
[arthas@21776]$ watch com.example.arthas.controller.Test111Controller test1 "{params,returnObj}" "#cost>1000" -x 3
Press Q or Ctrl+C to abort.
Affect(class count: 1 , method count: 1) cost in 31 ms, listenerId: 5
method=com.example.arthas.controller.Test111Controller.test1 location=AtExit
ts=2021-02-12 11:09:57; [cost=1001.225813ms] result=@ArrayList[
@Object[][
@String[ddd],
],
@Result[
code=@Integer[0],
msg=@String[success#100],
data=@ArrayList[
@String[aaa],
@String[bbb],
@String[ccc],
@String[ddd],
],
],
]
watch 观察入参数等于指定值的情况
使用'params[0] == "ddd"'
表示入参的第一个参数等于ddd
的情况。
watch com.example.arthas.controller.Test111Controller test1 '{params,returnObj}' 'params[0] == "ddd"' -x 3 -b -s
输出:
curl http://127.0.0.1:8080/test1?key=ddd
[arthas@21776]$ watch com.example.arthas.controller.Test111Controller test1 '{params,returnObj}' 'params[0] == "ddd"' -x 3 -b -s
Press Q or Ctrl+C to abort.
Affect(class count: 1 , method count: 1) cost in 32 ms, listenerId: 6
method=com.example.arthas.controller.Test111Controller.test1 location=AtEnter
ts=2021-02-12 11:27:19; [cost=0.01792ms] result=@ArrayList[
@Object[][
@String[ddd],
],
null,
]
method=com.example.arthas.controller.Test111Controller.test1 location=AtExit
ts=2021-02-12 11:27:19; [cost=5.242410807753551E9ms] result=@ArrayList[
@Object[][
@String[ddd],
],
@Result[
code=@Integer[0],
msg=@String[success#100],
data=@ArrayList[
@String[aaa],
@String[bbb],
@String[ccc],
@String[ddd],
],
],
]
备注
watch
命令进行观察,会对原始类进行加强,织入统计代码,使用stop
停止Arthas
会自动使用reset
命令对已加强的类进行还原,以免浪费性能。
参考
Views: 9,271 · Posted: 2021-05-01
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