Java 诊断工具 Arthas 常见命令（超详细实战教程）(二）

shell@Alicloud:~$ curl http://localhost:61000/user/0
{"timestamp":1655435063042,"status":500,"error":"Internal Server Error","exception":"java.lang.IllegalArgumentException","message":"id < 1","path":"/user/0"}

watch com.example.demo.arthas.user.UserController * '{params, throwExp}'

watch com.example.demo.arthas.user.UserController * '{params, throwExp}' -x 2

watch com.example.demo.arthas.user.UserController * '{params[0], target, returnObj}'

watch com.example.demo.arthas.user.UserController * "{params[0],throwExp}" -e

watch com.example.demo.arthas.user.UserController * '{params, returnObj}' '#cost>200'

shell@Alicloud:~$ curl http://localhost:61000/user/0
{"timestamp":1655436218020,"status":500,"error":"Internal Server Error","exception":"java.lang.IllegalArgumentException","message":"id < 1","path":"/user/0"}

jad --source-only com.example.demo.arthas.user.UserController > /tmp/UserController.java

vim /tmp/UserController.java

@GetMapping(value={"/user/{id}"})
public User findUserById(@PathVariable Integer id) {
    logger.info("id: {}", (Object)id);
    if (id != null && id < 1) {
        return new User(id, "name" + id);
        // throw new IllegalArgumentException("id < 1");
    }
    return new User(id.intValue(), "name" + id);
    }

[arthas@1266]$ sc -d *UserController | grep classLoaderHash
 classLoaderHash   19469ea2

mc --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader /tmp/UserController.java -d /tmp
[arthas@1266]$ mc --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader /tmp/UserController.java -d /tmp
Memory compiler output:
/tmp/com/example/demo/arthas/user/UserController.class
Affect(row-cnt:1) cost in 2879 ms.

mc -c 19469ea2 /tmp/UserController.java -d /tmp

[arthas@1266]$ redefine /tmp/com/example/demo/arthas/user/UserController.class
redefine success, size: 1, classes:
com.example.demo.arthas.user.UserController

shell@Alicloud:~$ curl http://localhost:61000/user/0
{"id":0,"name":"name0"}

[arthas@1266]$ sc -d *UserController | grep classLoaderHash
 classLoaderHash   19469ea2

ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader ‘@com.example.demo.arthas.user.UserController@logger’
[arthas@1266]$ ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader '@com.example.demo.arthas.user.UserController@logger'
@Logger[
    serialVersionUID=@Long[5454405123156820674],
    FQCN=@String[ch.qos.logback.classic.Logger],
    name=@String[com.example.demo.arthas.user.UserController],
    level=null,
    effectiveLevelInt=@Integer[20000],
    parent=@Logger[Logger[com.example.demo.arthas.user]],
    childrenList=null,
    aai=null,
    additive=@Boolean[true],
    loggerContext=@LoggerContext[ch.qos.logback.classic.LoggerContext[default]],
]

ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader '@com.example.demo.arthas.user.UserController@logger.setLevel(@ch.qos.logback.classic.Level@DEBUG)'

ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader '@org.slf4j.LoggerFactory@getLogger("root").setLevel(@ch.qos.logback.classic.Level@DEBUG)'

tt -t org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter invokeHandlerMethod

curl http://localhost:61000/user/1

tt -i 1000 -w 'target.getApplicationContext()'

tt -i 1000 -w ‘target.getApplicationContext().getBean(“helloWorldService”).getHelloMessage()’

[arthas@1266]$ tt -i 1000 -w 'target.getApplicationContext().getBean("helloWorldService").getHelloMessage()'
@String[Hello World]
Affect(row-cnt:1) cost in 1 ms.

trace javax.servlet.Filter *

+---[3.806273ms] javax.servlet.FilterChain:doFilter()
|   `---[3.447472ms] com.example.demo.arthas.AdminFilterConfig$AdminFilter:doFilter()
|       `---[0.17259ms] javax.servlet.http.HttpServletResponse:sendError()

stack javax.servlet.http.HttpServletResponse sendError 'params[0]==401'

thread

thread 2

thread -n 3

thread -n 3 -i 5000

thread -b