# jmethod-agent

**Repository Path**: t0mZ/jmethod-agent

## Basic Information

- **Project Name**: jmethod-agent
- **Description**: java方法运行时长统计工具，基于javaassist
- **Primary Language**: Unknown
- **License**: Not specified
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 1
- **Forks**: 0
- **Created**: 2021-12-15
- **Last Updated**: 2022-08-26

## Categories & Tags

**Categories**: Uncategorized

**Tags**: javaassist, Java

## README

Java 方法耗时分析工具
-
- 原理
```markdown
   使用javaassist对字节码加载时在进行修改, 在方法前后插入代码统计方法执行时长。 
```
- 环境
```markdown
    >= jdk1.8
```
- 使用方式
```markdown
    1. jvm参数 -javaagent:F:\workspace\jmethod-agent-1.0.jar
       默认搜索classpath根目录内文件名为jma.properties的配置文件

    2. jvm参数指定配置文件(配置文件不位于classpath下) -javaagent:F:\workspace\jmethod-agent-1.0.jar=C:\Users\tom\Downloads\abc.properties

    3. idea/Eclipse中 run/debug -> edit configuration -> VM Options 增加参数 -javaagent:jmethod-agent-1.0.jar
``` 
- jma.properties配置文件内容示例
```markdown
# 统计类MainTest的m1,m2方法耗时
tom.test.MainTest=m1,m2
# 只打印执行超过1秒的方法耗时信息
jma.cost.threshold=1000
```

- 运行效果
```markdown
java project:
    *2021-12-15T16:33:49.602 JMA [main] tom.jma.MethodPerfTransformer.<init>(MethodPerfTransformer.java:48) - Found 'jma.properties' file in local classpath
    *2021-12-15T16:33:49.637 JMA [main] tom.jma.MethodPerfTransformer.transform(MethodPerfTransformer.java:75) - Find transfer bytecode class: tom.test.MainTest
    *2021-12-15T16:33:49.822 JMA [main] tom.test.MainTest.m1(MainTest.java) - Method: m1 time-cost: 100ms
    *2021-12-15T16:33:50.023 JMA [main] tom.test.MainTest.m2(MainTest.java) - Method: m2 time-cost: 201ms

tomcat(spring):
    2021-12-15 16:35:51 [RMI TCP Connection(3)-127.0.0.1] INFO  org.springframework.web.servlet.DispatcherServlet - Initializing Servlet 'spring'
    *2021-12-15T16:35:51.804 JMA [RMI TCP Connection(3)-127.0.0.1] org...AbstractApplicationContext.prepareRefresh(AbstractApplicationContext.java) - Method: prepareRefresh time-cost: 0ms
    *2021-12-15T16:35:52.063 JMA [RMI TCP Connection(3)-127.0.0.1] org....AbstractApplicationContext.obtainFreshBeanFactory(AbstractApplicationContext.java) - Method: obtainFreshBeanFactory time-cost: 259ms
    *2021-12-15T16:35:52.063 JMA [RMI TCP Connection(3)-127.0.0.1] org...AbstractApplicationContext.prepareBeanFactory(AbstractApplicationContext.java) - Method: prepareBeanFactory time-cost: 0ms
```
- 参考资料
    - [javassist](http://www.javassist.org/tutorial/tutorial.html)
    - [blog](https://www.cnblogs.com/chiangchou/p/javassist.html#_label0_1)