# method-tracer

**Repository Path**: binaryFox/method-tracer

## Basic Information

- **Project Name**: method-tracer
- **Description**: AOP的一种实现,只要给定一个入口类,几乎把该类下面的所有方法及其方法的返回的类都能监控到.
其中操作比较有意思:
1. 动态字节码生成无参构造函数的类,骗过CGLIB检测
2. 自写类加载器加载类
3. 重写CGLIB代理类,不用通过构造函数,通过实体直接生成代理类
- **Primary Language**: Java
- **License**: Apache-2.0
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 2
- **Forks**: 0
- **Created**: 2020-12-24
- **Last Updated**: 2021-09-28

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# method-tracer

#### 介绍
想写一个数据库连接工具[Kettle]连接Redis的功能,所以要知道它调用了Driver的哪些类。但是苦于很少有代码侵入性低但是能监控所有执行方法返回值的.干脆自己撸一个.
代码比较少,但是解决了几个比较头疼的问题终于算是实现了。
只要给定一个入口类,几乎把该类下面的所有方法及其方法的返回的类都能监控到.
其中操作比较有意思:
1. 动态字节码生成无参构造函数的类,骗过CGLIB检测
2. 自写类加载器加载类
3. 重写CGLIB代理类,不用通过构造函数,通过实体直接生成代理类

#### 软件说明
1. 只要一个入口类被代理,入口下面的所有类都能被代理。
2. 在入口类的方法返回值上也加了代理。
3. 原生的CGLIB是不支持通过实体生成代理的,Enhancer方法的Crate函数是需要构造方法的,但是这个项目支持。
4. [重写了Enhancer方法](https://gitee.com/binaryFox/method-tracer/blob/master/src/main/java/wang/hex/TracerEnhancer.java)(无参构造函数的类,骗过CGLIB检测),重写类加载器,使用unsafe直接跳过构造函数(如果执行构造函数Java会报错的)。
5. [实现了简单的filter机制](https://gitee.com/binaryFox/method-tracer/blob/master/src/main/java/wang/hex/TracerMethodVisitor.java)


#### 使用教程
1.  测试包下 [TestDriver.class](https://gitee.com/binaryFox/method-tracer/blob/master/src/test/java/wang/hex/TestDriver.class) 有代码示意
执行效果如下 Driver下所有Connect PrepareStatement ResultSet 的方法都打印出来了
但是我们只对Driver加了代理
```
2020-12-24 15:48:53.644 DriverX - toString [[]] [wang.hex.DriverX@4bbfb90a] [0 ms] [e: ] 

2020-12-24 15:48:53.708 DriverX - connect [[jdbc:hx2:tcp://localhost:8977/./test, {user=sa, password=sa}]] [conn1: url=jdbc:h2:tcp://localhost:8977/./test user=SA] [34 ms] [e: ] 

2020-12-24 15:48:53.723 JdbcConnection - prepareStatement [[CREATE TABLE IF NOT EXISTS X1(ID INT)]] [prep2: CREATE TABLE IF NOT EXISTS X1(ID INT)] [1 ms] [e: ] 

2020-12-24 15:48:53.741 JdbcPreparedStatement - execute [[]] [false] [0 ms] [e: ] 

2020-12-24 15:48:53.741 JdbcPreparedStatement - close [[]] [] [0 ms] [e: ] 

2020-12-24 15:48:53.742 JdbcConnection - prepareStatement [[INSERT INTO X1 VALUES (?)]] [prep3: INSERT INTO X1 VALUES (?)] [0 ms] [e: ] 

2020-12-24 15:48:53.742 JdbcPreparedStatement - setInt [[1, 0]] [] [0 ms] [e: ] 

2020-12-24 15:48:53.743 JdbcPreparedStatement - execute [[]] [false] [0 ms] [e: ] 

2020-12-24 15:48:53.743 JdbcPreparedStatement - setInt [[1, 1]] [] [0 ms] [e: ] 

2020-12-24 15:48:53.743 JdbcPreparedStatement - execute [[]] [false] [0 ms] [e: ] 

2020-12-24 15:48:53.744 JdbcPreparedStatement - setInt [[1, 2]] [] [0 ms] [e: ] 

2020-12-24 15:48:53.744 JdbcPreparedStatement - execute [[]] [false] [0 ms] [e: ] 

2020-12-24 15:48:53.744 JdbcPreparedStatement - close [[]] [] [0 ms] [e: ] 

2020-12-24 15:48:53.748 JdbcConnection - prepareStatement [[SELECT * FROM X1]] [prep4: SELECT * FROM X1] [4 ms] [e: ] 

2020-12-24 15:48:53.752 JdbcPreparedStatement - executeQuery [[]] [rs7: columns: 1 rows: 6 pos: -1] [4 ms] [e: ] 

2020-12-24 15:48:53.773 JdbcResultSet - next [[]] [true] [1 ms] [e: ] 

2020-12-24 15:48:53.774 JdbcResultSet - getInt [[1]] [0] [0 ms] [e: ] 

0
2020-12-24 15:48:53.774 JdbcResultSet - next [[]] [true] [0 ms] [e: ] 

2020-12-24 15:48:53.774 JdbcResultSet - getInt [[1]] [1] [0 ms] [e: ] 

1
2020-12-24 15:48:53.774 JdbcResultSet - next [[]] [true] [0 ms] [e: ] 

2020-12-24 15:48:53.774 JdbcResultSet - getInt [[1]] [2] [0 ms] [e: ] 

2
2020-12-24 15:48:53.774 JdbcResultSet - next [[]] [true] [0 ms] [e: ] 

2020-12-24 15:48:53.774 JdbcResultSet - getInt [[1]] [0] [0 ms] [e: ] 

0
2020-12-24 15:48:53.775 JdbcResultSet - next [[]] [true] [0 ms] [e: ] 

2020-12-24 15:48:53.775 JdbcResultSet - getInt [[1]] [1] [0 ms] [e: ] 

1
2020-12-24 15:48:53.775 JdbcResultSet - next [[]] [true] [0 ms] [e: ] 

2020-12-24 15:48:53.775 JdbcResultSet - getInt [[1]] [2] [0 ms] [e: ] 

2
2020-12-24 15:48:53.775 JdbcResultSet - next [[]] [false] [0 ms] [e: ] 

2020-12-24 15:48:53.775 JdbcPreparedStatement - close [[]] [] [0 ms] [e: ] 


```