源代码跟踪技巧

今天药忘吃喽~ 2022-09-09 04:53 145阅读 0赞

### 源代码跟踪技巧 ###

*  一、在本机源代码编译调试
 *  二、注意控制台的输出日志
 *  三、一个断点包含多个方法调用时，可以用鼠标指定进入哪个方法调用。
 *  四、可以用Evaluate Expression 为变量设置值，从而改变调用路径
 *  五、调试代码一定要有侧重点，而不是关注所有方面，不然效率很低

# 一、在本机源代码编译调试 #

下载源代码通过IDE工具断点调试

# 二、注意控制台的输出日志 #

注意控制台的输出日志，很多执行流程都是可以从日志中找到蛛丝马迹的  
如：datalink 的任务启动流程，如下，整个任务

2021-08-29 15:20:49.670 [WorkerKeeper] INFO  com.ucar.datalink.biz.service.impl.TaskConfigServiceImpl - Time for querying task from db  is : 2ms
    2021-08-29 15:20:49.671 [WorkerKeeper] INFO  c.u.datalink.worker.core.runtime.coordinate.WorkerKeeper - task 1 target state change
    2021-08-29 15:20:49.671 [WorkerKeeper] INFO  c.u.datalink.worker.core.runtime.coordinate.WorkerKeeper - Handling task state change by transiting state to STARTED for task 1
    2021-08-29 15:20:49.671 [WorkerKeeper] INFO  com.ucar.datalink.worker.core.runtime.Worker - Setting task 1 state to STARTED
    2021-08-29 15:20:49.672 [Task-1-Reader-reader-mysql] INFO  com.ucar.datalink.reader.mysql.MysqlTaskReader - The filter for canal is test1.t_dl_test_attr,test1.t_dl_test_source.
    2021-08-29 15:20:49.676 [Task-1-Reader-reader-mysql] INFO  com.ucar.datalink.reader.mysql.MysqlTaskReader - init eventSink begin...
    2021-08-29 15:20:49.676 [Task-1-Reader-reader-mysql] INFO  com.ucar.datalink.reader.mysql.MysqlTaskReader - init eventSink end! 
    	 load CanalEventSink:com.alibaba.otter.canal.sink.entry.EntryEventSink
    2021-08-29 15:20:49.676 [Task-1-Reader-reader-mysql] INFO  c.u.d.reader.mysql.extend.CustomCanalInstanceWithManager - init eventParser begin...
    2021-08-29 15:20:49.676 [Task-1-Reader-reader-mysql] INFO  c.u.d.reader.mysql.extend.CustomCanalInstanceWithManager - init eventParser end! 
    	 load CanalEventParser:com.ucar.datalink.reader.mysql.extend.CustomInsideGroupMysqlEventParser
    2021-08-29 15:20:49.676 [Task-1-Reader-reader-mysql] INFO  com.ucar.datalink.reader.mysql.CanalTaskMetaManager - ClientIdentity is initialized for destination 1.
    2021-08-29 15:20:49.677 [destination = 1 , address = localhost/127.0.0.1:3306 , EventParser] INFO  c.u.d.r.mysql.extend.CustomInsideGroupMysqlEventParser - start heart beat.... 
    2021-08-29 15:20:49.677 [Task-1-Reader-reader-mysql] INFO  com.ucar.datalink.worker.core.runtime.WorkerTaskReader - TaskReader-reader-mysql finished initialization and start.
    2021-08-29 15:20:49.682 [destination = 1 , address = localhost/127.0.0.1:3306 , EventParser] WARN  c.u.d.r.mysql.extend.CustomInsideGroupMysqlEventParser - prepare to find start position just last position
     { "identity":{ "slaveId":-1,"sourceAddress":{ "address":"localhost","port":3306}},"postion":{ "included":false,"journalName":"mysql-bin.000006","position":80751,"serverId":1,"timestamp":1630221169000}}
    2021-08-29 15:20:49.682 [destination = 1 , address = localhost/127.0.0.1:3306 , EventParser] INFO  c.u.d.r.mysql.extend.CustomInsideGroupMysqlEventParser - find start position : EntryPosition[included=false,journalName=mysql-bin.000006,position=80751,serverId=1,timestamp=1630221169000]

# 三、一个断点包含多个方法调用时，可以用鼠标指定进入哪个方法调用。 #

如下图所示：  
![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA5bGx5beF_size_20_color_FFFFFF_t_70_g_se_x_16]

# 四、可以用Evaluate Expression 为变量设置值，从而改变调用路径 #

# 五、调试代码一定要有侧重点，而不是关注所有方面，不然效率很低 #

[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA5bGx5beF_size_20_color_FFFFFF_t_70_g_se_x_16]: /images/20220829/5aa5626275fb4affa3a92b6fd4f74646.png