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Exception resolution: the springboot project starts stuck without any exception information

Project scenario :

SpringBoot When the project starts Console Console log printing stuck , No abnormal information is printed


Problem description :

The previous project was good , But after I wrote part of the code , The project won't start ,SpringBoot When the project starts, it gets stuck , Logs don't print either , There is no specific information about the exception , One of my colleagues had a day .


Cause analysis :

I've had similar problems before . Now I list all my problem analysis below :

  1. Maybe it's a change pom.xml file , The project has not been completely updated , Leading to the introduction of jar There is a version problem or it is not introduced at all
  2. The project is Debug mode , Then there are some special breakpoints that cause the project to start stuck
  3. Project directory structure changes , Lead to some bean Not loaded into ? Or loaded multiple identical bean
  4. Some exceptions are not caught , At the same time, there is no global try-catch, Cause the project to jam
  5. Part of the code needs to be booted with the program , Use @PostConstruct、InitializingBean、ApplicationRunner To realize the loading of project initialization , If there is a remote connection , And the connection failed or abnormal , No, try-catch, It is also easy to cause the startup program to get stuck .

Solution :

For the analysis listed above , We can use the following solutions , Try it step by step

  1. If it is pom.xml The change didn't take effect , We just need to be right pom.xml again import that will do , In addition, consider removing idea cache
  2. If it is debug If it's caused by a breakpoint in the pattern , Remove all breakpoints and try again
  3. If it's a project directory structure change , This maven clean once , again install that will do
  4. If you can change the startup class , It is recommended that the main The code in the method is added with try-catch, In this way, you can know what the specific exception is when you start the project
  5. If we analyze which program self starting code causes the project startup to get stuck , I suggest checking the project startup snapshot , As follows :

Analyze what the current main thread is stuck with (waiting), For example, I am stuck due to the configuration problem of the data source

Final solution :6、 If none of the above problems can be solved , Then you can view the project startup log file , It's usually at the same level as the project or there's a log Directory storage , All the information will be recorded in it / Abnormal information

for example : Here's my colleague's exception :

Abnormal analysis : It's because he came from another project copy Over here mapper.xml file , It used to be mybatis, Now the project uses ibatis, Don't recognize <where> label ,ibatis Only support <dynamic prepend="where"> To use

Change to ibatis The way of identification is . Here we focus on how to find and analyze anomalies .

summary :

Project start stuck , There must be an abnormal reason , What we need is composure , Step by step, find the problem . The other thing is that people are CV Code , Especially when it comes to two different projects , Pay attention to the details !

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