com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

柔情只为你懂 2022-06-15 04:37 207阅读 0赞

org.apache.ibatis.exceptions.PersistenceException:  
Error querying database. Cause: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

Last packet sent to the server was 0 ms ago.  
The error may exist in mapper/usermapper.xml  
The error may involve com.hl.mybatis.first.mapper.UserMapper.findUserById  
The error occurred while executing a query  
Cause: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

Last packet sent to the server was 0 ms ago.  
at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:30)  
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:150)  
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:141)  
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectOne(DefaultSqlSession.java:77)  
at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:82)  
at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:59)  
at com.sun.proxy.*P**r**o**x**y*5.*f**i**n**d**U**s**e**r**B**y**I**d*(*U**n**k**n**o**w**n**S**o**u**r**c**e*)*a**t**c**o**m*.*h**l*.*m**y**b**a**t**i**s*.*f**i**r**s**t*.*t**e**s**t*.*U**s**e**r**M**a**p**p**e**r**T**e**s**t*.*t**e**s**t**f**i**n**d**U**s**e**r**B**y**I**D*(*U**s**e**r**M**a**p**p**e**r**T**e**s**t*.*j**a**v**a*:46)*a**t**s**u**n*.*r**e**f**l**e**c**t*.*N**a**t**i**v**e**M**e**t**h**o**d**A**c**c**e**s**s**o**r**I**m**p**l*.*i**n**v**o**k**e*0(*N**a**t**i**v**e**M**e**t**h**o**d*)*a**t**s**u**n*.*r**e**f**l**e**c**t*.*N**a**t**i**v**e**M**e**t**h**o**d**A**c**c**e**s**s**o**r**I**m**p**l*.*i**n**v**o**k**e*(*N**a**t**i**v**e**M**e**t**h**o**d**A**c**c**e**s**s**o**r**I**m**p**l*.*j**a**v**a*:57)*a**t**s**u**n*.*r**e**f**l**e**c**t*.*D**e**l**e**g**a**t**i**n**g**M**e**t**h**o**d**A**c**c**e**s**s**o**r**I**m**p**l*.*i**n**v**o**k**e*(*D**e**l**e**g**a**t**i**n**g**M**e**t**h**o**d**A**c**c**e**s**s**o**r**I**m**p**l*.*j**a**v**a*:43)*a**t**j**a**v**a*.*l**a**n**g*.*r**e**f**l**e**c**t*.*M**e**t**h**o**d*.*i**n**v**o**k**e*(*M**e**t**h**o**d*.*j**a**v**a*:606)*a**t**o**r**g*.*j**u**n**i**t*.*r**u**n**n**e**r**s*.*m**o**d**e**l*.*F**r**a**m**e**w**o**r**k**M**e**t**h**o**d*1.runReflectiveCall(FrameworkMethod.java:47)  
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)  
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)  
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)  
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)  
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271)  
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70)  
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)  
at org.junit.runners.ParentRunner3.*r**u**n*(*P**a**r**e**n**t**R**u**n**n**e**r*.*j**a**v**a*:238)*a**t**o**r**g*.*j**u**n**i**t*.*r**u**n**n**e**r**s*.*P**a**r**e**n**t**R**u**n**n**e**r*1.schedule(ParentRunner.java:63)  
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)  
at org.junit.runners.ParentRunner.access000(*P**a**r**e**n**t**R**u**n**n**e**r*.*j**a**v**a*:53)*a**t**o**r**g*.*j**u**n**i**t*.*r**u**n**n**e**r**s*.*P**a**r**e**n**t**R**u**n**n**e**r*2.evaluate(ParentRunner.java:229)  
at org.junit.runners.ParentRunner.run(ParentRunner.java:309)  
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)  
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)  
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)  
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)  
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)  
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)  
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

# 异常原因：MysQL没有连接，可能原因是MysQL服务没启动 #