Mybatis报错: org.apache.ibatis.exceptions.PersistenceException解决办法

mybatis报错: org.apache.ibatis.exceptions.persistenceexception解决办法

一、问题描述

写好配置文件用junit进行测试，一运行就报错:

org.apache.ibatis.exceptions.persistenceexception:  
### error querying database. cause: org.apache.ibatis.reflection.reflectionexception: error instantiating class com.fendo.entity.person with invalid types () or values (). cause: java.lang.nosuchmethodexception: com.fendo.entity.person.<init>() 
### the error may exist in com/fendo/entity/person.xml 
### the error may involve defaultparametermap 
### the error occurred while setting parameters 
### sql: select * from person 
### cause: org.apache.ibatis.reflection.reflectionexception: error instantiating class com.fendo.entity.person with invalid types () or values (). cause: java.lang.nosuchmethodexception: com.fendo.entity.person.<init>() 
  at org.apache.ibatis.exceptions.exceptionfactory.wrapexception(exceptionfactory.java:23) 
  at org.apache.ibatis.session.defaults.defaultsqlsession.selectlist(defaultsqlsession.java:107) 
  at org.apache.ibatis.session.defaults.defaultsqlsession.selectlist(defaultsqlsession.java:98) 
  at org.apache.ibatis.binding.mappermethod.executeformany(mappermethod.java:114) 
  at org.apache.ibatis.binding.mappermethod.execute(mappermethod.java:58) 
  at org.apache.ibatis.binding.mapperproxy.invoke(mapperproxy.java:43) 
  at com.sun.proxy.$proxy6.getpersons(unknown source) 
  at com.fendo.test.testmybatis.test(testmybatis.java:40) 
  at sun.reflect.nativemethodaccessorimpl.invoke0(native method) 
  at sun.reflect.nativemethodaccessorimpl.invoke(nativemethodaccessorimpl.java:62) 
  at sun.reflect.delegatingmethodaccessorimpl.invoke(delegatingmethodaccessorimpl.java:43) 
  at java.lang.reflect.method.invoke(method.java:498) 
  at org.junit.runners.model.frameworkmethod$1.runreflectivecall(frameworkmethod.java:50) 
  at org.junit.internal.runners.model.reflectivecallable.run(reflectivecallable.java:12) 
  at org.junit.runners.model.frameworkmethod.invokeexplosively(frameworkmethod.java:47) 
  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.internal.runners.statements.runafters.evaluate(runafters.java:27) 
  at org.junit.runners.parentrunner.runleaf(parentrunner.java:325) 
  at org.junit.runners.blockjunit4classrunner.runchild(blockjunit4classrunner.java:78) 
  at org.junit.runners.blockjunit4classrunner.runchild(blockjunit4classrunner.java:57) 
  at org.junit.runners.parentrunner$3.run(parentrunner.java:290) 
  at org.junit.runners.parentrunner$1.schedule(parentrunner.java:71) 
  at org.junit.runners.parentrunner.runchildren(parentrunner.java:288) 
  at org.junit.runners.parentrunner.access$000(parentrunner.java:58) 
  at org.junit.runners.parentrunner$2.evaluate(parentrunner.java:268) 
  at org.junit.runners.parentrunner.run(parentrunner.java:363) 
  at org.eclipse.jdt.internal.junit4.runner.junit4testreference.run(junit4testreference.java:86) 
  at org.eclipse.jdt.internal.junit.runner.testexecution.run(testexecution.java:38) 
  at org.eclipse.jdt.internal.junit.runner.remotetestrunner.runtests(remotetestrunner.java:459) 
  at org.eclipse.jdt.internal.junit.runner.remotetestrunner.runtests(remotetestrunner.java:675) 
  at org.eclipse.jdt.internal.junit.runner.remotetestrunner.run(remotetestrunner.java:382) 
  at org.eclipse.jdt.internal.junit.runner.remotetestrunner.main(remotetestrunner.java:192) 
caused by: org.apache.ibatis.reflection.reflectionexception: error instantiating class com.fendo.entity.person with invalid types () or values (). cause: java.lang.nosuchmethodexception: com.fendo.entity.person.<init>() 
  at org.apache.ibatis.reflection.factory.defaultobjectfactory.instantiateclass(defaultobjectfactory.java:83) 
  at org.apache.ibatis.reflection.factory.defaultobjectfactory.create(defaultobjectfactory.java:45) 
  at org.apache.ibatis.reflection.factory.defaultobjectfactory.create(defaultobjectfactory.java:38) 
  at org.apache.ibatis.executor.resultset.defaultresultsethandler.createresultobject(defaultresultsethandler.java:535) 
  at org.apache.ibatis.executor.resultset.defaultresultsethandler.createresultobject(defaultresultsethandler.java:514) 
  at org.apache.ibatis.executor.resultset.defaultresultsethandler.getrowvalue(defaultresultsethandler.java:334) 
  at org.apache.ibatis.executor.resultset.defaultresultsethandler.handlerowvaluesforsimpleresultmap(defaultresultsethandler.java:294) 
  at org.apache.ibatis.executor.resultset.defaultresultsethandler.handlerowvalues(defaultresultsethandler.java:269) 
  at org.apache.ibatis.executor.resultset.defaultresultsethandler.handleresultset(defaultresultsethandler.java:239) 
  at org.apache.ibatis.executor.resultset.defaultresultsethandler.handleresultsets(defaultresultsethandler.java:153) 
  at org.apache.ibatis.executor.statement.preparedstatementhandler.query(preparedstatementhandler.java:57) 
  at org.apache.ibatis.executor.statement.routingstatementhandler.query(routingstatementhandler.java:70) 
  at org.apache.ibatis.executor.simpleexecutor.doquery(simpleexecutor.java:57) 
  at org.apache.ibatis.executor.baseexecutor.queryfromdatabase(baseexecutor.java:259) 
  at org.apache.ibatis.executor.baseexecutor.query(baseexecutor.java:132) 
  at org.apache.ibatis.executor.cachingexecutor.query(cachingexecutor.java:105) 
  at org.apache.ibatis.executor.cachingexecutor.query(cachingexecutor.java:81) 
  at org.apache.ibatis.session.defaults.defaultsqlsession.selectlist(defaultsqlsession.java:104) 
  ... 31 more 
caused by: java.lang.nosuchmethodexception: com.fendo.entity.person.<init>() 
  at java.lang.class.getconstructor0(class.java:3082) 
  at java.lang.class.getdeclaredconstructor(class.java:2178) 
  at org.apache.ibatis.reflection.factory.defaultobjectfactory.instantiateclass(defaultobjectfactory.java:57) 
  ... 48 more 

二、解决方法

从上面的异常可以看出: java.lang.nosuchmethodexception: com.fendo.entity.person.<init>()

person这个实体类不能初始化，不能初始化的原因可能是没有构造方法，然后我查看了下类确实没有构造方法，为他添加个构造方法，就可以了。

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