java.lang.NoSuchMethodException: entity.City.()

最新推荐文章于 2022-01-11 10:44:57 发布

原创最新推荐文章于 2022-01-11 10:44:57 发布 · 256 阅读

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本文探讨了在使用MyBatis框架时遇到的一个常见问题：由于实体类仅提供了有参构造而未提供无参构造，导致在进行数据库查询时出现异常。文章详细分析了问题的原因，并提供了修改实体类构造方法的解决方案。

Cause: org.apache.ibatis.reflection.ReflectionException: Error instantiating class entity.City with invalid types () or values (). Cause: java.lang.NoSuchMethodException: entity.City.()
at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:26)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:111)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:102)
at org.apache.ibatis.binding.MapperMethod.executeForMany(MapperMethod.java:119)
at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:63)
at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:52)
at com.sun.proxy.AbstractConnectionHandler.process(AbstractProtocol.java:654)
at org.apache.tomcat.util.net.AprEndpoint $S o c k e t P r o c e s s o r . d o R u n (A p r E n d p o i n t . j a v a : 2532) a t o r g . a p a c h e . t o m c a t . u t i l . n e t . A p r E n d p o i n t$ SocketProcessor.run(AprEndpoint.java:2521)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor $W o r k e r . r u n (T h r e a d P o o l E x e c u t o r . j a v a : 617) a t o r g . a p a c h e . t o m c a t . u t i l . t h r e a d s . T a s k T h r e a d$ WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
Caused by: org.apache.ibatis.reflection.ReflectionException: Error instantiating class entity.City with invalid types () or values (). Cause: java.lang.NoSuchMethodException: entity.City.()
at org.apache.ibatis.reflection.factory.DefaultObjectFactory.instantiateClass(DefaultObjectFactory.java:86)
at org.apache.ibatis.reflection.factory.DefaultObjectFactory.create(DefaultObjectFactory.java:48)
at org.apache.ibatis.reflection.factory.DefaultObjectFactory.create(DefaultObjectFactory.java:41)
at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.createResultObject(DefaultResultSetHandler.java:539)
at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.createResultObject(DefaultResultSetHandler.java:518)
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:60)
at org.apache.ibatis.executor.statement.RoutingStatementHandler.query(RoutingStatementHandler.java:73)
at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:60)
at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:267)
at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:137)
at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:96)
at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:77)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:108)
… 80 more
Caused by: java.lang.NoSuchMethodException: entity.City.()
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:60)
… 97 more

错误原因：实体类提供了有参构造，但是没有提供无参构造。