Java的线程与进程以及线程的四种创建方式

目录

• 问题描述
• case代码截图
• 数据库DO
• controller定义
• dao定义
• mapper实现
• mysql相关properties配置
• 数据库数据
• 测试结果
• 具体错误信息
• 解决
• 总结

问题描述

这里我想测试某个与springboot相关的问题，结果在搭建mybatis时，发现没有成功从数据库中获取数据，报错信息为

com.mysql.cj.exceptions.DataConversionException: Unsupported conversion from LONG to java.sql.Timestamp

我仔细看了下代码，没啥问题。

case 代码截图

数据库DO

我这边偷懒了。

controller定义

dao定义

mapper实现

mysql相关 properties配置

数据库数据

测试结果

具体错误信息

2022-03-12 14:49:12.554 ERROR 43360 --- [nio-8088-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.dao.DataIntegrityViolationException: Error attempting to get column 'id' from result set.  Cause: java.sql.SQLDataException: Unsupported conversion from LONG to java.sql.Timestamp
; Unsupported conversion from LONG to java.sql.Timestamp; nested exception is java.sql.SQLDataException: Unsupported conversion from LONG to java.sql.Timestamp] with root cause

com.mysql.cj.exceptions.DataConversionException: Unsupported conversion from LONG to java.sql.Timestamp
	at com.mysql.cj.result.DefaultValueFactory.unsupported(DefaultValueFactory.java:70) ~[mysql-connector-java-8.0.23.jar:8.0.23]
	at com.mysql.cj.result.DefaultValueFactory.createFromLong(DefaultValueFactory.java:91) ~[mysql-connector-java-8.0.23.jar:8.0.23]
	at com.mysql.cj.protocol.a.MysqlTextValueDecoder.decodeInt8(MysqlTextValueDecoder.java:126) ~[mysql-connector-java-8.0.23.jar:8.0.23]
	at com.mysql.cj.protocol.result.AbstractResultsetRow.decodeAndCreateReturnValue(AbstractResultsetRow.java:113) ~[mysql-connector-java-8.0.23.jar:8.0.23]
	at com.mysql.cj.protocol.result.AbstractResultsetRow.getValueFromBytes(AbstractResultsetRow.java:243) ~[mysql-connector-java-8.0.23.jar:8.0.23]
	at com.mysql.cj.protocol.a.result.ByteArrayRow.getValue(ByteArrayRow.java:91) ~[mysql-connector-java-8.0.23.jar:8.0.23]
	at com.mysql.cj.jdbc.result.ResultSetImpl.getTimestamp(ResultSetImpl.java:933) ~[mysql-connector-java-8.0.23.jar:8.0.23]
	at com.mysql.cj.jdbc.result.ResultSetImpl.getTimestamp(ResultSetImpl.java:971) ~[mysql-connector-java-8.0.23.jar:8.0.23]
	at com.zaxxer.hikari.pool.HikariProxyResultSet.getTimestamp(HikariProxyResultSet.java) ~[HikariCP-4.0.3.jar:na]
	at org.apache.ibatis.type.DateTypeHandler.getNullableResult(DateTypeHandler.java:39) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.type.DateTypeHandler.getNullableResult(DateTypeHandler.java:28) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.type.BaseTypeHandler.getResult(BaseTypeHandler.java:85) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.createUsingConstructor(DefaultResultSetHandler.java:710) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.createByConstructorSignature(DefaultResultSetHandler.java:693) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.createResultObject(DefaultResultSetHandler.java:657) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.createResultObject(DefaultResultSetHandler.java:630) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.getRowValue(DefaultResultSetHandler.java:397) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.handleRowValuesForSimpleResultMap(DefaultResultSetHandler.java:354) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.handleRowValues(DefaultResultSetHandler.java:328) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.handleResultSet(DefaultResultSetHandler.java:301) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.handleResultSets(DefaultResultSetHandler.java:194) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.executor.statement.PreparedStatementHandler.query(PreparedStatementHandler.java:65) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.executor.statement.RoutingStatementHandler.query(RoutingStatementHandler.java:79) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:63) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:325) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:156) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:109) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:89) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:147) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:140) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectOne(DefaultSqlSession.java:76) ~[mybatis-3.5.6.jar:3.5.6]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_202]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_202]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_202]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_202]
	at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:427) ~[mybatis-spring-2.0.6.jar:2.0.6]
	at com.sun.proxy.$Proxy66.selectOne(Unknown Source) ~[na:na]
	at org.mybatis.spring.SqlSessionTemplate.selectOne(SqlSessionTemplate.java:160) ~[mybatis-spring-2.0.6.jar:2.0.6]
	at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:87) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.binding.MapperProxy$PlainMethodInvoker.invoke(MapperProxy.java:152) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:85) ~[mybatis-3.5.6.jar:3.5.6]
	at com.sun.proxy.$Proxy67.getById(Unknown Source) ~[na:na]
	at com.yichen.casetest.controller.JsonController.get(JsonController.java:27) ~[classes/:na]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_202]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_202]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_202]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_202]
	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-5.3.12.jar:5.3.12]
	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:150) ~[spring-web-5.3.12.jar:5.3.12]
	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:117) ~[spring-webmvc-5.3.12.jar:5.3.12]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895) ~[spring-webmvc-5.3.12.jar:5.3.12]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808) ~[spring-webmvc-5.3.12.jar:5.3.12]
	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.3.12.jar:5.3.12]
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1067) ~[spring-webmvc-5.3.12.jar:5.3.12]
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963) ~[spring-webmvc-5.3.12.jar:5.3.12]
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.3.12.jar:5.3.12]
	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.3.12.jar:5.3.12]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:655) ~[tomcat-embed-core-9.0.54.jar:4.0.FR]
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.3.12.jar:5.3.12]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:764) ~[tomcat-embed-core-9.0.54.jar:4.0.FR]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.54.jar:9.0.54]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.3.12.jar:5.3.12]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.12.jar:5.3.12]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
	at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.3.12.jar:5.3.12]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.12.jar:5.3.12]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.3.12.jar:5.3.12]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.12.jar:5.3.12]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:197) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) [tomcat-embed-core-9.0.54.jar:9.0.54]
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:540) [tomcat-embed-core-9.0.54.jar:9.0.54]
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135) [tomcat-embed-core-9.0.54.jar:9.0.54]
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.54.jar:9.0.54]
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) [tomcat-embed-core-9.0.54.jar:9.0.54]
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357) [tomcat-embed-core-9.0.54.jar:9.0.54]
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:382) [tomcat-embed-core-9.0.54.jar:9.0.54]
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) [tomcat-embed-core-9.0.54.jar:9.0.54]
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:895) [tomcat-embed-core-9.0.54.jar:9.0.54]
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1722) [tomcat-embed-core-9.0.54.jar:9.0.54]
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.54.jar:9.0.54]
	at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191) [tomcat-embed-core-9.0.54.jar:9.0.54]
	at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659) [tomcat-embed-core-9.0.54.jar:9.0.54]
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.54.jar:9.0.54]
	at java.lang.Thread.run(Thread.java:748) [na:1.8.0_202]

解决

这个错误信息提示，让我很困惑，我这里完全没有Long转timestamp的情况啊。这里的问题是因为resultMap中的type字段没有无参构造函数导致的

之后修改为如下，再次测试成功

总结

1、别偷懒，好好地区分DO和DTO就不会有这个问题了(一般DO都只有getter()和setter())

2、注意 mybatis dao中反参需要无参构造函数

3、数据库中时间和网页时间不一样问题(1、mapper中定义为Date。2、@JsonFOrmat注解)

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