问题发生

前端调用后端接口：

http://localhost:8088/index/sixNewItems/1

发生了异常：
后端返回500错误

控制台打印异常信息

Creating a new SqlSession
Registering transaction synchronization for SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@426fa5c7]
JDBC Connection [HikariProxyConnection@673063824 wrapping com.mysql.cj.jdbc.ConnectionImpl@59910e02] will be managed by Spring
==>  Preparing: SELECT f.id as rootCatId, f.`name` as rootCatName, f.slogan as slogan, f.cat_image as catImage, f.bg_color as bgColor, i.id as itemId, i.item_name as itemName, ii.url as itemUrl, i.created_time as createdTime FROM category f LEFT JOIN items i ON f.id = i.root_cat_id LEFT JOIN items_img ii ON i.id = ii.item_id WHERE f.type = 1 AND i.root_cat_id = ? AND ii.is_main = 1 ORDER BY i.created_time DESC LIMIT 0,6 
==> Parameters: 2(Integer)
<==    Columns: rootCatId, rootCatName, slogan, catImage, bgColor, itemId, itemName, itemUrl, createdTime
<==        Row: 2, 饼干/膨化, 嘎嘣脆，一听到声音就开吃, http://xxx:88/foodie/category/cookies.png, #f59cec, bingan-1001, 【天天吃货】彩虹马卡龙 下午茶 美眉最爱, http://xxx:88/foodie/bingan-1001/img1.png, 2019-09-09 14:45:34
Releasing transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@426fa5c7]
Transaction synchronization deregistering SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@426fa5c7]
Transaction synchronization closing SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@426fa5c7]
10月 24, 2021 6:56:05 下午 org.apache.catalina.core.StandardWrapperValve invoke
严重: 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 'itemId' from result set.  Cause: java.sql.SQLDataException: Cannot determine value type from string 'bingan-1001'
; Cannot determine value type from string 'bingan-1001'; nested exception is java.sql.SQLDataException: Cannot determine value type from string 'bingan-1001'] with root cause
com.mysql.cj.exceptions.DataConversionException: Cannot determine value type from string 'bingan-1001'
	at com.mysql.cj.result.AbstractNumericValueFactory.createFromBytes(AbstractNumericValueFactory.java:65)
	at com.mysql.cj.protocol.a.MysqlTextValueDecoder.decodeByteArray(MysqlTextValueDecoder.java:143)
	at com.mysql.cj.protocol.result.AbstractResultsetRow.decodeAndCreateReturnValue(AbstractResultsetRow.java:135)
	at com.mysql.cj.protocol.result.AbstractResultsetRow.getValueFromBytes(AbstractResultsetRow.java:243)
	at com.mysql.cj.protocol.a.result.ByteArrayRow.getValue(ByteArrayRow.java:91)
	at com.mysql.cj.jdbc.result.ResultSetImpl.getObject(ResultSetImpl.java:1316)
	at com.mysql.cj.jdbc.result.ResultSetImpl.getInt(ResultSetImpl.java:822)
	at com.mysql.cj.jdbc.result.ResultSetImpl.getInt(ResultSetImpl.java:843)
	at com.zaxxer.hikari.pool.HikariProxyResultSet.getInt(HikariProxyResultSet.java)
	at jdk.internal.reflect.GeneratedMethodAccessor82.invoke(Unknown Source)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.apache.ibatis.logging.jdbc.ResultSetLogger.invoke(ResultSetLogger.java:69)
	at com.sun.proxy.$Proxy111.getInt(Unknown Source)
	at org.apache.ibatis.type.IntegerTypeHandler.getNullableResult(IntegerTypeHandler.java:37)
	at org.apache.ibatis.type.IntegerTypeHandler.getNullableResult(IntegerTypeHandler.java:26)
	at org.apache.ibatis.type.BaseTypeHandler.getResult(BaseTypeHandler.java:81)
	at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.createRowKeyForMappedProperties(DefaultResultSetHandler.java:1062)
	at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.createRowKey(DefaultResultSetHandler.java:1019)
	at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.applyNestedResultMappings(DefaultResultSetHandler.java:946)
	at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.getRowValue(DefaultResultSetHandler.java:907)
	at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.handleRowValuesForNestedResultMap(DefaultResultSetHandler.java:870)
	at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.handleRowValues(DefaultResultSetHandler.java:326)
	at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.handleResultSet(DefaultResultSetHandler.java:301)
	at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.handleResultSets(DefaultResultSetHandler.java:194)
	at org.apache.ibatis.executor.statement.PreparedStatementHandler.query(PreparedStatementHandler.java:65)
	at org.apache.ibatis.executor.statement.RoutingStatementHandler.query(RoutingStatementHandler.java:79)
	at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:63)
	at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:324)
	at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:156)
	at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:109)
	at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:83)
	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:147)
	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:140)
	at jdk.internal.reflect.GeneratedMethodAccessor105.invoke(Unknown Source)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:426)
	at com.sun.proxy.$Proxy79.selectList(Unknown Source)
	at org.mybatis.spring.SqlSessionTemplate.selectList(SqlSessionTemplate.java:223)
	at org.apache.ibatis.binding.MapperMethod.executeForMany(MapperMethod.java:147)
	at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:80)
	at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:57)
	at com.sun.proxy.$Proxy85.getSixNewItemsLazy(Unknown Source)
	at com.ybqdren.service.impl.CategoryServiceImpl.getSixNewItemsLazy(CategoryServiceImpl.java:56)
	at com.ybqdren.service.impl.CategoryServiceImpl$$FastClassBySpringCGLIB$$d780dc5e.invoke(<generated>)
	at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218)
	at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:779)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163)
	at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:750)
	at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:123)
	at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:388)
	at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:119)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
	at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:750)
	at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:692)
	at com.ybqdren.service.impl.CategoryServiceImpl$$EnhancerBySpringCGLIB$$7d4d8c61.getSixNewItemsLazy(<generated>)
	at com.ybqdren.controller.IndexController.sixNewItems(IndexController.java:77)
	at jdk.internal.reflect.GeneratedMethodAccessor160.invoke(Unknown Source)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:197)
	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:141)
	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:106)
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895)
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808)
	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1064)
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963)
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)
	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:655)
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:764)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
	at org.springframework.web.filter.CorsFilter.doFilterInternal(CorsFilter.java:91)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
	at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:197)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357)
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:382)
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:893)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1726)
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
	at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)
	at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.base/java.lang.Thread.run(Thread.java:834)

接口的代码如下：

    @ApiOperation(value = "查询每个一级分类下面6条商品数据",notes = "查询每个一级分类下面6条商品数据",httpMethod = "GET" )
    @GetMapping("/sixNewItems/{rootCatId}")  //路径参数 {} @PathVariable
    public IMOOCJSONResult sixNewItems(
            @ApiParam(name = "rootCatId",value = "一级分类id",required = true) //为参数设置swigger信息
            @PathVariable Integer rootCatId){

        if(rootCatId == null){
            return IMOOCJSONResult.errorMsg("分类不存在");
        }

        List<CategoryVO> list = categoryService.getSixNewItemsLazy(rootCatId);
        return IMOOCJSONResult.ok(list);
    }

情况介绍/分析

从下图可以看出问题是发生Mapper对数据进行查询之后

且提示：

; Cannot determine value type from string 'bingan-1001'; nested exception is java.sql.SQLDataException: Cannot determine value type from string 'bingan-1001'] with root cause

问题解决

检查bean和数据库字段类型
bean:
mapper映射，itemId是items表的字段

items表

可以看到，id，也就是bean中itemId被映射的字段类型为varchar(64)，对应都java中应该是String，而bean中为integer，两者不对应，因此这个地方有问题，需要修改：

package com.ybqdren.pojo.vo;

import java.util.List;

/**
 * Wen(Joan) Zhao <withzhaowen@126.com>
 * 2021/10/22
 * 6个最新商品VO
 */
public class SimpleItemVO {
        private String itemId;
        private String itemName;
        private String url;

		....
}

此时再重新访问接口，就请求成功了：

参考资料

Cannot determine value type from string