### Cause: java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Integer几种解决方案

目录

分析

错误如下

解决方案

使用了日期转换函数

使用了 case when或者复杂的if判断

其他

扩展

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分析

从内容上来看java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Integer是一个常见的异常，通常发生在尝试将一个 String 类型的对象强制转换为 Integer 类型时。通常检查好类型和转换就好了

但是这个不太一样，发生在dao层向mybatis传参时产生的，且类型和传参本身并无问题，只是shardingsphere将字符串参数判定为了数字

错误如下

Caused by: org.apache.ibatis.exceptions.PersistenceException: 
### Error querying database.  Cause: java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Integer
### The error may exist in file [F:xxxMapper.xml]
### The error may involve defaultParameterMap
### The error occurred while setting parameters
### SQL: SELECT DATE_FORMAT(create_time, '%Y-%m-%d') AS stat_day_str,
........
### Cause: java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Integer
	at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:30)
	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:156)
	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:147)
	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:142)
	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.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:425)
	... 146 common frames omitted
Caused by: java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Integer
	at org.apache.shardingsphere.sql.parser.binder.segment.select.pagination.PaginationContext.getValue(PaginationContext.java:57)
	at org.apache.shardingsphere.sql.parser.binder.segment.select.pagination.PaginationContext.(PaginationContext.java:51)
	at org.apache.shardingsphere.sql.parser.binder.segment.select.pagination.engine.LimitPaginationContextEngine.createPaginationContext(LimitPaginationContextEngine.java:38)
	at org.apache.shardingsphere.sql.parser.binder.segment.select.pagination.engine.PaginationContextEngine.createPaginationContext(PaginationContextEngine.java:48)
	at org.apache.shardingsphere.sql.parser.binder.statement.dml.SelectStatementContext.(SelectStatementContext.java:100)
	at org.apache.shardingsphere.sql.parser.binder.SQLStatementContextFactory.getDMLStatementContext(SQLStatementContextFactory.java:103)
	at org.apache.shardingsphere.sql.parser.binder.SQLStatementContextFactory.newInstance(SQLStatementContextFactory.java:87)
	at org.apache.shardingsphere.underlying.route.DataNodeRouter.createRouteContext(DataNodeRouter.java:99)
	at org.apache.shardingsphere.underlying.route.DataNodeRouter.executeRoute(DataNodeRouter.java:89)
	at org.apache.shardingsphere.underlying.route.DataNodeRouter.route(DataNodeRouter.java:76)
	at org.apache.shardingsphere.underlying.pluggble.prepare.PreparedQueryPrepareEngine.route(PreparedQueryPrepareEngine.java:54)
	at org.apache.shardingsphere.underlying.pluggble.prepare.BasePrepareEngine.executeRoute(BasePrepareEngine.java:96)
	at org.apache.shardingsphere.underlying.pluggble.prepare.BasePrepareEngine.prepare(BasePrepareEngine.java:83)
	at org.apache.shardingsphere.shardingjdbc.jdbc.core.statement.ShardingPreparedStatement.prepare(ShardingPreparedStatement.java:183)
	at org.apache.shardingsphere.shardingjdbc.jdbc.core.statement.ShardingPreparedStatement.execute(ShardingPreparedStatement.java:143)
	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.apache.ibatis.logging.jdbc.PreparedStatementLogger.invoke(PreparedStatementLogger.java:58)
	at com.sun.proxy.$Proxy537.execute(Unknown Source)
	at org.apache.ibatis.executor.statement.PreparedStatementHandler.query(PreparedStatementHandler.java:65)
	at org.apache.ibatis.executor.statement.RoutingStatementHandler.query(RoutingStatementHandler.java:80)
	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.apache.ibatis.plugin.Plugin.invoke(Plugin.java:61)
	at com.sun.proxy.$Proxy535.query(Unknown Source)
	at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:65)
	at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:336)
	at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:158)
	at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:110)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.apache.ibatis.plugin.Invocation.proceed(Invocation.java:49)
	at com.zy.ygCore.plugin.QueryPlugin.intercept(QueryPlugin.java:66)
	at org.apache.ibatis.plugin.Plugin.invoke(Plugin.java:59)
	at com.sun.proxy.$Proxy534.query(Unknown Source)
	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.apache.ibatis.plugin.Plugin.invoke(Plugin.java:61)
	at com.sun.proxy.$Proxy534.query(Unknown Source)
	at com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor.intercept(MybatisPlusInterceptor.java:81)
	at org.apache.ibatis.plugin.Plugin.invoke(Plugin.java:59)
	at com.sun.proxy.$Proxy534.query(Unknown Source)
	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:154)
	... 153 common frames omitted

解决方案

应该是shardingsphere 的某个类型判断有问题，将字符串判断为数字类型，先说解决，以下是几种场景和解决方法

使用了日期转换函数

sql查询条件中的字段使用了日期转换函数，引发该错误的写法如下

WHERE DATE_FORMAT(start_time, '%H:%i') = #{startTime}

解决办法：
弃用日期函数，改变日期的比较方式

使用了 case when或者复杂的if判断

select 语句使用了 case when 语句，这个语句shrding sphere不支持

case when 替换为
if(“判断条件返回布尔值”，“为true时的值”，“为false时的值”) 

有时候下面这样的也不支持，建议分开查询，在where里做判断
sum( if(money > 0 and code = #{code,jdbcType=VARCHAR}, discount_money, 0) ) discountTranMoney

其他

看了几个同样碰到此问题帖子，发现使用的shardingsphere 版本为4.1.1 ，也许更高版本的已解决该问题，大家有时间可以试试看

此版本还哦于一些其他问题，例如：分表过多引起的问题/Apache ShardingSphere元数据加载慢_shardingsphere分表后又满了怎么办-CSDN博客

扩展

Apache ShardingSphere分表的简单使用和常见问题_org.apache.shardingsphere-CSDN博客