类型转换错误:java.util.ArrayList cannot be cast to com.github.pagehelper.Page

[cedhryi]

问题描述,正常的分页查询.代码:

public PageResult findPage(Integer pageNum, Integer pageSize) {
        PageHelper.startPage(pageNum,pageSize);

    (这行报错)  Page<TbBrand> pageResult = (Page<TbBrand>) tbBrandMapper.findAll();

        return new PageResult(pageResult.getTotal(),pageResult.getResult());
    }

报错的是第三行代码查询返回的时候类型转换错误,Page用的是PageHelper的, PageResult类是自定义的分页对象. 错误信息:

严重: Servlet.service() for servlet [springmvc] in context with path [] threw exception [Request processing failed; nested exception is java.lang.ClassCastException: java.util.ArrayList cannot be cast to com.github.pagehelper.Page] with root cause
java.lang.ClassCastException: java.util.ArrayList cannot be cast to com.github.pagehelper.Page
    at com.pinyougou.manager.service.impl.BrandServiceImpl.findPage(BrandServiceImpl.java:29)
    at com.alibaba.dubbo.common.bytecode.Wrapper1.invokeMethod(Wrapper1.java)
    at com.alibaba.dubbo.rpc.proxy.javassist.JavassistProxyFactory$1.doInvoke(JavassistProxyFactory.java:46)
    at com.alibaba.dubbo.rpc.proxy.AbstractProxyInvoker.invoke(AbstractProxyInvoker.java:72)
    at com.alibaba.dubbo.rpc.protocol.InvokerWrapper.invoke(InvokerWrapper.java:53)
    at com.alibaba.dubbo.rpc.filter.ExceptionFilter.invoke(ExceptionFilter.java:64)
    at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:91)
    at com.alibaba.dubbo.monitor.support.MonitorFilter.invoke(MonitorFilter.java:75)
    at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:91)
    at com.alibaba.dubbo.rpc.filter.TimeoutFilter.invoke(TimeoutFilter.java:42)
    at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:91)
    at com.alibaba.dubbo.rpc.protocol.dubbo.filter.TraceFilter.invoke(TraceFilter.java:78)
    at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:91)
    at com.alibaba.dubbo.rpc.filter.ContextFilter.invoke(ContextFilter.java:70)
    at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:91)
    at com.alibaba.dubbo.rpc.filter.GenericFilter.invoke(GenericFilter.java:132)
    at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:91)
    at com.alibaba.dubbo.rpc.filter.ClassLoaderFilter.invoke(ClassLoaderFilter.java:38)
    at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:91)
    at com.alibaba.dubbo.rpc.filter.EchoFilter.invoke(EchoFilter.java:38)
    at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:91)
    at com.alibaba.dubbo.rpc.protocol.dubbo.DubboProtocol$1.reply(DubboProtocol.java:113)
    at com.alibaba.dubbo.remoting.exchange.support.header.HeaderExchangeHandler.handleRequest(HeaderExchangeHandler.java:84)
    at com.alibaba.dubbo.remoting.exchange.support.header.HeaderExchangeHandler.received(HeaderExchangeHandler.java:170)
    at com.alibaba.dubbo.remoting.transport.DecodeHandler.received(DecodeHandler.java:52)
    at com.alibaba.dubbo.remoting.transport.dispatcher.ChannelEventRunnable.run(ChannelEventRunnable.java:82)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)

[cedhryi]

查询方法:tbBrandMaper.findAll()的返回值也是一个ArrayList类型....咋就会报错呢??

[abel533]

没有经过分页时，返回值不能强转。

[cedhryi]

谢谢...解答的很到位...问题已经解决 原因是spring配置文件忘了配置pageHelper.....

[bruceyoong]

谢谢...解答的很到位...问题已经解决 原因是spring配置文件忘了配置pageHelper.....

我的也是忘了在配置文件中配置pageHelper

[ddGypsy]

卧槽 我是sb

[Suzmixf]

怎么配置的呀？我的也是PageHelper.startPage(pageNum, pageSize);紧接着就是mapper查询，结果转换报错： java.lang.ClassCastException: java.util.ArrayList cannot be cast to com.github.pagehelper.Page