SpringBoot集成PageHelper时出现“在系统中发现了多个分页插件,请检查系统配置!”

近日在项目中使用SpringBoot集成PageHelper后，跑单元测试时出现了“在系统中发现了多个分页插件,请检查系统配置!”这个问题。

如下图所示：

org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.exceptions.PersistenceException: 





### Error querying database.  Cause: java.lang.RuntimeException: 在系统中发现了多个分页插件，请检查系统配置!





### Cause: java.lang.RuntimeException: 在系统中发现了多个分页插件，请检查系统配置!





 





	at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:77)





	at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:446)





	at com.sun.proxy.$Proxy109.selectList(Unknown Source)





	at org.mybatis.spring.SqlSessionTemplate.selectList(SqlSessionTemplate.java:230)





	at org.apache.ibatis.binding.MapperMethod.executeForMany(MapperMethod.java:137)





	at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:75)





	at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:59)





	at com.sun.proxy.$Proxy110.selectAll(Unknown Source)





	at com.lianjia.cto.ke.broadband.service.StationInfoService.selectPage(StationInfoService.java:27)





	at com.lianjia.cto.ke.broadband.service.StationInfoService$$FastClassBySpringCGLIB$$ee2f34a4.invoke(<generated>)





	at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)





	at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:738)





	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)





	at org.springframework.aop.framework.adapter.MethodBeforeAdviceInterceptor.invoke(MethodBeforeAdviceInterceptor.java:52)





	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:168)





	at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)





	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)





	at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:673)





	at com.lianjia.cto.ke.broadband.service.StationInfoService$$EnhancerBySpringCGLIB$$1da3a0f3.selectPage(<generated>)





	at com.lianjia.cto.ke.broadband.service.StationInfoServiceTest.selectPage(StationInfoServiceTest.java:27)





	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.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)





	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)





	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)





	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)





	at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)





	at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)





	at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)





	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)





	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:252)





	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:94)





	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)





	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)





	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)





	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)





	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)





	at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)





	at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)





	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)





	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:191)





	at org.junit.runner.JUnitCore.run(JUnitCore.java:137)





	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)





	at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)





	at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)





	at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)





Caused by: org.apache.ibatis.exceptions.PersistenceException: 





### Error querying database.  Cause: java.lang.RuntimeException: 在系统中发现了多个分页插件，请检查系统配置!





### Cause: java.lang.RuntimeException: 在系统中发现了多个分页插件，请检查系统配置!





	at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:30)





	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:150)





	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:141)





	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:433)





	... 46 more





Caused by: java.lang.RuntimeException: 在系统中发现了多个分页插件，请检查系统配置!





	at com.github.pagehelper.PageHelper.skip(PageHelper.java:55)





	at com.github.pagehelper.PageInterceptor.intercept(PageInterceptor.java:92)





	at org.apache.ibatis.plugin.Plugin.invoke(Plugin.java:61)





	at com.sun.proxy.$Proxy123.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:63)





	at com.sun.proxy.$Proxy123.query(Unknown Source)





	at com.github.pagehelper.PageInterceptor.executeAutoCount(PageInterceptor.java:201)





	at com.github.pagehelper.PageInterceptor.intercept(PageInterceptor.java:113)





	at org.apache.ibatis.plugin.Plugin.invoke(Plugin.java:61)





	at com.sun.proxy.$Proxy123.query(Unknown Source)





	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:148)





	... 52 more

先上结果：maven的pagehelper-spring-boot-starter这个依赖，提供了自动配置分页插件的功能，所以有两种方法解决这个问题

第一种，SpringBoot启动类的注解上排除这个自动配置

@SpringBootApplication(exclude = PageHelperAutoConfiguration.class)

第二种，在构建SqlSessionFactory时，不要再去手动添加分页的拦截器，在application.yml中进行配置pagehelper的属性，在SpringBoot启动时会将配置自动注入生成拦截器

# PageHelper配置





pagehelper:





     offsetAsPageNum: true





     rowBoundsWithCount: true





     reasonable: true





     returnPageInfo: true





     params: count=countSql

---

以下是解决问题的思路：

看到这个报错后，查看了一下配置，发现并没有配置多个PageHelper。于是查看了一下报错部分的源码，问题出现在一个skip方法中，如下图所示：

public class PageHelper extends PageMethod implements Dialect {





     //...





 





    @Override





    public boolean skip(MappedStatement ms, Object parameterObject, RowBounds rowBounds) {





        //此处的MSUtils.COUNT为一个常量值"_COUNT"





        if(ms.getId().endsWith(MSUtils.COUNT)){





            throw new RuntimeException("在系统中发现了多个分页插件，请检查系统配置!");





        }





       //...





    }





 





    //...





}

继续向上找，找到了分页插件的拦截器

public class PageInterceptor implements Interceptor {





    //...





    private String countSuffix = "_COUNT";





 





    @Override





    public Object intercept(Invocation invocation) throws Throwable {





        try {





            //...





 





            //调用方法判断是否需要进行分页，如果不需要，直接返回结果





            if (!dialect.skip(ms, parameter, rowBounds)) {





                //反射获取动态参数





                String msId = ms.getId();





                Configuration configuration = ms.getConfiguration();





                Map<String, Object> additionalParameters = (Map<String, Object>) additionalParametersField.get(boundSql);





                //判断是否需要进行 count 查询





                if (dialect.beforeCount(ms, parameter, rowBounds)) {





                    String countMsId = msId + countSuffix;





                    Long count;





                    //先判断是否存在手写的 count 查询





                    MappedStatement countMs = getExistedMappedStatement(configuration, countMsId);





                    if(countMs != null){





                        count = executeManualCount(executor, countMs, parameter, boundSql, resultHandler);





                    } else {





                        countMs = msCountMap.get(countMsId);





                        //自动创建





                        if (countMs == null) {





                            //根据当前的 ms 创建一个返回值为 Long 类型的 ms





                            countMs = MSUtils.newCountMappedStatement(ms, countMsId);





                            msCountMap.put(countMsId, countMs);





                        }





                        count = executeAutoCount(executor, countMs, parameter, boundSql, rowBounds, resultHandler);





                    }





                    //处理查询总数





                    //返回 true 时继续分页查询，false 时直接返回





                    if (!dialect.afterCount(count, parameter, rowBounds)) {





                        //当查询总数为 0 时，直接返回空的结果





                        return dialect.afterPage(new ArrayList(), parameter, rowBounds);





                    }





                }





                //判断是否需要进行分页查询





                if (dialect.beforePage(ms, parameter, rowBounds)) {





                    //生成分页的缓存 key





                    CacheKey pageKey = cacheKey;





                    //处理参数对象





                    parameter = dialect.processParameterObject(ms, parameter, boundSql, pageKey);





                    //调用方言获取分页 sql





                    String pageSql = dialect.getPageSql(ms, boundSql, parameter, rowBounds, pageKey);





                    BoundSql pageBoundSql = new BoundSql(configuration, pageSql, boundSql.getParameterMappings(), parameter);





                    //设置动态参数





                    for (String key : additionalParameters.keySet()) {





                        pageBoundSql.setAdditionalParameter(key, additionalParameters.get(key));





                    }





                    //执行分页查询





                    resultList = executor.query(ms, parameter, RowBounds.DEFAULT, resultHandler, pageKey, pageBoundSql);





                } else {





                    //不执行分页的情况下，也不执行内存分页





                    resultList = executor.query(ms, parameter, RowBounds.DEFAULT, resultHandler, cacheKey, boundSql);





                }





            } else {





                //rowBounds用参数值，不使用分页插件处理时，仍然支持默认的内存分页





                resultList = executor.query(ms, parameter, rowBounds, resultHandler, cacheKey, boundSql);





            }





            return dialect.afterPage(resultList, parameter, rowBounds);





        } finally {





            dialect.afterAll();





        }





    }





}

可以发现以_COUNT结尾的MappedStatement.id是由分页插件的拦截器自动生成的，而这个由分页插件的生成之后，怎么会又一次的调用skip方法呢？所以猜测是有多个分页插件的拦截器影响到了。于是查阅了一下相关的资料，发现PageHelper引入了SpringBoot的自动配置，以下是自动配置的源码：

@Configuration





@ConditionalOnBean(SqlSessionFactory.class)





@EnableConfigurationProperties(PageHelperProperties.class)





@AutoConfigureAfter(MybatisAutoConfiguration.class)





public class PageHelperAutoConfiguration {





 





    @Autowired





    private List<SqlSessionFactory> sqlSessionFactoryList;





 





    @Autowired





    private PageHelperProperties properties;





 





    /**





     * 接受分页插件额外的属性





     *





     * @return





     */





    @Bean





    @ConfigurationProperties(prefix = PageHelperProperties.PAGEHELPER_PREFIX)





    public Properties pageHelperProperties() {





        return new Properties();





    }





 





    @PostConstruct





    public void addPageInterceptor() {





        PageInterceptor interceptor = new PageInterceptor();





        Properties properties = new Properties();





        //先把一般方式配置的属性放进去





        properties.putAll(pageHelperProperties());





        //在把特殊配置放进去，由于close-conn 利用上面方式时，属性名就是 close-conn 而不是 closeConn，所以需要额外的一步





        properties.putAll(this.properties.getProperties());





        interceptor.setProperties(properties);





        for (SqlSessionFactory sqlSessionFactory : sqlSessionFactoryList) {





            sqlSessionFactory.getConfiguration().addInterceptor(interceptor);





        }





    }





 





}

至此，问题算是比较明白了，是因为多个分页拦截器的作用，导致了该异常的出现，所以全局只要保留一个就可以了。