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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。