解决方案：

1. 分页配置文件

    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor(){
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        interceptor.addInnerInterceptor(new PaginationInnerInterceptor());
        return interceptor;
    }

2. 查看自己有没有配置SqlSessionFactory，有的话，需要修改里面的配置，把分页拦截器放在这里，就生效了

    @Bean(name = "dataSqlSessionFactory")
    public SqlSessionFactory clusterSqlSessionFactory(@Qualifier("dataDataSource") DataSource clusterDataSource)
            throws Exception {

        MybatisSqlSessionFactoryBean bean = new MybatisSqlSessionFactoryBean();
        MybatisConfiguration configuration = new MybatisConfiguration();
        configuration.addInterceptor(mybatisPlusInterceptor());
        bean.setConfiguration(configuration);
        // 设置数据源
        bean.setDataSource(clusterDataSource);
        // 简化PO的引用
        bean.setTypeAliasesPackage("com.**");//这里我打码了，写你项目PO的包
        // 设置全局配置
        bean.setMapperLocations(new PathMatchingResourcePatternResolver()
                .getResources(DataConfMysqlSourceConfig.MAPPER_LOCATION));
        return bean.getObject();
    }

3. 如果报错

org.springframework.web.util.NestedServletException: Handler dispatch failed; nested exception is java.lang.NoSuchMethodError: net.sf.jsqlparser.statement.select.PlainSelect.getGroupBy()Lnet/sf/jsqlparser/statement/select/GroupByElement;
 

是因为版本冲突了，修改pagehelper1.2.5为1.3.1