Mybatis-pagehelper未生效问题记录

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Mybatis-pagehelper未生效问题记录

1.前言

仅个人观点：我平时从不使用类似于pagehelper或者springcache这类框架（这次是维护一个他人的项目代码），我宁愿自己写一些简单的实现，也不希望引入这些框架到项目中，让这个项目耦合了很多非必须的外部依赖，并且还很有可能出现问题，更重要的是，这些非必要的框架基本不会花时间去了解底层实现，所以一旦出了问题，没有几个小时肯定不好摆平。我很不喜欢这类框架，将一些简单的操作也要封装起来，导致整个项目特别臃肿，并且引入复杂的语法逻辑（比如springcache）或者有隐藏的性能问题，当然不排除在一些场景下，的确可以提高开发效率，但是综合来看，我觉得很多时候并不需要引入这类框架。

关于mybatispagehelper的介绍参考以下官方文档： 官方文档

2. 问题描述

我的项目中是引入了以下依赖：

com.github.pagehelper:pagehelper-spring-boot-starter:1.1.0

该starter包括以下依赖：

com.github.pagehelper:pagehelper-spring-boot-autoconfigure:1.1.0
com.github.pagehelper:pagehelper:5.0.0

程序：

PageHelper.startPage(req.getPageNum(), req.getPageSize());
List<Obj> list = objMapper.queryPage(req);
PageInfo pageInfo = new PageInfo<>(list);
return pageInfo;

如上，是一段正常使用pagehelper的代码，所有操作已经依赖导入都是正常的，但是执行的时候分页不生效，导致全表查询。

3. 问题原因

这是pagehelper的starter中的自动配置类

/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2017 abel533@gmail.com
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

package com.github.pagehelper.autoconfigure;

import com.github.pagehelper.PageInterceptor;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.boot.autoconfigure.MybatisAutoConfiguration;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.AutoConfigureAfter;
import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
import org.springframework.boot.bind.RelaxedPropertyResolver;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.EnvironmentAware;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.env.Environment;

import javax.annotation.PostConstruct;
import java.util.Map;
import java.util.Properties;

/**
 * 自定注入分页插件
 *
 * @author liuzh
 */
@Configuration
@ConditionalOnBean(SqlSessionFactory.class)
@EnableConfigurationProperties(PageHelperProperties.class)
@AutoConfigureAfter(MybatisAutoConfiguration.class)
public class PageHelperAutoConfiguration implements EnvironmentAware {

    @Autowired
    private SqlSessionFactory sqlSessionFactory;

    @Autowired
    private PageHelperProperties pageHelperProperties;

    private RelaxedPropertyResolver resolver;

    @Override
    public void setEnvironment(Environment environment) {
        resolver = new RelaxedPropertyResolver(environment, "pagehelper.");
    }

    @PostConstruct
    public void addPageInterceptor() {
        PageInterceptor interceptor = new PageInterceptor();
        Properties properties = pageHelperProperties.getProperties();
        Map<String, Object> subProperties = resolver.getSubProperties("");
        for (String key : subProperties.keySet()) {
            if (!properties.containsKey(key)) {
                properties.setProperty(key, resolver.getProperty(key));
            }
        }
        interceptor.setProperties(properties);
        sqlSessionFactory.getConfiguration().addInterceptor(interceptor);
    }

}

问题就出在这里，因为pagehelper原理就是利用mybatis拦截器进行分页sql封装，所以这里注册了拦截器，但是因为这个配置类@ConditionalOnBean(SqlSessionFactory.class),所以导致若加载此配置类的时候SqlSessionFactory还没有进行bean实例化，那么该配置类就不会生效，所以就会导致pagehelper不生效。

4. 解决办法

在项目中新写一个配置类，主要是保证在sqlsessionfactory之后，即@AutoConfigureAfter({SqlSessionFactory.class,MybatisAutoConfiguration.class}),如下：

package com.transsnet.palmpay.postpaymarketing.config;
/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2017 abel533@gmail.com
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

import com.github.pagehelper.PageInterceptor;
import com.github.pagehelper.autoconfigure.PageHelperProperties;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.boot.autoconfigure.MybatisAutoConfiguration;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.AutoConfigureAfter;
import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
import org.springframework.boot.bind.RelaxedPropertyResolver;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.EnvironmentAware;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.env.Environment;

import javax.annotation.PostConstruct;
import java.util.Map;
import java.util.Properties;

/**
 * 自定注入分页插件
 *
 * @author liuzh
 */
@Configuration
@EnableConfigurationProperties(PageHelperProperties.class)
@AutoConfigureAfter({SqlSessionFactory.class,MybatisAutoConfiguration.class})
public class MyPageHelperAutoConfiguration implements EnvironmentAware {

    @Autowired
    private SqlSessionFactory sqlSessionFactory;

    @Autowired
    private PageHelperProperties pageHelperProperties;

    private RelaxedPropertyResolver resolver;

    @Override
    public void setEnvironment(Environment environment) {
        resolver = new RelaxedPropertyResolver(environment, "pagehelper.");
    }

    @PostConstruct
    public void addPageInterceptor() {
        PageInterceptor interceptor = new PageInterceptor();
        Properties properties = pageHelperProperties.getProperties();
        Map<String, Object> subProperties = resolver.getSubProperties("");
        for (String key : subProperties.keySet()) {
            if (!properties.containsKey(key)) {
                properties.setProperty(key, resolver.getProperty(key));
            }
        }
        interceptor.setProperties(properties);
        sqlSessionFactory.getConfiguration().addInterceptor(interceptor);
    }

}

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最后编辑时间为: 2023/03/28 00:06