springboot使用Mybatis分页插件

    springboot整合mybatis可以使用springboot配置文件的形式，但是配置不了mybatis-config.xml文件（能够配置，但是不扫描），因此数据源和mybatis使用bean的形式处理，实现分页。

　一、添加数据源bean，代码如下

package tjresearch;
import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.support.http.StatViewServlet;
import com.alibaba.druid.support.http.WebStatFilter;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;

import java.sql.SQLException;

@Configuration
public class DataSourcesConfig {
    /**
     * druid初始化
     * @return
     * @throws SQLException
     */
    @Primary //默认数据源
    @Bean(name = "dataSource",destroyMethod = "close")
    public DruidDataSource Construction() throws SQLException {
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setUrl("jdbc:mysql://localhost:3306/website?useUnicode=true&characterEncoding=utf8");
        dataSource.setUsername("root");
        dataSource.setPassword("root");
        dataSource.setDriverClassName("com.mysql.jdbc.Driver");
        //配置最大连接
        dataSource.setMaxActive(20);
        //配置初始连接
        dataSource.setInitialSize(1);
        //配置最小连接
        dataSource.setMinIdle(1);
        //连接等待超时时间
        dataSource.setMaxWait(60000);
        //间隔多久进行检测,关闭空闲连接
        dataSource.setTimeBetweenEvictionRunsMillis(60000);
        //一个连接最小生存时间
        dataSource.setMinEvictableIdleTimeMillis(300000);
        //用来检测是否有效的sql
        dataSource.setValidationQuery("select 'x'");
        dataSource.setTestWhileIdle(true);
        dataSource.setTestOnBorrow(false);
        dataSource.setTestOnReturn(false);
        //打开PSCache,并指定每个连接的PSCache大小
        dataSource.setPoolPreparedStatements(true);
        dataSource.setMaxOpenPreparedStatements(20);
        //配置sql监控的filter
        dataSource.setFilters("stat,wall,log4j");
        try {
            dataSource.init();
        } catch (SQLException e) {
            throw new RuntimeException("druid datasource init fail");
        }
        return dataSource;
    }
}

　　二、配置mybatis

package tjresearch;

import java.util.Properties;

import javax.annotation.Resource;
import javax.sql.DataSource;

import org.apache.ibatis.plugin.Interceptor;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import org.springframework.transaction.annotation.TransactionManagementConfigurer;

import com.github.pagehelper.PageHelper;

/**
 * mybatis配置类
 * @author liuwei
 * 
 */
@Configuration
@EnableTransactionManagement
public class MybatisConfig implements TransactionManagementConfigurer{
    @Resource(name = "dataSource")
    DataSource dataSource;

    /**
     * 可以通过这个类,详细配置mybatis
     * @return
     */
//    @Bean
//    public org.apache.ibatis.session.Configuration mybatisSetting(){
//        org.apache.ibatis.session.Configuration configuration = new org.apache.ibatis.session.Configuration();
//
//        return null;
//    }

    @Bean(name = "sqlSessionFactory")
    public SqlSessionFactory sqlSessionFactoryBean() {

        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        bean.setTypeAliasesPackage("tjresearch.pojo");

        //分页插件,插件无非是设置mybatis的拦截器
        PageHelper pageHelper = new PageHelper();
        Properties properties = new Properties();
        properties.setProperty("reasonable", "true");
        properties.setProperty("supportMethodsArguments", "true");
        properties.setProperty("returnPageInfo", "check");
        properties.setProperty("params", "count=countSql");
        pageHelper.setProperties(properties);

        //添加插件
        bean.setPlugins(new Interceptor[]{pageHelper});

        //添加XML目录
        ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
        try {
            //设置xml扫描路径
            bean.setMapperLocations(resolver.getResources("classpath:mybatis/mapper/*.xml"));
            return bean.getObject();
        } catch (Exception e) {
            throw new RuntimeException("sqlSessionFactory init fail",e);
        }
    }

    /**
     * 用于实际查询的sql工具,传统dao开发形式可以使用这个,基于mapper代理则不需要注入
     * @param sqlSessionFactory
     * @return
     */
    @Bean(name = "sqlSessionTemplate")
    public SqlSessionTemplate sqlSessionTemplate(SqlSessionFactory sqlSessionFactory) {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
    /**
     * 事务管理,具体使用在service层加入@Transactional注解
     */
    @Bean(name = "transactionManager")
    @Override
    public PlatformTransactionManager annotationDrivenTransactionManager() {
        return new DataSourceTransactionManager(dataSource);
    }
}

三、controller可以实现分页效果，需要分页查询的代码紧贴PageHelper.startPage()方法。

@RequestMapping("/showItem")
    @ResponseBody
    public PageItem showItem(@RequestParam(required = true, defaultValue = "1") Integer pageNum,
            @RequestParam(required = true, defaultValue = "20") Integer pageSize){
        PageHelper.startPage(pageNum, pageSize);// 默认从第一页开始，每页五条
        List<Item> itemList = showService.findAllItem(); 
        PageInfo<Item> pageUser = new PageInfo<Item>(itemList);
        int allPage = pageUser.getPages();
        long total = pageUser.getTotal();
        List<Item> list = pageUser.getList();
        PageItem pageItem = new PageItem();
        pageItem.setAllPage(allPage);
        pageItem.setTotal(total);
        pageItem.setList(list);
        return pageItem;
    }

四、pom导入jar

        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper</artifactId>
            <version>4.1.0</version>
        </dependency>