多数据源使用pagehelper

在不同数据源中，使用不同的dialect配置 ，如果不配置的话，使用会报错Error querying database. Cause: java.lang.NullPointerException: 。因为使用了mabatis-plus，在mapper上添加@DS注解来区分数据源，没有数据源的配置文件，如果使用配置文件，也可以使用下面的配置来完成数据源的配置，类似下面的文件，

@Configuration
@MapperScan(basePackages = DataSource1Config.BASE_PACKAGE, sqlSessionFactoryRef = "datasource1SqlSessionFactory")
public class DataSource1Config {
 
    private static final Logger log = LogManager.getLogger(DataSource1Config.class);
 
    static final String BASE_PACKAGE = "com.transcend.demo.dao.datasource1";
    private static final String MAPPER_LOCATION = "classpath:mapper/datasource1/*.xml";
 
 
    @Primary
    @Bean(name = "datasource1")
    @ConfigurationProperties(prefix = "spring.datasource.mysql")
    public DataSource datasource1() {
//        return DataSourceBuilder.create().type(DruidDataSource.class).build();
        log.info("datasource1 开始初始化。");
        return new DruidDataSource();
    }
 
    @Primary
    @Bean(name = "datasource1TransactionManager")
    public DataSourceTransactionManager datasource1Transaction(@Qualifier("datasource1") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }
 
    @Primary
    @Bean(name = "datasource1SqlSessionFactory")
    public SqlSessionFactory datasource1SqlSessionFactory(@Qualifier("datasource1") DataSource dataSource) throws Exception {
        final SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
        factoryBean.setDataSource(dataSource);
        factoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources(DataSource1Config.MAPPER_LOCATION));
 
        //添加PageHelper插件
        Interceptor interceptor = new PageInterceptor();
        Properties properties = new Properties();
        //数据库
        properties.setProperty("helperDialect", "mysql");
        //是否将参数offset作为PageNum使用
        properties.setProperty("offsetAsPageNum", "true");
        //是否进行count查询
        properties.setProperty("rowBoundsWithCount", "true");
        //是否分页合理化
        properties.setProperty("reasonable", "false");
 
        interceptor.setProperties(properties);
        factoryBean.setPlugins(new Interceptor[] {interceptor});
 
        return factoryBean.getObject();
    }
 
    @Primary
    @Bean(name = "datasource1SqlSessionTemplate")
    public SqlSessionTemplate datasource1SqlSessionTemplate(@Qualifier("datasource1SqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

直接配置PageHelper 的bean来完成不同数据源的PageHelper 配置

  /*
    设置PageHelper属性  不同数据源 自动配置Dialect
    */
    @Bean
    public PageHelper pageHelper(){
        PageHelper pageHelper = new PageHelper();
        //添加配置，也可以指定文件路径
        Properties properties = new Properties();
        properties.setProperty("offsetAsPageNum","false");
        properties.setProperty("rowBoundsWithCount","false");
        properties.setProperty("pageSizeZero","true");
        properties.setProperty("reasonable","false");
        properties.setProperty("supportMethodsArguments","false");
        properties.setProperty("returnPageInfo","none");
        //这个属性非常重要  在oracle 和pg数据库中切换
        properties.setProperty("autoRuntimeDialect","true");
        pageHelper.setProperties(properties);
        return pageHelper;
    }