本例使用mysql作為數(shù)據(jù)庫，使用druid作為數(shù)據(jù)庫連接池
主要有單數(shù)據(jù)源和多數(shù)據(jù)源實(shí)例；
多數(shù)據(jù)源中又分為：1. 分包形式 2. aop形式 3. 注解形式

項(xiàng)目目錄結(jié)構(gòu)

catalog.png

MyBatis配置實(shí)現(xiàn)

springBoot相比于原來的Spring的模式就是減少xml配置，將它們用java代碼實(shí)現(xiàn)。

1. DataSource的bean，主要配置數(shù)據(jù)來源
2. SqlSessionFactoryBean的bean，引用 datasource，MyBatis配置，sql的xml掃描，以及各個插件的添加
3. MapperScannerConfigurer的bean的，主要設(shè)置基本掃描包，引用SqlSessionFactoryBean
4. DataSourceTransactionManager的bean，主要用設(shè)置事務(wù)

添加maven依賴

        <!-- aop -->        
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.8.4</version>
        </dependency>
        <!-- dataSource start -->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.2.0</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.38</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.0.20</version>
        </dependency>
        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper</artifactId>
            <version>5.0.0</version>
        </dependency>
        <!-- dataSource end -->

單數(shù)據(jù)源

基本配置

在application.yml中添加datasource配置：

spring:
  application:
    name: SpringBoot
  datasource:
    url: jdbc:mysql://localhost:3306/YanYPro?useUnicode=true&characterEncoding=UTF-8&&useSSL=false
    username: root
    password: *****
    driver-class-name: com.mysql.jdbc.Driver
    # 使用druid數(shù)據(jù)源
    type: com.alibaba.druid.pool.DruidDataSource
    # 初始化大小，最小，最大
    initialSize: 5
    minIdle: 5
    maxActive: 20
    # 配置獲取連接等待超時的時間
    maxWait: 60000
    # 配置間隔多久才進(jìn)行一次檢測，檢測需要關(guān)閉的空閑連接，單位是毫秒
    timeBetweenEvictionRunsMillis: 60000
    # 配置一個連接在池中最小生存的時間，單位是毫秒
    minEvictableIdleTimeMillis: 300000
    validationQuery: SELECT 1 FROM DUAL
    testWhileIdle: true
    testOnBorrow: false
    testOnReturn: false
    # 打開PSCache，并且指定每個連接上PSCache的大小
    poolPreparedStatements: true
    maxPoolPreparedStatementPerConnectionSize: 20
    # 配置監(jiān)控統(tǒng)計攔截的filters，去掉后監(jiān)控界面sql無法統(tǒng)計，'wall'用于防火墻
    filters: stat,wall,log4j
    # 通過connectProperties屬性來打開mergeSql功能；慢SQL記錄
    connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000
    # 合并多個DruidDataSource的監(jiān)控數(shù)據(jù)
    useGlobalDataSourceStat: true

配置mybatis-config:
以下只是實(shí)例，可自定義添加一些別的配置

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <!-- 全局參數(shù) -->
    <settings>
        <!-- 使全局的映射器啟用或禁用緩存。 -->
        <setting name="cacheEnabled" value="true"/>
        <!-- 全局啟用或禁用延遲加載。當(dāng)禁用時，所有關(guān)聯(lián)對象都會即時加載。 -->
        <setting name="lazyLoadingEnabled" value="true"/>
        <!-- 當(dāng)啟用時，有延遲加載屬性的對象在被調(diào)用時將會完全加載任意屬性。否則，每種屬性將會按需要加載。 -->
        <setting name="aggressiveLazyLoading" value="true"/>
        <!-- 是否允許單條sql 返回多個數(shù)據(jù)集  (取決于驅(qū)動的兼容性) default:true -->
        <setting name="multipleResultSetsEnabled" value="true"/>
        <!-- 是否可以使用列的別名 (取決于驅(qū)動的兼容性) default:true -->
        <setting name="useColumnLabel" value="true"/>
        <!-- 允許JDBC 生成主鍵。需要驅(qū)動器支持。如果設(shè)為了true，這個設(shè)置將強(qiáng)制使用被生成的主鍵，有一些驅(qū)動器不兼容不過仍然可以執(zhí)行。  default:false  -->
        <setting name="useGeneratedKeys" value="true"/>
        <!-- 指定 MyBatis 如何自動映射 數(shù)據(jù)基表的列 NONE：不隱射　PARTIAL:部分  FULL:全部  -->
        <setting name="autoMappingBehavior" value="PARTIAL"/>
        <!-- 這是默認(rèn)的執(zhí)行類型  （SIMPLE: 簡單； REUSE: 執(zhí)行器可能重復(fù)使用prepared statements語句；BATCH: 執(zhí)行器可以重復(fù)執(zhí)行語句和批量更新）  -->
        <setting name="defaultExecutorType" value="SIMPLE"/>
        <!-- 使用駝峰命名法轉(zhuǎn)換字段。 -->
        <setting name="mapUnderscoreToCamelCase" value="true"/>
        <!-- 設(shè)置本地緩存范圍 session:就會有數(shù)據(jù)的共享  statement:語句范圍 (這樣就不會有數(shù)據(jù)的共享 ) defalut:session -->
        <setting name="localCacheScope" value="SESSION"/>
        <!-- 設(shè)置但JDBC類型為空時,某些驅(qū)動程序 要指定值,default:OTHER，插入空值時不需要指定類型 -->
        <setting name="jdbcTypeForNull" value="NULL"/>
    </settings>
</configuration>

代碼實(shí)現(xiàn)

SingleMyBatisConfig的類實(shí)現(xiàn)

繼承EnvironmentAware并實(shí)現(xiàn)setEnvironment，為了獲取默認(rèn)配置文件application.yml的元素。

@Configuration
public class SingleMyBatisConfig implements EnvironmentAware{
  private final static Logger logger = LoggerFactory.getLogger(SingleMyBatisConfig.class);
    private static String MYBATIS_CONFIG = "mybatis-config.xml";
    //mybatis mapper resource 路徑
    private static String MAPPER_PATH = "classpath:/com/yany/mapper/single/**.xml";
    
    private RelaxedPropertyResolver propertyResolver;
    @Override
    public void setEnvironment(Environment environment) {
        this.propertyResolver = new RelaxedPropertyResolver(environment, "spring.datasource.");
    }

  .......
}

添加@Bean(name = "singleDataSource")，設(shè)置實(shí)現(xiàn)DataSource的bean

    /**
     * @return
     * @Primary 優(yōu)先方案，被注解的實(shí)現(xiàn)，優(yōu)先被注入
     */
    @Primary
    @Bean(name = "singleDataSource")
    public DataSource singleDataSource() {
        logger.info("datasource url:{}", propertyResolver.getProperty("url"));

        DruidDataSource datasource = new DruidDataSource();
        datasource.setUrl(propertyResolver.getProperty("url"));
        datasource.setDriverClassName(propertyResolver.getProperty("driver-class-name"));
        datasource.setUsername(propertyResolver.getProperty("username"));
        datasource.setPassword(propertyResolver.getProperty("password"));


        datasource.setInitialSize(Integer.valueOf(propertyResolver.getProperty("initialSize")));
        datasource.setMinIdle(Integer.valueOf(propertyResolver.getProperty("minIdle")));
        datasource.setMaxWait(Long.valueOf(propertyResolver.getProperty("maxWait")));
        datasource.setMaxActive(Integer.valueOf(propertyResolver.getProperty("maxActive")));
        datasource.setTimeBetweenEvictionRunsMillis(Long.valueOf(propertyResolver.getProperty("timeBetweenEvictionRunsMillis")));
        datasource.setMinEvictableIdleTimeMillis(Long.valueOf(propertyResolver.getProperty("minEvictableIdleTimeMillis")));
        datasource.setValidationQuery(propertyResolver.getProperty("validationQuery"));
        datasource.setTestWhileIdle(Boolean.parseBoolean(propertyResolver.getProperty("testWhileIdle")));
        datasource.setTestOnBorrow(Boolean.parseBoolean(propertyResolver.getProperty("testOnBorrow")));
        datasource.setTestOnReturn(Boolean.parseBoolean(propertyResolver.getProperty("testOnReturn")));
        datasource.setPoolPreparedStatements(Boolean.parseBoolean(propertyResolver.getProperty("poolPreparedStatements")));
        datasource.setMaxPoolPreparedStatementPerConnectionSize(Integer.valueOf(propertyResolver.getProperty("maxPoolPreparedStatementPerConnectionSize")));

        try {
            datasource.setFilters(propertyResolver.getProperty("filters"));
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return datasource;

    }

添加@Bean(name = "singleSqlSessionFactory")，設(shè)置實(shí)現(xiàn)SqlSessionFactoryBean

/**
     * 創(chuàng)建sqlSessionFactory實(shí)例
     *
     * @return
     */
    @Bean(name = "singleSqlSessionFactory")
    @Primary
    public SqlSessionFactoryBean createSqlSessionFactoryBean(@Qualifier("singleDataSource") DataSource singleDataSource) throws IOException {
        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        //設(shè)置mybatis configuration 掃描路徑
        sqlSessionFactoryBean.setConfigLocation(new ClassPathResource(MYBATIS_CONFIG));
        sqlSessionFactoryBean.setDataSource(singleDataSource);

        PathMatchingResourcePatternResolver pathMatchingResourcePatternResolver = new PathMatchingResourcePatternResolver();
        sqlSessionFactoryBean.setMapperLocations(pathMatchingResourcePatternResolver.getResources(MAPPER_PATH));
        return sqlSessionFactoryBean;
    }

添加@Bean(name = "singleTransactionManager")，設(shè)置實(shí)現(xiàn)事務(wù)DataSourceTransactionManager

    /**
     * 配置事務(wù)管理器
     */
    @Bean(name = "singleTransactionManager")
    @Primary
    public DataSourceTransactionManager transactionManager(@Qualifier("singleDataSource") DataSource singleDataSource) throws Exception {
        return new DataSourceTransactionManager(singleDataSource);
    }

以上SingleMyBatisConfig的配置完成，上面主要配置了數(shù)據(jù)源、SqlSessionFactoryBean、事務(wù)（DataSourceTransactionManager）。還差一個MapperScannerConfigurer的配置。

MapperScannerConfig

本來主要集中實(shí)現(xiàn)各個數(shù)據(jù)源的MapperScannerConfigurer

@Configuration
public class MapperScannerConfig {

    /**
     * 單數(shù)據(jù)源配置
     *
     * @return
     */
    @Bean
    public MapperScannerConfigurer createSingleMapperScannerConfigurer() {
        System.out.println("singleDataSource");
        MapperScannerConfigurer mapperScannerConfigurer = new MapperScannerConfigurer();
        mapperScannerConfigurer.setBasePackage("com.yany.dao.single");
        mapperScannerConfigurer.setSqlSessionFactoryBeanName("singleSqlSessionFactory");
        return mapperScannerConfigurer;
    }
}

以上即為單數(shù)據(jù)源使用配置，而具體的dao層的編寫以及sql的xml編寫詳情見：https://github.com/yany8060/SpringDemo.git
com.yany.dao.single中編寫單屬于的到接口
com.yany.mapper.single中編寫對應(yīng)的sql的xml

由于貼了比較多的代碼，在下一篇多數(shù)據(jù)中中將直接類比這篇中的代碼
詳情請見：https://github.com/yany8060/SpringDemo.git
博客：http://yany8060.xyz