SpringBoot 基础(一) mybatis 通过druid配置多数据库

本次使用sqlServer和MySQL；Oracle本机没有安装，所以先留到以后

demo地址

项目目录结构

1首先去pom种引入相关的maven

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.9.RELEASE</version>
        <relativePath/>
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.7</java.version>
    </properties>

    <dependencies>
<!--        springboot 相关-->
        <dependency>
            <groupId>org.example</groupId>
            <artifactId>01.Spring-Boot-Config</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.0.1</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>


        <!--sqlserver 驱动  -->
        <dependency>
            <groupId>com.microsoft.sqlserver</groupId>
            <artifactId>mssql-jdbc</artifactId>
            <version>6.4.0.jre8</version>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>

        <!-- mysql驱动 -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.22</version>
        </dependency>

        <!-- druid数据源驱动 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.10</version>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

2.然后再添加application.yml文件，这里有两种配置方式

方式1：

spring:
  datasource:
    druid:
      # 数据库访问配置, 使用druid数据源
      # 数据源1 mysql
      mysql:
        type: com.alibaba.druid.pool.DruidDataSource
        driver-class-name: com.mysql.cj.jdbc.Driver
        url: jdbc:mysql://127.0.0.1:33068/test?useUnicode=true&characterEncoding=utf8&serverTimezone=Asia/Shanghai
        username: root
        password: Ee123
      # 数据源2 sqlserver
      sqlserver:
        type: com.alibaba.druid.pool.DruidDataSource
        driver-class-name: com.microsoft.sqlserver.jdbc.SQLServerDriver
        url: jdbc:sqlserver://localhost:1433;DatabaseName=test
        username: sa
        password: Ee123
#      # 数据源3 oracle
#      oracle:
#        type: com.alibaba.druid.pool.DruidDataSource
#        driver-class-name: oracle.jdbc.driver.OracleDriver
#        url: jdbc:oracle:thin:@localhost:1521:ORCL
#        username: test
#        password: 123456
      # 连接池配置
      initial-size: 5
      min-idle: 5
      max-active: 20
      # 连接等待超时时间
      max-wait: 30000
      # 配置检测可以关闭的空闲连接间隔时间
      time-between-eviction-runs-millis: 60000
      # 配置连接在池中的最小生存时间
      min-evictable-idle-time-millis: 300000
      validation-query: select '1' from dual
      test-while-idle: true
      test-on-borrow: false
      test-on-return: false
      # 打开PSCache，并且指定每个连接上PSCache的大小
      pool-prepared-statements: true
      max-open-prepared-statements: 20
      max-pool-prepared-statement-per-connection-size: 20
      # 配置监控统计拦截的filters, 去掉后监控界面sql无法统计, 'wall'用于防火墙
      filters: stat,wall
      # Spring监控AOP切入点，如x.y.z.service.*,配置多个英文逗号分隔
      aop-patterns: com.springboot.servie.*

方式2：(这里是显示了数据库相关的配置，其余省略)

spring:
  datasource:
    mysql:     #数据源1
      driverClassName: com.mysql.cj.jdbc.Driver
      url: jdbc:mysql://127.0.0.1:33068/test?useUnicode=true&characterEncoding=utf8&serverTimezone=Asia/Shanghai
      username: root
      password: Ee123
      type: com.alibaba.druid.pool.DruidDataSource
    sqlserver:     #数据源3
      driverClassName: com.microsoft.sqlserver.jdbc.SQLServerDriver
      url: jdbc:sqlserver://localhost:1433;DatabaseName=test
      username: sa
      password: Ee123
      type: com.alibaba.druid.pool.DruidDataSource

3.配置dataSource

mysql：（sql写在xml文件种）

@Configuration
@MapperScan(basePackages = "com.item.springboot.mysqldao")
public class MysqlDatasourceConfig {
    //因为都是 DataSource 类型，二配置多个dataSource都会用到这个·，所以通过起名称，通过名字来区分
    @Primary
    @Bean(value = "mysqldataSource")
//目前使用application.yml 的是方式2 中的配置，如果使用方式1 则需要改为@ConfigurationProperties("spring.datasource.druid.mysql")
    @ConfigurationProperties("spring.datasource.mysql")
    public DataSource mysqlDataSource() {
        return DruidDataSourceBuilder.create().build();
    }
    @Primary
    @Bean
    public DataSourceTransactionManager mysqlTransactionManager(@Qualifier("mysqldataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }
    @Primary
    @Bean
    public SqlSessionFactory mysqlSqlSessionFactory(@Qualifier("mysqldataSource") DataSource dataSource) throws Exception {
        final SqlSessionFactoryBean sessionFactory=new SqlSessionFactoryBean();
        sessionFactory.setDataSource(dataSource);
        //如果不使用xml的方式配置mapper，则可以省去下面这行mapper location的配置。
        sessionFactory.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mapper/mysql/*.xml"));
        return  sessionFactory.getObject();
    }
}

sqlServer:(sql写在项目中)

@Configuration
@MapperScan(basePackages = "com.item.springboot.sqlserverMapper")
public class SqlServerDataSourceConfig {

    //数据源
    //@Primary

//目前使用application.yml 的是方式2 中的配置，如果使用方式1 则需要改为@ConfigurationProperties("spring.datasource.druid.mysql")

    @ConfigurationProperties(prefix = "spring.datasource.sqlserver")
    @Bean
    public DataSource tailDataSource(){
        return  new DruidDataSource();
    }

    //@Primary
    @Bean
    public DataSourceTransactionManager utailTransactionManager(@Qualifier("tailDataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }
    //@Primary
    @Bean
    public SqlSessionFactory tailSqlSessionFactory(@Qualifier("tailDataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        // bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath*:templates/test/*.xml"));
        return bean.getObject();
    }
    
}

4.sqlServer调用(简洁模式)

持久层：sqlserverMapper=》StudentMapper

@Mapper
public interface StudentMapper {
    @Select(" select *  from  test ")
    List<Map<String, Object>> getAll();
}

调用

@Repository
@Mapper
public interface StudentMapper {
    @Select(" select *  from  test ")
    List<Map<String, Object>> getAll();
}

5.mysql调用(传统模式)

5.1 xml中首先数据库查询

<?xml version="1.0" encoding="UTF-8" ?>    
    <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"   
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">     
<mapper namespace="com.item.springboot.mysqldao.MysqlStudentMapper">
    <select id="getAllStudents" resultType="java.util.Map">
        select * from student
    </select>
</mapper>

5.2mysqldao层实现对xml文件中数据库的调用

@Mapper
@Repository
public interface MysqlStudentMapper {
    List<Map<String, Object>> getAllStudents();
}

5.3service.impl实现对dao层的调用

@Service("studentService")
public class StudentServiceImpl implements StudentService {

    @Autowired
    private MysqlStudentMapper mysqlStudentMapper;
    @Override
    public List<Map<String, Object>> getAllStudentsFromMysql() {
        return this.mysqlStudentMapper.getAllStudents();
    }

}

5.4 service层对service.impl的调用

public interface StudentService {
    List<Map<String, Object>> getAllStudentsFromMysql();
}

5.5 controller 

    @Autowired
    private StudentService studentService;

    @RequestMapping("querystudentsfrommysql")
    public List<Map<String, Object>> queryStudentsFromMysql(){
        return studentService.getAllStudentsFromMysql();
    }

 注意·当前两个dataSource是不能同时使用的(mysql和sqlServer再同一时间只能使用一个)，因为在dataSource文件夹下配置的是同种类型。spring是通过类型进行加载