Spring Boot使用Druid配置Mybatis多数据源

Java, 数据存储, 数据库, 框架算法 / 作者： / / 发表评论 / Druid, Druid配置Mybatis多数据源, Mybatis, Mybatis多数据源, Spring Boot, SpringBoot, 多数据源, 多数据源配置

目前，业界流行的数据操作框架是 Mybatis，那 Druid 是什么呢？ Druid 是 Java 的数据库连接池组件。Druid 能够提供强大的监控和扩展功能。比如可以监控 SQL ，在监控业务可以查询慢查询 SQL 列表等。这里举个springboot-mutil-datasource工程案例： user 用户表在主库 master 上，地址表 city 在从库 slave上。

一、 Druid核心

Druid核心主要包括三部分：

  • DruidDriver：代理 Driver，能够提供基于 Filter－Chain 模式的插件体系。
  • DruidDataSource：高效可管理的数据库连接池 。
  • SQLParser：当业务数据量达到了一定程度，DBA 需要合理配置数据库资源。即配置主库的机器高配置，把核心高频的数据放在主库上；把次要的数据放在低配置的从库。开源节流嘛，把数据放在不同的数据库里，就需要通过不同的数据源进行操作数据。

二、数据库

1、主库master

CREATE DATABASE master;
 
DROP TABLE IF EXISTS `user`;
CREATE TABLE `user`  (
  `id` int(10) UNSIGNED NOT NULL AUTO_INCREMENT COMMENT '用户编号',
  `user_name` varchar(25) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '用户名称',
  `description` varchar(25) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '描述',
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 2 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;
 
INSERT user VALUES (1 ,'程序员','他有一个小网站');

2、从库slave

CREATE DATABASE slave;
 
DROP TABLE IF EXISTS `city`;
CREATE TABLE `city`  (
  `id` int(10) UNSIGNED NOT NULL AUTO_INCREMENT COMMENT '城市编号',
  `province_id` int(10) UNSIGNED NOT NULL COMMENT '省份编号',
  `city_name` varchar(25) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '城市名称',
  `description` varchar(25) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '描述',
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 2 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;
 
INSERT city VALUES (1 ,1,'北京市','tom的家在北京。');

三、代码实现

1、项目整体结构

com.springboot.config.ds包下包含了多数据源的配置，同样可以有第三个数据源，按照前几个复制即可resources/mapper下面有两个模块，分别是Mybatis不同数据源需要扫描的mapper.xml目录

Spring Boot使用Druid配置Mybatis多数据源插图

2、pom.xml依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.carry.elk</groupId>
    <artifactId>springboot-mutil-datasource</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>springboot-mutil-datasource</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.4.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <druid>1.0.31</druid>
    </properties>

    <dependencies>
        <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>1.3.2</version>
        </dependency>
        <!-- Druid 数据连接池依赖 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>${druid}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

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

3、application.properties两个数据源配置

## master 数据源配置
master.datasource.url=jdbc:mysql://localhost:3306/master?useUnicode=true&characterEncoding=utf8
master.datasource.username=root
master.datasource.password=123456
master.datasource.driverClassName=com.mysql.jdbc.Driver

## slave 数据源配置
slave.datasource.url=jdbc:mysql://localhost:3306/slave?useUnicode=true&characterEncoding=utf8
slave.datasource.username=root
slave.datasource.password=123456
slave.datasource.driverClassName=com.mysql.jdbc.Driver

#热部署
spring.devtools.restart.enabled=true

4、主数据源MasterDataSourceConfig配置

import javax.sql.DataSource;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;

import com.alibaba.druid.pool.DruidDataSource;

@Configuration
// 扫描 Mapper 接口并容器管理
@MapperScan(basePackages = MasterDataSourceConfig.PACKAGE, sqlSessionFactoryRef = "masterSqlSessionFactory")
public class MasterDataSourceConfig {

    // 精确到 master 目录，以便跟其他数据源隔离
    static final String PACKAGE = "com.springboot.dao.master";
    static final String MAPPER_LOCATION = "classpath:mapper/master/*.xml";

    @Value("${master.datasource.url}")
    private String url;

    @Value("${master.datasource.username}")
    private String user;

    @Value("${master.datasource.password}")
    private String password;

    @Value("${master.datasource.driverClassName}")
    private String driverClass;

    @Bean(name = "masterDataSource")
    @Primary
    public DataSource masterDataSource() {
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setDriverClassName(driverClass);
        dataSource.setUrl(url);
        dataSource.setUsername(user);
        dataSource.setPassword(password);
        return dataSource;
    }

    @Bean(name = "masterTransactionManager")
    @Primary
    public DataSourceTransactionManager masterTransactionManager() {
        return new DataSourceTransactionManager(masterDataSource());
    }

    @Bean(name = "masterSqlSessionFactory")
    @Primary
    public SqlSessionFactory masterSqlSessionFactory(@Qualifier("masterDataSource") DataSource masterDataSource)
            throws Exception {
        final SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();
        sessionFactory.setDataSource(masterDataSource);
        sessionFactory.setMapperLocations(
                new PathMatchingResourcePatternResolver().getResources(MasterDataSourceConfig.MAPPER_LOCATION));
        return sessionFactory.getObject();
    }
}

5、从数据源SlaveDataSourceConfig配置

import javax.sql.DataSource;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;

import com.alibaba.druid.pool.DruidDataSource;

@Configuration
// 扫描 Mapper 接口并容器管理
@MapperScan(basePackages = SlaveDataSourceConfig.PACKAGE, sqlSessionFactoryRef = "slaveSqlSessionFactory")
public class SlaveDataSourceConfig {

    // 精确到 slave 目录，以便跟其他数据源隔离
    static final String PACKAGE = "com.springboot.dao.slave";
    static final String MAPPER_LOCATION = "classpath:mapper/slave/*.xml";

    @Value("${slave.datasource.url}")
    private String url;

    @Value("${slave.datasource.username}")
    private String user;

    @Value("${slave.datasource.password}")
    private String password;

    @Value("${slave.datasource.driverClassName}")
    private String driverClass;

    @Bean(name = "slaveDataSource")
    public DataSource slaveDataSource() {
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setDriverClassName(driverClass);
        dataSource.setUrl(url);
        dataSource.setUsername(user);
        dataSource.setPassword(password);
        return dataSource;
    }

    @Bean(name = "slaveTransactionManager")
    public DataSourceTransactionManager slaveTransactionManager() {
        return new DataSourceTransactionManager(slaveDataSource());
    }

    @Bean(name = "slaveSqlSessionFactory")
    public SqlSessionFactory slaveSqlSessionFactory(@Qualifier("slaveDataSource") DataSource slaveDataSource)
            throws Exception {
        final SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();
        sessionFactory.setDataSource(slaveDataSource);
        sessionFactory.setMapperLocations(
                new PathMatchingResourcePatternResolver().getResources(SlaveDataSourceConfig.MAPPER_LOCATION));
        return sessionFactory.getObject();
    }
}

6、业务层代码

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import com.carry.springboot.dao.master.UserDao;
import com.carry.springboot.dao.slave.CityDao;
import com.carry.springboot.domain.City;
import com.carry.springboot.domain.User;
import com.carry.springboot.service.UserService;

@Service
public class UserServiceImpl implements UserService {

    @Autowired
    private UserDao userDao; // 主数据源

    @Autowired
    private CityDao cityDao; // 从数据源

    @Override
    public User findByName(String userName) {
        User user = userDao.findByName(userName);
        City city = cityDao.findByName("北京市");
        user.setCity(city);
        return user;
    }
}

四、测试

写个controller和request方法，这里的是http://localhost:8080/api/user。在浏览器中输入http://localhost:8080/api/user?userName=程序员，得到结果：

Spring Boot使用Druid配置Mybatis多数据源插图2
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