Spring Boot JDBC + Mybatis 配置多數據源 以及 採用Durid 做爲鏈接池

1 配置文件

在配置文件中配置兩個數據源配置，以及mybatis xml配置文件路徑

# mybatis  多數據源配置
mybatis.config-location = classpath:mapper/config/mybatis-config.xml

#################  mysql  數據源1 #################
spring.datasource.one.jdbc-url=jdbc:mysql://localhost:3306/user?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8&useSSL=true
spring.datasource.one.username=root
spring.datasource.one.password=root
#spring.datasource.one.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.one.driver-class-name=com.mysql.jdbc.Driver
#################  mysql  數據源1 #################

#################  mysql  數據源2 ################
spring.datasource.second.jdbc-url=jdbc:mysql://xxxxxxxxxx:3306/user?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8&useSSL=true
spring.datasource.second.username=root
spring.datasource.second.password=root
#spring.datasource.second.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.second.driver-class-name=com.mysql.jdbc.Driver
#################  mysql  數據源1 #################

2 數據庫配置代碼：

1 步驟

1 首先加載配置的數據源：手動將數據配置文件信息注入到數據源實例對象中。
2 根據建立的數據源，配置數據庫實例對象注入到SqlSessionFactory 中，構建對應的 SqlSessionFactory。
3 配置數據庫事務：將數據源添加到事務中。
4 將SqlSessionFactory 注入到SqlSessionTemplate 模板中
5 最後將上面建立的 SqlSessionTemplate 注入到對應的 Mapper 包路徑下，這樣這個包下面的 Mapper 都會使用第一個數據源來進行數據庫操做。

basePackages   指明 Mapper 地址。
sqlSessionTemplateRef    指定 Mapper 路徑下注入的 sqlSessionTemplate。

在多數據源的狀況下，不須要在啓動類添加：@MapperScan("com.xxx.mapper") 的註解。

2 項目結構：

3 第一個數據源

@Api("SqlSessionTemplate 注入到對應的 Mapper 包路徑下")
@Configuration
@MapperScan(basePackages = "com.example.demo.mapper.one", sqlSessionTemplateRef  = "oneSqlSessionTemplate")
public class OneDataSourceConfig {

    //------------------                 1 加載配置的數據源：   -------------------------------
    @Bean("oneDatasource")
    @ConfigurationProperties(prefix = "spring.datasource.one")
    @Primary //默認是這個庫
    public DataSource DataSource1Config(){
        return DataSourceBuilder.create().build();
    }





    //---------------------- 2 建立的數據源 構建對應的 SqlSessionFactory。  ----------------------

    @Bean(name = "oneSqlSessionFactory" )
    @Primary
    public SqlSessionFactory oneSqlSessionFactory(@Qualifier("oneDatasource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:/mapper/one/*.xml"));
        return bean.getObject();
    }


    //------------------------3  配置事務 --------------------------
    @Bean(name = "oneTransactionManager")
    @Primary
    public DataSourceTransactionManager oneTransactionManager(@Qualifier("oneDatasource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }



    //------------------------------- 4 注入 SqlSessionFactory 到 SqlSessionTemplate 中---------------------------------
    @Bean(name = "oneSqlSessionTemplate")
    @Primary
    public SqlSessionTemplate oneSqlSessionTemplate(@Qualifier("oneSqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }

}

第二個數據源

@Api("SqlSessionTemplate 注入到對應的 Mapper 包路徑下")
@Configuration
@MapperScan(basePackages = "com.example.demo.mapper.second", sqlSessionTemplateRef  = "secondSqlSessionTemplate")
public class SecondDataSourceConfig {


    //------------------                  加載配置的數據源：   -------------------------------


    @Bean("secondDatasource")
    @ConfigurationProperties(prefix = "spring.datasource.second")
    public DataSource DataSource2Config(){
        return DataSourceBuilder.create().build();
    }





    //---------------------- 建立的數據源 構建對應的 SqlSessionFactory。  ----------------------



    @Bean(name = "secondSqlSessionFactory")
    public SqlSessionFactory secondSqlSessionFactory(@Qualifier("secondDatasource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:/mapper/second/*.xml"));
        return bean.getObject();
    }

    //------------------------ 配置事務 --------------------------


    @Bean(name = "secondTransactionManager")
    public DataSourceTransactionManager secondTransactionManager(@Qualifier("secondDatasource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }


    //------------------------------- 注入 SqlSessionFactory 到 SqlSessionTemplate 中---------------------------------


    @Bean(name = "secondSqlSessionTemplate")
    public SqlSessionTemplate secondSqlSessionTemplate(@Qualifier("secondSqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }

}

3 xml文件

<?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>
</configuration>

4 mapper 類

public interface User1Mapper {
    public void inserts(User user);
}

public interface User2Mapper {
    public void inserts(User user);
}

5 mybatis mapper.xml

<?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.example.demo.mapper.one.User1Mapper">
    <insert id="inserts" parameterType="com.example.demo.pojo.User" useGeneratedKeys="true" keyProperty="id">
        insert into user(`name`,age) VALUE (#{name},#{age})
    </insert>
  
</mapper>

<?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.example.demo.mapper.one.User2Mapper">
    <insert id="inserts" parameterType="com.example.demo.pojo.User" useGeneratedKeys="true" keyProperty="id">
        insert into user(`name`,age) VALUE (#{name},#{age})
    </insert>
  
</mapper>

3 啓動成功

表示數據源建立成功，這裏鏈接池採用springboot默認的Hikari數據庫鏈接池(不須要配置)

6 測試

@Autowired
    User1Mapper user1Mapper;

    @Autowired
    User2Mapper user2Mapper;
    @Test
    public void test(){
        user1Mapper.inserts(new User(22L, "a123456",1));
        user1Mapper.inserts(new User(33L, "b123456", 1));
        user2Mapper.inserts(new User(44L, "b123456", 1));
    }

結果

7 更換數據源配置

官方文檔 ： https://github.com/alibaba/dr...

增長配置文件 , 更換爲durid數據源

1 配置文件增長配置屬性

#  StatViewServlet 配置
spring.datasource.druid.stat-view-servlet.login-username=admin
spring.datasource.druid.stat-view-servlet.login-password=admin

# 配置 StatFilter
spring.datasource.druid.filter.stat.log-slow-sql=true
spring.datasource.druid.filter.stat.slow-sql-millis=2000

# Druid 數據源 1 配置
spring.datasource.druid.one.initial-size=3
spring.datasource.druid.one.min-idle=3
spring.datasource.druid.one.max-active=10
spring.datasource.druid.one.max-wait=60000

# Druid 數據源 2 配置
spring.datasource.druid.second.initial-size=6
spring.datasource.druid.second.min-idle=6
spring.datasource.druid.second.max-active=20
spring.datasource.druid.second.max-wait=120000

將上面數據庫配置文件前綴加上druid

如：

#  StatViewServlet 配置
spring.datasource.druid.stat-view-servlet.login-username=admin
spring.datasource.druid.stat-view-servlet.login-password=admin

# 配置 StatFilter
spring.datasource.druid.filter.stat.log-slow-sql=true
spring.datasource.druid.filter.stat.slow-sql-millis=2000

# Druid 數據源 1 配置
spring.datasource.druid.one.initial-size=3
spring.datasource.druid.one.min-idle=3
spring.datasource.druid.one.max-active=10
spring.datasource.druid.one.max-wait=60000

# Druid 數據源 2 配置
spring.datasource.druid.second.initial-size=6
spring.datasource.druid.second.min-idle=6
spring.datasource.druid.second.max-active=20
spring.datasource.druid.second.max-wait=120000

#mybatis.type-aliases-package = com.example.demo.pojo
#################  mysql  數據源1 #################
spring.datasource.druid.one.url=jdbc:mysql://localhost:3306/user?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8&useSSL=true
spring.datasource.druid.one.username=root
spring.datasource.druid.one.password=root
spring.datasource.druid.one.driver-class-name=com.mysql.jdbc.Driver
#################  mysql  數據源1 #################

#################  mysql  數據源2 #################
spring.datasource.druid.second.url=jdbc:mysql://xxxxxxxxxxx:3306/user?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8&useSSL=true
spring.datasource.druid.second.username=root
spring.datasource.druid.second.password=root
spring.datasource.druid.second.driver-class-name=com.mysql.jdbc.Driver
#################  mysql  數據源1 #################

2 引入依賴

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

而後在加載數據源配置哪兒讀取配置文件註解改成

@ConfigurationProperties(prefix = "spring.datasource.druid.one")
@ConfigurationProperties(prefix = "spring.datasource.druid.second")

啓動後發現配置成功

過程當中可能會遇到問題

Failed to configure a DataSource: 'url' attribute is not specified and no embedded datasource could be configured.
Reason: Failed to determine a suitable driver class

緣由是：url連接寫錯了 , SpringBoot duridd沒法配置到 數據源url

錯誤：spring.datasource.druid.one.jdbc-url=jdbc:mysql://localhost:3306/user?   這是jdbc的url連接

正確 ： spring.datasource.druid.one.url=jdbc:mysql://localhost:3306/user?   這是鏈接池用的url