一、主流的多数据源支持方式
将数据源对象作为参数，传递到调用方法内部，这种方式增加额外的编码。如：JDBC多数据源添加方式
将Repository操作接口分包存放，Spring扫描不同的包，自动注入不同的数据源。这种方式实现简单，也是一种“约定大于配置”思想的典型应用。本文将以这种方式实现JPA的多数据源支持
二、修改application.yml配置多数据源
server:
port: 8098
spring:
#通用的数据源配置
datasource:
primary:
driver-class-name: com.mysql.jdbc.Driver
jdbc-url: jdbc:mysql://123.57.87.54:3306/ssm?useSSL=false&useUnicode=true&characterEncoding=utf8
username: bms
password: bms@2018
secondary:
driver-class-name: com.mysql.jdbc.Driver
jdbc-url: jdbc:mysql://123.57.87.54:3306/ssm2?useSSL=false&useUnicode=true&characterEncoding=utf8
username: bms
password: bms@2018
jpa:
#这个参数是在建表的时候，将默认的存储引擎切换为 InnoDB 用的
database-platform: org.hibernate.dialect.MySQL5InnoDBDialect
#配置在日志中打印出执行的 SQL 语句信息。
show-sql: true
hibernate:
#配置指明在程序启动的时候要删除并且创建实体类对应的表
ddl-auto: validate
三、 两组数据持久化接口及实体类,放到不同的package里面
@Data
@AllArgsConstructor
@NoArgsConstructor
@Builder
@Entity
@Table(name ="article")
public class Article {
@Id
@GeneratedValue(strategy= GenerationType.IDENTITY)
private Integer id;
private String author;
private String title;
private String content;
@JsonFormat(locale="zh", timezone="GMT+8", pattern="yyyy-MM-dd HH:mm:ss")
private Date createTime;
}
@Repository
public interface ArticleRepository extends JpaRepository<Article,Integer> {
}
四、第一组JPA数据持久层配置
配置JPA的数据持久层，需要配置：
DataSource数据源
EntityManager 实体管理器
EntityManagerFactoryBean 实体管理器工厂
PlatformTransactionManager 事务管理器
依次把上面的Bean配置并实例化，注入到Spring上下文中即可。或者更简单的说，下面的这段配置就是一个模板配置、固定配置。如果你自己去实现，唯一需要改动的地方就是com.dj.dao.testssm换成你自己的JpaRepository类所在的package路径。
package com.dj.config;
import org.springframework.boot.autoconfigure.orm.jpa.HibernateProperties;
import org.springframework.boot.autoconfigure.orm.jpa.HibernateSettings;
import org.springframework.boot.autoconfigure.orm.jpa.JpaProperties;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.boot.orm.jpa.EntityManagerFactoryBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import javax.annotation.Resource;
import javax.persistence.EntityManager;
import javax.sql.DataSource;
import java.util.Map;
@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(
entityManagerFactoryRef="entityManagerFactoryPrimary",
transactionManagerRef="transactionManagerPrimary",
basePackages= { "com.dj.dao.testssm" }) //换成你自己的Repository所在位置
public class JPAPrimaryConfig {
@Resource
private JpaProperties jpaProperties;
@Resource
private HibernateProperties hibernateProperties;
@Primary
@Bean(name = "primaryDataSource")
@ConfigurationProperties(prefix="spring.datasource.primary") //使用application.yml的primary数据源配置
public DataSource primaryDataSource() {
return DataSourceBuilder.create().build();
}
@Primary
@Bean(name = "entityManagerPrimary") //primary实体管理器
public EntityManager entityManager(EntityManagerFactoryBuilder builder) {
return entityManagerFactoryPrimary(builder).getObject().createEntityManager();
}
@Primary
@Bean(name = "entityManagerFactoryPrimary") //primary实体工厂
public LocalContainerEntityManagerFactoryBean entityManagerFactoryPrimary (EntityManagerFactoryBuilder builder) {
Map<String,Object> properties =
hibernateProperties.determineHibernateProperties(
jpaProperties.getProperties(),
new HibernateSettings());
return builder.dataSource(primaryDataSource())
.properties(properties)
.packages("com.dj.model.modelssm") //换成你自己的实体类所在位置
.persistenceUnit("primaryPersistenceUnit")
.build();
}
@Primary
@Bean(name = "transactionManagerPrimary") //primary事务管理器
public PlatformTransactionManager transactionManagerPrimary(EntityManagerFactoryBuilder builder) {
return new JpaTransactionManager(entityManagerFactoryPrimary(builder).getObject());
}
}
五、第二组JPA数据持久层配置
因为我们要做双数据源、所以仿造上面的第一组配置，再写一组配置。区别是：
没有@Primary注解，因为这一组配置不是默认配置，该组数据源不是默认数据源。这个注解前面章节也讲过。
注意本组的Repository扫描路径是com.dj.model.modelssm2，不是modelssm
package com.dj.config;
import org.springframework.boot.autoconfigure.orm.jpa.HibernateProperties;
import org.springframework.boot.autoconfigure.orm.jpa.HibernateSettings;
import org.springframework.boot.autoconfigure.orm.jpa.JpaProperties;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.boot.orm.jpa.EntityManagerFactoryBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import javax.annotation.Resource;
import javax.persistence.EntityManager;
import javax.sql.DataSource;
import java.util.Map;
@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(
entityManagerFactoryRef="entityManagerFactorySecondary",
transactionManagerRef="transactionManagerSecondary",
basePackages= { "com.dj.dao.testssm2" }) //换成你自己的Repository所在位置
public class JPASecondaryConfig {
@Resource
private JpaProperties jpaProperties;
@Resource
private HibernateProperties hibernateProperties;
@Bean(name = "secondaryDataSource")
@ConfigurationProperties(prefix="spring.datasource.secondary") //使用application.yml的secondary数据源配置
public DataSource secondaryDataSource() {
return DataSourceBuilder.create().build();
}
@Bean(name = "entityManagerSecondary") //secondary实体管理器
public EntityManager entityManager(EntityManagerFactoryBuilder builder) {
return entityManagerFactorySecondary(builder).getObject().createEntityManager();
}
@Bean(name = "entityManagerFactorySecondary")
public LocalContainerEntityManagerFactoryBean entityManagerFactorySecondary (EntityManagerFactoryBuilder builder) {
Map<String,Object> properties =
hibernateProperties.determineHibernateProperties(
jpaProperties.getProperties(),
new HibernateSettings());
return builder
.dataSource(secondaryDataSource())
.properties(properties)
.packages("com.dj.model.modelssm2") //换成你自己的实体类所在位置
.persistenceUnit("secondaryPersistenceUnit")
.build();
}
@Bean(name = "transactionManagerSecondary")
PlatformTransactionManager transactionManagerSecondary(EntityManagerFactoryBuilder builder) {
return new JpaTransactionManager(entityManagerFactorySecondary(builder).getObject());
}
}
六、测试
package com.dj;
import com.dj.dao.testssm.ArticleRepository;
import com.dj.dao.testssm2.UserRepository;
import com.dj.model.modelssm.Article;
import com.dj.model.modelssm2.User;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
import java.util.Date;
@RunWith(SpringRunner.class)
@SpringBootTest
public class SpringBootjpaTest {
@Autowired
private ArticleRepository articleRepository;
@Autowired
private UserRepository userRepository;
@Test
public void jpaTest(){
Article article = Article.builder()
.id(25)
.author("zimug")
.content("spring boot 从青铜到王者")
.createTime(new Date())
//.reader(readers)
.title("t133333").build();
User user = User.builder()
.user_name("zimug")
.address("ok")
.birthday(new Date())
.sex("南")
.build();
//先构造一个Article对象article，这个操作针对testdb
articleRepository.save(article);
//在构造一个Message对象message，这个操作针对testdb2
userRepository.save(user);
}
}