Spring Boot 多数据源配置（JPA）

目录

前言

前置环境

pom

yml

Entity

Dao

Config

Controller

演示

前言

一般一个系统至少有一个数据源，用来持久化业务数据以及查询。单个数据源的系统很常见，在 Spring Boot 框架下配置也很简单。在约定大于配置这个思想下，只需要在配置文件中简单配置下数据库连接信息就行了。

除了单数据源系统，在实际工作中，还会遇到多数据源系统。有可能是因为业务需要，以实际中做过的资产清查相关的项目为例，数据的存储分成了两个库，一个当前库和归档库，系统就需要配置两个数据源来满足业务需求。也有可能是技术架构，比如 MySQL 数据库使用了主从复制架构来实现读写分离，然后在应用层做分流，就需要配置主库和从库数据源，并在代码中决定使用哪个库进行数据库操作。

以下是Spring Boot JPA 多数据源的配置教程

前置环境

JDK8 + SringBoot2 + MySQL8

分别创建数据库 test1 test2

分别在两个数据库中创建 user 表

create table user (
    id int auto_increment primary key,
    username varchar(255),
    password varchar(255)
);

在test1.user 表中插入数据

insert into user(username, password) values('张三', '123456');

在test2.user 表中插入数据

insert into user(username, password) values('李四', '123456');

pom

    <dependencyManagement><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-dependencies</artifactId><version>${spring-boot.version}</version><type>pom</type><scope>import</scope></dependency></dependencies></dependencyManagement><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-jpa</artifactId></dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId></dependency><dependencies>

yml

server:port: 8888spring:datasource:primary:url: jdbc:mysql://localhost:3306/test1?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=UTC&allowPublicKeyRetrieval=trueusername: rootpassword: mysqldriver-class-name: com.mysql.cj.jdbc.Driversecondary:url: jdbc:mysql://localhost:3306/test2?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=UTC&allowPublicKeyRetrieval=trueusername: rootpassword: mysqldriver-class-name: com.mysql.cj.jdbc.Driverjpa:primary:show-sql: trueproperties:hibernate:hbm2ddl:auto: updatedialect: org.hibernate.dialect.MySQL5InnoDBDialectsecondary:show-sql: trueproperties:hibernate:hbm2ddl:auto: updatedialect: org.hibernate.dialect.MySQL5InnoDBDialect

Entity

主库和从库的实体类需要放在不同的包下，以本文为例

主库的实体类包路径为：com.jpa.entity.primary

@Entity
@Table ( name = "user")
public class PrimaryUserEntity {private Integer id;private String username;private String password;@Id@GeneratedValue ( strategy = GenerationType.IDENTITY)@Column ( name = "id" )public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}@Basic@Column ( name = "username" )public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}@Basic@Column ( name = "password" )public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}}

从库的实体类包路径为：com.jpa.entity.secondary

@Entity
@Table ( name = "user")
public class SecondaryUserEntity {private Integer id;private String username;private String password;@Id@GeneratedValue ( strategy = GenerationType.IDENTITY)@Column ( name = "id" )public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}@Basic@Column ( name = "username" )public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}@Basic@Column ( name = "password" )public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}}

Dao

主库和从库的Dao需要放在不同的包下，以本文为例

主库的Dao包路径为：com.jpa.dao.primary

@Repository (value = IPrimaryUserDao.DAO_BEAN_NAME )
public interface IPrimaryUserDao extends JpaRepository<PrimaryUserEntity, Integer> {String DAO_BEAN_NAME = "primaryUserDao";
}

从库的Dao包路径为：com.jpa.dao.secondary

@Repository (value = ISecondaryUserDao.DAO_BEAN_NAME )
public interface ISecondaryUserDao extends JpaRepository<SecondaryUserEntity, Integer> {String DAO_BEAN_NAME = "secondaryUserDao";
}

Config

记得将类中的两个包路径修改成自己项目的包路径

REPOSITORY_PACKAGE

ENTITY_PACKAGE

主库数据源配置

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories (basePackages = PrimaryDatasourceAndJpaConfig.REPOSITORY_PACKAGE,entityManagerFactoryRef = "primaryEntityManagerFactory",transactionManagerRef = "primaryTransactionManager"
)
public class PrimaryDatasourceAndJpaConfig {private static final String REPOSITORY_PACKAGE = "com.jpa.dao.primary";private static final String ENTITY_PACKAGE = "com.jpa.entity.primary";//--------------数据源配置-------------------/*** 扫描spring.datasource.primary开头的配置信息** @return 数据源配置信息*/@Primary@Bean(name = "primaryDataSourceProperties")@ConfigurationProperties(prefix = "spring.datasource.primary")public DataSourceProperties dataSourceProperties() {return new DataSourceProperties();}/*** 取主库数据源对象** @param dataSourceProperties 注入名为primaryDataSourceProperties的bean* @return 数据源对象*/@Primary@Bean(name = "primaryDataSource")public DataSource dataSource(@Qualifier("primaryDataSourceProperties") DataSourceProperties dataSourceProperties) {return dataSourceProperties.initializeDataSourceBuilder().build();}/*** 扫描spring.jpa.primary开头的配置信息** @return jpa配置信息*/@Primary@Bean (name = "primaryJpaProperties")@ConfigurationProperties (prefix = "spring.jpa.primary")public JpaProperties jpaProperties() {return new JpaProperties();}/*** 获取主库实体管理工厂对象** @param primaryDataSource 注入名为primaryDataSource的数据源* @param jpaProperties     注入名为primaryJpaProperties的jpa配置信息* @param builder           注入EntityManagerFactoryBuilder* @return 实体管理工厂对象*/@Primary@Bean(name = "primaryEntityManagerFactory")public LocalContainerEntityManagerFactoryBean entityManagerFactoryBean(@Qualifier ("primaryDataSource") DataSource primaryDataSource,@Qualifier("primaryJpaProperties") JpaProperties jpaProperties,EntityManagerFactoryBuilder builder) {return builder// 设置数据源.dataSource(primaryDataSource)// 设置jpa配置.properties(jpaProperties.getProperties())// 设置实体包名.packages(ENTITY_PACKAGE)// 设置持久化单元名，用于@PersistenceContext注解获取EntityManager时指定数据源.persistenceUnit("primaryPersistenceUnit").build();}/*** 获取实体管理对象** @param factory 注入名为primaryEntityManagerFactory的bean* @return 实体管理对象*/@Primary@Bean(name = "primaryEntityManager")public EntityManager entityManager(@Qualifier("primaryEntityManagerFactory") EntityManagerFactory factory) {return factory.createEntityManager();}/*** 获取主库事务管理对象** @param factory 注入名为primaryEntityManagerFactory的bean* @return 事务管理对象*/@Primary@Bean(name = "primaryTransactionManager")public JpaTransactionManager transactionManager(@Qualifier("primaryEntityManagerFactory") EntityManagerFactory factory) {return new JpaTransactionManager(factory);}
}

从库数据源配置

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(basePackages = SecondaryDatasourceAndJpaConfig.REPOSITORY_PACKAGE,entityManagerFactoryRef = "secondaryEntityManagerFactory",transactionManagerRef = "secondaryTransactionManager"
)
public class SecondaryDatasourceAndJpaConfig {static final String REPOSITORY_PACKAGE = "com.jpa.dao.secondary";static final String ENTITY_PACKAGE = "com.jpa.entity.secondary";//--------------数据源配置-------------------/*** 扫描spring.datasource.secondary开头的配置信息** @return 数据源配置信息*/@Bean(name = "secondaryDataSourceProperties")@ConfigurationProperties(prefix = "spring.datasource.secondary")public DataSourceProperties dataSourceProperties() {return new DataSourceProperties();}/*** 获取次数据源对象** @param dataSourceProperties 注入名为secondaryDataSourceProperties的bean* @return 数据源对象*/@Bean("secondaryDataSource")public DataSource dataSource(@Qualifier("secondaryDataSourceProperties") DataSourceProperties dataSourceProperties) {return dataSourceProperties.initializeDataSourceBuilder().build();}/*** 扫描spring.jpa.secondary** @return jpa配置信息*/@Bean(name = "secondaryJpaProperties")@ConfigurationProperties(prefix = "spring.jpa.secondary")public JpaProperties jpaProperties() {return new JpaProperties();}/*** 获取次库实体管理工厂对象** @param secondaryDataSource 注入名为secondaryDataSource的数据源* @param jpaProperties       注入名为secondaryJpaProperties的jpa配置信息* @param builder             注入EntityManagerFactoryBuilder* @return 实体管理工厂对象*/@Bean(name = "secondaryEntityManagerFactory")public LocalContainerEntityManagerFactoryBean entityManagerFactory(@Qualifier("secondaryDataSource") DataSource secondaryDataSource,@Qualifier("secondaryJpaProperties") JpaProperties jpaProperties,EntityManagerFactoryBuilder builder) {return builder// 设置数据源.dataSource(secondaryDataSource)// 设置jpa配置.properties(jpaProperties.getProperties())// 设置实体包名.packages(ENTITY_PACKAGE)// 设置持久化单元名，用于@PersistenceContext注解获取EntityManager时指定数据源.persistenceUnit("secondaryPersistenceUnit").build();}/*** 获取实体管理对象** @param factory 注入名为secondaryEntityManagerFactory的bean* @return 实体管理对象*/@Bean(name = "secondaryEntityManager")public EntityManager entityManager(@Qualifier("secondaryEntityManagerFactory") EntityManagerFactory factory) {return factory.createEntityManager();}/*** 获取事务管理对象** @param factory 注入名为secondaryEntityManagerFactory的bean* @return 事务管理对象*/@Bean(name = "secondaryTransactionManager")public JpaTransactionManager transactionManager(@Qualifier("secondaryEntityManagerFactory") EntityManagerFactory factory) {return new JpaTransactionManager(factory);}
}

Controller

主库

@RestController
@RequestMapping(value = "/primary")
public class PrimaryJpaController {@Resourceprivate IPrimaryUserDao primaryUserDao;@RequestMapping(value = "/findAll", method = RequestMethod.GET)public List<PrimaryUserEntity> findAll() {return primaryUserDao.findAll();}
}

从库

@RestController
@RequestMapping(value = "/secondary")
public class SecondaryJpaController{@Resourceprivate ISecondaryUserDao secondaryUserDao;@RequestMapping(value = "/findAll", method = RequestMethod.GET)public List<SecondaryUserEntity> findAll() {return secondaryUserDao.findAll();}
}

演示

请求 /primary/findAll

请求 /secondary/findAll