spring boot(学习笔记第九课)
- MyBatis多数据库配置，Spring Data JPA多数据库配置
学习内容：
- MyBatis多数据库配置
- Spring Data JPA多数据库配置
1. MyBatis多数据库配置
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准备多个数据库，配置数据库连接信息。
#database spring.datasource.one.type=com.alibaba.druid.pool.DruidDataSource spring.datasource.one.url=jdbc:mysql://127.0.0.1:3306/springboot spring.datasource.one.username=finlay spring.datasource.one.password=123456 spring.datasource.two.type=com.alibaba.druid.pool.DruidDataSource spring.datasource.two.url=jdbc:postgresql://127.0.0.1:5432/springboot spring.datasource.two.username=finlay spring.datasource.two.password=123456 -
因为使用一个
Entity类，所以在两个库里面加一个表book。
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需要将
MyBatis的xml文件加载，所以加入resources。<build> <resources> <resource> <directory>src/main/java</directory> <includes> <include>**/*.xml</include> </includes> </resource> <resource> <directory>src/main/resources</directory> </resource> </resources> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> -
加入必要的依赖。
mybatis的依赖。druild的连接池依赖。postgreSQL的依赖。mysql的依赖。<dependency> <groupId>com.alibaba</groupId> <artifactId>druid</artifactId> <version>1.1.9</version> </dependency> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid-spring-boot-starter</artifactId> <version>1.2.9</version> </dependency> <dependency> <groupId>org.postgresql</groupId> <artifactId>postgresql</artifactId> <scope>runtime</scope> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>8.0.28</version> <scope>runtime</scope> </dependency>
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定义
DataSourceConfig的@Configuration的配置类，将application.properties中定义的接续信息加载成bean。@Configuration public class DataSourceConfig { @Bean(value = "dsOne") @ConfigurationProperties(value = "spring.datasource.one") DataSource dsOne() { return DruidDataSourceBuilder.create().build(); } @Bean(value = "dsTwo") @ConfigurationProperties(value = "spring.datasource.two") DataSource dsTwo() { return DruidDataSourceBuilder.create().build(); } } -
分别定义两个
repository下面的包，分别是datasource1和datasource2。因为需要将不同的数据库指定给不同的包。
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在
datasource1分别定义BookMapper1和BookMapper1.xml。同样定义BookMapper2和BookMapper2.xml在datasource2中，和MyBatis单数据库相同。BookMapper1.java
@Mapper public interface BookMapper1 { public List<Book> getAllBooks(); }BookMapper1.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.repository.datasource1.BookMapper1"> <select id="getAllBooks" resultType="com.example.demo.entity.Book"> select * from book; </select> </mapper>BookMapper2.java
* @Mapper public interface BookMapper2{ public List<Book> getAllBooks(); }BookMapper2.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.repository.datasource2.BookMapper2"> <select id="getAllBooks" resultType="com.example.demo.entity.Book"> select * from book; </select> </mapper> -
对
BookMapper1.java进行配置，让其指向datasource1。@Configuration @MapperScan(value = "com.example.demo.repository.datasource1", sqlSessionFactoryRef = "sqlSessionFactoryBean1") public class MyBatisConfigOne { @Autowired @Qualifier("dsOne") DataSource dsOne; @Bean public SqlSessionFactory sqlSessionFactoryBean1() throws Exception { SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean(); sqlSessionFactoryBean.setDataSource(dsOne); return sqlSessionFactoryBean.getObject(); } @Bean public SqlSessionTemplate sqlSessionTemplate1() throws Exception { return new SqlSessionTemplate(sqlSessionFactoryBean1()); } } -
对
BookMapper2.java进行配置，让其指向datasource2。@Configuration @MapperScan(value = "com.example.demo.repository.datasource2", sqlSessionFactoryRef = "sqlSessionFactoryBean2") public class MyBatisConfigTwo { @Autowired @Qualifier("dsTwo") DataSource dsTwo; @Bean public SqlSessionFactory sqlSessionFactoryBean2() throws Exception { SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean(); sqlSessionFactoryBean.setDataSource(dsTwo); return sqlSessionFactoryBean.getObject(); } @Bean public SqlSessionTemplate sqlSessionTemplate2() throws Exception { return new SqlSessionTemplate(sqlSessionFactoryBean2()); } } -
定义
controller，使用BookMapper1和BookMapper2分别从两个数据库读出数据@GetMapping("/multidb") @ResponseBody public String multidb() { List<Book> book1 = bookMapper1.getAllBooks(); List<Book> book2 = bookMapper2.getAllBooks(); return book1.toString() + book2.toString(); }
11.访问https://localhost:8080/multidb，会显示从两个数据库的数据。
2. Spring Data JPA多数据库配置
- 加入必要的
Spring Data JPA依赖<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-jpa</artifactId> </dependency> - 在
application.properties中加入Spring Data JAP的配置。#database spring.datasource.one.type=com.alibaba.druid.pool.DruidDataSource spring.datasource.one.url=jdbc:mysql://127.0.0.1:3306/springboot spring.datasource.one.username=finlay spring.datasource.one.password=123456 spring.datasource.two.type=com.alibaba.druid.pool.DruidDataSource spring.datasource.two.url=jdbc:postgresql://127.0.0.1:5432/springboot spring.datasource.two.username=finlay spring.datasource.two.password=123456 spring.jpa.properties.hibernate.hbm2ddl.auto=update spring.jpa.properties.show-sql=truehbm2ddl.auto=updatehbm2ddl.auto表示没有表的场合，会建立表，但是如果表已经存在，数据不会清空。 - 创建
dataSource的配置bean。
*注意，务必在一个dataSource*上增加@primary注解。@Configuration public class DataSourceConfig { @Bean(value = "dsOne") @ConfigurationProperties(value = "spring.datasource.one") @Primary DataSource dsOne() { return DruidDataSourceBuilder.create().build(); } @Bean(value = "dsTwo") @ConfigurationProperties(value = "spring.datasource.two") DataSource dsTwo() { return DruidDataSourceBuilder.create().build(); } } - 在
package com.example.demo.repository.jpa.datasource1;中增加@Configration，设定该package下面的repository都使用该dsOne的数据库配置。
注意，entityManagerFactoryBeanOne的上面增加@primary注解。@Configuration @EnableTransactionManagement @EnableJpaRepositories(basePackages = "com.example.demo.repository.jpa.datasource1", entityManagerFactoryRef = "entityManagerFactoryBeanOne", transactionManagerRef = "platformTransactionManagerOne") public class JpaConfigOne { @Resource(name = "dsOne") public DataSource dsOne; @Autowired JpaProperties jpaProperties; @Bean @Primary public LocalContainerEntityManagerFactoryBean entityManagerFactoryBeanOne( EntityManagerFactoryBuilder builder ) { return builder.dataSource(dsOne).properties( jpaProperties.getProperties()) .packages("com.example.demo.entity") .persistenceUnit("pu2") .build(); } @Bean PlatformTransactionManager platformTransactionManagerOne( EntityManagerFactoryBuilder builder ) { LocalContainerEntityManagerFactoryBean factoryBeanOne = entityManagerFactoryBeanOne(builder); return new JpaTransactionManager(Objects.requireNonNull(factoryBeanOne.getObject())); } } - 在
package com.example.demo.repository.jpa.datasource1里面，定义UserDaoOne。public interface UserDaoTwo extends JpaRepository<UserMaster,Integer> { } - 在
package com.example.demo.repository.jpa.datasource1;中增加@Configration，设定该package下面的repository都使用该dsOne的数据库配置。
注意，entityManagerFactoryBeanOne的上面增加@primary注解。@Configuration @EnableTransactionManagement @EnableJpaRepositories(basePackages = "com.example.demo.repository.jpa.datasource2", entityManagerFactoryRef = "entityManagerFactoryBeanTwo", transactionManagerRef = "platformTransactionManagerTwo") public class JpaConfigTwo { @Resource(name = "dsTwo") public DataSource dsTwo; @Autowired JpaProperties jpaProperties; @Bean public LocalContainerEntityManagerFactoryBean entityManagerFactoryBeanTwo( EntityManagerFactoryBuilder builder ){ return builder.dataSource(dsTwo).properties( jpaProperties.getProperties()) .packages("com.example.demo.entity") .persistenceUnit("pu2") .build(); } @Bean PlatformTransactionManager platformTransactionManagerTwo( EntityManagerFactoryBuilder builder ){ LocalContainerEntityManagerFactoryBean factoryBeanTwo = entityManagerFactoryBeanTwo(builder); return new JpaTransactionManager(Objects.requireNonNull(factoryBeanTwo.getObject())); } } - 在
package com.example.demo.repository.jpa.datasource2里面，定义UserDaoTwo。public interface UserDaoTwo extends JpaRepository<UserMaster,Integer> { } - 定义
@Entity类。@Entity(name = "user_master") @Data public class UserMaster { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Integer id; private Integer age; private String name; private String gender; } - 在
controller中定义DAO，进行测试。@Autowired UserDaoOne userDaoOne; @Autowired UserDaoTwo userDaoTwo; @GetMapping("/multidb_jpa") @ResponseBody public void multiDBJpa(){ UserMaster user = new UserMaster(); user.setAge(10); user.setGender("boy"); user.setName("allen"); userDaoOne.save(user); user.setName("finlay"); userDaoTwo.save(user); } - 执行完
https://localhost:8080/multidb_jpa之后两个数据库都会建立user_master的表，数据会增加一条。