在 spring boot 中动态设置 hibernate.dialect 属性

Question

我已经浏览了有关如何正确设置hibernate.dialect属性的可用示例和教程，但没有发现适合我的情况的方法。

本教程最适合我，但它缺乏动态设置hibernate.dialect属性的能力，因为我有不同类型的数据库要连接：

• 微软SQL
• 甲骨文
• H2
• MySQL

由于方言不正确，我的 JPA（删除/更新）查询失败。

使用以下实现完美的@Configuration ，我如何能够在运行时为每个数据源动态设置hibernate.dialect ？

先感谢您。

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(
        basePackages = "com.example.multidb",
        entityManagerFactoryRef = "multiEntityManager",
        transactionManagerRef = "multiTransactionManager"
)
public class PersistenceConfiguration {

    private final String PACKAGE_SCAN = "com.example.multidb";    

    @Primary
    @Bean(name = "mainDataSource")
    @ConfigurationProperties("app.datasource.main")
    public DataSource mainDataSource() {
        return DataSourceBuilder.create().type(HikariDataSource.class).build();
    }    

    @Bean(name = "clientADataSource")
    @ConfigurationProperties("app.datasource.clienta")
    public DataSource clientADataSource() {
        return DataSourceBuilder.create().type(HikariDataSource.class).build();
    }

    @Bean(name = "clientBDataSource")
    @ConfigurationProperties("app.datasource.clientb")
    public DataSource clientBDataSource() {
        return DataSourceBuilder.create().type(HikariDataSource.class).build();
    }

    @Bean(name = "multiRoutingDataSource")
    public DataSource multiRoutingDataSource() {
        Map<Object, Object> targetDataSources = new HashMap<>();

        targetDataSources.put(DBTypeEnum.MAIN, mainDataSource());
        targetDataSources.put(DBTypeEnum.CLIENT_A, clientADataSource());
        targetDataSources.put(DBTypeEnum.CLIENT_B, clientBDataSource());

        MultiRoutingDataSource multiRoutingDataSource = new MultiRoutingDataSource();

        multiRoutingDataSource.setDefaultTargetDataSource(mainDataSource());
        multiRoutingDataSource.setTargetDataSources(targetDataSources);        

        return multiRoutingDataSource;
    }   

    @Bean(name = "multiEntityManager")
    public LocalContainerEntityManagerFactoryBean multiEntityManager() {
        LocalContainerEntityManagerFactoryBean em = new LocalContainerEntityManagerFactoryBean();

        em.setDataSource(multiRoutingDataSource());
        em.setPackagesToScan(PACKAGE_SCAN);

        HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();

        em.setJpaVendorAdapter(vendorAdapter);
        em.setJpaProperties(hibernateProperties());        

        return em;
    }

    @Bean(name = "multiTransactionManager")
    public PlatformTransactionManager multiTransactionManager() {
        JpaTransactionManager transactionManager
                = new JpaTransactionManager();
        transactionManager.setEntityManagerFactory(
                multiEntityManager().getObject());        

        return transactionManager;
    }

    @Primary
    @Bean(name = "dbSessionFactory")
    public LocalSessionFactoryBean dbSessionFactory() {
        LocalSessionFactoryBean sessionFactoryBean = new LocalSessionFactoryBean();

        sessionFactoryBean.setDataSource(multiRoutingDataSource());
        sessionFactoryBean.setPackagesToScan(PACKAGE_SCAN);
        sessionFactoryBean.setHibernateProperties(hibernateProperties());

        return sessionFactoryBean;
    }

    private Properties hibernateProperties() {
        Properties properties = new Properties();
        properties.put("hibernate.show_sql", true);
        properties.put("hibernate.format_sql", true);        

        //set hibernate.dialect for each datasource

        return properties;
    }
}

Answer 1

我已经为您创建了一个工作示例，我将在此处对其进行描述，但是如果您想自己跳入代码， 则可以在此 GitHub 存储库中找到它。

就我而言，我创建了两个数据源，一个用于User ，另一个用于Item 。

这里的实体：

package com.marcosbarbero.so.multiple.ds.entity.user;

import lombok.Data;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

@Data
@Entity
@Table(schema = "user")
public class User {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Integer id;

    private String name;

    @Column(unique = true, nullable = false)
    private String email;

    private int age;
}

package com.marcosbarbero.so.multiple.ds.entity.item;

import lombok.Data;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

@Data
@Entity
@Table(schema = "item")
public class Item {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private int id;

    private String name;
}

请注意，为每个域设置不同的包很重要。 然后我创建了Repositories

package com.marcosbarbero.so.multiple.ds.repository.user;

import com.marcosbarbero.so.multiple.ds.entity.user.User;
import org.springframework.data.jpa.repository.JpaRepository;

public interface UserRepository extends JpaRepository<User, Integer> {
}

package com.marcosbarbero.so.multiple.ds.repository.item;

import com.marcosbarbero.so.multiple.ds.entity.item.Item;
import org.springframework.data.jpa.repository.JpaRepository;

public interface ItemRepository extends JpaRepository<Item, Integer> {
}

回购没有什么特别之处。 让我们转到最后一部分，即配置。

1. 我创建了一个@ConfigurationProperties类来外部化我的配置，请耐心@ConfigurationProperties ，我知道命名不是最好的:)

package com.marcosbarbero.so.multiple.ds.config;

import lombok.Data;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;

import java.util.HashMap;
import java.util.Map;

@Data
@Component
@ConfigurationProperties(prefix = "multi-datasource")
public class MultipleDataSourceProperties {

    private UserDataSourceProperties user = new UserDataSourceProperties();

    private ItemDataSourceProperties item = new ItemDataSourceProperties();

    @Data
    public static class UserDataSourceProperties {
        private HibernateProperties hibernate = new HibernateProperties();
    }

    @Data
    public static class ItemDataSourceProperties {
        private HibernateProperties hibernate = new HibernateProperties();
    }

    @Data
    public static class HibernateProperties {
        private Map<String, String> properties = new HashMap<>();
    }

}

我们很快就会看到属性配置文件。

2. 现在让我们为User创建DataSource ：

package com.marcosbarbero.so.multiple.ds.config;

import com.zaxxer.hikari.HikariDataSource;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jdbc.DataSourceBuilder;
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.orm.jpa.vendor.HibernateJpaVendorAdapter;
import org.springframework.transaction.PlatformTransactionManager;

import javax.sql.DataSource;

@Configuration
@EnableJpaRepositories(
        basePackages = "com.marcosbarbero.so.multiple.ds.repository.user",
        entityManagerFactoryRef = "userEntityManager",
        transactionManagerRef = "userTransactionManager"
)
public class UserDataSourceConfig {

    private final MultipleDataSourceProperties properties;

    public UserDataSourceConfig(MultipleDataSourceProperties properties) {
        this.properties = properties;
    }

    @Bean
    @Primary
    public LocalContainerEntityManagerFactoryBean userEntityManager() {
        LocalContainerEntityManagerFactoryBean em = new LocalContainerEntityManagerFactoryBean();
        em.setDataSource(userDataSource());
        em.setPackagesToScan("com.marcosbarbero.so.multiple.ds.entity.user");

        HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
        em.setJpaVendorAdapter(vendorAdapter);
        em.setJpaPropertyMap(properties.getUser().getHibernate().getProperties());

        return em;
    }

    @Primary
    @Bean
    @ConfigurationProperties("multi-datasource.user")
    public DataSource userDataSource() {
        return DataSourceBuilder.create().type(HikariDataSource.class).build();
    }

    @Primary
    @Bean
    public PlatformTransactionManager userTransactionManager() {
        JpaTransactionManager transactionManager = new JpaTransactionManager();
        transactionManager.setEntityManagerFactory(userEntityManager().getObject());
        return transactionManager;
    }
}

在这门课上对你来说重要的部分是em.setJpaPropertyMap(properties.getUser().getHibernate().getProperties()); 它从上面定义的@ConfigurationProperties类中获取用户的 Hibernate 配置属性。

3. 现在让我们对Item做同样的事情：

package com.marcosbarbero.so.multiple.ds.config;

import com.zaxxer.hikari.HikariDataSource;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jdbc.DataSourceBuilder;
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.orm.jpa.vendor.HibernateJpaVendorAdapter;
import org.springframework.transaction.PlatformTransactionManager;

import javax.sql.DataSource;

@Configuration
@EnableJpaRepositories(
        basePackages = "com.marcosbarbero.so.multiple.ds.repository.item",
        entityManagerFactoryRef = "itemEntityManager",
        transactionManagerRef = "itemTransactionManager"
)
public class ItemDataSourceConfig {

    private final MultipleDataSourceProperties properties;

    public ItemDataSourceConfig(MultipleDataSourceProperties properties) {
        this.properties = properties;
    }

    @Bean
    @Primary
    public LocalContainerEntityManagerFactoryBean itemEntityManager() {
        LocalContainerEntityManagerFactoryBean em = new LocalContainerEntityManagerFactoryBean();
        em.setDataSource(itemDataSource());
        em.setPackagesToScan("com.marcosbarbero.so.multiple.ds.entity.item");

        HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
        em.setJpaVendorAdapter(vendorAdapter);
        em.setJpaPropertyMap(properties.getItem().getHibernate().getProperties());

        return em;
    }

    @Primary
    @Bean
    @ConfigurationProperties("multi-datasource.item")
    public DataSource itemDataSource() {
        return DataSourceBuilder.create().type(HikariDataSource.class).build();
    }

    @Primary
    @Bean
    public PlatformTransactionManager itemTransactionManager() {
        JpaTransactionManager transactionManager = new JpaTransactionManager();
        transactionManager.setEntityManagerFactory(itemEntityManager().getObject());
        return transactionManager;
    }
}

4. application.properties

multi-datasource.item.jdbcUrl=jdbc:h2:mem:spring_jpa_item;DB_CLOSE_DELAY=-1;INIT=CREATE SCHEMA IF NOT EXISTS ITEM
multi-datasource.item.username=sa
multi-datasource.item.password=sa

multi-datasource.item.hibernate.properties.hibernate.hbm2ddl.auto=create-drop
multi-datasource.item.hibernate.properties.hibernate.cache.use_second_level_cache=false
multi-datasource.item.hibernate.properties.hibernate.cache.use_query_cache=false
multi-datasource.item.hibernate.properties.hibernate.dialect=org.hibernate.dialect.PostgreSQLDialect

multi-datasource.user.jdbcUrl=jdbc:h2:mem:spring_jpa_user;DB_CLOSE_DELAY=-1;INIT=CREATE SCHEMA IF NOT EXISTS USER
multi-datasource.user.username=sa
multi-datasource.user.password=sa

multi-datasource.user.hibernate.properties.hibernate.hbm2ddl.auto=create-drop
multi-datasource.user.hibernate.properties.hibernate.cache.use_second_level_cache=false
multi-datasource.user.hibernate.properties.hibernate.cache.use_query_cache=false
multi-datasource.user.hibernate.properties.hibernate.dialect=org.hibernate.dialect.OracleDialect

5. 一些单元测试

package com.marcosbarbero.so;

import com.marcosbarbero.so.multiple.ds.entity.item.Item;
import com.marcosbarbero.so.multiple.ds.entity.user.User;
import com.marcosbarbero.so.multiple.ds.repository.item.ItemRepository;
import com.marcosbarbero.so.multiple.ds.repository.user.UserRepository;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

import static org.junit.jupiter.api.Assertions.assertNotNull;

@SpringBootTest
public class JPAMultipleDBTest {

    @Autowired
    private UserRepository userRepository;

    @Autowired
    private ItemRepository itemRepository;

    @Test
    public void whenCreatingUser_thenCreated() {
        User user = new User();
        user.setName("John");
        user.setEmail("john@test.com");
        user.setAge(20);
        user = userRepository.save(user);

        assertNotNull(userRepository.findById(user.getId()));
    }

    @Test
    public void whenCreatingProduct_thenCreated() {
        Item item = new Item();
        item.setName("Book");
        item.setId(2);
        item = itemRepository.save(item);

        assertNotNull(itemRepository.findById(item.getId()));
    }
}

我认为还值得一提的是，为了使其一切正常，我禁用了DataSourceAutoConfiguration ，就这么简单：

@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)

同样，这一切都可以在这个 GitHub repo 中找到。