Spring Boot 多数据库从辅助数据库中提供空值答案

【问题标题】：Spring Boot Multiple Database giving null values from secondary databaseSpring Boot 多数据库从辅助数据库中提供空值
【发布时间】：2020-12-10 22:54:58
【问题描述】：

我配置了 2 个数据库，使 1 个数据库成为主数据库。我能够从主数据库中获取数据库，但辅助数据库给了我空结果。辅助数据库表的相应配置正在主模式中创建，结果为空。下面是我写的代码。

数据库配置。

@Bean
    @ConfigurationProperties(prefix="com.example.studentmanagement.datasource")
    public DataSource studentDataSource() {
        DataSource dataSource=DataSourceBuilder.create().build();
        return dataSource;
    }
    
    
    @Bean
    @Primary
    @ConfigurationProperties(prefix="com.example.ordermanagement.datasource")
    public DataSource orderDataSource() {
        DataSource dataSource=DataSourceBuilder.create().build();
        return dataSource;
    }

我正在使用带有 spring 数据存储库的 entitymanager 工厂来获取数据。下面是主要和次要配置。

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(basePackages ="com.example.SpringBootMultipleDbs.Customer.Repos",entityManagerFactoryRef = "orderEntityManagerFactoryBean",
transactionManagerRef = "orderTransactionManager")
public class PrimaryConfig {
    
    @Bean
    @Primary
    public LocalContainerEntityManagerFactoryBean orderEntityManagerFactoryBean(DataSource orderDataSource) {
        LocalContainerEntityManagerFactoryBean localContainerEntityManagerFactoryBean=new LocalContainerEntityManagerFactoryBean();
        localContainerEntityManagerFactoryBean.setDataSource(orderDataSource);
        localContainerEntityManagerFactoryBean.setPackagesToScan("com.example.SpringBootMultipleDbs.Customer.Entities");
        localContainerEntityManagerFactoryBean.setJpaVendorAdapter(new HibernateJpaVendorAdapter());
        Map<String,Object> jpaPropertiesMap=new HashMap<>();
        jpaPropertiesMap.put("hibernate.dialect", org.hibernate.dialect.MySQL5Dialect.class);
        jpaPropertiesMap.put("hibernate.hbm2ddl.auto","update");
        jpaPropertiesMap.put("hibernate.format_sql", true);
        jpaPropertiesMap.put("hibernate.show_sql", true);
        jpaPropertiesMap.put("hibernate.implicit_naming_strategy", org.hibernate.boot.model.naming.ImplicitNamingStrategyLegacyJpaImpl.class);
        jpaPropertiesMap.put("hibernate.physical_naming_strategy",org.hibernate.boot.model.naming.PhysicalNamingStrategyStandardImpl.class);
        localContainerEntityManagerFactoryBean.setJpaPropertyMap(jpaPropertiesMap);
        return localContainerEntityManagerFactoryBean;
        
    }
    
    @Bean
    @Primary
    public JpaTransactionManager orderTransactionManager(LocalContainerEntityManagerFactoryBean orderEntityManagerFactoryBean) {
        JpaTransactionManager jpaTransactionManager=new JpaTransactionManager();
        jpaTransactionManager.setEntityManagerFactory(orderEntityManagerFactoryBean.getObject());
        return jpaTransactionManager;
    }

}

辅助配置

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(basePackages ="com.example.SpringBootMultipleDbs.Department.Repos",entityManagerFactoryRef = "studentEntityManagerFactoryBean",
transactionManagerRef = "studentTransactionManager")
public class SecondaryConfig {
    
    @Bean
    public LocalContainerEntityManagerFactoryBean studentEntityManagerFactoryBean(DataSource studentDataSource) {
        LocalContainerEntityManagerFactoryBean localContainerEntityManagerFactoryBean=new LocalContainerEntityManagerFactoryBean();
        localContainerEntityManagerFactoryBean.setDataSource(studentDataSource);
        localContainerEntityManagerFactoryBean.setPackagesToScan("com.example.SpringBootMultipleDbs.Department.Entities");
        localContainerEntityManagerFactoryBean.setJpaVendorAdapter(new HibernateJpaVendorAdapter());
        Map<String,Object> jpaPropertiesMap=new HashMap<>();
        jpaPropertiesMap.put("hibernate.dialect", org.hibernate.dialect.MySQL5Dialect.class);
        jpaPropertiesMap.put("hibernate.format_sql", true);
        jpaPropertiesMap.put("hibernate.show_sql", true);
        jpaPropertiesMap.put("hibernate.implicit_naming_strategy", org.hibernate.boot.model.naming.ImplicitNamingStrategyLegacyJpaImpl.class);
        jpaPropertiesMap.put("hibernate.physical_naming_strategy",org.hibernate.boot.model.naming.PhysicalNamingStrategyStandardImpl.class);
        localContainerEntityManagerFactoryBean.setJpaPropertyMap(jpaPropertiesMap);
        return localContainerEntityManagerFactoryBean;
        
    }
    
    
    
    
    @Bean
    public JpaTransactionManager studentTransactionManager(LocalContainerEntityManagerFactoryBean studentEntityManagerFactoryBean) {
        JpaTransactionManager jpaTransactionManager=new JpaTransactionManager();
        jpaTransactionManager.setEntityManagerFactory(studentEntityManagerFactoryBean.getObject());
        return jpaTransactionManager;
    }
    

}

下面是 spring data jpa 存储库类，它为我获取 null 数据映射到辅助数据库配置。

public interface DepartmentRepo extends JpaRepository<Department,Integer> {
    
    public Department findByDeptId(Integer id); 

}

application.yml 文件

com:
  example:
    studentmanagement:
      datasource:
        driverClassName: com.mysql.jdbc.Driver
        jdbcUrl: jdbc:mysql://localhost:3306/student
        username: root
        password: root123
    ordermanagement:
      datasource:
        driverClassName: com.mysql.jdbc.Driver
        jdbcUrl: jdbc:mysql://localhost:3306/order
        username: root
        password: root123 
        
            
server:
  port: 8085
  servlet:
    context-path: /SpringBootDbs

【问题讨论】：

标签： mysql database spring-boot spring-data-jpa

【解决方案1】：

您必须将配置和配置使用者代码保存在不同的包中。在您的情况下，因为您有 2 个 DB 用于学生管理，另一个用于订单管理，因此您还需要在代码中打包层次结构。您的包结构应如下所示。

com.example.orderManagement //OrderManagement Config和订单的所有消费者代码都应该在这里

com.example.Studentmanagement //学生管理配置和学生的所有消费者代码都在这里

【讨论】：