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springboot + JPA 配置双数据源实战

springboot + JPA 配置双数据源

1、首先配置application.yml文件设置主从数据库

spring:
servlet:
  multipart:
    max-file-size: 20MB
    max-request-size: 20MB
profiles:
  active: @activatedProperties@
thymeleaf:
  mode: LEGACYHTML5
  encoding: UTF-8
  cache: false
http:
  encoding:
    charset: UTF-8
    enabled: true
    force: true
jpa:
  hibernate:
    ddl-auto: none
  properties:
    hibernate:
      dialect: org.hibernate.dialect.MySQL5Dialect
  show-sql: true
  database: mysql

datasource:
  primary:
    jdbc-url: jdbc:mysql://192.168.2.180:3306/ssdt-rfid?serverTimezone=Asia/Shanghai
    username: root
    password: root
    driver-class-name: com.mysql.cj.jdbc.Driver

  secondary:
    jdbc-url: jdbc:mysql://127.0.0.1:3306/isite?serverTimezone=Asia/Shanghai
    username: root
    password: 654321
    driver-class-name: com.mysql.cj.jdbc.Driver

在datasource中存在primary（主数据源）和secondary （副数据源）两个配置，
dialect: org.hibernate.dialect.MySQL5Dialect配置
MySQLDialect是MySQL5.X之前的版本,MySQL5Dialect是MySQL5.X之后的版本

2、使用配置类读取application.yml配置的两个数据源

并将其注入到Spring的IOC容器中

package com.springboot.***.***.config; 
import org.springframework.beans.factory.annotation.Qualifier;
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 javax.sql.DataSource; 

/**
* @author： SUN
* @version: 1.0
* @date： 2019/12/24 13:12
* @description：
*/
@Configuration
public class DataSourceConfig {  
  @Bean(name = "primaryDataSource")
  @Qualifier("primaryDataSource")
  @Primary
  @ConfigurationProperties(prefix = "spring.datasource.primary")  //  读取配置文件主数据源参数
  public DataSource primaryDataSource() {
      return DataSourceBuilder.create().build();
  }

  @Bean(name = "secondaryDataSource")
  @Qualifier("secondaryDataSource")
  @ConfigurationProperties(prefix = "spring.datasource.secondary")  //  读取配置文件副数据源参数
  public DataSource secondaryDataSource() {
      return DataSourceBuilder.create().build();
  } 
}

注解解释：

@Configuration：SpringBoot启动将该类作为配置类，同配置文件一起加载
@Bean：将该实体注入到IOC容器中
@Qualifier：指定数据源名称，与Bean中的name属性原理相同，主要是为了确保注入成功
@Primary：指定主数据源
@ConfigurationProperties：将配置文件中的数据源读取进到方法中，进行build

3、然后通过类的方式配置两个数据源

对于主次数据源的DAO层接口以及实体POJO类需放在不同目录下，由以下两个配置类中分别指定路径

（1）主数据源

package com.springboot.****.****.config; 
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
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.core.env.Environment;
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.persistence.EntityManager;
import javax.sql.DataSource;
import java.util.HashMap;
import java.util.Map;

/**
* @author： SUN
* @version: 1.0
* @date： 2019/12/24 13:25
* @description：
*/
@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(
      entityManagerFactoryRef = "entityManagerFactoryPrimary",
      transactionManagerRef = "transactionManagerPrimary",
      basePackages = {"com.springboot.****.****.repository"})    // 指定该数据源操作的DAO接口包与副数据源作区分
public class PrimaryConfig { 
  private String url;

  public String getUrl() {
      return url;
  }

  public void setUrl(String url) {
      this.url = url;
  }

  @Autowired
  @Qualifier("primaryDataSource")
  private DataSource primaryDataSource;

  @Primary
  @Bean(name = "entityManagerPrimary")
  public EntityManager entityManager(EntityManagerFactoryBuilder builder) {
      return entityManagerFactoryPrimary(builder).getObject().createEntityManager();
  }

  @Primary
  @Bean(name = "entityManagerFactoryPrimary")
  public LocalContainerEntityManagerFactoryBean entityManagerFactoryPrimary(EntityManagerFactoryBuilder builder) {
      return builder
              .dataSource(primaryDataSource)
              .properties(getVendorProperties())
              .packages("com.springboot.****.****.domain.entity")         //设置实体类所在位置与副数据源区分
              .persistenceUnit("primaryPersistenceUnit")
              .build();
  }

  private Map getVendorProperties() {
      HashMap<String, Object> properties = new HashMap<>();
      properties.put("hibernate.dialect",
              env.getProperty("hibernate.dialect"));
      properties.put("hibernate.ddl-auto",
              "create");
      properties.put("hibernate.physical_naming_strategy",
              "org.springframework.boot.orm.jpa.hibernate.SpringPhysicalNamingStrategy");
      properties.put("hibernate.implicit_naming_strategy",
              "org.springframework.boot.orm.jpa.hibernate.SpringImplicitNamingStrategy");
      return properties;
  }

  @Autowired
  private Environment env; 
  @Primary
  @Bean(name = "transactionManagerPrimary")
  public PlatformTransactionManager transactionManagerPrimary(EntityManagerFactoryBuilder builder) {
      return new JpaTransactionManager(entityManagerFactoryPrimary(builder).getObject());
  } 
}

（2）次数据源

package com.springboot.****.****.config; 
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.orm.jpa.EntityManagerFactoryBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.env.Environment;
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.persistence.EntityManager;
import javax.sql.DataSource;
import java.util.HashMap;
import java.util.Map;
/**
* @author： SUN
* @version: 1.0
* @date： 2019/12/24 13:59
* @description：
*/
@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(
      entityManagerFactoryRef = "entityManagerFactorySecondary",
      transactionManagerRef = "transactionManagerSecondary",
      basePackages = {"com.springboot.****.****.secRepository"}) //设置DAO接口层所在包位置与主数据源区分
public class SecondaryConfig {

  @Autowired
  @Qualifier("secondaryDataSource")
  private DataSource secondaryDataSource;

  @Bean(name = "entityManagerSecondary")
  public EntityManager entityManager(EntityManagerFactoryBuilder builder) {
      return entityManagerFactorySecondary(builder).getObject().createEntityManager();
  }

  @Bean(name = "entityManagerFactorySeAcondary")
  public LocalContainerEntityManagerFactoryBean entityManagerFactorySecondary(EntityManagerFactoryBuilder builder) {
      return builder
              .dataSource(secondaryDataSource)
              .properties(getVendorProperties())
              .packages("com.springboot.****.****.secEntity")      //设置实体类所在包的位置与主数据源区分
              .persistenceUnit("primaryPersistenceUnit")
              .build();
  }

  private Map getVendorProperties() {
      HashMap<String, Object> properties = new HashMap<>();
      properties.put("hibernate.hbm2ddl.auto",
              env.getProperty("hibernate.hbm2ddl.auto"));
      properties.put("hibernate.ddl-auto",
              env.getProperty("update"));
      properties.put("hibernate.dialect",
              env.getProperty("hibernate.dialect"));
      properties.put("hibernate.physical_naming_strategy",
              "org.springframework.boot.orm.jpa.hibernate.SpringPhysicalNamingStrategy");
      properties.put("hibernate.implicit_naming_strategy",
              "org.springframework.boot.orm.jpa.hibernate.SpringImplicitNamingStrategy");
      return properties;
  }

  @Autowired
  private Environment env;

  @Bean(name = "transactionManagerSecondary")
  PlatformTransactionManager transactionManagerSecondary(EntityManagerFactoryBuilder builder) {
      return new JpaTransactionManager(entityManagerFactorySecondary(builder).getObject());
  }
}

这两个类主要配置每个数据源，包括事务管理器、以及实体管理器等配置。

注：必须要指定DAO接口所在的包以及实体类所在的包。每个数据源主要操作它指定的资源（DAO接口CURD、实体类）

4、启动类主函数入口

SpringBoot启动类需关闭注解 --程序启动加载的仓库（@EnableJpaRepositories），因为在数据源配置类中已经开启了

@SpringBootApplication
@EnableAsync //开启异步调用
//@EnableJpaRepositories(basePackages = {""}
public class TouchPmsApplication { 
  public static void main(String[] args) {
      SpringApplication.run(TouchPmsApplication.class, args);
  } 
}

以上为个人经验，希望能给大家一个参考，也希望大家多多支持编程宝库。

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