从零开始学springboot-jpa-多数据源

作者: 码哥说 | 来源:发表于2019-03-20 16:13 被阅读7次

前言

之前我们做过jpa访问mysql的案例，那么jpa如何设置多数据源访问呢？本节我们就来做jpa多数据源的案例

创建空项目

IDEA创建一个空依赖springboot项目

1.png

2.png

添加依赖

pom.xml：

 <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>
            <scope>runtime</scope>
        </dependency>

3.png

添加配置

application.yml:

spring:
  datasource:
    master:
      username: root
      password: 123456
      url: jdbc:mysql://192.168.145.131:3306/test
      driver-class-name: com.mysql.cj.jdbc.Driver
    slave:
      username: root
      password: 123456
      url: jdbc:mysql://192.168.145.131:3306/test2
      driver-class-name: com.mysql.cj.jdbc.Driver
  jpa:
    properties:
      hibernate:
        hbm2ddl:
          auto: update

master/slave可以自己任意命名，数据源可以随意增加多个

建库

我们新增test/test2数据库
test新建表

DROP TABLE IF EXISTS `student`;
CREATE TABLE `student` (
  `id` int(11) NOT NULL,
  `age` int(11) NOT NULL,
  `grade` int(11) NOT NULL,
  `name` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;

INSERT INTO `student` VALUES ('1', '1', '1', '1');

test2新建表：

DROP TABLE IF EXISTS `teacher`;
CREATE TABLE `teacher` (
  `id` int(11) NOT NULL,
  `age` varchar(255) DEFAULT NULL,
  `course` varchar(255) DEFAULT NULL,
  `name` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1;

INSERT INTO `teacher` VALUES ('1', '1', '1', '1');

完善

目录结构

4.png

我们先完善配置包类
config/DataSourceConfig:

package com.mrcoder.sbjpamultidb.config;

import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.jdbc.DataSourceProperties;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import javax.sql.DataSource;

@Configuration
public class DataSourceConfig {
    //master库
    @Primary
    @Bean(name = "masterDataSourceProperties")
    @Qualifier("masterDataSourceProperties")
    @ConfigurationProperties(prefix = "spring.datasource.master")
    public DataSourceProperties masterDataSourceProperties() {
        return new DataSourceProperties();
    }

    @Primary
    @Bean(name = "masterDataSource")
    @Qualifier("masterDataSource")
    @ConfigurationProperties(prefix = "spring.datasource.master")
    public DataSource masterDataSource(@Qualifier("masterDataSourceProperties") DataSourceProperties dataSourceProperties) {
        return dataSourceProperties.initializeDataSourceBuilder().build();
    }

    //slave库
    @Bean(name = "slaveDataSourceProperties")
    @Qualifier("slaveDataSourceProperties")
    @ConfigurationProperties(prefix = "spring.datasource.slave")
    public DataSourceProperties slaveDataSourceProperties() {
        return new DataSourceProperties();
    }

    @Bean(name = "slaveDataSource")
    @Qualifier("slaveDataSource")
    @ConfigurationProperties(prefix = "spring.datasource.slave")
    public DataSource slaveDataSource(@Qualifier("slaveDataSourceProperties") DataSourceProperties dataSourceProperties) {
        return dataSourceProperties.initializeDataSourceBuilder().build();
    }

}
```

config/MasterConfig:

```
package com.mrcoder.sbjpamultidb.config;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.orm.jpa.HibernateProperties;
import org.springframework.boot.autoconfigure.orm.jpa.HibernateSettings;
import org.springframework.boot.autoconfigure.orm.jpa.JpaProperties;
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.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.annotation.Resource;
import javax.persistence.EntityManager;
import javax.sql.DataSource;
import java.util.Map;

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(
        entityManagerFactoryRef = "masterEntityManagerFactory",
        transactionManagerRef = "masterTransactionManager",
        basePackages = {"com.mrcoder.sbjpamultidb.entity.master"})

public class MasterConfig {
    @Autowired
    private HibernateProperties hibernateProperties;
    @Resource
    @Qualifier("masterDataSource")
    private DataSource masterDataSource;

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

    @Resource
    private JpaProperties jpaProperties;

//    private Map<String, Object> getVendorProperties() {
//        return jpaProperties.getHibernateProperties(new HibernateSettings());
//    }

    /**
     * 设置实体类所在位置
     */
    @Primary
    @Bean(name = "masterEntityManagerFactory")
    public LocalContainerEntityManagerFactoryBean masterEntityManagerFactory(EntityManagerFactoryBuilder builder) {

        Map<String, Object> properties = hibernateProperties.determineHibernateProperties(
                jpaProperties.getProperties(), new HibernateSettings());
        return builder
                .dataSource(masterDataSource)
                .packages("com.mrcoder.sbjpamultidb.entity.master")
                .persistenceUnit("masterPersistenceUnit")
                .properties(properties)
                .build();
    }

    @Primary
    @Bean(name = "masterTransactionManager")
    public PlatformTransactionManager masterTransactionManager(EntityManagerFactoryBuilder builder) {
        return new JpaTransactionManager(masterEntityManagerFactory(builder).getObject());
    }
}
```

config/SlaveConfig:

```
package com.mrcoder.sbjpamultidb.config;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.orm.jpa.HibernateProperties;
import org.springframework.boot.autoconfigure.orm.jpa.HibernateSettings;
import org.springframework.boot.autoconfigure.orm.jpa.JpaProperties;
import org.springframework.boot.orm.jpa.EntityManagerFactoryBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
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.annotation.Resource;
import javax.persistence.EntityManager;
import javax.sql.DataSource;
import java.util.Map;


@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(
        entityManagerFactoryRef = "slaveEntityManagerFactory",
        transactionManagerRef = "slaveTransactionManager",
        basePackages = {"com.mrcoder.sbjpamultidb.entity.slave"})//repository的目录
public class SlaveConfig {

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

    @Autowired
    private HibernateProperties hibernateProperties;

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

    @Resource
    private JpaProperties jpaProperties;

//    private Map<String, Object> getVendorProperties() {
//        return jpaProperties.getHibernateProperties(new HibernateSettings());
//    }

    @Bean(name = "slaveEntityManagerFactory")
    public LocalContainerEntityManagerFactoryBean slaveEntityManagerFactory(EntityManagerFactoryBuilder builder) {

        Map<String, Object> properties = hibernateProperties.determineHibernateProperties(
                jpaProperties.getProperties(), new HibernateSettings());
        return builder
                .dataSource(slaveDataSource)
                .packages("com.mrcoder.sbjpamultidb.entity.slave")//实体类的目录
                .persistenceUnit("slavePersistenceUnit")
                .properties(properties)
                .build();
    }

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

}

```

controller/JpaMultidbController：

```
package com.mrcoder.sbjpamultidb.controller;

import com.mrcoder.sbjpamultidb.entity.master.StudentDao;
import com.mrcoder.sbjpamultidb.entity.slave.TeacherDao;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class JpaMultidbController {

    @Autowired
    private StudentDao studentDao;

    @Autowired
    private TeacherDao teacherDao;

    @RequestMapping("/list")
    public void list() {
        System.out.println(studentDao.findAll());
        System.out.println(teacherDao.findAll());
    }
}

```


entity/master/Student:

```
package com.mrcoder.sbjpamultidb.entity.master;

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

@Entity
public class Student {

    @Id
    @GeneratedValue
    private int id;

    private String name;

    private int age;

    private int grade;

    public Student() {
    }

    public Student(String name, int age, int grade) {
        this.name = name;
        this.age = age;
        this.grade = grade;
    }

    @Override
    public String toString() {
        return "Student{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", age=" + age +
                ", grade=" + grade +
                '}';
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public int getGrade() {
        return grade;
    }

    public void setGrade(int grade) {
        this.grade = grade;
    }
}

```


entity/master/StudentDao:

```
package com.mrcoder.sbjpamultidb.entity.master;
import org.springframework.data.jpa.repository.JpaRepository;

public interface StudentDao extends JpaRepository<Student, Integer> {


}

```

entity/slave/Teacher:

```
package com.mrcoder.sbjpamultidb.entity.slave;

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

@Entity
public class Teacher {

    @Id
    @GeneratedValue
    private int id;
    private String name;
    private String age;
    private String course;

    public Teacher() {
    }

    public Teacher(String name, String age, String course) {
        this.name = name;
        this.age = age;
        this.course = course;
    }

    @Override
    public String toString() {
        return "Teacher{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", age='" + age + '\'' +
                ", course='" + course + '\'' +
                '}';
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getAge() {
        return age;
    }

    public void setAge(String age) {
        this.age = age;
    }

    public String getCourse() {
        return course;
    }

    public void setCourse(String course) {
        this.course = course;
    }
}

```



entity/slave/TeacherDao:

```
package com.mrcoder.sbjpamultidb.entity.slave;
import org.springframework.data.jpa.repository.JpaRepository;

public interface TeacherDao extends JpaRepository<Teacher,Integer> {

}
```


## 运行
![5.png](https://img.haomeiwen.com/i16747124/fdc5d3cc3908b343.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)

## 项目地址

https://github.com/MrCoderStack/SpringBootDemo/tree/master/sb-jpa-multidb

https://gitee.com/MrCoderStack/SpringBootDemo/tree/master/sb-jpa-multidb

## 请关注我的订阅号
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从零开始学springboot-jpa-多数据源

前言

创建空项目

添加依赖

添加配置

建库

完善

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