本篇文章主要介绍SpringBoot框架实现Jpa多源数据库的配置，本次使用国产数据库达梦数据库做为数据源。

1.准备工作

在pom.xml文件中引入Spring Data Jpa依赖：

org.springframework.boot

spring-boot-starter-data-jpa

在application.yml中添加数据库的相关配置：

spring:

datasource:

one:

driver-class-name: dm.jdbc.driver.DmDriver

url: jdbc:dm://127.0.0.1:5236/TESTONE

username: TESTONE

password: 1234567890

type: com.alibaba.druid.pool.DruidDataSource

two:

driver-class-name: dm.jdbc.driver.DmDriver

url: jdbc:dm://127.0.0.1:5237/TESTTWO

username: TESTTWO

password: 1234567890

type: com.alibaba.druid.pool.DruidDataSource

jpa:

properties:

hibernate.dialect: org.hibernate.dialect.Oracle10gDialect

show-sql: ture

编写DataSourceConfig配置文件：

@Configuration

public class DataSourceConfig {

@Bean

@ConfigurationProperties("spring.datasource.one")

@Primary

DataSource dsOne(){

return DruidDataSourceBuilder.create().build();

}

@Bean

@ConfigurationProperties("spring.datasource.two")

DataSource dsTwo(){

return DruidDataSourceBuilder.create().build();

}

}

2.创建JPA配置

根据配置好的数据源创建两个不同的JPA配置，代码如下(示例)：

第一个jpa配置：

@Configuration

@EnableTransactionManagement

@EnableJpaRepositories(basePackages = "org.xiaoyang.dao1",//持久层路径

entityManagerFactoryRef = "entityManagerFactoryBeanOne",

transactionManagerRef = "platformTransactionManagerOne")

public class JpaConfigOne {

@Resource(name = "dsOne")

DataSource dsOne;

@Autowired

JpaProperties jpaProperties;

@Bean

@Primary

LocalContainerEntityManagerFactoryBean entityManagerFactoryBeanOne(EntityManagerFactoryBuilder builder){

return builder.dataSource(dsOne)

.properties(jpaProperties.getProperties())

.packages("org.xiaoyang.entity")//实体类路径

.persistenceUnit("pu1")

.build();

}

@Bean

PlatformTransactionManager platformTransactionManagerOne(EntityManagerFactoryBuilder builder){

LocalContainerEntityManagerFactoryBean factoryOne = entityManagerFactoryBeanOne(builder);

return new JpaTransactionManager(factoryOne.getObject());

}

}

第二个jpa配置：

@Configuration

@EnableTransactionManagement

@EnableJpaRepositories(basePackages = "org.xiaoyang.dao2",//持久层路径

entityManagerFactoryRef = "entityManagerFactoryBeanTwo",

transactionManagerRef = "platformTransactionManagerTwo")

public class JpaConfigOne {

@Resource(name = "dsTwo")

DataSource dsTwo;

@Autowired

JpaProperties jpaProperties;

@Bean

LocalContainerEntityManagerFactoryBean entityManagerFactoryBeanTwo(EntityManagerFactoryBuilder builder){

return builder.dataSource(dsTwo)

.properties(jpaProperties.getProperties())

.packages("org.xiaoyang.entity")//实体类路径

.persistenceUnit("pu1")

.build();

}

@Bean

PlatformTransactionManager platformTransactionManagerTwo(EntityManagerFactoryBuilder builder){

LocalContainerEntityManagerFactoryBean factoryOne = entityManagerFactoryBeanTwo(builder);

return new JpaTransactionManager(factoryOne.getObject());

}

}

3.创建实体类

在org.xiaoyang.entity包(包路径一定要和JPA配置类中的路径相同)创建实体类User：

@Entity(name="t_user")

public class User{

@Id

@GeneratedValue(strategy = GenerationType.IDENTITY)

private Integer id;

private String name;

private String age;

//省略getter/setter方法

}

4.创建Repository

分别在org.xiaoyang.dao1包和org.xiaoyang.dao2包(包路径一定要和JPA配置类中的路径相同)创建Repository：

UserDao1代码如下：

public interface UserDao1 extends JpaRepository{}

UserDao2代码如下：

public interface UserDao2 extends JpaRepository{}

5.注解+切面实现两个数据源事物统一

编写获取事务管理器数组的注解：

@Target({ElementType.METHOD})

@Retention(RetentionPolicy.RUNTIME)

@Inherited

@Documented

public @interface MultiDataSourceTransactional {

/**

* 事务管理器数组

*/

String[] transactionManagers();

}

编写通过注解+切面实现两个数据源事物统一的配置类：

/**

* 注解+切面实现两个数据源事物统一

*/

@Component

@Aspect

public class MultiDataSourceTransactionAspect {

/**

* 线程本地变量：为什么使用栈？※为了达到后进先出的效果※

*/

private static final ThreadLocal>> THREAD_LOCAL = new ThreadLocal<>();

/**

* 用于获取事务管理器

*/

@Autowired

private ApplicationContext applicationContext;

/**

* 事务声明

*/

private DefaultTransactionDefinition def = new DefaultTransactionDefinition();

{

// 非只读模式

def.setReadOnly(false);

// 事务隔离级别：采用数据库的

def.setIsolationLevel(TransactionDefinition.ISOLATION_DEFAULT);

// 事务传播行为

def.setPropagationBehavior(TransactionDefinition.PROPAGATION_REQUIRED);

}

/**

* 切面

* 路径必须和编写获取事务管理器数组的注解路径相同

*/

@Pointcut("@annotation(org.xiaoyang.anotations.MultiDataSourceTransactional)")

public void pointcut() {

}

/**

* 声明事务

*

* @param transactional 注解

*/

@Before("pointcut() && @annotation(transactional)")

public void before(MultiDataSourceTransactional transactional) {

// 根据设置的事务名称按顺序声明，并放到ThreadLocal里

String[] transactionManagerNames = transactional.transactionManagers();

Stack> pairStack = new Stack<>();

for (String transactionManagerName : transactionManagerNames) {

JpaTransactionManager transactionManager = applicationContext.getBean(transactionManagerName, JpaTransactionManager.class);

TransactionStatus transactionStatus = transactionManager.getTransaction(def);

pairStack.push(new Pair(transactionManager, transactionStatus));

}

THREAD_LOCAL.set(pairStack);

System.out.println("====pairStack size========");

}

/**

* 提交事务

*/

@AfterReturning("pointcut()")

public void afterReturning() {

// ※栈顶弹出(后进先出)

Stack> pairStack = THREAD_LOCAL.get();

while (!pairStack.empty()) {

Pair pair = pairStack.pop();

pair.getKey().commit(pair.getValue());

}

THREAD_LOCAL.remove();

}

/**

* 回滚事务

*/

@AfterThrowing(value = "pointcut()")

public void afterThrowing() {

// ※栈顶弹出(后进先出)

Stack> pairStack = THREAD_LOCAL.get();

while (!pairStack.empty()) {

Pair pair = pairStack.pop();

pair.getKey().rollback(pair.getValue());

}

THREAD_LOCAL.remove();

}

}

6.创建Service

通过Service调用Dao层并配置注解实现业务逻辑：

UserService代码如下：

public interface UserService {

//两个库同时增加数据

void addUser(User user);

//数据库一增加数据

void addUserOne(User user);

//数据库二增加数据

void addUserTwo(User user);

}

UserServiceImpl代码如下：

@Service

public class UserServiceImpl implements UserService {

@Autowired

private UserDao1 userDao1;

@Autowired

private UserDao2 userDao2;

//同时操作两个数据库需要调用自定义注解添加事务组

@Override

@MultiDataSourceTransactional(transactionManagers = {"platformTransactionManagerOne","platformTransactionManagerTwo"})

public void addUser(User user) {

try {

user.setName("小洋同学");

user.setAge("23");

userDao1.save(user);

userDao2.save(user);

} catch (Exception e) {

e.printStackTrace();

}

}

//单独操作数据库需要标明事务的名称

@Override

@Transactional("platformTransactionManagerOne")

public void addUserOne(User user) {

try {

user.setName("小洋同学111");

user.setAge("23");

userDao1.save(user);

} catch (Exception e) {

e.printStackTrace();

}

}

//单独操作数据库需要标明事务的名称

@Override

@Transactional("platformTransactionManagerTwo")

public void addUserTwo(User user) {

try {

user.setName("小洋同学222");

user.setAge("23");

userDao2.save(user);

} catch (Exception e) {

e.printStackTrace();

}

}

}

7.创建Controller

通过Controller调用Service层实现接口功能，代码如下：

@RestController

public class UserController {

@Autowired

private UserService userService;

@RequestMapping("/adduser")

public void addUser() {

User user= new User();

userService.addUser(user);

}

@RequestMapping("/adduserone")

public void addUserOne() {

User user= new User();

userService.addUserOne(user);

}

@RequestMapping("/addusertwo")

public void addUserTwo() {

User user= new User();

userService.addUserTwo(user);

}