JPA多源数据库配置（达梦数据库）
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：
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
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<User,Integer>{
}
UserDao2代码如下：
public interface UserDao2 extends JpaRepository<User,Integer>{
}
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<Stack<Pair<JpaTransactionManager, TransactionStatus>>> 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<Pair<JpaTransactionManager, TransactionStatus>> 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<Pair<JpaTransactionManager, TransactionStatus>> pairStack = THREAD_LOCAL.get();
while (!pairStack.empty()) {
Pair<JpaTransactionManager, TransactionStatus> 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<Pair<JpaTransactionManager, TransactionStatus>> pairStack = THREAD_LOCAL.get();
while (!pairStack.empty()) {
Pair<JpaTransactionManager, TransactionStatus> 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);
}
来源：oschina
链接：https://my.oschina.net/u/4415089/blog/4698803