Spring Boot MyBatis cluster database access implementation
This example describes the manner Spring Boot program to access a database cluster, Reading Library polling load balancing. Before reading this example, it is recommended that you have AOP basics of programming , mybatis will use the basic functions, basic concepts of database cluster, so you can quickly understand and implement it
MySql master-slave configuration
About configuration, see " MySQL master-slave replication configuration "
Spring Boot implementation
Separate reading and writing to do is to choose which one SQL database to perform, as to who will do it select the database children, in general, there are two implementations, namely:
- 1. middleware, such as Atlas, cobar, TDDL, mycat, heisenberg, Oceanus, vitess, OneProxy etc.
- 2. Use the program to achieve its own, using the Spring Boot provides routing data source and AOP, quick and easy to implement (this article to introduce the method)
Program code implementation
1. First, we configurations pom.xml, add the necessary dependencies examples
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>2.1.0</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-aop</artifactId>
</dependency>
</dependencies>2. Data Source Routing function RoutingDataSource.java
To a specific data source specific key-based routing. It maintains a set of target internal data sources, and did a mapping between the data source and the target routing key, a method based on key lookup data source.
a. Class diagram
b. the code is very simple, get under DBContext method calls on it
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;
public class RoutingDataSource extends AbstractRoutingDataSource {
@Override
protected Object determineCurrentLookupKey() {
return DBContext.get();
}
}3. Data source context class DBContext.java
import com.easy.mybatis.multidatasource.enums.DBTypeEnum;
import lombok.extern.slf4j.Slf4j;
import java.util.concurrent.atomic.AtomicInteger;
@Slf4j
public class DBContext {
private static final ThreadLocal<DBTypeEnum> dbContext = new ThreadLocal<>();
private static final AtomicInteger counter = new AtomicInteger(-1);
public static void set(DBTypeEnum dbType) {
dbContext.set(dbType);
}
public static DBTypeEnum get() {
return dbContext.get();
}
public static void master() {
set(DBTypeEnum.MASTER);
log.info("切换到master库");
}
public static void slave() {
// 读库负载均衡(轮询方式)
int index = counter.getAndIncrement() % 2;
log.info("slave库访问线程数==>{}", counter.get());
if (index == 0) {
set(DBTypeEnum.SLAVE1);
log.info("切换到slave1库");
} else {
set(DBTypeEnum.SLAVE2);
log.info("切换到slave2库");
}
}
}
4. Database enumeration class DBTypeEnum.java
public enum DBTypeEnum {
MASTER, SLAVE1, SLAVE2
}Here we configure three libraries, which are writing a library Master, 2 Ge Reading Library slave1, slave2
5. Database configuration class DataSourceConfig.java
package com.easy.mybatis.multidatasource.config;
import com.easy.mybatis.multidatasource.enums.DBTypeEnum;
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 javax.sql.DataSource;
import java.util.HashMap;
import java.util.Map;
@Configuration
public class DataSourceConfig {
@Bean
@ConfigurationProperties("spring.datasource.master")
public DataSource masterDataSource() {
return DataSourceBuilder.create().build();
}
@Bean
@ConfigurationProperties("spring.datasource.slave1")
public DataSource slave1DataSource() {
return DataSourceBuilder.create().build();
}
@Bean
@ConfigurationProperties("spring.datasource.slave2")
public DataSource slave2DataSource() {
return DataSourceBuilder.create().build();
}
@Bean
public DataSource myRoutingDataSource(@Qualifier("masterDataSource") DataSource masterDataSource,
@Qualifier("slave1DataSource") DataSource slave1DataSource,
@Qualifier("slave2DataSource") DataSource slave2DataSource) {
Map<Object, Object> targetDataSources = new HashMap<>();
targetDataSources.put(DBTypeEnum.MASTER, masterDataSource);
targetDataSources.put(DBTypeEnum.SLAVE1, slave1DataSource);
targetDataSources.put(DBTypeEnum.SLAVE2, slave2DataSource);
RoutingDataSource routingDataSource = new RoutingDataSource();
routingDataSource.setDefaultTargetDataSource(masterDataSource);
routingDataSource.setTargetDataSources(targetDataSources);
return routingDataSource;
}
}
6.mybatis configuration class DataSourceConfig.java
package com.easy.mybatis.multidatasource.config;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import javax.annotation.Resource;
import javax.sql.DataSource;
@EnableTransactionManagement
@Configuration
@MapperScan("com.easy.mybatis.multidatasource.mapper")
public class MyBatisConfig {
@Resource(name = "myRoutingDataSource")
private DataSource myRoutingDataSource;
@Bean
public SqlSessionFactory sqlSessionFactory() throws Exception {
SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
sqlSessionFactoryBean.setDataSource(myRoutingDataSource);
sqlSessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mapper/*.xml"));
return sqlSessionFactoryBean.getObject();
}
@Bean
public PlatformTransactionManager platformTransactionManager() {
return new DataSourceTransactionManager(myRoutingDataSource);
}
}7. aspect class DataSourceAop.java
package com.easy.mybatis.multidatasource.config;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;
import org.springframework.stereotype.Component;
@Aspect
@Component
public class DataSourceAop {
@Pointcut("@annotation(com.easy.mybatis.multidatasource.annotation.Master) " +
"|| execution(* com.easy.mybatis.multidatasource.service..*.insert*(..)) " +
"|| execution(* com.easy.mybatis.multidatasource.service..*.add*(..)) " +
"|| execution(* com.easy.mybatis.multidatasource.service..*.update*(..)) " +
"|| execution(* com.easy.mybatis.multidatasource.service..*.edit*(..)) " +
"|| execution(* com.easy.mybatis.multidatasource.service..*.delete*(..)) " +
"|| execution(* com.easy.mybatis.multidatasource.service..*.remove*(..))")
public void writePointcut() {
}
@Pointcut("!@annotation(com.easy.mybatis.multidatasource.annotation.Master) " +
"&& (execution(* com.easy.mybatis.multidatasource.service..*.select*(..)) " +
"|| execution(* com.easy.mybatis.multidatasource.service..*.get*(..)))")
public void readPointcut() {
}
@Before("writePointcut()")
public void write() {
DBContext.master();
}
@Before("readPointcut()")
public void read() {
DBContext.slave();
}
}8. Annotation class Master.java
package com.easy.mybatis.multidatasource.annotation;
/**
* 主库，可读写
*/
public @interface Master {
}9. The user xml, mapper, service class
UserMapper.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.easy.mybatis.multidatasource.mapper.UserMapper">
<select id="selectById" resultType="com.easy.mybatis.multidatasource.entity.User" parameterType="int">
SELECT * from user WHERE id = #{id}
</select>
<select id="selectList" resultType="com.easy.mybatis.multidatasource.entity.User">
SELECT * from user
</select>
<insert id="insert" parameterType="com.easy.mybatis.multidatasource.entity.User">
INSERT into user(id,name,age,email) VALUES(#{id}, #{name},#{age},#{email})
</insert>
<update id="updateById" parameterType="com.easy.mybatis.multidatasource.entity.User">
UPDATE user SET name =#{name}, age =#{age},email =#{email} WHERE id =#{id}
</update>
<delete id="deleteById" parameterType="int">
DELETE FROM user WHERE id =#{id}
</delete>
</mapper>
UserMapper.java
package com.easy.mybatis.multidatasource.mapper;
import com.easy.mybatis.multidatasource.entity.User;
import org.springframework.stereotype.Repository;
import java.io.Serializable;
import java.util.List;
@Repository
public interface UserMapper {
/**
* 插入一条记录
*
* @param entity 实体对象
*/
int insert(User entity);
/**
* 根据 ID 删除
*
* @param id 主键ID
*/
int deleteById(Serializable id);
/**
* 根据 ID 修改
*
* @param entity 实体对象
*/
int updateById(User entity);
/**
* 根据 ID 查询
*
* @param id 主键ID
*/
User selectById(Serializable id);
List<User> selectList();
}UserServiceImpl.java
package com.easy.mybatis.multidatasource.service.impl;
import com.easy.mybatis.multidatasource.annotation.Master;
import com.easy.mybatis.multidatasource.entity.User;
import com.easy.mybatis.multidatasource.mapper.UserMapper;
import com.easy.mybatis.multidatasource.service.IUserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.io.Serializable;
import java.util.List;
@Service
public class UserServiceImpl implements IUserService {
@Autowired
private UserMapper userMapper;
/**
* 插入一条记录
*
* @param entity 实体对象
*/
@Override
public int insert(User entity) {
return userMapper.insert(entity);
}
/**
* 根据 ID 删除
*
* @param id 主键ID
*/
@Override
public int deleteById(Serializable id) {
return userMapper.deleteById(id);
}
/**
* 根据 ID 修改
*
* @param entity 实体对象
*/
@Override
public int updateById(User entity) {
return userMapper.updateById(entity);
}
/**
* 根据 ID 查询
*
* @param id 主键ID
*/
@Master
@Override
public User selectById(Serializable id) {
return userMapper.selectById(id);
}
@Override
public List<User> selectList() {
return userMapper.selectList();
}
}Here we note that access should have been selectById Reading Library (slave library), I am here by way of comment, it refers to the manual may write library (master library)
10. Finally, I pasted yaml profile application.yml
# DataSource Config
spring:
datasource:
master:
driver-class-name: com.mysql.cj.jdbc.Driver
jdbc-url: jdbc:mysql://localhost:3306/easy_web?useSSL=false&serverTimezone=UTC
username: root
password: 123456
slave1:
driver-class-name: com.mysql.cj.jdbc.Driver
jdbc-url: jdbc:mysql://localhost:3306/easy_web?useSSL=false&serverTimezone=UTC
username: root
password: 123456
slave2:
driver-class-name: com.mysql.cj.jdbc.Driver
jdbc-url: jdbc:mysql://localhost:3306/easy_web?useSSL=false&serverTimezone=UTC
username: root
password: 123456The configuration file is configured with three data sources (here I am for the convenience, the three data sources refer to the same libraries, the actual production environment will be different libraries and read and write user)
Writing test cases to see the results, calling the situation analysis database
1. The unit test classes MultiDataSourceServiceTest.java
package com.easy.mybatis.multidatasource;
import com.easy.mybatis.multidatasource.entity.User;
import com.easy.mybatis.multidatasource.service.IUserService;
import lombok.extern.slf4j.Slf4j;
import org.junit.FixMethodOrder;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.MethodSorters;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
import javax.annotation.Resource;
import java.util.List;
import static org.assertj.core.api.Assertions.assertThat;
/**
* <p>
* 内置 CRUD 演示
* </p>
*/
@RunWith(SpringRunner.class)
@SpringBootTest
@Slf4j
//指定单元测试按字母顺序执行
@FixMethodOrder(value = MethodSorters.NAME_ASCENDING)
public class MultiDataSourceServiceTest {
@Resource
private IUserService userService;
@Test
public void aInsert() {
User user = new User();
user.setId(20l);
user.setName("小羊");
user.setAge(3);
user.setEmail("[email protected]");
log.info("开始执行insert方法，id={}", user.getId());
assertThat(userService.insert(user));
// 成功直接拿会写的 ID
assertThat(user.getId()).isNotNull();
}
@Test
public void bUpdate() {
User user = new User();
user.setId(20l);
user.setName("小羊update");
user.setAge(3);
user.setEmail("[email protected]");
log.info("开始执行updateById方法，id={}", user.getId());
assertThat(userService.updateById(user) > 0);
}
@Test
public void cSelectById() {
int id = 20;
log.info("开始执行selectById方法，id={}", id);
log.info("数据为=={}", userService.selectById(id));
}
@Test
public void dDelete() {
int id = 20;
log.info("开始执行deleteById方法，id={}", id);
assertThat(userService.deleteById(id));
}
@Test
public void eSelectList() {
for (int i = 0; i < 5; i++) {
log.info("开始执行selectList方法，index={}", i);
List<User> list = userService.selectList();
log.info("查询到的数据为，list={}", list);
}
}
}2. Review the results of the console
2019-08-29 16:36:04.684 INFO 13028 --- [ main] c.e.m.m.MultiDataSourceServiceTest : Starting MultiDataSourceServiceTest on YHE6OR5UXQJ6D35 with PID 13028 (started by Administrator in E:\project\spring-boot-demo\mybatis-multi-datasource)
2019-08-29 16:36:04.685 INFO 13028 --- [ main] c.e.m.m.MultiDataSourceServiceTest : No active profile set, falling back to default profiles: default
2019-08-29 16:36:08.172 INFO 13028 --- [ main] o.s.s.concurrent.ThreadPoolTaskExecutor : Initializing ExecutorService 'applicationTaskExecutor'
2019-08-29 16:36:08.814 INFO 13028 --- [ main] c.e.m.m.MultiDataSourceServiceTest : Started MultiDataSourceServiceTest in 4.85 seconds (JVM running for 5.918)
2019-08-29 16:36:09.008 INFO 13028 --- [ main] c.e.m.m.MultiDataSourceServiceTest : 开始执行insert方法，id=20
2019-08-29 16:36:09.018 INFO 13028 --- [ main] c.e.m.multidatasource.config.DBContext : 切换到master库
2019-08-29 16:36:09.054 INFO 13028 --- [ main] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Starting...
2019-08-29 16:36:09.256 INFO 13028 --- [ main] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Start completed.
2019-08-29 16:36:09.547 INFO 13028 --- [ main] c.e.m.m.MultiDataSourceServiceTest : 开始执行updateById方法，id=20
2019-08-29 16:36:09.548 INFO 13028 --- [ main] c.e.m.multidatasource.config.DBContext : 切换到master库
2019-08-29 16:36:09.731 INFO 13028 --- [ main] c.e.m.m.MultiDataSourceServiceTest : 开始执行selectById方法，id=20
2019-08-29 16:36:09.732 INFO 13028 --- [ main] c.e.m.multidatasource.config.DBContext : 切换到master库
2019-08-29 16:36:10.213 INFO 13028 --- [ main] c.e.m.m.MultiDataSourceServiceTest : 数据为==User(id=20, name=小羊update, age=3, [email protected])
2019-08-29 16:36:10.216 INFO 13028 --- [ main] c.e.m.m.MultiDataSourceServiceTest : 开始执行deleteById方法，id=20
2019-08-29 16:36:10.216 INFO 13028 --- [ main] c.e.m.multidatasource.config.DBContext : 切换到master库
2019-08-29 16:36:10.402 INFO 13028 --- [ main] c.e.m.m.MultiDataSourceServiceTest : 开始执行selectList方法，index=0
2019-08-29 16:36:10.403 INFO 13028 --- [ main] c.e.m.multidatasource.config.DBContext : slave库访问线程数==>0
2019-08-29 16:36:10.403 INFO 13028 --- [ main] c.e.m.multidatasource.config.DBContext : 切换到slave2库
2019-08-29 16:36:10.405 INFO 13028 --- [ main] com.zaxxer.hikari.HikariDataSource : HikariPool-2 - Starting...
2019-08-29 16:36:10.418 INFO 13028 --- [ main] com.zaxxer.hikari.HikariDataSource : HikariPool-2 - Start completed.
2019-08-29 16:36:10.422 INFO 13028 --- [ main] c.e.m.m.MultiDataSourceServiceTest : 查询到的数据为，list=[User(id=1, name=Jone, age=18, [email protected]), User(id=2, name=mp, age=null, [email protected]), User(id=5, name=Billie, age=24, [email protected])]
2019-08-29 16:36:10.422 INFO 13028 --- [ main] c.e.m.m.MultiDataSourceServiceTest : 开始执行selectList方法，index=1
2019-08-29 16:36:10.422 INFO 13028 --- [ main] c.e.m.multidatasource.config.DBContext : slave库访问线程数==>1
2019-08-29 16:36:10.422 INFO 13028 --- [ main] c.e.m.multidatasource.config.DBContext : 切换到slave1库
2019-08-29 16:36:10.422 INFO 13028 --- [ main] com.zaxxer.hikari.HikariDataSource : HikariPool-3 - Starting...
2019-08-29 16:36:10.428 INFO 13028 --- [ main] com.zaxxer.hikari.HikariDataSource : HikariPool-3 - Start completed.
2019-08-29 16:36:10.429 INFO 13028 --- [ main] c.e.m.m.MultiDataSourceServiceTest : 查询到的数据为，list=[User(id=1, name=Jone, age=18, [email protected]), User(id=2, name=mp, age=null, [email protected]), User(id=5, name=Billie, age=24, [email protected])]
2019-08-29 16:36:10.429 INFO 13028 --- [ main] c.e.m.m.MultiDataSourceServiceTest : 开始执行selectList方法，index=2
2019-08-29 16:36:10.429 INFO 13028 --- [ main] c.e.m.multidatasource.config.DBContext : slave库访问线程数==>2
2019-08-29 16:36:10.429 INFO 13028 --- [ main] c.e.m.multidatasource.config.DBContext : 切换到slave2库
2019-08-29 16:36:10.431 INFO 13028 --- [ main] c.e.m.m.MultiDataSourceServiceTest : 查询到的数据为，list=[User(id=1, name=Jone, age=18, [email protected]), User(id=2, name=mp, age=null, [email protected]), User(id=5, name=Billie, age=24, [email protected])]
2019-08-29 16:36:10.431 INFO 13028 --- [ main] c.e.m.m.MultiDataSourceServiceTest : 开始执行selectList方法，index=3
2019-08-29 16:36:10.431 INFO 13028 --- [ main] c.e.m.multidatasource.config.DBContext : slave库访问线程数==>3
2019-08-29 16:36:10.431 INFO 13028 --- [ main] c.e.m.multidatasource.config.DBContext : 切换到slave1库
2019-08-29 16:36:10.432 INFO 13028 --- [ main] c.e.m.m.MultiDataSourceServiceTest : 查询到的数据为，list=[User(id=1, name=Jone, age=18, [email protected]), User(id=2, name=mp, age=null, [email protected]), User(id=5, name=Billie, age=24, [email protected])]
2019-08-29 16:36:10.432 INFO 13028 --- [ main] c.e.m.m.MultiDataSourceServiceTest : 开始执行selectList方法，index=4
2019-08-29 16:36:10.433 INFO 13028 --- [ main] c.e.m.multidatasource.config.DBContext : slave库访问线程数==>4
2019-08-29 16:36:10.433 INFO 13028 --- [ main] c.e.m.multidatasource.config.DBContext : 切换到slave2库
2019-08-29 16:36:10.435 INFO 13028 --- [ main] c.e.m.m.MultiDataSourceServiceTest : 查询到的数据为，list=[User(id=1, name=Jone, age=18, [email protected]), User(id=2, name=mp, age=null, [email protected]), User(id=5, name=Billie, age=24, [email protected])]
2019-08-29 16:36:10.444 INFO 13028 --- [ Thread-2] o.s.s.concurrent.ThreadPoolTaskExecutor : Shutting down ExecutorService 'applicationTaskExecutor'
2019-08-29 16:36:10.446 INFO 13028 --- [ Thread-2] com.zaxxer.hikari.HikariDataSource : HikariPool-2 - Shutdown initiated...
2019-08-29 16:36:10.463 INFO 13028 --- [ Thread-2] com.zaxxer.hikari.HikariDataSource : HikariPool-2 - Shutdown completed.
2019-08-29 16:36:10.463 INFO 13028 --- [ Thread-2] com.zaxxer.hikari.HikariDataSource : HikariPool-3 - Shutdown initiated...
2019-08-29 16:36:10.497 INFO 13028 --- [ Thread-2] com.zaxxer.hikari.HikariDataSource : HikariPool-3 - Shutdown completed.
2019-08-29 16:36:10.497 INFO 13028 --- [ Thread-2] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Shutdown initiated...
2019-08-29 16:36:10.500 INFO 13028 --- [ Thread-2] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Shutdown completed.- We saw service in the insert, updateById, deleteById method of execution is writable library (master library)
- And selectById method, because of the way we use manual annotation cut in service to the master database, so the data will not go to the library to read a slave (to solve some developers are not standardized, the situation with a write query interface library method)
- selectList method, we call the cycle five times, see the results and success in slave1 slave2 polling read