SpringBoot学习---第五篇：动态数据源（多数据源自动切换）
目录
一、应用场景
二、准备工作
2.1 创建数据表
2.2 添加依赖
2.3 生成 bean、dao、mapper
三、动态数据源
3.1 配置文件 application.properties
3.2 动态数据源核心代码
3.3 启动类添加注解
四、使用方法
4.1 Controller
4.2 Service
五、测试
六、Springboot2.0动态多数据源切换
参考文献
一、应用场景
项目需要从自己的数据库上读取和管理数据外，还有一部分业务涉及到其他多个数据库。
为了能够灵活地指定具体的数据库，本文基于注解和AOP的方法实现多数据源自动切换。在使用过程中，只需要添加注解就可以使用，简单方便。
二、准备工作
2.1 创建数据表
USE test;
CREATE TABLE `user` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(255) NOT NULL,
`age` int(11) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8
USE test1;
CREATE TABLE `teacher` (
`tid` int(11) NOT NULL AUTO_INCREMENT,
`tname` varchar(255) NOT NULL,
`tage` int(11) NOT NULL,
PRIMARY KEY (`tid`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8
USE test2;
CREATE TABLE `student` (
`sid` int(11) NOT NULL AUTO_INCREMENT,
`sname` varchar(255) NOT NULL,
`sage` int(11) NOT NULL,
PRIMARY KEY (`sid`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf82.2 添加依赖
spring boot：1.5.8.RELEASE
mysql：5.1.44
mybatis:1.3.2
druid:1.1.3
4.0.0
com.example
dynamic-data-source
0.0.1-SNAPSHOT
jar
dynamic-data-source
Demo project for Spring Boot
org.springframework.boot
spring-boot-starter-parent
1.5.8.RELEASE
UTF-8
UTF-8
1.8
org.springframework.boot
spring-boot-starter-web
mysql
mysql-connector-java
runtime
org.mybatis.spring.boot
mybatis-spring-boot-starter
1.3.2
org.springframework.boot
spring-boot-starter-aop
com.alibaba
druid
1.1.3
org.springframework.boot
spring-boot-starter-test
test
org.springframework.boot
spring-boot-maven-plugin
org.mybatis.generator
mybatis-generator-maven-plugin
1.3.2
true
true
2.3 生成 bean、dao、mapper
使用MyBatis Generator自动生成，方法如下：https://blog.csdn.net/cllaure/article/details/81483858
三、动态数据源
3.1 配置文件 application.properties
custom.datasource.defaultname=default
custom.datasource.names=ds1,ds2
# 默认数据源
custom.datasource.driver-class-name=com.mysql.jdbc.Driver
custom.datasource.url=jdbc:mysql://localhost:3306/test
custom.datasource.username=root
custom.datasource.password=root
# 更多数据源
custom.datasource.ds1.driver-class-name=com.mysql.jdbc.Driver
custom.datasource.ds1.url=jdbc:mysql://localhost:3306/test1
custom.datasource.ds1.username=root
custom.datasource.ds1.password=root
custom.datasource.ds2.driver-class-name=com.mysql.jdbc.Driver
custom.datasource.ds2.url=jdbc:mysql://localhost:3306/test2
custom.datasource.ds2.username=root
custom.datasource.ds2.password=root
custom.datasource.filters=stat
custom.datasource.maxActive=100
custom.datasource.initialSize=1
custom.datasource.minIdle=1
custom.datasource.timeBetweenEvictionRunsMillis=60000
custom.datasource.minEvictableIdleTimeMillis=300000
custom.datasource.validationQuery=select 'x'
custom.datasource.testWhileIdle=true
custom.datasource.testOnBorrow=false
custom.datasource.testOnReturn=false
custom.datasource.poolPreparedStatements=true
custom.datasource.maxOpenPreparedStatements=100
mybatis.type-aliases-package=com.example.demo.model.*
mybatis.mapper-locations=classpath:mapper/**/*.xml3.2 动态数据源核心代码
DynamicDataSource：动态数据源切换；
DynamicDataSourceAspect：利用AOP切面实现数据源的动态切换；
DynamicDataSourceContextHolder：动态切换数据源；
DynamicDataSourceRegister：动态数据源注册；
TargetDataSource：在方法上使用，用于指定使用哪个数据源。package com.example.demo.datasource;
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;
/**
* 动态数据源
*/
public class DynamicDataSource extends AbstractRoutingDataSource {
@Override
protected Object determineCurrentLookupKey() {
return DynamicDataSourceContextHolder.getDataSourceType();
}
}package com.example.demo.datasource;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;
/**
* 切换数据源Advice
*/
@Aspect
@Order(-1)// 保证该AOP在@Transactional之前执行
@Component
public class DynamicDataSourceAspect {
private static final Logger logger = LoggerFactory.getLogger(DynamicDataSourceAspect.class);
@Before("@annotation(ds)")
public void changeDataSource(JoinPoint point, TargetDataSource ds) throws Throwable {
String dsId = ds.name();
if (!DynamicDataSourceContextHolder.containsDataSource(dsId)) {
logger.error("数据源[{}]不存在，使用默认数据源 > {}", ds.name(), point.getSignature());
}else {
logger.debug("Use DataSource : {} > {}", dsId, point.getSignature());
DynamicDataSourceContextHolder.setDataSourceType(dsId);
}
}
@After("@annotation(ds)")
public void restoreDataSource(JoinPoint point, TargetDataSource ds) {
logger.debug("Revert DataSource : {} > {}", ds.name(), point.getSignature());
DynamicDataSourceContextHolder.clearDataSourceType();
}
}package com.example.demo.datasource;
import java.util.ArrayList;
import java.util.List;
public class DynamicDataSourceContextHolder {
private static final ThreadLocal contextHolder = new ThreadLocal<>();
public static List dataSourceIds = new ArrayList<>();
public static void setDataSourceType(String dataSourceType) {
contextHolder.set(dataSourceType);
}
public static String getDataSourceType() {
return contextHolder.get();
}
public static void clearDataSourceType() {
contextHolder.remove();
}
/**
* 判断指定DataSrouce当前是否存在
*/
public static boolean containsDataSource(String dataSourceId){
return dataSourceIds.contains(dataSourceId);
}
}
package com.example.demo.datasource;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.MutablePropertyValues;
import org.springframework.beans.PropertyValues;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.GenericBeanDefinition;
import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;
import org.springframework.boot.bind.RelaxedDataBinder;
import org.springframework.boot.bind.RelaxedPropertyResolver;
import org.springframework.context.EnvironmentAware;
import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
import org.springframework.core.convert.ConversionService;
import org.springframework.core.convert.support.DefaultConversionService;
import org.springframework.core.env.Environment;
import org.springframework.core.type.AnnotationMetadata;
import javax.sql.DataSource;
import java.util.HashMap;
import java.util.Map;
/**
* 动态数据源注册
* 启动动态数据源请在启动类中 添加 @Import(DynamicDataSourceRegister.class)
*/
public class DynamicDataSourceRegister
implements ImportBeanDefinitionRegistrar, EnvironmentAware {
private static final Logger logger = LoggerFactory.getLogger(DynamicDataSourceRegister.class);
private ConversionService conversionService = new DefaultConversionService();
private PropertyValues dataSourcePropertyValues;
// 如配置文件中未指定数据源类型，使用该默认值
private static final Object DATASOURCE_TYPE_DEFAULT = "com.alibaba.druid.pool.DruidDataSource";
// 数据源
private DataSource defaultDataSource;
private Map customDataSources = new HashMap<>();
private static String DB_NAME = "names";
private static String DB_DEFAULT_VALUE = "custom.datasource"; //配置文件中前缀
@Value("${bi.datasource.defaultname}")
private String defaultDbname;
//加载多数据源配置
@Override
public void setEnvironment(Environment env) {
initDefaultDataSource(env);
initCustomDataSources(env);
}
//初始化主数据源
private void initDefaultDataSource(Environment env) {
// 读取主数据源
RelaxedPropertyResolver propertyResolver = new RelaxedPropertyResolver(env, DB_DEFAULT_VALUE+".");
Map dsMap = new HashMap<>();
dsMap.put("type", propertyResolver.getProperty("type"));
dsMap.put("driver-class-name", propertyResolver.getProperty("driver-class-name"));
dsMap.put("url", propertyResolver.getProperty("url"));
dsMap.put("username", propertyResolver.getProperty("username"));
dsMap.put("password", propertyResolver.getProperty("password"));
defaultDataSource = buildDataSource(dsMap);
customDataSources.put(defaultDbname,defaultDataSource);//默认数据源放到动态数据源里
dataBinder(defaultDataSource, env);
}
//为DataSource绑定更多数据
private void dataBinder(DataSource dataSource, Environment env) {
RelaxedDataBinder dataBinder = new RelaxedDataBinder(dataSource);
//dataBinder.setValidator(new LocalValidatorFactory().run(this.applicationContext));
dataBinder.setConversionService(conversionService);
dataBinder.setIgnoreNestedProperties(false);//false
dataBinder.setIgnoreInvalidFields(false);//false
dataBinder.setIgnoreUnknownFields(true);//true
if (dataSourcePropertyValues == null) {
Map rpr = new RelaxedPropertyResolver(env, DB_DEFAULT_VALUE).getSubProperties(".");
Map values = new HashMap(rpr);
// 排除已经设置的属性
values.remove("type");
values.remove("driver-class-name");
values.remove("url");
values.remove("username");
values.remove("password");
dataSourcePropertyValues = new MutablePropertyValues(values);
}
dataBinder.bind(dataSourcePropertyValues);
}
//初始化更多数据源
private void initCustomDataSources(Environment env) {
// 读取配置文件获取更多数据源，也可以通过defaultDataSource读取数据库获取更多数据源
RelaxedPropertyResolver propertyResolver = new RelaxedPropertyResolver(env,DB_DEFAULT_VALUE+".");
String dsPrefixs = propertyResolver.getProperty(DB_NAME);
for (String dsPrefix : dsPrefixs.split(",")) {// 多个数据源
Map dsMap = propertyResolver.getSubProperties(dsPrefix + ".");
DataSource ds = buildDataSource(dsMap);
customDataSources.put(dsPrefix, ds);
dataBinder(ds, env);
}
}
@Override
public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {
Map targetDataSources = new HashMap();
// 将主数据源添加到更多数据源中
targetDataSources.put("dataSource", defaultDataSource);
DynamicDataSourceContextHolder.dataSourceIds.add("dataSource");
// 添加更多数据源
targetDataSources.putAll(customDataSources);
for (String key : customDataSources.keySet()) {
DynamicDataSourceContextHolder.dataSourceIds.add(key);
}
// 创建DynamicDataSource
GenericBeanDefinition beanDefinition = new GenericBeanDefinition();
beanDefinition.setBeanClass(DynamicDataSource.class);
beanDefinition.setSynthetic(true);
MutablePropertyValues mpv = beanDefinition.getPropertyValues();
mpv.addPropertyValue("defaultTargetDataSource", defaultDataSource);
mpv.addPropertyValue("targetDataSources", targetDataSources);
registry.registerBeanDefinition("dataSource", beanDefinition);
logger.info("Dynamic DataSource Registry");
}
//创建DataSource
@SuppressWarnings("unchecked")
public DataSource buildDataSource(Map dsMap) {
try {
Object type = dsMap.get("type");
if (type == null)
type = DATASOURCE_TYPE_DEFAULT;// 默认DataSource
Class dataSourceType;
dataSourceType = (Class) Class.forName((String) type);
String driverClassName = dsMap.get("driver-class-name").toString();
String url = dsMap.get("url").toString();
String username = dsMap.get("username").toString();
String password = dsMap.get("password").toString();
DataSourceBuilder factory = DataSourceBuilder.create().driverClassName(driverClassName).url(url)
.username(username).password(password).type(dataSourceType);
return factory.build();
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
return null;
}
} package com.example.demo.datasource;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
// 在方法上使用，用于指定使用哪个数据源
@Target({ ElementType.METHOD, ElementType.TYPE })
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface TargetDataSource {
String name();
}3.3 启动类添加注解
添加注解 @Import ：注册动态多数据源；
添加 @MapperScan ：将项目中对应的mapper类的路径加进来
package com.example.demo;
import com.example.demo.datasource.DynamicDataSourceRegister;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Import;
@SpringBootApplication
@Import({DynamicDataSourceRegister.class}) // 注册动态多数据源
@MapperScan("com.example.demo.dao")//将项目中对应的mapper类的路径加进来就可以了
public class DynamicDataSourceApplication {
public static void main(String[] args) {
SpringApplication.run(DynamicDataSourceApplication.class, args);
}
}四、使用方法
4.1 Controller
package com.example.demo.controller;
import com.example.demo.model.Student;
import com.example.demo.model.Teacher;
import com.example.demo.model.User;
import com.example.demo.service.DynamicDataSourceService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;
@RestController
@RequestMapping(value = "/dds")
public class DynamicDataSourceController {
@Autowired
private DynamicDataSourceService service;
@RequestMapping(value = "/user/{id}")
public User getAllUserData(@PathVariable Integer id){
return service.getUserData(id);
}
@RequestMapping(value = "/teacher/{id}")
public Teacher getAllTeacherData(@PathVariable Integer id) {
return service.getTeacherData(id);
}
@RequestMapping(value = "/student/{id}")
public Student getAllStudentData(@PathVariable Integer id) {
return service.getStudentData(id);
}
}
4.2 Service
注解@TargetDataSource 不能直接在接口类Mapper上使用，所以在Service上使用。
package com.example.demo.service;
import com.example.demo.dao.StudentMapper;
import com.example.demo.dao.TeacherMapper;
import com.example.demo.dao.UserMapper;
import com.example.demo.datasource.TargetDataSource;
import com.example.demo.model.Student;
import com.example.demo.model.Teacher;
import com.example.demo.model.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
@Service
public class DynamicDataSourceService {
@Autowired
private UserMapper userMapper;
@Autowired
private TeacherMapper teacherMapper;
@Autowired
private StudentMapper studentMapper;
//不指定数据源使用默认数据源
public User getUserData(Integer id) {
return userMapper.selectByPrimaryKey(id);
}
//指定数据源-ds1
@TargetDataSource(name="ds1")
public Teacher getTeacherData(Integer id) {
return teacherMapper.selectByPrimaryKey(id);
}
//指定数据源-ds2
@TargetDataSource(name="ds2")
public Student getStudentData(Integer id) {
return studentMapper.selectByPrimaryKey(id);
}
}
五、测试
- localhost:8080//dds/user/1
- localhost:8080//dds/teacher/1
- localhost:8080//dds/student/1
六、Springboot2.0动态多数据源切换
Springboot 1.x 到 Springboot 2.0配置变化有一点变化。主要是 RelaxedPropertyResolver不再可以Environment自动处理。
主要 是 DynamicDataSourceRegister 中有部分方法不一样。其他方法都不需要修改。
package com.example.demo.datasource;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.MutablePropertyValues;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.GenericBeanDefinition;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.context.EnvironmentAware;
import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
import org.springframework.core.env.Environment;
import org.springframework.core.type.AnnotationMetadata;
import javax.sql.DataSource;
import java.util.HashMap;
import java.util.Map;
/**
* 动态数据源注册
* 启动动态数据源请在启动类中 添加 @Import(DynamicDataSourceRegister.class)
*/
public class DynamicDataSourceRegister
implements ImportBeanDefinitionRegistrar, EnvironmentAware {
private static final Logger logger = LoggerFactory.getLogger(DynamicDataSourceRegister.class);
// 如配置文件中未指定数据源类型，使用该默认值
private static final Object DATASOURCE_TYPE_DEFAULT = "com.alibaba.druid.pool.DruidDataSource";
// 数据源
private DataSource defaultDataSource;
private Map customDataSources = new HashMap<>();
private static String DB_NAME = "names";
private static String DB_DEFAULT_VALUE = "custom.datasource";
@Value("${bi.datasource.defaultname}")
private String defaultDbname;
/**
* 加载多数据源配置
*/
@Override
public void setEnvironment(Environment env) {
initDefaultDataSource(env);
initCustomDataSources(env);
}
/**
* 1.5.8 初始化主数据源
*/
// private void initDefaultDataSource(Environment env) {
// // 读取主数据源
// RelaxedPropertyResolver propertyResolver = new RelaxedPropertyResolver(env, DB_DEFAULT_VALUE+".");
// Map dsMap = new HashMap<>();
// dsMap.put("type", propertyResolver.getProperty("type"));
// dsMap.put("driver-class-name", propertyResolver.getProperty("driver-class-name"));
// dsMap.put("url", propertyResolver.getProperty("url"));
// dsMap.put("username", propertyResolver.getProperty("username"));
// dsMap.put("password", propertyResolver.getProperty("password"));
//
// defaultDataSource = buildDataSource(dsMap);
// customDataSources.put(defaultDbname,defaultDataSource);//默认数据源放到动态数据源里
// dataBinder(defaultDataSource, env);
// }
/**
* 2.0.4 初始化主数据源
*/
private void initDefaultDataSource(Environment env) {
// 读取主数据源
Map dsMap = new HashMap<>();
dsMap.put("type", env.getProperty(DB_DEFAULT_VALUE + "." + "type"));
dsMap.put("driver-class-name", env.getProperty(DB_DEFAULT_VALUE + "." + "driver-class-name"));
dsMap.put("url", env.getProperty(DB_DEFAULT_VALUE + "." + "url"));
dsMap.put("username", env.getProperty(DB_DEFAULT_VALUE + "." + "username"));
dsMap.put("password", env.getProperty(DB_DEFAULT_VALUE + "." + "password"));
defaultDataSource = buildDataSource(dsMap);
// customDataSources.put(defaultDbname,defaultDataSource);//默认数据源放到动态数据源里
// dataBinder(defaultDataSource, env);
}
/**
* 为DataSource绑定更多数据
*
*/
// private void dataBinder(DataSource dataSource, Environment env) {
// RelaxedDataBinder dataBinder = new RelaxedDataBinder(dataSource);
// //dataBinder.setValidator(new LocalValidatorFactory().run(this.applicationContext));
// dataBinder.setConversionService(conversionService);
// dataBinder.setIgnoreNestedProperties(false);//false
// dataBinder.setIgnoreInvalidFields(false);//false
// dataBinder.setIgnoreUnknownFields(true);//true
// if (dataSourcePropertyValues == null) {
// Map rpr = new RelaxedPropertyResolver(env, DB_DEFAULT_VALUE).getSubProperties(".");
// Map values = new HashMap(rpr);
// // 排除已经设置的属性
// values.remove("type");
// values.remove("driver-class-name");
// values.remove("url");
// values.remove("username");
// values.remove("password");
// dataSourcePropertyValues = new MutablePropertyValues(values);
// }
// dataBinder.bind(dataSourcePropertyValues);
// }
// 初始化更多数据源
private void initCustomDataSources(Environment env) {
// 读取配置文件获取更多数据源，也可以通过defaultDataSource读取数据库获取更多数据源
// RelaxedPropertyResolver propertyResolver = new RelaxedPropertyResolver(env,DB_DEFAULT_VALUE+".");
String dsPrefixs = env.getProperty(DB_DEFAULT_VALUE + "." + DB_NAME);
for (String dsPrefix : dsPrefixs.split(",")) {// 多个数据源
Map dsMap = new HashMap<>();
dsMap.put("type", env.getProperty(DB_DEFAULT_VALUE + "." + dsPrefix + ".type"));
dsMap.put("driver-class-name", env.getProperty(DB_DEFAULT_VALUE + "." + dsPrefix + ".driver-class-name"));
dsMap.put("url", env.getProperty(DB_DEFAULT_VALUE + "." + dsPrefix + ".url"));
dsMap.put("username", env.getProperty(DB_DEFAULT_VALUE + "." + dsPrefix + ".username"));
dsMap.put("password", env.getProperty(DB_DEFAULT_VALUE + "." + dsPrefix + ".password"));
DataSource ds = buildDataSource(dsMap);
customDataSources.put(dsPrefix, ds);
}
}
@Override
public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {
Map targetDataSources = new HashMap();
// 将主数据源添加到更多数据源中
targetDataSources.put("dataSource", defaultDataSource);
DynamicDataSourceContextHolder.dataSourceIds.add("dataSource");
// 添加更多数据源
targetDataSources.putAll(customDataSources);
for (String key : customDataSources.keySet()) {
DynamicDataSourceContextHolder.dataSourceIds.add(key);
}
// 创建DynamicDataSource
GenericBeanDefinition beanDefinition = new GenericBeanDefinition();
beanDefinition.setBeanClass(DynamicDataSource.class);
beanDefinition.setSynthetic(true);
MutablePropertyValues mpv = beanDefinition.getPropertyValues();
mpv.addPropertyValue("defaultTargetDataSource", defaultDataSource);
mpv.addPropertyValue("targetDataSources", targetDataSources);
registry.registerBeanDefinition("dataSource", beanDefinition);
logger.info("Dynamic DataSource Registry");
}
// 创建DataSource
@SuppressWarnings("unchecked")
public DataSource buildDataSource(Map dsMap) {
try {
Object type = dsMap.get("type");
if (type == null)
type = DATASOURCE_TYPE_DEFAULT;// 默认DataSource
Class dataSourceType;
dataSourceType = (Class) Class.forName((String) type);
String driverClassName = dsMap.get("driver-class-name").toString();
String url = dsMap.get("url").toString();
String username = dsMap.get("username").toString();
String password = dsMap.get("password").toString();
DataSourceBuilder factory = DataSourceBuilder.create().driverClassName(driverClassName).url(url)
.username(username).password(password).type(dataSourceType);
return factory.build();
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
return null;
}
}
参考文献
Spring Boot 动态数据源（多数据源自动切换）