SpringBoot+Mybatis+Druid动态多数据源
背景
前两天突然想起了，咕泡老师写的源代码中有关于多数据源的实现。翻出来看了看，想移植到springboot里面去，可是移动过去，不起作用，而后又百度了些大神做法，还是不起作用，故自己研究了一番，最终实现了mybatis的动态数据源。水平有限，还请大佬轻喷，希望能和各位大佬多多交流。今日才察觉到，这种方式有线程安全性的问题，慎用，使用中，多个不同库的jdbc同时inser，updata操作，有可能出现非预期的结果。
配置多数据源
application.yml配置：
#
spring:
datasource:
type: com.alibaba.druid.pool.DruidDataSource
url: jdbc:mysql://127.0.0.1:3306/test_db?useUnicode=true&characterEncoding=utf8
username: root
password: root
driver-class-name: com.mysql.jdbc.Driver
initialSize: 1
minIdle: 1
maxActive: 200
maxWait: 60000
timeBetweenEvictionRunsMillis: 60000
minEvictableIdleTimeMillis: 300000
validationQuery: SELECT 'x'
testWhileIdle: true
testOnBorrow: false
testOnReturn: false
poolPreparedStatements: false
maxPoolPreparedStatementPerConnectionSize: 20
filters: stat,log4j,wall
connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000
useGlobalDataSourceStat: true
datasource2:
type: com.alibaba.druid.pool.DruidDataSource
url: jdbc:mysql://127.0.0.1:3306/db_test3?useUnicode=true&characterEncoding=utf8
username: root
password: root
driver-class-name: com.mysql.jdbc.Driver
initialSize: 1
minIdle: 1
maxActive: 200
maxWait: 60000
timeBetweenEvictionRunsMillis: 60000
minEvictableIdleTimeMillis: 300000
validationQuery: SELECT 'x'
testWhileIdle: true
testOnBorrow: false
testOnReturn: false
poolPreparedStatements: false
maxPoolPreparedStatementPerConnectionSize: 20
filters: stat,log4j,wall
connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000
useGlobalDataSourceStat: true
mybatis:
mapper-locations: classpath:mapper/*.xml
type-aliases-package: com.liulei.study.xmlbatisboot.domain
default:
dataSource: dataSource1
我这里配置了两个mysql数据源。配置bean，dataSource1 如下：
import com.alibaba.druid.pool.DruidDataSource;
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;
import java.sql.SQLException;
//解决 spring.datasource.filters=stat,wall,log4j 无法正常注册进去
@Configuration
@ConfigurationProperties(prefix = "spring.datasource")
public class IDataSource1 {
private String url;
private String username;
private String password;
private String driverClassName;
private int initialSize;
private int minIdle;
private int maxActive;
private int maxWait;
private int timeBetweenEvictionRunsMillis;
private int minEvictableIdleTimeMillis;
private String validationQuery;
private boolean testWhileIdle;
private boolean testOnBorrow;
private boolean testOnReturn;
private boolean poolPreparedStatements;
private int maxPoolPreparedStatementPerConnectionSize;
private String filters;
private String connectionProperties;
private boolean useGlobalDataSourceStat;
public String getUrl() {
return url;
}
public void setUrl(String url) {
this.url = url;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getDriverClassName() {
return driverClassName;
}
public void setDriverClassName(String driverClassName) {
this.driverClassName = driverClassName;
}
public int getInitialSize() {
return initialSize;
}
public void setInitialSize(int initialSize) {
this.initialSize = initialSize;
}
public int getMinIdle() {
return minIdle;
}
public void setMinIdle(int minIdle) {
this.minIdle = minIdle;
}
public int getMaxActive() {
return maxActive;
}
public void setMaxActive(int maxActive) {
this.maxActive = maxActive;
}
public int getMaxWait() {
return maxWait;
}
public void setMaxWait(int maxWait) {
this.maxWait = maxWait;
}
public int getTimeBetweenEvictionRunsMillis() {
return timeBetweenEvictionRunsMillis;
}
public void setTimeBetweenEvictionRunsMillis(int timeBetweenEvictionRunsMillis) {
this.timeBetweenEvictionRunsMillis = timeBetweenEvictionRunsMillis;
}
public int getMinEvictableIdleTimeMillis() {
return minEvictableIdleTimeMillis;
}
public void setMinEvictableIdleTimeMillis(int minEvictableIdleTimeMillis) {
this.minEvictableIdleTimeMillis = minEvictableIdleTimeMillis;
}
public String getValidationQuery() {
return validationQuery;
}
public void setValidationQuery(String validationQuery) {
this.validationQuery = validationQuery;
}
public boolean isTestWhileIdle() {
return testWhileIdle;
}
public void setTestWhileIdle(boolean testWhileIdle) {
this.testWhileIdle = testWhileIdle;
}
public boolean isTestOnBorrow() {
return testOnBorrow;
}
public void setTestOnBorrow(boolean testOnBorrow) {
this.testOnBorrow = testOnBorrow;
}
public boolean isTestOnReturn() {
return testOnReturn;
}
public void setTestOnReturn(boolean testOnReturn) {
this.testOnReturn = testOnReturn;
}
public boolean isPoolPreparedStatements() {
return poolPreparedStatements;
}
public void setPoolPreparedStatements(boolean poolPreparedStatements) {
this.poolPreparedStatements = poolPreparedStatements;
}
public int getMaxPoolPreparedStatementPerConnectionSize() {
return maxPoolPreparedStatementPerConnectionSize;
}
public void setMaxPoolPreparedStatementPerConnectionSize(int maxPoolPreparedStatementPerConnectionSize) {
this.maxPoolPreparedStatementPerConnectionSize = maxPoolPreparedStatementPerConnectionSize;
}
public String getFilters() {
return filters;
}
public void setFilters(String filters) {
this.filters = filters;
}
public String getConnectionProperties() {
return connectionProperties;
}
public void setConnectionProperties(String connectionProperties) {
this.connectionProperties = connectionProperties;
}
public boolean isUseGlobalDataSourceStat() {
return useGlobalDataSourceStat;
}
public void setUseGlobalDataSourceStat(boolean useGlobalDataSourceStat) {
this.useGlobalDataSourceStat = useGlobalDataSourceStat;
}
@Bean(name="dataSource1") //声明其为Bean实例
public DataSource dataSource() {
DruidDataSource datasource = new DruidDataSource();
datasource.setUrl(url);
datasource.setUsername(username);
datasource.setPassword(password);
datasource.setDriverClassName(driverClassName);
//configuration
datasource.setInitialSize(initialSize);
datasource.setMinIdle(minIdle);
datasource.setMaxActive(maxActive);
datasource.setMaxWait(maxWait);
datasource.setTimeBetweenEvictionRunsMillis(timeBetweenEvictionRunsMillis);
datasource.setMinEvictableIdleTimeMillis(minEvictableIdleTimeMillis);
datasource.setValidationQuery(validationQuery);
datasource.setTestWhileIdle(testWhileIdle);
datasource.setTestOnBorrow(testOnBorrow);
datasource.setTestOnReturn(testOnReturn);
datasource.setPoolPreparedStatements(poolPreparedStatements);
datasource.setMaxPoolPreparedStatementPerConnectionSize(maxPoolPreparedStatementPerConnectionSize);
try {
datasource.setFilters(filters);
} catch (SQLException e) {
System.err.println("druid configuration initialization filter: " + e);
}
datasource.setConnectionProperties(connectionProperties);
return datasource;
}
}
dataSource2 如下：
import com.alibaba.druid.pool.DruidDataSource;
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;
import java.sql.SQLException;
//解决 spring.datasource.filters=stat,wall,log4j 无法正常注册进去
@Configuration
@ConfigurationProperties(prefix = "spring.datasource2")
public class IDataSource2 {
private String url;
private String username;
private String password;
private String driverClassName;
private int initialSize;
private int minIdle;
private int maxActive;
private int maxWait;
private int timeBetweenEvictionRunsMillis;
private int minEvictableIdleTimeMillis;
private String validationQuery;
private boolean testWhileIdle;
private boolean testOnBorrow;
private boolean testOnReturn;
private boolean poolPreparedStatements;
private int maxPoolPreparedStatementPerConnectionSize;
private String filters;
private String connectionProperties;
private boolean useGlobalDataSourceStat;
public String getUrl() {
return url;
}
public void setUrl(String url) {
this.url = url;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getDriverClassName() {
return driverClassName;
}
public void setDriverClassName(String driverClassName) {
this.driverClassName = driverClassName;
}
public int getInitialSize() {
return initialSize;
}
public void setInitialSize(int initialSize) {
this.initialSize = initialSize;
}
public int getMinIdle() {
return minIdle;
}
public void setMinIdle(int minIdle) {
this.minIdle = minIdle;
}
public int getMaxActive() {
return maxActive;
}
public void setMaxActive(int maxActive) {
this.maxActive = maxActive;
}
public int getMaxWait() {
return maxWait;
}
public void setMaxWait(int maxWait) {
this.maxWait = maxWait;
}
public int getTimeBetweenEvictionRunsMillis() {
return timeBetweenEvictionRunsMillis;
}
public void setTimeBetweenEvictionRunsMillis(int timeBetweenEvictionRunsMillis) {
this.timeBetweenEvictionRunsMillis = timeBetweenEvictionRunsMillis;
}
public int getMinEvictableIdleTimeMillis() {
return minEvictableIdleTimeMillis;
}
public void setMinEvictableIdleTimeMillis(int minEvictableIdleTimeMillis) {
this.minEvictableIdleTimeMillis = minEvictableIdleTimeMillis;
}
public String getValidationQuery() {
return validationQuery;
}
public void setValidationQuery(String validationQuery) {
this.validationQuery = validationQuery;
}
public boolean isTestWhileIdle() {
return testWhileIdle;
}
public void setTestWhileIdle(boolean testWhileIdle) {
this.testWhileIdle = testWhileIdle;
}
public boolean isTestOnBorrow() {
return testOnBorrow;
}
public void setTestOnBorrow(boolean testOnBorrow) {
this.testOnBorrow = testOnBorrow;
}
public boolean isTestOnReturn() {
return testOnReturn;
}
public void setTestOnReturn(boolean testOnReturn) {
this.testOnReturn = testOnReturn;
}
public boolean isPoolPreparedStatements() {
return poolPreparedStatements;
}
public void setPoolPreparedStatements(boolean poolPreparedStatements) {
this.poolPreparedStatements = poolPreparedStatements;
}
public int getMaxPoolPreparedStatementPerConnectionSize() {
return maxPoolPreparedStatementPerConnectionSize;
}
public void setMaxPoolPreparedStatementPerConnectionSize(int maxPoolPreparedStatementPerConnectionSize) {
this.maxPoolPreparedStatementPerConnectionSize = maxPoolPreparedStatementPerConnectionSize;
}
public String getFilters() {
return filters;
}
public void setFilters(String filters) {
this.filters = filters;
}
public String getConnectionProperties() {
return connectionProperties;
}
public void setConnectionProperties(String connectionProperties) {
this.connectionProperties = connectionProperties;
}
public boolean isUseGlobalDataSourceStat() {
return useGlobalDataSourceStat;
}
public void setUseGlobalDataSourceStat(boolean useGlobalDataSourceStat) {
this.useGlobalDataSourceStat = useGlobalDataSourceStat;
}
@Bean(name="dataSource2") //声明其为Bean实例
public DataSource dataSource2() {
DruidDataSource datasource = new DruidDataSource();
datasource.setUrl(url);
datasource.setUsername(username);
datasource.setPassword(password);
datasource.setDriverClassName(driverClassName);
//configuration
datasource.setInitialSize(initialSize);
datasource.setMinIdle(minIdle);
datasource.setMaxActive(maxActive);
datasource.setMaxWait(maxWait);
datasource.setTimeBetweenEvictionRunsMillis(timeBetweenEvictionRunsMillis);
datasource.setMinEvictableIdleTimeMillis(minEvictableIdleTimeMillis);
datasource.setValidationQuery(validationQuery);
datasource.setTestWhileIdle(testWhileIdle);
datasource.setTestOnBorrow(testOnBorrow);
datasource.setTestOnReturn(testOnReturn);
datasource.setPoolPreparedStatements(poolPreparedStatements);
datasource.setMaxPoolPreparedStatementPerConnectionSize(maxPoolPreparedStatementPerConnectionSize);
try {
datasource.setFilters(filters);
} catch (SQLException e) {
System.err.println("druid configuration initialization filter: " + e);
}
datasource.setConnectionProperties(connectionProperties);
return datasource;
}
}
配置SqlSessionFactory
实际上对于Mybatis来说，可以省略这个配置，springboot会默认创建，但是这里为了后面操作的方便性，自己配置一个SqlSessionFactory:
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.Resource;
import javax.sql.DataSource;
@Configuration
@MapperScan("com.liulei.study.xmlbatisboot.dao")
public class MybatisSqlSessionFactoryConfig {
@Autowired
@Qualifier("dataSource1")
private DataSource dataSource1;
@Value("${mybatis.mapper-locations}")
private Resource[] mapperLocations;
@Value("${mybatis.type-aliases-package}")
private String typeAliasesPackage;
@Bean(name = "sqlSessionFactory")
public SqlSessionFactory sqlSessionFactory() throws Exception {
SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
factoryBean.setDataSource(dataSource1); //
factoryBean.setMapperLocations(mapperLocations);
factoryBean.setTypeAliasesPackage(typeAliasesPackage);
return factoryBean.getObject();
}
}
创建DataSourceHelper辅助类，动态切换数据源
import org.apache.ibatis.mapping.Environment;
import org.apache.ibatis.session.Configuration;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.transaction.SpringManagedTransactionFactory;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;
import javax.sql.DataSource;
import java.util.HashMap;
import java.util.Map;
@Component
public class DataSourceHelper implements InitializingBean,ApplicationContextAware {
private ApplicationContext applicationContext;
private static Map Environments;
private static Configuration configuration;
private SqlSessionFactory sqlSessionFactory;
@Override
public void afterPropertiesSet() throws Exception {
//获取所有数据源
Map dataSources = applicationContext.getBeansOfType(DataSource.class);
sqlSessionFactory = applicationContext.getBean(SqlSessionFactory.class);
//获取sqlSessionFactory的configuration
configuration = sqlSessionFactory.getConfiguration();
Environment environment;
if(Environments==null){
Environments=new HashMap(dataSources.size());
}
for (Map.Entry entry : dataSources.entrySet()) {
environment=new Environment(SqlSessionFactoryBean.class.getSimpleName(),
new SpringManagedTransactionFactory(),entry.getValue());
//初始化所有数据源的environment，便于之后切换数据源使用
Environments.put(entry.getKey(),environment);
}
}
@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
this.applicationContext=applicationContext;
}
public static void setSqlSessionFactoryEnvironment(String dsName){
//切换Mybatis的Environment
configuration.setEnvironment(Environments.get(dsName));
}
}
有必要说一下，这里实现了InitializingBean，和ApplicationContextAware接口，实现的目的不多说，不明白的朋友请自行学习spring。并且这里@Component注解不可少，这和单纯使用spring有区别。
另外afterPropertiesSet方法里，最终的目的是初始化Environment 的Map集合，待之后使用。
使用DataSourceHelper，实现动态切换数据源
@RestController
@RequestMapping("/test")
@EnableTransactionManagement
public class TestController {
@Autowired
private PersonService personService;
@RequestMapping("/getPersonById")
public T getPersonById(@RequestParam String id){
return (T)personService.getPersonById(id);
}
@RequestMapping("/insert")
public int insertPerson(){
Person person;
for(int age=28;age<33;age++){
person = new Person();
person.setId("sdfdf");
person.setName("adsfdf");
person.setAddress("adsfdf");
person.setAge(age);
if(age<30)
//这里做了切换数据源
DataSourceHelper.setSqlSessionFactoryEnvironment("dataSource2");
else
//这里做了切换数据源
DataSourceHelper.setSqlSessionFactoryEnvironment("dataSource1");
personService.insertPerson(person);
}
return 0;
}
}
这里只需要调用 DataSourceHelper.setSqlSessionFactoryEnvironment(“dataSource2”)方法即可实现切换数据源，省略mapper.xml和PersonService的代码。但是这样做不太方便。故有了下面的aop的方式。
Aop的方式动态切换数据源
首先，定义注解：
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.METHOD})
public @interface DS {
String value() default "dataSource1";
}
然后，定义Aop
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
import org.aspectj.lang.reflect.MethodSignature;
import java.lang.reflect.Method;
@Aspect
@Component
public class DynamicDataSourceAspect {
@Value("${default.dataSource}")
private String DEFAULT_SOURCE;
@Before("@annotation(DS)")
public void beforeSwitchDS(JoinPoint point){
//获得当前访问的class
Class className = point.getTarget().getClass();
//获得访问的方法名
String methodName = point.getSignature().getName();
//得到方法的参数的类型
Class[] argClass = ((MethodSignature)point.getSignature()).getParameterTypes();
String dataSource = DEFAULT_SOURCE;
try {
// 得到访问的方法对象
Method method = className.getMethod(methodName, argClass);
// 判断是否存在@DS注解
if (method.isAnnotationPresent(DS.class)) {
DS annotation = method.getAnnotation(DS.class);
// 取出注解中的数据源名
dataSource = annotation.value();
}
} catch (Exception e) {
e.printStackTrace();
}
// 切换数据源
DataSourceHelper.setSqlSessionFactoryEnvironment(dataSource);
}
/*@After("@annotation(DS)")
public void afterSwitchDS(JoinPoint point) {
DataSourceHelper.setSqlSessionFactoryEnvironment(DEFAULT_SOURCE);
}*/
}
这里注释了@After("@annotation(DS)这一部分，如果有需要，可以打开注释，做一些其他的操作。
然后使用方法:
@Service
@Transactional
public class PersonService {
@Autowired
private PersonMapper personMapper;
public Person getPersonById(String id){
return personMapper.getPersonById(id);
}
@DS("dataSource2")
public int insertPerson(Person person){
return personMapper.insertPerson(person);
}
}
只需要加上注解就可以指定，该操作的数据源了。
总结
本篇所实现的切换数据源的方式，仍然侵入到了mybatis中去，并不是很好的做法，但是没办法继承AbstractRoutingDataSource类的方法，不管用。所以我阅读了一下mybatis的源码，找到了这种方法，如果哪位大佬有更好的方法，请不吝赐教，大家互相学习，共同进步。
项目git地址： https://github.com/Lewis-Liulei/springboot.git
里面commo包下的类并没有使用到，DynamicDataSource类和DynamicDataSourceEntry类可以删掉。