springboot（五）读写分离，多个读库，Druid监控

1、修改mybatis.properties

# 主数据源，默认的
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/db
spring.datasource.username=root
spring.datasource.password=123456

# 初始化大小，最小，最大
spring.datasource.initialSize=5
spring.datasource.minIdle=5
spring.datasource.maxActive=20
# 配置获取连接等待超时的时间
spring.datasource.maxWait=60000
# 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒
spring.datasource.timeBetweenEvictionRunsMillis=60000
# 配置一个连接在池中最小生存的时间，单位是毫秒
spring.datasource.minEvictableIdleTimeMillis=300000
spring.datasource.validationQuery=SELECT 1 FROM DUAL
spring.datasource.testWhileIdle=true
spring.datasource.testOnBorrow=false
spring.datasource.testOnReturn=false
# 打开PSCache，并且指定每个连接上PSCache的大小
spring.datasource.poolPreparedStatements=true
spring.datasource.maxPoolPreparedStatementPerConnectionSize=20

# 从数据源
spring.slave.type=com.alibaba.druid.pool.DruidDataSource
spring.slave.driver-class-name=com.mysql.jdbc.Driver
spring.slave.url=jdbc:mysql://127.0.0.1:3308/db
spring.slave.username=root
spring.slave.password=123456
spring.slave.initialSize=5
spring.slave.minIdle=5
spring.slave.maxActive=20
# 配置获取连接等待超时的时间
spring.slave.maxWait=60000
# 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒
spring.slave.timeBetweenEvictionRunsMillis=60000
# 配置一个连接在池中最小生存的时间，单位是毫秒
spring.slave.minEvictableIdleTimeMillis=300000
spring.slave.validationQuery=SELECT 1 FROM DUAL
spring.slave.testWhileIdle=true
spring.slave.testOnBorrow=false
spring.slave.testOnReturn=false
# 打开PSCache，并且指定每个连接上PSCache的大小
spring.slave.poolPreparedStatements=true
spring.slave.maxPoolPreparedStatementPerConnectionSize=20

spring.read2.type=com.alibaba.druid.pool.DruidDataSource
spring.read2.driver-class-name=com.mysql.jdbc.Driver
spring.read2.url=jdbc:mysql://127.0.0.1:3309/db
spring.read2.username=root
spring.read2.password=123456
spring.read2.initialSize=5
spring.read2.minIdle=5
spring.read2.maxActive=20
# 配置获取连接等待超时的时间
spring.read2.maxWait=60000
# 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒
spring.read2.timeBetweenEvictionRunsMillis=60000
# 配置一个连接在池中最小生存的时间，单位是毫秒
spring.read2.minEvictableIdleTimeMillis=300000
spring.read2.validationQuery=SELECT 1 FROM DUAL
spring.read2.testWhileIdle=true
spring.read2.testOnBorrow=false
spring.read2.testOnReturn=false
# 打开PSCache，并且指定每个连接上PSCache的大小
spring.read2.poolPreparedStatements=true
spring.read2.maxPoolPreparedStatementPerConnectionSize=20

# 配置监控统计拦截的filters，去掉后监控界面sql无法统计，'wall'用于防火墙
spring.datasource.filters=stat,wall,logback
# 通过connectProperties属性来打开mergeSql功能；慢SQL记录
spring.datasource.connectionProperties=druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000
# 合并多个DruidDataSource的监控数据
spring.datasource.useGlobalDataSourceStat=true

# 配置监控统计拦截的filters，去掉后监控界面sql无法统计，'wall'用于防火墙
spring.slave.filters=stat,wall,logback
# 通过connectProperties属性来打开mergeSql功能；慢SQL记录
spring.slave.connectionProperties=druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000
# 合并多个DruidDataSource的监控数据
spring.slave.useGlobalDataSourceStat=true

# 配置监控统计拦截的filters，去掉后监控界面sql无法统计，'wall'用于防火墙
spring.read2.filters=stat,wall,logback
# 通过connectProperties属性来打开mergeSql功能；慢SQL记录
spring.read2.connectionProperties=druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000
# 合并多个DruidDataSource的监控数据
spring.read2.useGlobalDataSourceStat=true

2、创建DataBaseConfiguration读取mybatis.properties配置文件

package com.demo.mybatis;

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;
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.util.ArrayList;
import java.util.List;

/**
* Created by huguoju on 2016/12/29.
* 数据库配置：解析properties文件
*/
@Slf4j
@Configuration
public class DataBaseConfiguration {
@Value("${spring.datasource.type}")
private Class<? extends DataSource> dataSourceType;

@Bean(name="writeDataSource", destroyMethod = "close", initMethod="init")
@Primary
@ConfigurationProperties(prefix = "spring.datasource",locations = "classpath:mybatis/mybatis.properties")
public DataSource writeDataSource() {
log.info("-------------------- writeDataSource init ---------------------");
return DataSourceBuilder.create().type(dataSourceType).build();
}
/**
* 有多少个从库就要配置多少个
* @return
*/
@Bean(name = "readDataSource1")
@ConfigurationProperties(prefix = "spring.slave",locations = "classpath:mybatis/mybatis.properties")
public DataSource readDataSourceOne(){
log.info("-------------------- readDataSourceOne init ---------------------");
return DataSourceBuilder.create().type(dataSourceType).build();
}

@Bean(name = "readDataSource2")
@ConfigurationProperties(prefix = "spring.read2",locations = "classpath:mybatis/mybatis.properties")
public DataSource readDataSourceTwo() {
log.info("-------------------- readDataSourceTwo init ---------------------");
return DataSourceBuilder.create().type(dataSourceType).build();
}
@Bean("readDataSources")
public List<DataSource> readDataSources(){
List<DataSource> dataSources=new ArrayList<>();
dataSources.add(readDataSourceOne());
dataSources.add(readDataSourceTwo());
return dataSources;
}
}

最新版本的springboot的@ConfigurationProperties去掉了locations属性，改用@PropertySource指定其他的配置文件，@PropertySource不能作用在方法上，要写在类上
添加引用：importorg.springframework.context.annotation.PropertySource;

package com.demo.mybatis;

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;
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 org.springframework.context.annotation.PropertySource;
import javax.sql.DataSource;
import java.util.ArrayList;
import java.util.List;

/**
* Created by huguoju on 2016/12/29.
* 数据库配置：解析properties文件
*/
@Slf4j
@Configuration
@PropertySource("classpath:mybatis/mybatis.properties")
public class DataBaseConfiguration {
@Value("${spring.datasource.type}")
private Class<? extends DataSource> dataSourceType;

@Bean(name="writeDataSource", destroyMethod = "close", initMethod="init")
@Primary
@ConfigurationProperties(prefix = "spring.datasource")
public DataSource writeDataSource() {
log.info("-------------------- writeDataSource init ---------------------");
return DataSourceBuilder.create().type(dataSourceType).build();
}
/**
* 有多少个从库就要配置多少个
* @return
*/
@Bean(name = "readDataSource1")
@ConfigurationProperties(prefix = "spring.slave")
public DataSource readDataSourceOne(){
log.info("-------------------- readDataSourceOne init ---------------------");
return DataSourceBuilder.create().type(dataSourceType).build();
}

@Bean(name = "readDataSource2")
@ConfigurationProperties(prefix = "spring.read2")
public DataSource readDataSourceTwo() {
log.info("-------------------- readDataSourceTwo init ---------------------");
return DataSourceBuilder.create().type(dataSourceType).build();
}
@Bean("readDataSources")
public List<DataSource> readDataSources(){
List<DataSource> dataSources=new ArrayList<>();
dataSources.add(readDataSourceOne());
dataSources.add(readDataSourceTwo());
return dataSources;
}
}


3、创建DataSourceType，枚举区分读写库

package com.demo.mybatis;

import lombok.Getter;

/**
* Created by huguoju on 2016/12/29.
*/
public enum DataSourceType {
read("read", "从库"),
write("write", "主库");
@Getter
private String type;
@Getter
private String name;

DataSourceType(String type, String name) {
this.type = type;
this.name = name;
}
}

4、创建DataSourceContextHolder，本地线程全局变量

package com.demo.mybatis;

import lombok.extern.slf4j.Slf4j;

/**
* Created by huguoju on 2016/12/29.
* 本地线程全局变量
*/
@Slf4j
public class DataSourceContextHolder  {
private static final ThreadLocal<String> local = new ThreadLocal<String>();

public static ThreadLocal<String> getLocal() {
return local;
}

/**
* 读可能是多个库
*/
public static void read() {

local.set(DataSourceType.read.getType());
}

/**
* 写只有一个库
*/
public static void write() {
log.debug("writewritewrite");
local.set(DataSourceType.write.getType());
}

public static String getJdbcType() {
return local.get();
}
}

5、创建MyAbstractRoutingDataSource，多数据源切换

package com.demo.mybatis;

import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;

import java.util.concurrent.atomic.AtomicInteger;

/**
* Created by huguoju on 2016/12/29.
* 多数据源切换
*/
public class MyAbstractRoutingDataSource extends AbstractRoutingDataSource {
private final int dataSourceNumber;
private AtomicInteger count = new AtomicInteger(0);

public MyAbstractRoutingDataSource(int dataSourceNumber) {
this.dataSourceNumber = dataSourceNumber;
}

@Override
protected Object determineCurrentLookupKey() {
String typeKey = DataSourceContextHolder.getJdbcType();
if (typeKey.equals(DataSourceType.write.getType()))
return DataSourceType.write.getType();
// 读 简单负载均衡
int number = count.getAndAdd(1);
int lookupKey = number % dataSourceNumber;
return new Integer(lookupKey);
}
}

6、创建MybatisConfiguration或者将MyBatisConfig修改，配置mybatis

package com.demo.mybatis;

import lombok.extern.slf4j.Slf4j;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.context.annotation.*;
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;
import org.springframework.transaction.annotation.EnableTransactionManagement;

import javax.annotation.Resource;
import javax.sql.DataSource;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
* Created by huguoju on 2016/12/28.
* 配置mybatis
*/
@Slf4j
@Configuration
@ConditionalOnClass({EnableTransactionManagement.class})
@Import({ DataBaseConfiguration.class})
@MapperScan(basePackages={"com.demo.mapper"})
public class MybatisConfiguration {
@Value("${spring.datasource.type}")
private Class<? extends DataSource> dataSourceType;

@Value("${datasource.readSize}")
private String dataSourceSize;
@Resource(name = "writeDataSource")
private DataSource dataSource;
@Resource(name = "readDataSources")
private List<DataSource> readDataSources;

@Bean
@ConditionalOnMissingBean
public SqlSessionFactory sqlSessionFactory() throws Exception {
SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
sqlSessionFactoryBean.setDataSource(roundRobinDataSouceProxy());
sqlSessionFactoryBean.setTypeAliasesPackage("com.demo.model");
sqlSessionFactoryBean.getObject().getConfiguration().setMapUnderscoreToCamelCase(true);
return sqlSessionFactoryBean.getObject();
}
/**
* 有多少个数据源就要配置多少个bean
* @return
*/
@Bean
public AbstractRoutingDataSource roundRobinDataSouceProxy() {
int size = Integer.parseInt(dataSourceSize);
MyAbstractRoutingDataSource proxy = new MyAbstractRoutingDataSource(size);
Map<Object, Object> targetDataSources = new HashMap<Object, Object>();
// DataSource writeDataSource = SpringContextHolder.getBean("writeDataSource");
// 写
targetDataSources.put(DataSourceType.write.getType(),dataSource);
// targetDataSources.put(DataSourceType.read.getType(),readDataSource);
//多个读数据库时
for (int i = 0; i < size; i++) {
targetDataSources.put(i, readDataSources.get(i));
}
proxy.setDefaultTargetDataSource(dataSource);
proxy.setTargetDataSources(targetDataSources);
return proxy;
}
}

7、创建DataSourceTransactionManager，自定义事物

package com.demo.mybatis;

import lombok.extern.slf4j.Slf4j;
import org.springframework.boot.autoconfigure.jdbc.DataSourceTransactionManagerAutoConfiguration;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.transaction.annotation.EnableTransactionManagement;

import javax.annotation.Resource;
import javax.sql.DataSource;

/**
* 自定义事务
* Created by huguoju on 2016/12/29.
*/
@Configuration
@EnableTransactionManagement
@Slf4j
public class DataSourceTransactionManager extends DataSourceTransactionManagerAutoConfiguration {
/**
* 自定义事务
* MyBatis自动参与到spring事务管理中，无需额外配置，只要org.mybatis.spring.SqlSessionFactoryBean引用的数据源与DataSourceTransactionManager引用的数据源一致即可，否则事务管理会不起作用。
* @return
*/
@Resource(name = "writeDataSource")
private DataSource dataSource;
@Bean(name = "transactionManager")
public org.springframework.jdbc.datasource.DataSourceTransactionManager transactionManagers() {
log.info("-------------------- transactionManager init ---------------------");
return new org.springframework.jdbc.datasource.DataSourceTransactionManager(dataSource);
}
}

8、创建DataSourceAop,切换数据源

package com.demo.mybatis;

import lombok.extern.slf4j.Slf4j;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.springframework.stereotype.Component;

/**
* Created by huguoju on 2016/12/29.
* 拦截设置本地线程变量
*/
@Aspect
@Component
@Slf4j
public class DataSourceAop {
@Before("execution(* com.demo.mapper..*.select*(..)) || execution(* com.demo.mapper..*.get*(..))")
public void setReadDataSourceType() {
DataSourceContextHolder.read();
log.info("dataSource切换到：Read");
}

@Before("execution(* com.demo.mapper..*.insert*(..)) || execution(* com.demo.mapper..*.update*(..))")
public void setWriteDataSourceType() {
DataSourceContextHolder.write();
log.info("dataSource切换到：write");
}
}

以上就完成了，测试类省略了，测试类只要一个select和insert的sql语句就可以，在DataSourceAop的切换方法里打断点，就可以看出来切换数据了，

druid监控全部库， 只要设置useGlobalDataSourceStat=true就可以了。