spring boot + mybatis + mysql + mycat 动态分离 四
主题思路是：
通过aop技术，根据请求后台的方式进行切换datasource 源，是写还是读数据。
1、上篇博文说明了mysql 的动态分离。现在需要整合spring boot 进行整合搭建服务,demo项目
2、回忆下mybatis ，一般都是把mybatis 做dao层。
首先需要引入pom.xml
4.0.0
com.mycat.demo
damayicDemo
0.0.1-SNAPSHOT
org.springframework.boot
spring-boot-starter-parent
2.0.4.RELEASE
org.springframework.boot
spring-boot-starter-aop
org.springframework.boot
spring-boot-starter-web
org.mybatis.spring.boot
mybatis-spring-boot-starter
1.3.2
org.yaml
snakeyaml
1.23
com.alibaba
fastjson
1.2.62
mysql
mysql-connector-java
runtime
org.springframework.boot
spring-boot-starter-test
test
com.alibaba
druid
1.0.23
org.springframework.boot
spring-boot-maven-plugin
2、配置application.yml 读写对象
spring:
datasource:
###可读数据源
select:
jdbc-url: jdbc:mysql://nginx.fandong.com:8066/testdb
driver-class-name: com.mysql.jdbc.Driver
username: user
password: user
####可写数据源
update:
jdbc-url: jdbc:mysql://nginx.fandong.com:8066/testdb
driver-class-name: com.mysql.jdbc.Driver
username: root
password: root
type: com.alibaba.druid.pool.DruidDataSource3、配置datasource 源
/**
*
*/
package com.dynamic.demo.config;
import javax.sql.DataSource;
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;
/**
* @author fandong
*
*/
@Configuration
public class DataSourceConfig {
@Bean(name="selectDataSource")
@ConfigurationProperties(prefix = "spring.datasource.select")
public DataSource dataSource1() {
return DataSourceBuilder.create().build();
}
@Bean(name="updateDataSource")
@ConfigurationProperties(prefix = "spring.datasource.update")
public DataSource dataSource2() {
return DataSourceBuilder.create().build();
}
}
4、缓存数据源
/**
*
*/
package com.dynamic.demo.config;
import org.springframework.context.annotation.Lazy;
import org.springframework.stereotype.Component;
/**
* @author fandong
*
*/
@Component
@Lazy(false)
public class DataSourceContextHolder {
private static final ThreadLocal contextHolder = new ThreadLocal<>();
// 设置数据源类型
public static void setDbType(String dbType) {
contextHolder.set(dbType);
}
public static String getDbType() {
return contextHolder.get();
}
public static void clearDbType() {
contextHolder.remove();
}
}
5、使用AbstractRoutingDataSource 进行路由当前的数据源。
package com.dynamic.demo.config;
import java.util.HashMap;
import java.util.Map;
import javax.sql.DataSource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.annotation.Primary;
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;
import org.springframework.stereotype.Component;
@Component
@Primary
public class DynamicDataSource extends AbstractRoutingDataSource {
@Autowired
@Qualifier("selectDataSource")
private DataSource selectDataSource;
@Autowired
@Qualifier("updateDataSource")
private DataSource updateDataSource;
/**
* 这个是主要的方法，返回的是生效的数据源名称
*/
@Override
protected Object determineCurrentLookupKey() {
System.out.println("DataSourceContextHolder：：：" + DataSourceContextHolder.getDbType());
return DataSourceContextHolder.getDbType();
}
/**
* 配置数据源信息
*/
@Override
public void afterPropertiesSet() {
Map map = new HashMap<>();
map.put("selectDataSource", selectDataSource);
map.put("updateDataSource", updateDataSource);
setTargetDataSources(map);
setDefaultTargetDataSource(updateDataSource);
super.afterPropertiesSet();
}
} 6、使用aop 在进行方法执行时进行拦截
package com.dynamic.demo.aop;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.springframework.context.annotation.Lazy;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;
import com.dynamic.demo.config.DataSourceContextHolder;
// 使用AOP动态切换不同的数据源
@Aspect
@Component
@Lazy(false)
@Order(0) // Order设定AOP执行顺序 使之在数据库事务上先执行
public class SwitchDataSourceAOP {
// 这里切到你的方法目录
@Before("execution(* com.dynamic.demo.service.*.*(..))")
public void process(JoinPoint joinPoint) {
String methodName = joinPoint.getSignature().getName();
if (methodName.startsWith("get") || methodName.startsWith("count") || methodName.startsWith("find")
|| methodName.startsWith("list") || methodName.startsWith("select") || methodName.startsWith("check")) {
DataSourceContextHolder.setDbType("selectDataSource");
} else {
// 切换dataSource
DataSourceContextHolder.setDbType("updateDataSource");
}
}
}---调用过程
1、 首先把两个数据源进行实例化。
2、在调用select、update 方法是使用aop进行拦截，获取拦截的方法名称判断调用哪个数据实例，将数据实例key添加到ThreadLocal 中。
3、 在AbstractRoutingDataSource 调用 determineTargetDataSource 方法进行获取当前的实例。
在determineTargetDataSource 方法中调用了determineCurrentLookupKey 获取当前执行的方法数据key值。
在重写的方法
protected DataSource determineTargetDataSource() {
Assert.notNull(this.resolvedDataSources, "DataSource router not initialized");
Object lookupKey = determineCurrentLookupKey();
DataSource dataSource = this.resolvedDataSources.get(lookupKey);
if (dataSource == null && (this.lenientFallback || lookupKey == null)) {
dataSource = this.resolvedDefaultDataSource;
}
if (dataSource == null) {
throw new IllegalStateException("Cannot determine target DataSource for lookup key [" + lookupKey + "]");
}
return dataSource;
}重写的方法，把数据示例注入中。
/**
* 配置数据源信息
*/
@Override
public void afterPropertiesSet() {
Map map = new HashMap<>();
map.put("selectDataSource", selectDataSource);
map.put("updateDataSource", updateDataSource);
setTargetDataSources(map);
setDefaultTargetDataSource(updateDataSource);
super.afterPropertiesSet();
} 这样即可动态切换数据。
剩下就是mybatis 的创建entity
/**
*
*/
package com.dynamic.demo.entity;
import org.springframework.stereotype.Component;
/**
* @author fandong
*
*/
@Component
public class T1Entity {
private String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
创建mapper 接口方法
/**
*
*/
package com.dynamic.demo.mapper;
import java.util.List;
import javax.websocket.server.PathParam;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Select;
import com.dynamic.demo.entity.T1Entity;
/**
* @author fandong
*
*/
public interface T1Mapper {
@Select("select name from t1")
List findT1();
@Insert("insert into t1 (name) values(#{name})")
void update(@PathParam("entity") T1Entity entity);
}
创建service
/**
*
*/
package com.dynamic.demo.service;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import com.dynamic.demo.entity.T1Entity;
import com.dynamic.demo.mapper.T1Mapper;
/**
* @author fandong
*
*/
@Service
public class T1Service {
@Autowired
public T1Mapper t1Mapper;
public List getEntities(){
System.out.println("打印kkkk");
return t1Mapper.findT1();
}
public void update(T1Entity entity) {
System.out.println("插入。。。");
t1Mapper.update(entity);
}
}
创建Controller 方法
/**
*
*/
package com.dynamic.demo.controller;
import java.util.ArrayList;
import java.util.List;
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.ResponseBody;
import org.springframework.web.bind.annotation.RestController;
import com.alibaba.fastjson.JSON;
import com.dynamic.demo.entity.T1Entity;
import com.dynamic.demo.service.T1Service;
/**
* @author fandong
*
*/
@RestController
public class Hello {
@Autowired
private T1Service t1Service;
@RequestMapping("/findEntities")
public String getEntity() {
List entities = t1Service.getEntities();
for(T1Entity entity : entities) {
System.out.println(entity.getName());
}
String jsonString = JSON.toJSONString(entities);
return jsonString;
}
@RequestMapping("/insert/{name}")
public void insert(@PathVariable("name") String name) {
System.out.println("insert value:"+ name);
T1Entity t1Entity = new T1Entity();
t1Entity.setName(name);
t1Service.update(t1Entity);
}
}
测试：
