MySQL分布式集群-3.SpringBoot，Mybatis，MySQL读写分离

1.概要

• 读写分离分为master、slave两台MySQL服务器
• 在appcation.yml配置多数据源
• 为多数据源配置读写路由
• 在AOP中根据方法名或者@Master、@Slave来选择连接不同的数据库

2.代码

• application.yml

spring:
  banner:
    location: banner.txt

  datasource:
    master:
      driver-class-name: com.mysql.jdbc.Driver
      url: jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf8&useSSL=false
      username: root
      password: **********
    slave:
      driver-class-name: com.mysql.jdbc.Driver
      url: jdbc:mysql://localhost:3306/boot_mybatis_plus?useUnicode=true&characterEncoding=utf8&useSSL=false
      username: root
      password: **********

  thymeleaf:
    cache: false
    check-template: true
    check-template-location: true
    encoding: UTF-8
    prefix: classpath:/templates

security:
  oauth2:
    client:
      client-id: user-client
      client-secret: 123
      user-authorization-uri: http://localhost:8088/oauth/authorize
      access-token-uri: http://localhost:8088/oauth/token
    resource:
      id: user-client
      user-info-uri: user-info
    authorization:
      check-token-access: http://localhost:8088/oauth/check_token

mybatis:
  mapper-locations: classpath:/mapper/*.xml

server:
  port: 8080

• DynamicDataSource.java

package com.ctgu.tools;

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

import javax.sql.DataSource;
import java.util.Map;

public class DynamicDataSource extends AbstractRoutingDataSource {

    private static final ThreadLocal<String> contextHolder = new ThreadLocal<>();

//    public DynamicDataSource(DataSource defaultTargetDataSource, Map<Object, Object> targetDataSources) {
//        super.setDefaultTargetDataSource(defaultTargetDataSource);
//        super.setTargetDataSources(targetDataSources);
//        super.afterPropertiesSet();
//    }

    @Override
    protected Object determineCurrentLookupKey() {
        return getDataSource();
    }

    public static void setDataSource(String dataSource) {
        contextHolder.set(dataSource);
    }

    public static String getDataSource() {
        return contextHolder.get();
    }

    public static void clearDataSource() {
        contextHolder.remove();
    }

}

• DataSource.java

package com.ctgu.tools;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target({ElementType.TYPE, ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface DataSource {
    String value();
}

• DynamicDataSourceConfig.java

package com.ctgu.config;

import com.ctgu.tools.DynamicDataSource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Lazy;
import org.springframework.context.annotation.Primary;

import javax.sql.DataSource;
import java.util.HashMap;
import java.util.Map;

@Configuration
@EnableAutoConfiguration(exclude = {DataSourceAutoConfiguration.class})
public class DynamicDataSourceConfig {

    @Autowired
    @Lazy
    private DataSource masterDataSource;

    @Autowired
    @Lazy
    private DataSource slaveDataSource;

    @Bean
    @Primary
    public DynamicDataSource dataSource(){
        DynamicDataSource dynamicDataSource = new DynamicDataSource();
        Map<Object, Object> map = new HashMap<>();
        map.put("ds1", masterDataSource);
        map.put("ds2", slaveDataSource);
        System.out.println(map);
        dynamicDataSource.setDefaultTargetDataSource(slaveDataSource);
        dynamicDataSource.setTargetDataSources(map);
        return dynamicDataSource;
    }

}

• DataSourceConfig.java

package com.ctgu.config;

import com.alibaba.druid.spring.boot.autoconfigure.DruidDataSourceBuilder;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import javax.sql.DataSource;

@Configuration
public class DataSourceConfig {

    @Bean
    @ConfigurationProperties(prefix = "spring.datasource.master")
    public DataSource masterDataSource(){
        return DruidDataSourceBuilder.create().build();
    }

    @Bean
    @ConfigurationProperties(prefix = "spring.datasource.slave")
    public DataSource slaveDataSource(){
        return DruidDataSourceBuilder.create().build();
    }

}

• DataSourceAspect.java

package com.ctgu.aop;

import com.ctgu.tools.DataSource;
import com.ctgu.tools.DynamicDataSource;
import lombok.extern.slf4j.Slf4j;
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.springframework.stereotype.Component;

@Aspect
@Slf4j
@Component
public class DataSourceAspect {

    @Before("execution(* com.ctgu.service..*.*(..))&&@annotation(ds)")
    public void changeDataSource(JoinPoint point, DataSource ds) throws Throwable {
        String key = ds.value();
        System.out.println(key);
        if(key != null && !key.trim().equals("")) {
            DynamicDataSource.setDataSource(key);
        }
    }

    @After("execution(* com.ctgu.service..*.*(..))&&@annotation(ds)")
    public void restoreDataSource(JoinPoint point, DataSource ds) {
        DynamicDataSource.clearDataSource();
    }
}

• Application.java

package com.ctgu;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.EnableAspectJAutoProxy;

/**
 * Hello world!
 */
@EnableAspectJAutoProxy
@SpringBootApplication
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

• pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.4.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.ctgu</groupId>
    <artifactId>ds</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-aop</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-security</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.10</version>
        </dependency>

        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.0.1</version>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.6</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.47</version>
        </dependency>
    </dependencies>
</project>

网上随便搜搜就有了，也就遇到个循环依赖问题而已，加上@Lazy和@EnableAutoConfiguration(exclude = {DataSourceAutoConfiguration.class})

就完事了