springboot-mybatis整合多数据源方式之一AOP法

约定不等于承诺〃 2022-02-24 08:04 234阅读 0赞

**环境： intellij idea 2017.1.4 + spring boot 1.5.9**

简介： 用这种方式实现多数据源的前提必须要清楚两个知识点：AOP原理和AbstractRoutingDataSource抽象类。

1、AOP：相当于拦截器，只要满足要求的都会被拦截过来，然后进行一些列的操作。具体需要自己去体会。。。

2、AbstractRoutingDataSource：这个类是实现多数据源的关键，他的作用就是动态切换数据源，实质：有多少个数据源就存多少个数据源在targetDataSources（是AbstractRoutingDataSource的一个map类型的属性，其中value为每个数据源，key表示每个数据源的名字）这个属性中，然后根据determineCurrentLookupKey（）这个方法获取当前数据源在map中的key值，然后determineTargetDataSource（）方法中动态获取当前数据源，如果当前数据源不存并且默认数据源也不存在就抛出异常。

public abstract class AbstractRoutingDataSource extends AbstractDataSource implements InitializingBean {
        //多数据源map集合
        private Map<Object, Object> targetDataSources;
        //默认数据源
        private Object defaultTargetDataSource;
        //其实就是targetDataSources，后面的afterPropertiesSet（）方法会将targetDataSources赋值给resolvedDataSources
        private Map<Object, DataSource> resolvedDataSources;
        private DataSource resolvedDefaultDataSource;
        public void setTargetDataSources(Map<Object, Object> targetDataSources) {
            this.targetDataSources = targetDataSources;
        }
        protected DataSource determineTargetDataSource() {
            Assert.notNull(this.resolvedDataSources, "DataSource router not initialized");
            Object lookupKey = this.determineCurrentLookupKey();
            DataSource 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 + "]");
            } else {
                return dataSource;
            }
        }
        protected abstract Object determineCurrentLookupKey();
    }

具体实现：

1、定义一个动态数据源：继承AbstractRoutingDataSource 抽象类，并重写determineCurrentLookupKey（）方法

public class DynamicDataSource extends AbstractRoutingDataSource {
    
        @Override
        protected Object determineCurrentLookupKey() {
            DataSourceType.DataBaseType dataBaseType = DataSourceType.getDataBaseType();
            return dataBaseType;
        }
    }

项目文件结构：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2h1d2VpMjAwMw_size_16_color_FFFFFF_t_70][]

附上代码：

application.properties

#spring.datasource.driverClassName=com.mysql.jdbc.Driver
    #spring.datasource.url=jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8
    #spring.datasource.username=root
    #spring.datasource.password=
    #mybatis.mapper-locations: classpath:mapper/*.xml
    
    server.port=8080
    ## test1 database
    spring.datasource.db1.url=jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8&serverTimezone=UTC&useSSL=false
    spring.datasource.db1.username=root
    spring.datasource.db1.password=
    spring.datasource.db1.driver-class-name=com.mysql.cj.jdbc.Driver
    ## test2 database
    spring.datasource.db2.url=jdbc:mysql://localhost:3306/news?useUnicode=true&characterEncoding=UTF-8&serverTimezone=UTC&useSSL=false
    spring.datasource.db2.username=root
    spring.datasource.db2.password=
    spring.datasource.db2.driver-class-name=com.mysql.cj.jdbc.Driver

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>
    
    	<groupId>com.neo</groupId>
    	<artifactId>spring-boot-hello</artifactId>
    	<version>1.0</version>
    	<packaging>jar</packaging>
    
    	<name>spring-boot-hello</name>
    	<description>Demo project for Spring Boot</description>
    
    	<parent>
    		<groupId>org.springframework.boot</groupId>
    		<artifactId>spring-boot-starter-parent</artifactId>
    		<version>1.5.9.RELEASE</version>
    		
    	</parent>
    
    	<properties>
    		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    		<java.version>1.8</java.version>
    	</properties>
    
    	<dependencies>
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-jdbc</artifactId>
    		</dependency>
    		<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.mybatis.spring.boot</groupId>
    			<artifactId>mybatis-spring-boot-starter</artifactId>
    			<version>1.3.2</version>
    		</dependency>
    		<dependency>
    			<groupId>mysql</groupId>
    			<artifactId>mysql-connector-java</artifactId>
    			<version>8.0.11</version>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-test</artifactId>
    			<scope>test</scope>
    		</dependency>
    	</dependencies>
    	
    	<build>
    		<plugins>
    			<plugin>
    				<groupId>org.springframework.boot</groupId>
    				<artifactId>spring-boot-maven-plugin</artifactId>
    			</plugin>
    		</plugins>
    	</build>
    	
    
    </project>

注：springboot 原来用的是2.0，但有个类（org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;）会找不到，切到1.5.9反而可以。

entity

package com.neo.entity;
    
    import org.springframework.stereotype.Component;
    
    
    @Component
    public class Sound {
        private Long id;
    
        public Long getId() {
            return id;
        }
    
        public void setId(Long id) {
            this.id = id;
        }
    
        public String getTitle() {
            return title;
        }
    
        public void setTitle(String title) {
            this.title = title;
        }
    
        private String title;
    }
    
    
    package com.neo.entity;
    
    import org.springframework.stereotype.Component;
    
    
    @Component
    public class User {
        private Long id;
        private String username;
        private int age;
        public Long getId() {
            return id;
        }
        public void setId(Long id) {
            this.id = id;
        }
        public String getUsername() {
            return username;
        }
        public void setUsername(String username) {
            this.username = username;
        }
        public int getAge() {
            return age;
        }
        public void setAge(int age) {
            this.age = age;
        }
    }

mapper

package com.neo.mapper.db1;
    
    import com.neo.entity.User;
    import org.apache.ibatis.annotations.Mapper;
    import org.springframework.stereotype.Repository;
    
    import java.util.List;
    
    @Repository
    public interface  UserMapper {
        //获取用户名单
        List<User> getUser() throws Exception;
        //根据id删除用户
        void deleteUser(int id)throws Exception;
        //新增用户
        void addUser(User user)throws Exception;
    
        //修改用户信息
        void updateUser(User user) throws Exception;
    
    //    //用注解实现的
    //    //获取用户名单
    //    @Select("select * from user")
    //    public List<User> getUser() throws Exception;
    //    //根据id删除用户
    //    @Delete("delete from user where id = #{id}")
    //    public void deleteUser(int id)throws Exception;
    //    //新增用户
    //    @Insert("insert into user(id,username,age)values(#{id},#{username},#{age})")
    //    public void addUser(User user)throws Exception;
    //    //修改用户信息
    //    @Update("update user set username = #{name} where id = #{id}")
    //    public void updateUser(User user) throws Exception;
    }
    
    
    package com.neo.mapper.db2;
    
    import com.neo.entity.Sound;
    import org.apache.ibatis.annotations.Mapper;
    import org.springframework.stereotype.Repository;
    
    import java.util.List;
    
    @Repository
    public interface SoundMapper {
        //获取列表
        List<Sound> getSound() throws Exception;
        //根据id删除
        void deleteSound(int id)throws Exception;
        //新增
        void addSound(Sound sound)throws Exception;
    
        //修改信息
        //public void updateSound(Sound sound) throws Exception;
    
    }

mappering

<?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://www.mybatis.org/dtd/mybatis-3-mapper.dtd">
    <mapper namespace="com.neo.mapper.db1.UserMapper">
        <select id="getUser" resultType="com.neo.entity.User">
            select * from user
            <where>
                <if test="username != null">
                    username=#{username}
                </if>
    
                <if test="age!= null">
                    and age=#{age}
                </if>
            </where>
        </select>
        <delete id="deleteUser" parameterType="Integer">
            delete from user where id =#{id}
        </delete>
        <insert id="addUser" parameterType="com.neo.entity.User">
        insert into user(id,username,age)values(#{id},#{username},#{age})
    </insert>
        <update id="updateUser" parameterType="com.neo.entity.User">
            update user
            <set>
                <if test = "username != null">
                    user.username = #{username},
                </if>
                <if test = "age != 0">
                    user.age = #{age}
                </if>
            </set>
            where id = #{id}
        </update>
    </mapper>
    
    
    <?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://www.mybatis.org/dtd/mybatis-3-mapper.dtd">
    <mapper namespace="com.neo.mapper.db2.SoundMapper">
        <select id="getSound" resultType="com.neo.entity.Sound">
            select * from t_sound
            <where>
                <if test="title != null">
                    title=#{title}
                </if>
    
                <if test="id!= null">
                    and id=#{id}
                </if>
            </where>
        </select>
        <delete id="deleteSound" parameterType="Integer">
            delete from t_sound where id =#{id}
        </delete>
        <insert id="addSound" parameterType="com.neo.entity.Sound">
        insert into t_sound(id,title)values(#{id},#{title})
    </insert>
        <update id="updateSound" parameterType="com.neo.entity.Sound">
            update t_sound
            <set>
                <if test = "title != null">
                    sound.title = #{title},
                </if>
            </set>
            where id = #{id}
        </update>
    </mapper>

dao

package com.neo.dao;
    
    import com.neo.entity.Sound;
    import com.neo.mapper.db2.SoundMapper;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Component;
    
    import java.util.List;
    
    
    @Component
    
    public class SoundDao {
        @Autowired
        private SoundMapper tm1;
    
        public List<Sound> getSound() {
    
            try {
               return tm1.getSound();
            } catch (Exception e) {
                e.printStackTrace();
            }
            return  null;
        }
    }
    
    
    package com.neo.dao;
    
    import com.neo.entity.User;
    import com.neo.mapper.db1.UserMapper;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Component;
    
    import java.util.List;
    
    
    @Component
    public class UserDao {
        @Autowired
        private UserMapper tm1;
    
        public List<User> getUser() {
    
            try {
               return tm1.getUser();
            } catch (Exception e) {
                e.printStackTrace();
            }
            return  null;
        }
    }

service

package com.neo.service.db1;
    
    import com.neo.dao.SoundDao;
    import com.neo.dao.UserDao;
    import com.neo.entity.Sound;
    import com.neo.entity.User;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Component;
    import org.springframework.stereotype.Service;
    import org.springframework.transaction.annotation.Transactional;
    
    import java.util.List;
    
    
    @Service
    public class UserService {
        @Autowired
        private UserDao ts1;
    
        @Transactional
        public List<User> getUser(){
            return ts1.getUser();
        }
    }
    
    
    package com.neo.service.db2;
    
    import com.neo.dao.SoundDao;
    
    import com.neo.entity.Sound;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    import org.springframework.transaction.annotation.Transactional;
    
    import java.util.List;
    
    @Service
    public class SoundService {
        @Autowired
        private SoundDao ts1;
    
        @Transactional
        public List<Sound> getSound(){
            return ts1.getSound();
        }
    }

datasource

package com.neo.datasource;
    
    import org.aspectj.lang.annotation.Aspect;
    import org.aspectj.lang.annotation.Before;
    import org.springframework.stereotype.Component;
    
    @Aspect
    
    @Component
    public class DataSourceAop {
    	@Before("execution(* com.neo.service.db1..*(..))")
    	public void setDataSource2test01() {
    		System.err.println("test01业务");
    		DataSourceType.setDataBaseType(DataSourceType.DataBaseType.DB1);
    	}
    	@Before("execution(* com.neo.service.db2..*(..))")
    	public void setDataSource2test02() {
    		System.err.println("test02业务");
    		DataSourceType.setDataBaseType(DataSourceType.DataBaseType.DB2);
    	}
    }
    
    
    package com.neo.datasource;
    
    import org.apache.ibatis.session.SqlSessionFactory;
    import org.mybatis.spring.SqlSessionFactoryBean;
    import org.mybatis.spring.annotation.MapperScan;
    import org.springframework.beans.factory.annotation.Qualifier;
    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.core.io.support.PathMatchingResourcePatternResolver;
    
    import javax.sql.DataSource;
    import java.util.HashMap;
    import java.util.Map;
    
    @Configuration
    @MapperScan(basePackages = "com.neo.mapper", sqlSessionFactoryRef = "SqlSessionFactory")
    public class DataSourceConfig {
    	@Primary
    	@Bean(name = "db1DataSource")
    	@ConfigurationProperties(prefix = "spring.datasource.db1")
    	public DataSource getDateSource1() {
    		return DataSourceBuilder.create().build();
    	}
    
    	@Bean(name = "db2DataSource")
    	@ConfigurationProperties(prefix = "spring.datasource.db2")
    	public DataSource getDateSource2() {
    		return DataSourceBuilder.create().build();
    	}
    
    	@Bean(name = "dynamicDataSource")
    	public DynamicDataSource DataSource(@Qualifier("db1DataSource") DataSource db1DataSource,
    			@Qualifier("db2DataSource") DataSource db2DataSource) {
    		Map<Object, Object> targetDataSource = new HashMap<>();
    		targetDataSource.put(DataSourceType.DataBaseType.DB1, db1DataSource);
    		targetDataSource.put(DataSourceType.DataBaseType.DB2, db2DataSource);
    		DynamicDataSource dataSource = new DynamicDataSource();
    		dataSource.setTargetDataSources(targetDataSource);
    		dataSource.setDefaultTargetDataSource(db1DataSource);
    		return dataSource;
    	}
    
    	@Bean(name = "SqlSessionFactory")
    	public SqlSessionFactory test1SqlSessionFactory(@Qualifier("dynamicDataSource") DataSource dynamicDataSource)
    			throws Exception {
    		SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
    		bean.setDataSource(dynamicDataSource);
    		bean.setMapperLocations(
    				new PathMatchingResourcePatternResolver().getResources("classpath*:mappering/*/*.xml"));
    		return bean.getObject();
    	}
    
    }
    
    
    package com.neo.datasource;
    
    public class DataSourceType {
    
    	public enum DataBaseType {
    		DB1, DB2
    	}
    
    	// 使用ThreadLocal保证线程安全
    	private static final ThreadLocal<DataBaseType> TYPE = new ThreadLocal<DataBaseType>();
    
    	// 往当前线程里设置数据源类型
    	public static void setDataBaseType(DataBaseType dataBaseType) {
    		if (dataBaseType == null) {
    			throw new NullPointerException();
    		}
    		System.err.println("[将当前数据源改为]：" + dataBaseType);
    		TYPE.set(dataBaseType);
    	}
    
    	// 获取数据源类型
    	public static DataBaseType getDataBaseType() {
    		DataBaseType dataBaseType = TYPE.get() == null ? DataBaseType.DB1 : TYPE.get();
    		System.err.println("[获取当前数据源的类型为]：" + dataBaseType);
    		return dataBaseType;
    	}
    
    	// 清空数据类型
    	public static void clearDataBaseType() {
    		TYPE.remove();
    	}
    
    }
    
    
    package com.neo.datasource;
    
    import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;
    
    public class DynamicDataSource extends AbstractRoutingDataSource {
    
    	@Override
    	protected Object determineCurrentLookupKey() {
    		DataSourceType.DataBaseType dataBaseType = DataSourceType.getDataBaseType();
    		return dataBaseType;
    	}
    
    }

control

package com.neo.controller;
    
    import com.neo.entity.Sound;
    import com.neo.service.db2.SoundService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    import java.util.List;
    
    
    @RestController
    public class SoundController {
    
        @Autowired
        private SoundService soundService;
        @Autowired
        private Sound sound;
        //显示用户
        @RequestMapping("sound/list")
        public List<Sound> index() throws Exception {
            return soundService.getSound();
        }
    
    //    //增加用户
    //    @RequestMapping("sound/add")
    //    public String addSound() throws Exception {
    //        sound.setTitle("平凡之路");
    //        soundService.addSound(sound);
    //        return "增加";
    //    }
    }
    
    
    package com.neo.controller;
    
    import com.neo.entity.User;
    import com.neo.service.db1.UserService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    import java.util.List;
    
    
    @RestController
    public class UserController {
    
        @Autowired
        private UserService userService;
        @Autowired
        private User user;
        //显示用户
        @RequestMapping("list")
        public List<User> index() throws Exception {
            return userService.getUser();
        }
    //    //删除用户
    //    @RequestMapping("delete/{id}")
    //    public String delete(@PathVariable int id) throws Exception {
    //        userService.deleteUser(id);
    //        return "你已经删掉了id为"+id+"的用户";
    //    }
    //    //增加用户
    //    @RequestMapping("addUser")
    //    public String addUser() throws Exception {
    //        user.setAge(33);
    //        user.setUsername("阿花");
    //        userService.addUser(user);
    //        return "增加用户";
    //    }
    }

启动类

package com.neo;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    
    @SpringBootApplication
    public class HelloApplication {
    
    	public static void main(String[] args) {
    		SpringApplication.run(HelloApplication.class, args);
    	}
    }

项目完整包下载地址： [下载 ][Link 1]

\--- end ---

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2h1d2VpMjAwMw_size_16_color_FFFFFF_t_70]: /images/20220224/ac61bd08fb5349dc979d0bd28ac16484.png
[Link 1]: https://download.csdn.net/download/huwei2003/11085514