<!--spring boot核心-->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter</artifactId>
</dependency>
<!--spring boot 測(cè)試-->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
    <scope>test</scope>
</dependency>
<!--mysql 驅(qū)動(dòng)-->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
</dependency>
<!-- druid -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid-spring-boot-starter</artifactId>
    <version>1.1.10</version>
</dependency>
<!--mybatis-->
<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.0.0</version>
</dependency>
<!--aspectj 注解代理-->
<dependency>
    <groupId>org.aspectj</groupId>
    <artifactId>aspectjweaver</artifactId>
</dependency>

package com.example.dynamic.datasource.config;
 
publicclass DataSourceContextHolder {
 
    /**
     * 設(shè)置線程獨(dú)立變量，用于存儲(chǔ)數(shù)據(jù)源唯一標(biāo)記
     */
    privatestaticfinal ThreadLocal<String> DATASOURCE_HOLDER = new ThreadLocal<>();
 
    /**
     * 設(shè)置數(shù)據(jù)源
     * @param dataSourceName 數(shù)據(jù)源名稱
     */
    public static void set(String dataSourceName){
        DATASOURCE_HOLDER.set(dataSourceName);
    }
 
    /**
     * 獲取當(dāng)前線程的數(shù)據(jù)源
     * @return 數(shù)據(jù)源名稱
     */
    public static String get(){
        return DATASOURCE_HOLDER.get();
    }
 
    /**
     * 刪除當(dāng)前數(shù)據(jù)源
     */
    public static void remove(){
        DATASOURCE_HOLDER.remove();
    }
 
}

package com.example.dynamic.datasource.config;
 
@Configuration
publicclass DataSourceConfig {
 
    @Bean(name = "db1")
    @ConfigurationProperties(prefix = "spring.datasource.db1.druid")
    public DataSource db1(){
        return DruidDataSourceBuilder.create().build();
    }
 
    @Bean(name = "db2")
    @ConfigurationProperties(prefix = "spring.datasource.db2.druid")
    public DataSource db2(){
        return DruidDataSourceBuilder.create().build();
    }
 
    @Bean
    @Primary
    public DynamicDataSource createDynamicDataSource(){
        // 配置數(shù)據(jù)源集合，其中key代表數(shù)據(jù)源名稱，DataSourceContextHolder中緩存的就是這個(gè)key
        Map<Object,Object> dataSourceMap = new HashMap<>();
        dataSourceMap.put("db1",db1());
        dataSourceMap.put("db2",db2());
 
        // 注入動(dòng)態(tài)數(shù)據(jù)源到bean工廠
        DynamicDataSource dynamicDataSource = new DynamicDataSource();
        // 設(shè)置默認(rèn)數(shù)據(jù)源
        dynamicDataSource.setDefaultTargetDataSource(db1());
        // 設(shè)置動(dòng)態(tài)數(shù)據(jù)源集
        dynamicDataSource.setTargetDataSources(dataSourceMap);
        return dynamicDataSource;
    }
}

package com.example.dynamic.datasource.config.aop;
 
@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface DbSource {
 
    /**
     * 數(shù)據(jù)源key值
     * @return
     */
    String value() default "db1";
}

package com.example.dynamic.datasource.config.aop;
 
@Order(1)
@Aspect
@Component
publicclass DbSourceAspect {
 
    privatestaticfinal Logger LOGGER = LoggerFactory.getLogger(DbSourceAspect.class);
 
 
    @Pointcut("@annotation(com.example.dynamic.datasource.config.aop.DbSource)")
    public void dynamicDataSource(){}
 
    @Around("dynamicDataSource()")
    public Object datasourceAround(ProceedingJoinPoint point) throws Throwable {
        // 獲取要切換的數(shù)據(jù)源名稱
        MethodSignature methodSignature = (MethodSignature)point.getSignature();
        Method method = methodSignature.getMethod();
        DbSource dbSource = method.getAnnotation(DbSource.class);
        LOGGER.info("select dataSource:" + dbSource.value());
        DataSourceContextHolder.set(dbSource.value());
        try {
            return point.proceed();
        } finally {
            DataSourceContextHolder.remove();
        }
    }
}

@Service
public class UserInfoService {
 
    @Autowired
    private UserInfoMapper userInfoMapper;
 
    @Transactional
    @DbSource(value = "db1")
    public void add(UserInfo entity){
        userInfoMapper.insert(entity);
    }
}

@Service
public class AccountInfoService {
 
    @Autowired
    private AccountInfoMapper accountInfoMapper;
 
    @Transactional
    @DbSource(value = "db2")
    public void add(AccountInfo entity){
        accountInfoMapper.insert(entity);
    }
}

CREATE TABLE`tb_db_info` (
`id`int(11) unsignedNOTNULL AUTO_INCREMENT,
`db_name`varchar(50) DEFAULTNULL,
`db_url`varchar(200) DEFAULTNULL,
`driver_class_name`varchar(100) DEFAULTNULL,
`username`varchar(80) DEFAULTNULL,
`password`varchar(80) DEFAULTNULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=3DEFAULTCHARSET=utf8mb4;

# 配置默認(rèn)數(shù)據(jù)源
spring.datasource.url=jdbc:mysql://localhost:3306/test
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.driver-class-name=com.mysql.jdbc.Driver

package com.example.dynamic.datasource.entity;
 
publicclass DbInfo {
 
    /**
     * 主鍵ID
     */
    private Integer id;
 
    /**
     * 數(shù)據(jù)庫(kù)key，即保存Map中的key
     */
    private String dbName;
 
    /**
     * 數(shù)據(jù)庫(kù)地址
     */
    private String dbUrl;
 
    /**
     * 數(shù)據(jù)庫(kù)驅(qū)動(dòng)
     */
    private String driverClassName;
 
    /**
     * 數(shù)據(jù)庫(kù)用戶名
     */
    private String username;
 
    /**
     * 數(shù)據(jù)庫(kù)密碼
     */
    private String password;
 
    // set、get方法等...
}

public interface DbInfoMapper {
 
    List<DbInfo> findAll();
}

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.example.dynamic.datasource.mapper.DbInfoMapper">
 
    <select id="findAll" resultType="com.example.dynamic.datasource.entity.DbInfo">
        select
        id
        ,db_name as dbName
        ,db_url as dbUrl
        ,driver_class_name as driverClassName
        ,username
        ,password
        from tb_db_info
        order by id
    </select>
</mapper>

public class DynamicDataSource extends AbstractRoutingDataSource {
 
    @Override
    protected Object determineCurrentLookupKey() {
        return DataSourceContextHolder.get();
    }
 
    /**
     * 重新加載數(shù)據(jù)源集合
     * @param dbList
     */
    public void loadDataSources(List<DbInfo> dbList){
        try {
            Map<Object, Object> targetDataSourceMap = new HashMap<>();
            for (DbInfo source : dbList) {
                // 初始化數(shù)據(jù)源
                DruidDataSource dataSource = new DruidDataSource();
                dataSource.setDriverClassName(source.getDriverClassName());
                dataSource.setUrl(source.getDbUrl());
                dataSource.setUsername(source.getUsername());
                dataSource.setPassword(source.getPassword());
                dataSource.setInitialSize(1);
                dataSource.setMinIdle(1);
                dataSource.setMaxActive(5);
                dataSource.setTestWhileIdle(true);
                dataSource.setTestOnBorrow(true);
                dataSource.setValidationQuery("select 1 ");
                dataSource.init();
                targetDataSourceMap.put(source.getDbName(), dataSource);
            }
            super.setTargetDataSources(targetDataSourceMap);
            // 重新初始化resolvedDataSources對(duì)象
            super.afterPropertiesSet();
        } catch (Exception e){
            e.printStackTrace();
        }
    }
}

@Configuration
publicclass DataSourceConfig {
 
    @Autowired
    private DataSourceProperties basicProperties;
 
    /**
     * 注入動(dòng)態(tài)數(shù)據(jù)源
     * @param dataSource
     * @return
     */
    @Bean
    @Primary
    public DynamicDataSource dynamicDataSource(){
        // 獲取初始數(shù)據(jù)源
        DataSource defaultDataSource = basicProperties.initializeDataSourceBuilder().build();
 
        Map<Object,Object> targetDataSources = new HashMap<>();
        targetDataSources.put("defaultDataSource", defaultDataSource);
        // 注入動(dòng)態(tài)數(shù)據(jù)源
        DynamicDataSource dynamicDataSource = new DynamicDataSource();
        // 設(shè)置默認(rèn)數(shù)據(jù)源
        dynamicDataSource.setDefaultTargetDataSource(defaultDataSource);
        // 設(shè)置動(dòng)態(tài)數(shù)據(jù)源集
        dynamicDataSource.setTargetDataSources(targetDataSources);
        return dynamicDataSource;
    }
}