/**
 * @author: jiangjs
 * @description:
 * @date: 2023/7/27 11:21
 **/
public class DataSourceContextHolder {
    //此類提供線程局部變量。這些變量不同于它們的正常對應(yīng)關(guān)系是每個(gè)線程訪問一個(gè)線程(通過get、set方法),有自己的獨(dú)立初始化變量的副本。
    private static final 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 setDataSource(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 getDataSource(){
        return DATASOURCE_HOLDER.get();
    }

    /**
     * 刪除當(dāng)前數(shù)據(jù)源
     */
    public static void removeDataSource(){
        DATASOURCE_HOLDER.remove();
    }

}

/**
 * @author: jiangjs
 * @description: 實(shí)現(xiàn)動(dòng)態(tài)數(shù)據(jù)源，根據(jù)AbstractRoutingDataSource路由到不同數(shù)據(jù)源中
 * @date: 2023/7/27 11:18
 **/
public class DynamicDataSource extends AbstractRoutingDataSource {

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

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

#設(shè)置數(shù)據(jù)源
spring:
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    druid:
      master:
        url: jdbc:mysql://xxxxxx:3306/test1?characterEncoding=utf-8&allowMultiQueries=true&zeroDateTimeBehavior=convertToNull&useSSL=false
        username: root
        password: 123456
        driver-class-name: com.mysql.cj.jdbc.Driver
      slave:
        url: jdbc:mysql://xxxxx:3306/test2?characterEncoding=utf-8&allowMultiQueries=true&zeroDateTimeBehavior=convertToNull&useSSL=false
        username: root
        password: 123456
        driver-class-name: com.mysql.cj.jdbc.Driver
      initial-size: 15
      min-idle: 15
      max-active: 200
      max-wait: 60000
      time-between-eviction-runs-millis: 60000
      min-evictable-idle-time-millis: 300000
      validation-query: ""
      test-while-idle: true
      test-on-borrow: false
      test-on-return: false
      pool-prepared-statements: false
      connection-properties: false
/**
 * @author: jiangjs
 * @description: 設(shè)置數(shù)據(jù)源
 * @date: 2023/7/27 11:34
 **/
@Configuration
public class DateSourceConfig {

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

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

    @Bean(name = "dynamicDataSource")
    @Primary
    public DynamicDataSource createDynamicDataSource(){
        Map<Object,Object> dataSourceMap = new HashMap<>();
        DataSource defaultDataSource = masterDataSource();
        dataSourceMap.put("master",defaultDataSource);
        dataSourceMap.put("slave",slaveDataSource());
        return new DynamicDataSource(defaultDataSource,dataSourceMap);
    }

}

create table test_user(
  user_name varchar(255) not null comment '用戶名'
)

insert into test_user (user_name) value ('master');

insert into test_user (user_name) value ('slave');

@GetMapping("/getData.do/{datasourceName}")
public String getMasterData(@PathVariable("datasourceName") String datasourceName){
    DataSourceContextHolder.setDataSource(datasourceName);
    TestUser testUser = testUserMapper.selectOne(null);
    DataSourceContextHolder.removeDataSource();
    return testUser.getUserName();
}

@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)

/**
 * @author: jiangjs
 * @description:
 * @date: 2023/7/27 14:39
 **/
@Target({ElementType.METHOD,ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
public @interface DS {
    String value() default "master";
}

@Aspect
@Component
@Slf4j
public class DSAspect {

    @Pointcut("@annotation(com.jiashn.dynamic_datasource.dynamic.aop.DS)")
    public void dynamicDataSource(){}

    @Around("dynamicDataSource()")
    public Object datasourceAround(ProceedingJoinPoint point) throws Throwable {
        MethodSignature signature = (MethodSignature)point.getSignature();
        Method method = signature.getMethod();
        DS ds = method.getAnnotation(DS.class);
        if (Objects.nonNull(ds)){
            DataSourceContextHolder.setDataSource(ds.value());
        }
        try {
            return point.proceed();
        } finally {
            DataSourceContextHolder.removeDataSource();
        }
    }
}

@GetMapping("/getMasterData.do")
public String getMasterData(){
    TestUser testUser = testUserMapper.selectOne(null);
    return testUser.getUserName();
}

@GetMapping("/getSlaveData.do")
@DS("slave")
public String getSlaveData(){
    TestUser testUser = testUserMapper.selectOne(null);
    return testUser.getUserName();
}

/**
 * @author: jiangjs
 * @description: 數(shù)據(jù)源實(shí)體
 * @date: 2023/7/27 15:55
 **/
@Data
@Accessors(chain = true)
public class DataSourceEntity {

    /**
     * 數(shù)據(jù)庫地址
     */
    private String url;
    /**
     * 數(shù)據(jù)庫用戶名
     */
    private String userName;
    /**
     * 密碼
     */
    private String passWord;
    /**
     * 數(shù)據(jù)庫驅(qū)動(dòng)
     */
    private String driverClassName;
    /**
     * 數(shù)據(jù)庫key，即保存Map中的key
     */
    private String key;
}

/**
 * @author: jiangjs
 * @description: 實(shí)現(xiàn)動(dòng)態(tài)數(shù)據(jù)源，根據(jù)AbstractRoutingDataSource路由到不同數(shù)據(jù)源中
 * @date: 2023/7/27 11:18
 **/
@Slf4j
public class DynamicDataSource extends AbstractRoutingDataSource {

    private final Map<Object,Object> targetDataSourceMap;

    public DynamicDataSource(DataSource defaultDataSource,Map<Object, Object> targetDataSources){
        super.setDefaultTargetDataSource(defaultDataSource);
        super.setTargetDataSources(targetDataSources);
        this.targetDataSourceMap = targetDataSources;
    }

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

    /**
     * 添加數(shù)據(jù)源信息
     * @param dataSources 數(shù)據(jù)源實(shí)體集合
     * @return 返回添加結(jié)果
     */
    public void createDataSource(List<DataSourceEntity> dataSources){
        try {
            if (CollectionUtils.isNotEmpty(dataSources)){
                for (DataSourceEntity ds : dataSources) {
                    //校驗(yàn)數(shù)據(jù)庫是否可以連接
                    Class.forName(ds.getDriverClassName());
                    DriverManager.getConnection(ds.getUrl(),ds.getUserName(),ds.getPassWord());
                    //定義數(shù)據(jù)源
                    DruidDataSource dataSource = new DruidDataSource();
                    BeanUtils.copyProperties(ds,dataSource);
                    //申請連接時(shí)執(zhí)行validationQuery檢測連接是否有效，這里建議配置為TRUE，防止取到的連接不可用
                    dataSource.setTestOnBorrow(true);
                    //建議配置為true，不影響性能，并且保證安全性。
                    //申請連接的時(shí)候檢測，如果空閑時(shí)間大于timeBetweenEvictionRunsMillis，執(zhí)行validationQuery檢測連接是否有效。
                    dataSource.setTestWhileIdle(true);
                    //用來檢測連接是否有效的sql，要求是一個(gè)查詢語句。
                    dataSource.setValidationQuery("select 1 ");
                    dataSource.init();
                    this.targetDataSourceMap.put(ds.getKey(),dataSource);
                }
                super.setTargetDataSources(this.targetDataSourceMap);
                // 將TargetDataSources中的連接信息放入resolvedDataSources管理
                super.afterPropertiesSet();
                return Boolean.TRUE;
            }
        }catch (ClassNotFoundException | SQLException e) {
            log.error("---程序報(bào)錯(cuò)---:{}", e.getMessage());
        }
        return Boolean.FALSE;
    }

    /**
     * 校驗(yàn)數(shù)據(jù)源是否存在
     * @param key 數(shù)據(jù)源保存的key
     * @return 返回結(jié)果，true：存在，false：不存在
     */
    public boolean existsDataSource(String key){
        return Objects.nonNull(this.targetDataSourceMap.get(key));
    }
}

insert into test_db_info(url, username, password,driver_class_name, name)
value ('jdbc:mysql://xxxxx:3306/test2?characterEncoding=utf-8&allowMultiQueries=true&zeroDateTimeBehavior=convertToNull&useSSL=false',
       'root','123456','com.mysql.cj.jdbc.Driver','add_slave')

/**
 * @author: jiangjs
 * @description:
 * @date: 2023/7/27 16:56
 **/
@Component
public class LoadDataSourceRunner implements CommandLineRunner {
    @Resource
    private DynamicDataSource dynamicDataSource;
    @Resource
    private TestDbInfoMapper testDbInfoMapper;
    @Override
    public void run(String... args) throws Exception {
        List<TestDbInfo> testDbInfos = testDbInfoMapper.selectList(null);
        if (CollectionUtils.isNotEmpty(testDbInfos)) {
            List<DataSourceEntity> ds = new ArrayList<>();
            for (TestDbInfo testDbInfo : testDbInfos) {
                DataSourceEntity sourceEntity = new DataSourceEntity();
                BeanUtils.copyProperties(testDbInfo,sourceEntity);
                sourceEntity.setKey(testDbInfo.getName());
                ds.add(sourceEntity);
            }
            dynamicDataSource.createDataSource(ds);
        }
    }
}