SpringBoot整合多数据源,切换.

向右看齐 2022-12-07 11:40 254阅读 0赞

测试库为ORACLE数据库,其实都一样 ,参考地址: [https://www.cnblogs.com/lhat/p/11970554.html][https_www.cnblogs.com_lhat_p_11970554.html]

测试源码 :  链接：https://pan.baidu.com/s/1b6UJaGi73868djLjdhWUjQ   提取码：zsq6

1.配置文件,重点在于配置三个数据库连接

spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
    
    #默认数据源
    spring.datasource.default-datasource.url=jdbc:oracle:thin:@localhost:1521:orcl
    spring.datasource.default-datasource.username=ZHANG
    spring.datasource.default-datasource.password=Zhenghe123
    spring.datasource.default-datasource.driver-class-name=oracle.jdbc.driver.OracleDriver
    
    #多数据源
    #数据源1
    spring.datasource.target-datasources.datasource1.url=jdbc:oracle:thin:@localhost:1521:orcl
    spring.datasource.target-datasources.datasource1.username=ZHANG
    spring.datasource.target-datasources.datasource1.password=Zhenghe123
    spring.datasource.target-datasources.datasource1.driver-class-name=oracle.jdbc.driver.OracleDriver
    #数据源2
    spring.datasource.target-datasources.datasource2.url=jdbc:oracle:thin:@localhost:1521:orcl
    spring.datasource.target-datasources.datasource2.username=SHENG
    spring.datasource.target-datasources.datasource2.password=Zhenghe123
    spring.datasource.target-datasources.datasource2.driver-class-name=oracle.jdbc.driver.OracleDriver
    
    # 初始连接数
    spring.datasource.druid.initial-size=10
    # 最大连接池数量
    spring.datasource.druid.max-active=100
    # 最小连接池数量
    spring.datasource.druid.min-idle=10
    # 配置获取连接等待超时的时间
    spring.datasource.druid.max-wait=60000
    # 打开PSCache，并且指定每个连接上PSCache的大小
    spring.datasource.druid.pool-prepared-statements=true
    spring.datasource.druid.max-pool-prepared-statement-per-connection-size=20
    # 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒
    spring.datasource.druid.time-between-eviction-runs-millis=60000
    # 配置一个连接在池中最小生存的时间，单位是毫秒
    spring.datasource.druid.min-evictable-idle-time-millis=300000
    #spring.datasource.druid.validation-query=SELECT 1 FROM DUAL
    #spring.datasource.druid.test-while-idle=true
    #spring.datasource.druid.test-on-borrow=false
    #spring.datasource.druid.test-on-return=false
            
    #===mybatis 配置===
    # 注意：一定要对应mapper映射xml文件的所在路径
    mybatis.mapper-locations=classpath*:mapper/*.xml
    # Mybatis SQL语句控制台打印
    mybatis.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl
    #开启驼峰命名  譬如数据库create_time 自动映射pojo属性createTime
    mybatis.configuration.map-underscore-to-camel-case=true

2.排除不自动扫数据源配置类

@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class})
    @MapperScan("com.zhang.oracledb.mapper")
    public class OracledbApplication {
    
        public static void main(String[] args) {
            SpringApplication.run(OracledbApplication.class, args);
        }
    
    }

3.创建枚举类,作为数据源的key

public enum  DataSourceType {
    
        /** 默认数据源key */
        DEFAULT_DATASOURCE,
    
        /** 数据源1key*/
        DATASOURCE1,
    
        /** 数据源2key*/
        DATASOURCE2,
    
    }

4.核心配置,实例化所有数据源

@Configuration
    public class DataSourceConfig {
    
        @Bean //读取默认数据源,并实例化
        @ConfigurationProperties(prefix = "spring.datasource.default-datasource")
        public DataSource defaultDataSource() {
            return DruidDataSourceBuilder.create().build();
        }
    
        @Bean //读取数据源1,并实例化
        @ConfigurationProperties(prefix = "spring.datasource.target-datasources.datasource1")
        public DataSource dataSource1() {
            return DruidDataSourceBuilder.create().build();
        }
    
        @Bean //读取数据源2,并实例化
        @ConfigurationProperties(prefix = "spring.datasource.target-datasources.datasource2")
        public DataSource dataSource2() {
            return DruidDataSourceBuilder.create().build();
        }
    
        @Bean
        @Primary
        public DataSource dynamicDataSource(DataSource defaultDataSource, DataSource dataSource1, DataSource dataSource2) {
            // 注意：该方法的参数名称要和前面前面三个datasource对象在Spring容器中的bean名称一样
            // 或者使用 @Qualifier 指定具体的bean
            Map<Object, Object> targetDataSources = new HashMap<>();
            targetDataSources.put(DataSourceType.DEFAULT_DATASOURCE.name(), defaultDataSource);
            targetDataSources.put(DataSourceType.DATASOURCE1.name(), dataSource1);
            targetDataSources.put(DataSourceType.DATASOURCE2.name(), dataSource2);
            return new DynamicDataSource(defaultDataSource, targetDataSources);
        }
    }

5.新建 DynamicDataSource类继承 AbstractRoutingDataSource ,添加构造方法把所有数据源加入和重写 determineCurrentLookupKey方法

public class DynamicDataSource extends AbstractRoutingDataSource {
    
        public DynamicDataSource(DataSource defaultTargetDataSource, Map<Object, Object> targetDataSources) {
            super.setDefaultTargetDataSource(defaultTargetDataSource);
            super.setTargetDataSources(targetDataSources);
            super.afterPropertiesSet();
        }
    
        //获取数据源的核心方法, 通过key获取数据源
        @Override
        protected Object determineCurrentLookupKey() {
            return DataSourceContextHolder.getDataSourceType();
        }
    }

6.核心方法详解

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3poYW5nc2hlbmdxaWFuZzE2OA_size_16_color_FFFFFF_t_70][]

7.使用本地线程变量,控制数据源切换

/**
     * 本地线程类,获取切换移除数据源
     **/
    public class DataSourceContextHolder {
    
        public static final ThreadLocal<String> CONTEXT_HOLDER = new ThreadLocal<String>();
    
        public static void setDataSourceType(String dsType) {
            CONTEXT_HOLDER.set(dsType);
        }
    
        public static String getDataSourceType() {
            return CONTEXT_HOLDER.get();
        }
    
        public static void removeDataSourceType() {
            CONTEXT_HOLDER.remove();
        }
    }

8.测试

@GetMapping("/test1")
        public List<Map<String, Object>> test(String dataSourceIndex) {
            // 根据参数值的不同，切换数据源
            if ("1".equals(dataSourceIndex)) {
                //获取数据源1
                DataSourceContextHolder.setDataSourceType(DataSourceType.DATASOURCE1.name());
            } else if ("2".equals(dataSourceIndex)) {
                //获取数据源2
                DataSourceContextHolder.setDataSourceType(DataSourceType.DATASOURCE2.name());
            }
            List<Map<String, Object>> mapList = testMapper.selectList();
            // 清除线程内部变量数据源key ,此步一定不能少
            DataSourceContextHolder.removeDataSourceType();
            return null;
        }

[https_www.cnblogs.com_lhat_p_11970554.html]: https://www.cnblogs.com/lhat/p/11970554.html
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3poYW5nc2hlbmdxaWFuZzE2OA_size_16_color_FFFFFF_t_70]: /images/20221123/4b03801122074eb2b7b52a0a5e1f7697.png