本篇文章为大家展示了如何在Spring Boot中利用 aop 实现一个读写分离功能,内容简明扼要并且容易理解,绝对能使你眼前一亮,通过这篇文章的详细介绍希望你能有所收获。
环境部署
数据库:MySql
库数量:2个,一主一从
开始项目
首先,毫无疑问,先开始搭建一个SpringBoot工程,然后在pom文件中引入如下依赖:
<dependencies> <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>1.3.2</version> </dependency> <dependency> <groupId>tk.mybatis</groupId> <artifactId>mapper-spring-boot-starter</artifactId> <version>2.1.5</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>8.0.16</version> </dependency> <!-- 动态数据源 所需依赖 ### start--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-jdbc</artifactId> <scope>provided</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-aop</artifactId> <scope>provided</scope> </dependency> <!-- 动态数据源 所需依赖 ### end--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <optional>true</optional> </dependency> <dependency> <groupId>com.alibaba</groupId> <artifactId>fastjson</artifactId> <version>1.2.4</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-jpa</artifactId> </dependency> </dependencies>
目录结构
引入基本的依赖后,整理一下目录结构,完成后的项目骨架大致如下:
建表
创建一张表user,在主库执行sql语句同时在从库生成对应的表数据
DROP TABLE IF EXISTS `user`; CREATE TABLE `user` ( `user_id` bigint(20) NOT NULL COMMENT '用户id', `user_name` varchar(255) DEFAULT '' COMMENT '用户名称', `user_phone` varchar(50) DEFAULT '' COMMENT '用户手机', `address` varchar(255) DEFAULT '' COMMENT '住址', `weight` int(3) NOT NULL DEFAULT '1' COMMENT '权重,大者优先', `created_at` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '创建时间', `updated_at` datetime DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT '更新时间', PRIMARY KEY (`user_id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; INSERT INTO `user` VALUES ('1196978513958141952', '测试1', '18826334748', '广州市海珠区', '1', '2019-11-20 10:28:51', '2019-11-22 14:28:26'); INSERT INTO `user` VALUES ('1196978513958141953', '测试2', '18826274230', '广州市天河区', '2', '2019-11-20 10:29:37', '2019-11-22 14:28:14'); INSERT INTO `user` VALUES ('1196978513958141954', '测试3', '18826273900', '广州市天河区', '1', '2019-11-20 10:30:19', '2019-11-22 14:28:30');
主从数据源配置
application.yml,主要信息是主从库的数据源配置
server: port: 8001 spring: jackson: date-format: yyyy-MM-dd HH:mm:ss time-zone: GMT+8 datasource: type: com.alibaba.druid.pool.DruidDataSource driver-class-name: com.mysql.cj.jdbc.Driver master: url: jdbc:mysql://127.0.0.1:3307/user?serverTimezone=Asia/Shanghai&useUnicode=true&characterEncoding=UTF-8&autoReconnect=true&failOverReadOnly=false&useSSL=false&zeroDateTimeBehavior=convertToNull&allowMultiQueries=true username: root password: slave: url: jdbc:mysql://127.0.0.1:3308/user?serverTimezone=Asia/Shanghai&useUnicode=true&characterEncoding=UTF-8&autoReconnect=true&failOverReadOnly=false&useSSL=false&zeroDateTimeBehavior=convertToNull&allowMultiQueries=true username: root password:
因为有一主一从两个数据源,我们用枚举类来代替,方便我们使用时能对应
@Getter public enum DynamicDataSourceEnum { MASTER("master"), SLAVE("slave"); private String dataSourceName; DynamicDataSourceEnum(String dataSourceName) { this.dataSourceName = dataSourceName; } }
数据源配置信息类 DataSourceConfig,这里配置了两个数据源,masterDb和slaveDb
@Configuration @MapperScan(basePackages = "com.xjt.proxy.mapper", sqlSessionTemplateRef = "sqlTemplate") public class DataSourceConfig { // 主库 @Bean @ConfigurationProperties(prefix = "spring.datasource.master") public DataSource masterDb() { return DruidDataSourceBuilder.create().build(); } /** * 从库 */ @Bean @ConditionalOnProperty(prefix = "spring.datasource", name = "slave", matchIfMissing = true) @ConfigurationProperties(prefix = "spring.datasource.slave") public DataSource slaveDb() { return DruidDataSourceBuilder.create().build(); }
/** * 主从动态配置 */ @Bean public DynamicDataSource dynamicDb(@Qualifier("masterDb") DataSource masterDataSource, @Autowired(required = false) @Qualifier("slaveDb") DataSource slaveDataSource) { DynamicDataSource dynamicDataSource = new DynamicDataSource(); Map<Object, Object> targetDataSources = new HashMap<>(); targetDataSources.put(DynamicDataSourceEnum.MASTER.getDataSourceName(), masterDataSource); if (slaveDataSource != null) { targetDataSources.put(DynamicDataSourceEnum.SLAVE.getDataSourceName(), slaveDataSource); } dynamicDataSource.setTargetDataSources(targetDataSources); dynamicDataSource.setDefaultTargetDataSource(masterDataSource); return dynamicDataSource; } @Bean public SqlSessionFactory sessionFactory(@Qualifier("dynamicDb") DataSource dynamicDataSource) throws Exception { SqlSessionFactoryBean bean = new SqlSessionFactoryBean(); bean.setMapperLocations( new PathMatchingResourcePatternResolver().getResources("classpath*:mapper/*Mapper.xml")); bean.setDataSource(dynamicDataSource); return bean.getObject(); } @Bean public SqlSessionTemplate sqlTemplate(@Qualifier("sessionFactory") SqlSessionFactory sqlSessionFactory) { return new SqlSessionTemplate(sqlSessionFactory); } @Bean(name = "dataSourceTx") public DataSourceTransactionManager dataSourceTx(@Qualifier("dynamicDb") DataSource dynamicDataSource) { DataSourceTransactionManager dataSourceTransactionManager = new DataSourceTransactionManager(); dataSourceTransactionManager.setDataSource(dynamicDataSource); return dataSourceTransactionManager; } }
设置路由
设置路由的目的为了方便查找对应的数据源,我们可以用ThreadLocal保存数据源的信息到每个线程中,方便我们需要时获取
public class DataSourceContextHolder { private static final ThreadLocal<String> DYNAMIC_DATASOURCE_CONTEXT = new ThreadLocal<>(); public static void set(String datasourceType) { DYNAMIC_DATASOURCE_CONTEXT.set(datasourceType); } public static String get() { return DYNAMIC_DATASOURCE_CONTEXT.get(); } public static void clear() { DYNAMIC_DATASOURCE_CONTEXT.remove(); } }
获取路由
public class DynamicDataSource extends AbstractRoutingDataSource { @Override protected Object determineCurrentLookupKey() { return DataSourceContextHolder.get(); } }
AbstractRoutingDataSource的作用是基于查找key路由到对应的数据源,它内部维护了一组目标数据源,并且做了路由key与目标数据源之间的映射,提供基于key查找数据源的方法。
数据源的注解
为了可以方便切换数据源,我们可以写一个注解,注解中包含数据源对应的枚举值,默认是主库,
@Retention(RetentionPolicy.RUNTIME) @Target(ElementType.METHOD) @Documented public @interface DataSourceSelector { DynamicDataSourceEnum value() default DynamicDataSourceEnum.MASTER; boolean clear() default true; }
aop切换数据源
到这里,aop终于可以现身出场了,这里我们定义一个aop类,对有注解的方法做切换数据源的操作,具体代码如下:
@Slf4j @Aspect @Order(value = 1) @Component public class DataSourceContextAop { @Around("@annotation(com.xjt.proxy.dynamicdatasource.DataSourceSelector)") public Object setDynamicDataSource(ProceedingJoinPoint pjp) throws Throwable { boolean clear = true; try { Method method = this.getMethod(pjp); DataSourceSelector dataSourceImport = method.getAnnotation(DataSourceSelector.class); clear = dataSourceImport.clear(); DataSourceContextHolder.set(dataSourceImport.value().getDataSourceName()); log.info("========数据源切换至:{}", dataSourceImport.value().getDataSourceName()); return pjp.proceed(); } finally { if (clear) { DataSourceContextHolder.clear(); } } } private Method getMethod(JoinPoint pjp) { MethodSignature signature = (MethodSignature)pjp.getSignature(); return signature.getMethod(); } }
到这一步,我们的准备配置工作就完成了,下面开始测试效果。更多springboot文章,查看往期:SpringBoot内容聚合
先写好Service文件,包含读取和更新两个方法,
@Service public class UserService { @Autowired private UserMapper userMapper; @DataSourceSelector(value = DynamicDataSourceEnum.SLAVE) public List<User> listUser() { List<User> users = userMapper.selectAll(); return users; } @DataSourceSelector(value = DynamicDataSourceEnum.MASTER) public int update() { User user = new User(); user.setUserId(Long.parseLong("1196978513958141952")); user.setUserName("修改后的名字2"); return userMapper.updateByPrimaryKeySelective(user); } @DataSourceSelector(value = DynamicDataSourceEnum.SLAVE) public User find() { User user = new User(); user.setUserId(Long.parseLong("1196978513958141952")); return userMapper.selectByPrimaryKey(user); } }
根据方法上的注解可以看出,读的方法走从库,更新的方法走主库,更新的对象是userId为1196978513958141953 的数据,
然后我们写个测试类测试下是否能达到效果,
@RunWith(SpringRunner.class) @SpringBootTest class UserServiceTest { @Autowired UserService userService; @Test void listUser() { List<User> users = userService.listUser(); for (User user : users) { System.out.println(user.getUserId()); System.out.println(user.getUserName()); System.out.println(user.getUserPhone()); } } @Test void update() { userService.update(); User user = userService.find(); System.out.println(user.getUserName()); } }
测试结果:
1、读取方法
2、更新方法
执行之后,比对数据库就可以发现主从库都修改了数据,说明我们的读写分离是成功的。当然,更新方法可以指向从库,这样一来就只会修改到从库的数据,而不会涉及到主库。
上述内容就是如何在Spring Boot中利用 aop 实现一个读写分离功能,你们学到知识或技能了吗?如果还想学到更多技能或者丰富自己的知识储备,欢迎关注亿速云行业资讯频道。
免责声明:本站发布的内容(图片、视频和文字)以原创、转载和分享为主,文章观点不代表本网站立场,如果涉及侵权请联系站长邮箱:is@yisu.com进行举报,并提供相关证据,一经查实,将立刻删除涉嫌侵权内容。