SpringBoot读写分离组件开发详解-益强资讯优选

环境：springboot2.2.6RELEASE

实现目标：一写多读，读写读可以任意配置多个，分离默认都是组件从写库中进行操作，只有符合条件的详解方法(指定的目标方法或者标有指定注解的方法才会从读库中操作)。独立打成一个jar包放入本地仓库。读写

实现原理：通过aop。分离

1.pom.xml配置文件

<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-jpa</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-configuration-processor</artifactId> <optional>true</optional> </dependency>

2.application.yml配置文件

pack: datasource: pointcut: execution(public * net.greatsoft.service.base.*.*(..)) || execution(public * net.greatsoft.service.xxx.*.*(..)) master: driverClassName: oracle.jdbc.driver.OracleDriver jdbcUrl: jdbc:oracle:thin:@10.100.102.113:1521/orcl username: test password: test minimumIdle: 10 maximumPoolSize: 200 autoCommit: true idleTimeout: 30000 poolName: MbookHikariCP maxLifetime: 1800000 connectionTimeout: 30000 connectionTestQuery: SELECT 1 FROM DUAL slaves: - driverClassName: oracle.jdbc.driver.OracleDriver jdbcUrl: jdbc:oracle:thin:@10.100.102.113:1521/orcl username: dc password: dc minimumIdle: 10 maximumPoolSize: 200 autoCommit: true idleTimeout: 30000 poolName: MbookHikariCP maxLifetime: 1800000 connectionTimeout: 30000 connectionTestQuery: SELECT 1 FROM DUAL - driverClassName: oracle.jdbc.driver.OracleDriver jdbcUrl: jdbc:oracle:thin:@10.100.102.113:1521/orcl username: empi password: empi minimumIdle: 10 maximumPoolSize: 200 autoCommit: true idleTimeout: 30000 poolName: MbookHikariCP maxLifetime: 1800000 connectionTimeout: 30000 connectionTestQuery: SELECT 1 FROM DUAL

pointcut：定义切点，组件那些方法是详解需要拦截(从读库中操作)。

master：写库配置。源码下载读写

slaves：读库配置(List集合)。分离

3.属性配置类

@Component @ConfigurationProperties(prefix = "pack.datasource") public class RWDataSourceProperties { private String pointcut ; private HikariConfig master ; private List<HikariConfig> slaves = new ArrayList<>(); }

4.读写配置类

public class RWConfig { private static Logger logger = LoggerFactory.getLogger(RWConfig.class) ; @Bean public HikariDataSource masterDataSource(RWDataSourceProperties rwDataSourceProperties) { return new HikariDataSource(rwDataSourceProperties.getMaster()) ; } @Bean public List<HikariDataSource> slaveDataSources(RWDataSourceProperties rwDataSourceProperties) { List<HikariDataSource> lists = new ArrayList<>() ; for(HikariConfig config : rwDataSourceProperties.getSlaves()) { lists.add(new HikariDataSource(config)) ; } return lists ; } @Bean @Primary @DependsOn({"masterDataSource",组件 "slaveDataSources"}) public AbstractRoutingDataSource routingDataSource(@Qualifier("masterDataSource")DataSource masterDataSource, @Qualifier("slaveDataSources")List<HikariDataSource> slaveDataSources) { BaseRoutingDataSource ds = new BaseRoutingDataSource() ; Map<Object, Object> targetDataSources = new HashMap<>(2) ; targetDataSources.put("master", masterDataSource) ; for (int i = 0; i < slaveDataSources.size(); i++) { targetDataSources.put("slave-" + i, slaveDataSources.get(i)) ; } ds.setDefaultTargetDataSource(masterDataSource) ; ds.setTargetDataSources(targetDataSources) ; return ds ; } }

5.数据源路由

public class BaseRoutingDataSource extends AbstractRoutingDataSource { @Resource private DataSourceHolder holder; @Override protected Object determineCurrentLookupKey() { return holder.get() ; } }

public class DataSourceHolder { private ThreadLocal<Integer> context = new ThreadLocal<Integer>() { @Override protected Integer initialValue() { return 0 ; } }; @Resource private BaseSlaveLoad slaveLoad ; public String get() { Integer type = context.get() ; return type == null || type == 0 ? "master" : "slave-" + slaveLoad.load() ; } public void set(Integer type) { context.set(type) ; } }

通过aop动态设置context的内容值，0为从写库中操作，详解其它的读写都在读库中操作。

BaseSlaveLoad类为到底从那个读库中选取的分离一个算法类，默认实现使用的组件是轮询算法。

public interface BaseSlaveLoad { int load() ; }

public abstract class AbstractSlaveLoad implements BaseSlaveLoad { @Resource protected List<HikariDataSource> slaveDataSources ; }

这里定义一个抽象类注入了读库列表，所有的香港云服务器实现类从该类中继承即可。

public class PollingLoad extends AbstractSlaveLoad { private int index = 0 ; private int size = 1 ; @PostConstruct public void init() { size = slaveDataSources.size() ; } @Override public int load() { int n = index ; synchronized (this) { index = (++index) % size ; } return n ; } }

配置成Bean

@Bean @ConditionalOnMissingBean public BaseSlaveLoad slaveLoad() { return new PollingLoad() ; } @Bean public DataSourceHolder dataSourceHolder() { return new DataSourceHolder() ; }

6.数据源AOP

public class DataSourceAspect implements MethodInterceptor { private DataSourceHolder holder ; public DataSourceAspect(DataSourceHolder holder) { this.holder = holder ; } @Override public Object invoke(MethodInvocation invocation) throws Throwable { Method method = invocation.getMethod() ; String methodName = method.getName() ; SlaveDB slaveDB = method.getAnnotation(SlaveDB.class) ; if (slaveDB == null) { slaveDB = method.getDeclaringClass().getAnnotation(SlaveDB.class) ; } if (methodName.startsWith("find") || methodName.startsWith("get") || methodName.startsWith("query") || methodName.startsWith("select") || methodName.startsWith("list") || slaveDB != null) { holder.set(1) ; } else { holder.set(0) ; } return invocation.proceed(); } }

应该切点需要动态配置，所以这里采用spring aop的方式来配置

@Bean public AspectJExpressionPointcutAdvisor logAdvisor(RWDataSourceProperties props, DataSourceHolder holder) { AspectJExpressionPointcutAdvisor advisor = new AspectJExpressionPointcutAdvisor() ; logger.info("执行表达式：{}", props.getPointcut()) ; advisor.setExpression(props.getPointcut()) ; advisor.setAdvice(new DataSourceAspect(holder)) ; return advisor ; }

7.Enable开启功能

public class RWImportSelector implements ImportSelector { @Override public String[] selectImports(AnnotationMetadata importingClassMetadata) { return new String[] {RWConfig.class.getName()} ; } }

这里的RWConfig为我们上面的配置类

@Retention(RetentionPolicy.RUNTIME) @Target(ElementType.TYPE) @Documented @Import({RWImportSelector.class}) public @interface EnableRW { }

@Documented @Retention(RUNTIME) @Target({ TYPE, METHOD }) public @interface SlaveDB { }

有@SlaveDB的注解方法会类都会从读库中操作。

到此读写分离组件开发完成。

8.打包安装到本地仓库

mvn install -Dmaven.test.skip=true

9.新建base-web项目

引入依赖

<dependency> <groupId>com.pack</groupId> <artifactId>xg-component-rw</artifactId> <version>1.0.0</version> </dependency>

启动类添加注解开启读写分离功能

@SpringBootApplication @EnableRW public class BaseWebApplication { public static void main(String[] args) { SpringApplication.run(BaseWebApplication.class, args); } }

测试：

第一次查询：