关于多数据源:MOor掰泡馍式教学实现多数据源

4次阅读

共计 12667 个字符，预计需要花费 32 分钟才能阅读完成。

本文次要介绍一种 优雅、平安、易用，反对事务管理 的 Spring Boot 整合多数据源的形式，本文中不针对多数据源是什么、为什么用、什么时候用做介绍，小伙伴可依据本身状况酌情驳回

舒适提醒：
基于以下常识有肯定利用与实际后，能更好地了解本篇文章

Lambda、ThreadLocal、栈、队列、自定义注解
IoC、AOP、Druid、Maven、Spring Boot

因为本文次要解说代码的具体实现，代码与正文较多，若感到浏览体验不佳，可配合开源代码，应用代码编辑器进行浏览
多数据源 Gitee 地址
对应我的项目模块为 hei-dynamic-datasource

通过配置类与 yml 配置文件先拆卸好默认数据源与多数据源
再通过自定义注解与 AOP，找到指标类或办法，并指定其应用的数据源 Key 值
最初通过继承 AbstractRoutingDataSource 类，返回经 AOP 解决后的数据源 Key 值，从第一步拆卸好的数据源中找到对应配置并利用

在类或办法上加上 @DataSource(“value”)就能够指定不同数据源

@Service
// 办法上的注解比类上注解优先级更高
@DataSource("slave2")
public class DynamicDataSourceTestService {
    @Autowired
    private SysUserDao sysUserDao;

    @Transactional
    public void updateUser(Long id){SysUserEntity user = new SysUserEntity();
        user.setUserId(id);
        user.setMobile("13500000002");
        sysUserDao.updateById(user);
    }

    @Transactional
    @DataSource("slave1")
    public void updateUserBySlave1(Long id){SysUserEntity user = new SysUserEntity();
        user.setUserId(id);
        user.setMobile("13500000001");
        sysUserDao.updateById(user);
    }

    @DataSource("slave2")
    @Transactional
    public void updateUserBySlave2(Long id){SysUserEntity user = new SysUserEntity();
        user.setUserId(id);
        user.setMobile("13500000003");
        sysUserDao.updateById(user);

        // 测试事务
        int i = 1/0;
    }
}

@RunWith(SpringRunner.class)
@SpringBootTest
public class DynamicDataSourceTest {
    @Autowired
    private DynamicDataSourceTestService dynamicDataSourceTestService;

    @Test
    public void test(){
        Long id = 1L;

        dynamicDataSourceTestService.updateUser(id);
        dynamicDataSourceTestService.updateUserBySlave1(id);
        dynamicDataSourceTestService.updateUserBySlave2(id);
    }

}

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-aop</artifactId>
</dependency>

dynamic:
  datasource:
    slave1:
      driver-class-name: com.mysql.cj.jdbc.Driver
      url: jdbc:mysql://localhost:3306/hei?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai
      username: root
      password: 123456
    slave2:
      driver-class-name: com.mysql.cj.jdbc.Driver
      url: jdbc:mysql://localhost:3306/hei?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai
      username: root
      password: 123456

// 定义作用范畴为（办法、接口、类、枚举、注解）@Target({ElementType.METHOD, ElementType.TYPE})
// 保障运行时能被 JVM 或应用反射的代码应用
@Retention(RetentionPolicy.RUNTIME)
// 生成 Javadoc 时让应用了 @DataSource 这个注解的中央输入 @DataSource 这个注解或不同内容
@Documented
// 类继承中让子类继承父类 @DataSource 注解
@Inherited
public @interface DataSource {// @DataSource 注解里传的参，这里次要传配置文件中不同数据源的标识，如 @DataSource("slave1")
    String value() default "";}

// 申明、定义切面类
@Aspect
@Component
/**
 * 让该 bean 的执行程序优先级最高，并不能管制加载入 IoC 的程序
 * 如果一个办法被多个 @Around 加强，那就能够应用该注解指定程序
 */
@Order(Ordered.HIGHEST_PRECEDENCE)
public class DataSourceAspect {protected Logger logger = LoggerFactory.getLogger(getClass());

    // 指明告诉在应用 @DataSource 注解标注下才触发
    @Pointcut("@annotation(io.renren.commons.dynamic.datasource.annotation.DataSource)" +
            "|| @within(io.renren.commons.dynamic.datasource.annotation.DataSource)")
    public void dataSourcePointCut() {}

    // 对告诉办法的具体实现并采纳盘绕告诉设定办法与切面的执行程序，即在办法执行前和后触发
    @Around("dataSourcePointCut()")
    /**
     * ProceedingJoinPoint 继承了 JoinPoint，相较于 JoinPoint 裸露了 proceed 办法，该类仅配合实现 around 告诉
     * JoinPoint 类，用来获取代理类和被代理类的信息
     * 调用 proceed 办法，示意继续执行指标办法（即加了 @DataSource 注解的办法）*/
    public Object around(ProceedingJoinPoint point) throws Throwable {

        // 通过反射取得被代理类（指标对象）Class targetClass = point.getTarget().getClass();
        System.out.println("targetClass:" + targetClass);
        /**
         * 取得被代理类（指标对象）的办法签名
         * signature 加签是一种简略、低成本、保障数据安全的形式
         */
        MethodSignature signature = (MethodSignature) point.getSignature();
        /**
         * 取得被代理类（指标对象）的办法
         * 这里取得办法也能够通过反射和 getTarget()，但步骤更多更简单
         */
        Method method = signature.getMethod();
        System.out.println("method:" + method);

        // 取得被代理类（指标对象）的注解对象
        DataSource targetDataSource = (DataSource) targetClass.getAnnotation(DataSource.class);
        System.out.println("targetDataSource:" + targetDataSource);
        // 取得被代理类（指标对象）的办法的注解对象
        DataSource methodDataSource = method.getAnnotation(DataSource.class);
        System.out.println("methodDataSource:" + methodDataSource);
        // 判断被代理类（指标对象）的注解对象或者被代理类（指标对象）的办法的注解对象不为空
        if (targetDataSource != null || methodDataSource != null) {
            String value;
            // 优先用被代理类（指标对象）的办法的注解对象的值进行后续赋值
            if (methodDataSource != null) {value = methodDataSource.value();
            } else {value = targetDataSource.value();
            }

            /**
             * DynamicContextHolder 是本人实现的栈数据结构
             * 将注解对象的值入栈
             */
            DynamicContextHolder.push(value);
            logger.debug("set datasource is {}", value);
        }

        try {
            // 继续执行被代理类（指标对象）的办法
            return point.proceed();} finally {
            // 清空栈中数据
            DynamicContextHolder.poll();
            logger.debug("clean datasource");
        }
    }
}

public class DynamicContextHolder {
    /**
     * Lambda 结构 本地线程变量
     * 用于防止屡次创立数据库连贯或者多线程应用同一个数据库连贯
     * 缩小数据库连贯创立敞开对程序执行效率的影响与服务器压力
     *
     * 这里应用数组队列实现栈数据结构，实现函数部分状态所需的后进先出 "LIFO" 环境
     */
    private static final ThreadLocal<Deque<String>> CONTEXT_HOLDER = ThreadLocal.withInitial(ArrayDeque::new);

    /**
     * 取得以后线程数据源
     *
     * @return 数据源名称
     */
    public static String peek() {return CONTEXT_HOLDER.get().peek();}

    /**
     * 设置以后线程数据源
     *
     * @param dataSource 数据源名称
     */
    public static void push(String dataSource) {CONTEXT_HOLDER.get().push(dataSource);
    }

    /**
     * 清空以后线程数据源
     */
    public static void poll() {Deque<String> deque = CONTEXT_HOLDER.get();
        deque.poll();
        if (deque.isEmpty()) {CONTEXT_HOLDER.remove();
        }
    }

}

public class DynamicDataSource extends AbstractRoutingDataSource {

    /**
     * 返回以后上下文环境的数据源 key
     * 后续会依据这个 key 去找到对应的数据源属性
     */
    @Override
    protected Object determineCurrentLookupKey() {return DynamicContextHolder.peek();
    }

}

/**
 * 通过 @EnableConfigurationProperties(DynamicDataSourceProperties.class)
 * 将 DynamicDataSourceProperties.class 注入到 Spring 容器中 
 */
@Configuration
@EnableConfigurationProperties(DynamicDataSourceProperties.class)
public class DynamicDataSourceConfig {
    // 这里 properties 曾经蕴含了 yml 配置中所对应的多数据源的属性了
    @Autowired
    private DynamicDataSourceProperties properties;

    /**
     * 通过 @ConfigurationProperties 与 @Bean，将 yml 配置文件对于 druid 中的属性配置，转化成 bean，并将 bean 注入到容器中
     * 这里作用是通过 autowire 作为参数利用到上面的 dynamicDataSource()办法中
     */
    @Bean
    @ConfigurationProperties(prefix = "spring.datasource.druid")
    public DataSourceProperties dataSourceProperties() {return new DataSourceProperties();
    }

    /**
     * 通过 @Bean 告知 Spring 容器，该办法会返回 DynamicDataSource 对象
     * 通过 dynamicDataSource()配置多数据源抉择逻辑，次要配置指标数据源和默认数据源
     */
    @Bean
    public DynamicDataSource dynamicDataSource(DataSourceProperties dataSourceProperties) {
        // 实例化本人实现的多数据源，其中实现了获取以后线程数据源名称的办法
        DynamicDataSource dynamicDataSource = new DynamicDataSource();
        // 设置多数据源属性
        dynamicDataSource.setTargetDataSources(getDynamicDataSource());

        // 工厂办法创立 Druid 数据源
        DruidDataSource defaultDataSource = DynamicDataSourceFactory.buildDruidDataSource(dataSourceProperties);
        // 设置默认数据源属性
        dynamicDataSource.setDefaultTargetDataSource(defaultDataSource);

        return dynamicDataSource;
    }

    private Map<Object, Object> getDynamicDataSource(){Map<String, DataSourceProperties> dataSourcePropertiesMap = properties.getDatasource();
        Map<Object, Object> targetDataSources = new HashMap<>(dataSourcePropertiesMap.size());
        dataSourcePropertiesMap.forEach((k, v) -> {DruidDataSource druidDataSource = DynamicDataSourceFactory.buildDruidDataSource(v);
            targetDataSources.put(k, druidDataSource);
        });

        return targetDataSources;
    }

}

// 这里拜访权限是包公有
class DynamicDataSourceFactory {static DruidDataSource buildDruidDataSource(DataSourceProperties properties) {DruidDataSource druidDataSource = new DruidDataSource();
        druidDataSource.setDriverClassName(properties.getDriverClassName());
        druidDataSource.setUrl(properties.getUrl());
        druidDataSource.setUsername(properties.getUsername());
        druidDataSource.setPassword(properties.getPassword());

        druidDataSource.setInitialSize(properties.getInitialSize());
        druidDataSource.setMaxActive(properties.getMaxActive());
        druidDataSource.setMinIdle(properties.getMinIdle());
        druidDataSource.setMaxWait(properties.getMaxWait());
        druidDataSource.setTimeBetweenEvictionRunsMillis(properties.getTimeBetweenEvictionRunsMillis());
        druidDataSource.setMinEvictableIdleTimeMillis(properties.getMinEvictableIdleTimeMillis());
        druidDataSource.setMaxEvictableIdleTimeMillis(properties.getMaxEvictableIdleTimeMillis());
        druidDataSource.setValidationQuery(properties.getValidationQuery());
        druidDataSource.setValidationQueryTimeout(properties.getValidationQueryTimeout());
        druidDataSource.setTestOnBorrow(properties.isTestOnBorrow());
        druidDataSource.setTestOnReturn(properties.isTestOnReturn());
        druidDataSource.setPoolPreparedStatements(properties.isPoolPreparedStatements());
        druidDataSource.setMaxOpenPreparedStatements(properties.getMaxOpenPreparedStatements());
        druidDataSource.setSharePreparedStatements(properties.isSharePreparedStatements());

        try {druidDataSource.setFilters(properties.getFilters());
            druidDataSource.init();} catch (SQLException e) {e.printStackTrace();
        }
        return druidDataSource;
    }
}

public class DataSourceProperties {
    /**
     * 可动静配置的数据库连贯属性
     */
    private String driverClassName;
    private String url;
    private String username;
    private String password;

    /**
     * Druid 默认参数
     */
    private int initialSize = 2;
    private int maxActive = 10;
    private int minIdle = -1;
    private long maxWait = 60 * 1000L;
    private long timeBetweenEvictionRunsMillis = 60 * 1000L;
    private long minEvictableIdleTimeMillis = 1000L * 60L * 30L;
    private long maxEvictableIdleTimeMillis = 1000L * 60L * 60L * 7;
    private String validationQuery = "select 1";
    private int validationQueryTimeout = -1;
    private boolean testOnBorrow = false;
    private boolean testOnReturn = false;
    private boolean testWhileIdle = true;
    private boolean poolPreparedStatements = false;
    private int maxOpenPreparedStatements = -1;
    private boolean sharePreparedStatements = false;
    private String filters = "stat,wall";

    public String getDriverClassName() {return driverClassName;}

    public void setDriverClassName(String driverClassName) {this.driverClassName = driverClassName;}

    public String getUrl() {return url;}

    public void setUrl(String url) {this.url = url;}

    public String getUsername() {return username;}

    public void setUsername(String username) {this.username = username;}

    public String getPassword() {return password;}

    public void setPassword(String password) {this.password = password;}

    public int getInitialSize() {return initialSize;}

    public void setInitialSize(int initialSize) {this.initialSize = initialSize;}

    public int getMaxActive() {return maxActive;}

    public void setMaxActive(int maxActive) {this.maxActive = maxActive;}

    public int getMinIdle() {return minIdle;}

    public void setMinIdle(int minIdle) {this.minIdle = minIdle;}

    public long getMaxWait() {return maxWait;}

    public void setMaxWait(long maxWait) {this.maxWait = maxWait;}

    public long getTimeBetweenEvictionRunsMillis() {return timeBetweenEvictionRunsMillis;}

    public void setTimeBetweenEvictionRunsMillis(long timeBetweenEvictionRunsMillis) {this.timeBetweenEvictionRunsMillis = timeBetweenEvictionRunsMillis;}

    public long getMinEvictableIdleTimeMillis() {return minEvictableIdleTimeMillis;}

    public void setMinEvictableIdleTimeMillis(long minEvictableIdleTimeMillis) {this.minEvictableIdleTimeMillis = minEvictableIdleTimeMillis;}

    public long getMaxEvictableIdleTimeMillis() {return maxEvictableIdleTimeMillis;}

    public void setMaxEvictableIdleTimeMillis(long maxEvictableIdleTimeMillis) {this.maxEvictableIdleTimeMillis = maxEvictableIdleTimeMillis;}

    public String getValidationQuery() {return validationQuery;}

    public void setValidationQuery(String validationQuery) {this.validationQuery = validationQuery;}

    public int getValidationQueryTimeout() {return validationQueryTimeout;}

    public void setValidationQueryTimeout(int validationQueryTimeout) {this.validationQueryTimeout = validationQueryTimeout;}

    public boolean isTestOnBorrow() {return testOnBorrow;}

    public void setTestOnBorrow(boolean testOnBorrow) {this.testOnBorrow = testOnBorrow;}

    public boolean isTestOnReturn() {return testOnReturn;}

    public void setTestOnReturn(boolean testOnReturn) {this.testOnReturn = testOnReturn;}

    public boolean isTestWhileIdle() {return testWhileIdle;}

    public void setTestWhileIdle(boolean testWhileIdle) {this.testWhileIdle = testWhileIdle;}

    public boolean isPoolPreparedStatements() {return poolPreparedStatements;}

    public void setPoolPreparedStatements(boolean poolPreparedStatements) {this.poolPreparedStatements = poolPreparedStatements;}

    public int getMaxOpenPreparedStatements() {return maxOpenPreparedStatements;}

    public void setMaxOpenPreparedStatements(int maxOpenPreparedStatements) {this.maxOpenPreparedStatements = maxOpenPreparedStatements;}

    public boolean isSharePreparedStatements() {return sharePreparedStatements;}

    public void setSharePreparedStatements(boolean sharePreparedStatements) {this.sharePreparedStatements = sharePreparedStatements;}

    public String getFilters() {return filters;}

    public void setFilters(String filters) {this.filters = filters;}
}

/**
 * 通过 @ConfigurationProperties 指定读取 yml 的前缀关键字
 * 配合 setDatasource()，即读取 dynamic.datasource 下的配置，将配置属性转化成 bean
 * 容器执行程序是，在 bean 被实例化后，会调用后置解决，递归的查找属性，通过反射注入值
 *
 * 因为该类只在 DynamicDataSourceConfig 类中应用，没有其它中央用到，所以没有应用 @Component
 * 而是在 DynamicDataSourceConfig 类中用 @EnableConfigurationProperties 定义为 bean
 */
@ConfigurationProperties(prefix = "dynamic")
public class DynamicDataSourceProperties {private Map<String, DataSourceProperties> datasource = new LinkedHashMap<>();

    public Map<String, DataSourceProperties> getDatasource() {return datasource;}

    public void setDatasource(Map<String, DataSourceProperties> datasource) {this.datasource = datasource;}
}

以上代码均已提交到开源我的项目中，对应我的项目模块为 hei-dynamic-datasource
有须要的小伙伴可点击下方链接，clone 代码到本地
多数据源 Gitee 地址

正文完

多数据源

发表至：多数据源

2022-04-06

0

关于多数据源:MOor掰泡馍式教学实现多数据源

关于数据库:我和TiDB的故事-毫无准备地不期而遇却想说与你相遇好幸运

关于多数据源:MOor掰泡馍式教学实现多数据源

一、引言

二、大抵思路

三、测试用例

四、我的项目构造

五、代码示例及解析

5.1、maven 相干依赖

5.2、yml 配置

5.3、自定义注解(DataSource)

5.4、切面类(DataSourceAspect)

5.5、多数据源上下文操作反对类(DynamicContextHolder)

5.6、多数据源类(DynamicDataSource)

5.7、多数据源配置类(DynamicDataSourceConfig)

5.8、多数据源工厂类(DynamicDataSourceFactory)

5.9、数据源属性类(DataSourceProperties)

5.10、多数据源属性类(DynamicDataSourceProperties)

六、最初

站内搜索