如何为 Spring Datasource 创建自定义重试逻辑？

Question

我正在连接到 Azure SQL 数据库，下一个任务是在连接失败时创建自定义重试逻辑。我希望重试逻辑在启动时（如果需要）以及应用程序运行时出现连接失败时运行。我做了一个测试，从我的应用程序中删除了 IP 限制，然后导致我的应用程序出现异常（如例外）。我想在抛出该异常时进行处理，以便我可以触发一个作业来验证应用程序和服务器是否配置正确。我正在寻找一种可以处理这些异常并重试数据库事务的解决方案？

数据源配置

@Bean
@Primary
public DataSource dataSource() { 
     return DataSourceBuilder
            .create()
            .username("username")
            .password("password")
            .url("jdbc:sqlserver://contoso.database.windows.net:1433;database=*********;user=******@*******;password=*****;encrypt=true;trustServerCertificate=false;hostNameInCertificate=*.database.windows.net;loginTimeout=30;")
            .driverClassName("com.microsoft.sqlserver.jdbc.SQLServerDriver")
            .build();
}

应用程序属性

spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.SQLServerDialect
spring.jpa.show-sql=true
logging.level.org.springframework.web: ERROR
logging.level.org.hibernate: ERROR
spring.datasource.tomcat.max-wait=10000
spring.datasource.tomcat.max-active=1
spring.datasource.tomcat.test-on-borrow=true
spring.jpa.hibernate.ddl-auto=update

Answer 1

以下代码可以帮助您为 Spring Boot 上的数据源创建重试逻辑：

package com.example.demo;

import java.sql.Connection;
import java.sql.SQLException;

import javax.sql.DataSource;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.Order;
import org.springframework.jdbc.datasource.AbstractDataSource;
import org.springframework.retry.annotation.Backoff;
import org.springframework.retry.annotation.EnableRetry;
import org.springframework.retry.annotation.Retryable;

@SpringBootApplication
@EnableRetry
public class DemoApplication {

    @Order(Ordered.HIGHEST_PRECEDENCE)
    private class RetryableDataSourceBeanPostProcessor implements BeanPostProcessor {
        @Override
        public Object postProcessBeforeInitialization(Object bean, String beanName)
                throws BeansException {
            if (bean instanceof DataSource) {
                bean = new RetryableDataSource((DataSource)bean);
            }
            return bean;
        }

        @Override
        public Object postProcessAfterInitialization(Object bean, String beanName)
                throws BeansException {
            return bean;
        }
    }

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }

    @Bean
    public BeanPostProcessor dataSouceWrapper() {
        return new RetryableDataSourceBeanPostProcessor();
    }
}

class RetryableDataSource extends AbstractDataSource {

    private DataSource delegate;

    public RetryableDataSource(DataSource delegate) {
        this.delegate = delegate;
    }

    @Override
    @Retryable(maxAttempts=10, backoff=@Backoff(multiplier=2.3, maxDelay=30000))
    public Connection getConnection() throws SQLException {
        return delegate.getConnection();
    }

    @Override
    @Retryable(maxAttempts=10, backoff=@Backoff(multiplier=2.3, maxDelay=30000))
    public Connection getConnection(String username, String password)
            throws SQLException {
        return delegate.getConnection(username, password);
    }

}