如何为Spring数据源创建自定义重试逻辑？

Question

我正在连接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故障时都能运行。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（例外）。我想处理引发异常的时间，以便触发一个作业，验证应用程序和服务器是否正确配置。我正在寻找一个解决方案，在那里我可以处理这些异常并重试DB事务？

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

不确定您认为什么是定制的，但是通过利用pom，Spring boot和Aspectj有一个现成的选项。mavern项目中的xml，因为spring重试取决于Aspectj：

在项目pom中添加以下依赖项。xml:

<dependency>
    <groupId>org.springframework.retry</groupId>
    <artifactId>spring-retry</artifactId>
    <version>${version}</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-aspects</artifactId>
    <version>${version}</version>
</dependency>

Answer 2

以下代码可以帮助您在Spring Boot上为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);
    }

}