Use SpringBoot ApplicationListener listener - listen ApplicationReadyEvent event

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SpringBoot listeners

ApplicationContext event mechanism is the observer design pattern through the class and ApplicationEvent ApplicationListener interface enables ApplicationContext event handling.
If there is a ApplicationListener Bean container whenever ApplicationContext release ApplicationEvent, ApplicationListener Bean will automatically be triggered. This event mechanism must require the program to display the trigger.

spring boot of event types supported are as follows:

• ApplicationFailedEvent: The event starts operation failed to spring boot
• ApplicationPreparedEvent: ready to trigger the context context
• ApplicationReadyEvent: context is already ready when the trigger
• ApplicationStartedEvent: spring boot start listening class
• SpringApplicationEvent：获取SpringApplication
• ApplicationEnvironmentPreparedEvent: Environmental prepared

SpringBoot event monitor ApplicationReadyEvent use case

Custom listeners

Mybatis solve multiple data sources, you can designate a specified data source when the project starts

package com.sl.listener;

import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.support.SqlSessionDaoSupport;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.context.event.ApplicationReadyEvent;
import org.springframework.context.ApplicationListener;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.stereotype.Component;

import javax.annotation.Resource;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.stream.Stream;


/**
 * @author shuliangzhao
 * @Title: MyApplicationEventListener
 * @ProjectName spring-boot-learn
 * @Description: TODO
 * @date 2019/10/17 20:24
 */
@Component
public class MyApplicationEventListener implements ApplicationListener<ApplicationReadyEvent> {


    @Resource(name = "targetSqlSessionTemplate")
    private SqlSessionTemplate targetSqlSessionTemplate;
    
    @Resource(name = "midSqlSessionTemplate")
    private SqlSessionTemplate midSqlSessionTemplate;

    //包名 不同的包名以逗号分隔
    @Value("{taget.source}")
    private String targetSource;

    //包名
    @Value("{mid.source}")
    private String midSource;

    @Override
    public void onApplicationEvent(ApplicationReadyEvent applicationReadyEvent) {
        ConfigurableApplicationContext applicationContext = applicationReadyEvent.getApplicationContext();
        Map<String, SqlSessionDaoSupport> beanMap = applicationContext.getBeansOfType(SqlSessionDaoSupport.class);
        String[] targetScanPath = targetSource.split(",");
        String[] midScanPath = midSource.split(",");
        List<String> targetList = Arrays.asList(targetScanPath);
        List<String> midList = Arrays.asList(midScanPath);
        beanMap.forEach((k,v) -> {
            String name = v.getClass().getPackage().getName();
            if (targetList.contains(name)) {
                v.setSqlSessionTemplate(targetSqlSessionTemplate);
            }else if (midList.contains(name)) {
                v.setSqlSessionTemplate(midSqlSessionTemplate);
            }                                                 
        } );
    }
}