InitializingBean应用场景一

假设设计一个事件模块，为了降低与其它模块之间的耦合性我们可以这样设计

 

 

1、事件模块的接口package com.hdx.common.hdxspringinit.event;

/**
 * 事件模块接口
 */
public interface EventInterface {

    /**
     * 事件类型
     * @return
     */
    public String eventType();

    /**
     * 执行事件
     * @return
     */
    public void executeEvent();
}

2、事件工厂接口

package com.hdx.common.hdxspringinit.event;

/**
 * 事件工厂注册类
 */
public interface Eventfactory {

    /**
     * 注册事件
     */
    public void registerEvent(EventInterface eventInterface);

    /**
     * 根据事件类型获取事件执行器
     */
    public EventInterface getEvent(String eventType);
}

 

3、事件管理器接口

package com.hdx.common.hdxspringinit.event;

/**
 * 事件调度管理器
 */
public interface EventManager {

    /**
     * 执行事件
     * @param eventType
     */
    public void excuteEvent(String eventType);
}

 

4、事件具体实现

package com.hdx.common.hdxspringinit.evnettest;

import com.hdx.common.hdxspringinit.event.EventInterface;
import org.springframework.stereotype.Component;

@Component
public class DeleteEvent implements EventInterface {
    @Override
    public String eventType() {
        return "delete";
    }

    @Override
    public void executeEvent() {
        System.out.printf("执行删除事件业务：com.hdx.common.hdxspringinit.evnettest.DeleteEvent.executeEvent");
    }
}

package com.hdx.common.hdxspringinit.evnettest;

import com.hdx.common.hdxspringinit.event.EventInterface;
import org.springframework.stereotype.Component;

@Component
public class UpdateEvent implements EventInterface {
    @Override
    public String eventType() {
        return "update";
    }

    @Override
    public void executeEvent() {
        System.out.printf("执行删除事件业务：com.hdx.common.hdxspringinit.evnettest.UpdateEvent.executeEvent");
    }
}

 

5、事件工厂类默认实现

package com.hdx.common.hdxspringinit.event.impl;

import com.hdx.common.hdxspringinit.event.EventInterface;
import com.hdx.common.hdxspringinit.event.Eventfactory;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.stereotype.Component;

import java.util.HashMap;
import java.util.Map;

@Component
public class EventfactoryImpl implements Eventfactory, InitializingBean {

    private final Map<String, EventInterface> eventInterfaceMap = new HashMap<>();

    @Autowired
    private ApplicationContext applicationContext;

    /**
     * 注册事件
     */
    @Override
    public void registerEvent(EventInterface eventInterface) {
        String eventType = eventInterface.eventType();
        EventInterface eventInterface1 = eventInterfaceMap.get(eventType);
        if (eventInterface1 == null) {
            eventInterfaceMap.put(eventType, eventInterface);
        }
    }

    @Override
    public EventInterface getEvent(String eventType) {
        return eventInterfaceMap.get(eventType);
    }


    @Override
    public void afterPropertiesSet() throws Exception {
        Map<String, EventInterface> events = applicationContext.getBeansOfType(EventInterface.class);
        for (EventInterface eventInterface : events.values()) {
            registerEvent(eventInterface);
        }
    }
}

 

 

6、事件管理器默认实现

package com.hdx.common.hdxspringinit.event.impl;

import com.hdx.common.hdxspringinit.event.EventInterface;
import com.hdx.common.hdxspringinit.event.EventManager;
import com.hdx.common.hdxspringinit.event.Eventfactory;
import org.springframework.beans.factory.annotation.Autowired;

/**
 * 默认事件管理器实现
 */
public class DefaultEventManagerImpl implements EventManager {

    @Autowired
    private Eventfactory eventfactory;

    @Override
    public void excuteEvent(String eventType) {
        EventInterface eventInterface = eventfactory.getEvent(eventType);
        if(eventInterface != null) {
            eventInterface.executeEvent();
        }

    }
}

 

 

 扩展知识点

ConditionalOnProperty 属性

name 在属性文件（.properties）中配置的key

havingValue 在属性文件（.properties）中配置的value

matchIfMissing 默认是否有效（如果属性文件中没有配置）

 

import org.springframework.context.annotation.Configuration;

@ConditionalOnProperty(name = "spring.datasource.type", 
        havingValue = "org.apache.tomcat.jdbc.pool.DataSource",
        matchIfMissing = true)