• BeanFactory結構圖
• Spring容器啟動過程
• Bean例項化過程

1、bean實現Aware介面的意義（圖中檢查Aware相關介面並設定相關依賴）

package com.anotation.bean;

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;

@Component
public class Dog implements ApplicationContextAware {

	private String name;

	//10公；20母
	private Integer sex;
	
	private ApplicationContext applicationContext;

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public Integer getSex() {
		return sex;
	}

	public void setSex(Integer sex) {
		this.sex = sex;
	}

	public Dog(){
		System.out.println("dog constructor...");
	}
	
	//物件建立並賦值之後呼叫
	@PostConstruct
	public void init(){
		System.out.println("
 
[email protected]");
	}
	
	//容器移除物件之前呼叫
	@PreDestroy
	public void detory(){
		System.out.println("[email protected]");
	}

	//實現ApplicationContextAware介面，並重寫他的setApplicationContext()方法，可以讓當前物件擁有容器的ApplicationContext引用
	@Override
	public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
		this.applicationContext = applicationContext;
	}

	@Override
	public String toString() {
		return "Dog{" + "name='" + name + '\'' + ", sex=" + sex + '}';
	}
}
 

2、實現BeanPostProcessor的作用：他的兩個方法都傳入了物件例項的引用，這為我們擴充套件容器的物件例項化過程中的行為提供了極大的便利，我們幾乎可以對傳入的物件例項做任何操作

package com.anotation.bean;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.stereotype.Component;

/**
 *
 * 建立一個BeanPost類，實現BeanPostProcessor介面。
 * 在其postProcessAfterInitialization()方法中修改通過引數傳入的受管Bean，然後返回。
 * 由於它處理容器中的每一個Bean，因此在修改前，應判斷Bean是否為我們要處理的Bean。
 * 可以通過傳入Bean的型別判定，也可以通過傳入Bean的名字判定
 *
 * @author zhengchao
 */
@Component
public class MyBeanPostProcessor implements BeanPostProcessor {

    @Override
    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {

        System.out.println("postProcessBeforeInitialization..." + beanName + "=>" + bean);
        System.out.println("BeanPostProcessor.postProcessAfterInitialization 正在預處理！");
        //過濾特定型別的bean來修改bean的屬性或其為其進行增強（AOP就是基於此原理）
        if ((bean instanceof Dog)){
            Dog dog = (Dog) bean;
            dog.setName("范冰冰");
            dog.setSex(20);
            return bean;
        }
        return bean;
    }

    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        System.out.println("postProcessAfterInitialization..." + beanName + "=>" + bean);
        return bean;
    }
}
 

3、spring Aop手寫實現

public interface ITask {
    void execute();
}

public class TaskImpl implements ITask{
    @Override
    public void execute() {
        Date date = new Date();
        System.out.println("資訊：["+date+"] 呼叫了execute()方法。");
    }
}

import org.springframework.aop.AfterReturningAdvice;
import org.springframework.aop.MethodBeforeAdvice;
import java.lang.reflect.Method;
import java.util.Date;
/**
 * 基於jdk的動態代理實現自己的aop: pointcut&&advice （還有一種cglib）
 */
public class MethodBeforeAdviceImpl implements MethodBeforeAdvice, AfterReturningAdvice {

    //攔截方法之前執行
    @Override
    public void before(Method arg0, Object[] arg1, Object arg2) throws Throwable {
        Date date = new Date();
        System.out.println("資訊：["+date+"] 呼叫了before()方法。");
    }

    //攔截方法返回結果之後執行
    @Override
    public void afterReturning(Object returnValue, Method method, Object[] args, Object target)
            throws Throwable {
        Date date = new Date();
        System.out.println("資訊：["+date+"] 呼叫了afterReturning()方法。");
    }
}

public class MainTest {

    public static void main(String[] args) {
        TaskImpl task = new TaskImpl();

        NameMatchMethodPointcut pc=new NameMatchMethodPointcut();
        pc.addMethodName("execute");

        Advice advice=new MethodBeforeAdviceImpl();
        Advisor advisor=new DefaultPointcutAdvisor(pc,advice);

        //建立BeanOne代理
        ProxyFactory pf1=new ProxyFactory();
        pf1.addAdvisor(advisor);
        pf1.setTarget(task);
        ITask proxyObject = (ITask)pf1.getProxy();
        proxyObject.execute();
    }
}

返回：
資訊：[Mon Oct 22 21:28:12 CST 2018] 呼叫了before()方法。
資訊：[Mon Oct 22 21:28:12 CST 2018] 呼叫了execute()方法。
資訊：[Mon Oct 22 21:28:12 CST 2018] 呼叫了afterReturning()方法。

to be continue