- BeanFactory結構圖
- Spring容器啓動過程
- Bean實例化過程
1、bean實現Aware接口的意義(圖中檢查Aware相關接口並設置相關依賴)
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...");
}
//對象創建並賦值之後調用
@PostConstruct
public void init(){
System.out.println("Dog....@PostConstruct...");
}
//容器移除對象之前調用
@PreDestroy
public void detory(){
System.out.println("Dog....@PreDestroy...");
}
//實現ApplicationContextAware接口,並重寫他的setApplicationContext()方法,可以讓當前對象擁有容器的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對象實例的引用,這爲我們擴展容器的對象實例化過程中的行爲提供了極大的便利,我們幾乎可以對傳入的對象實例做任何操作
package com.anotation.bean;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.stereotype.Component;
/**
*
* 創建一個BeanPost類,實現BeanPostProcessor接口。
* 在其postProcessAfterInitialization()方法中修改通過參數傳入的受管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是否爲我們要處理的Bean。
* 可以通過傳入Bean的類型判定,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!");
//過濾特定類型的bean來修改bean的屬性或其爲其進行增強(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;
}
}
to be continue