spring框架学习记录 3

context的component-scan

component.xml

Login.java

package com.component.entity;

import org.springframework.stereotype.Component;

@Component("entity")// 如果注解中没有值，getbean中name为类名首字母小写，有值name则为参数值
public class Login {
    String account;
    String password;
    public Login(){
        System.out.println("@Component...");
    }
    public Login(String account, String password){
        this.account=account;
        this.password=password;
        System.out.println("@Component param...");
    }


}

Test.java

package com.component;

import com.component.controller.LoginController;
import com.component.dao.LoginDAO;
import com.component.dao.LoginDAOImpl;
import com.component.entity.Login;
import com.component.service.LoginService;
import com.component.service.LoginServiceImpl;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Test {
    public static void main(String[] args) {
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("component.xml");
        Login login = applicationContext.getBean("entity", Login.class);
        LoginController loginController = applicationContext.getBean("controllerId", LoginController.class);
        LoginDAO loginDAO = applicationContext.getBean("repositoryId", LoginDAOImpl.class);
        LoginService loginService = applicationContext.getBean("serviceId", LoginServiceImpl.class);
        System.out.println(login);
        System.out.println(loginController);
        System.out.println(loginDAO);
        System.out.println(loginService);
    }
}

Q:spring中，factorybean与beanFactory的区别

BeanFactory文件

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by Fernflower decompiler)
//

package org.springframework.beans.factory;

import org.springframework.beans.BeansException;
import org.springframework.core.ResolvableType;

public interface BeanFactory {
    String FACTORY_BEAN_PREFIX = "&";

    Object getBean(String var1) throws BeansException;

     T getBean(String var1, Class var2) throws BeansException;

     T getBean(Class var1) throws BeansException;

    Object getBean(String var1, Object... var2) throws BeansException;

     T getBean(Class var1, Object... var2) throws BeansException;

    boolean containsBean(String var1);

    boolean isSingleton(String var1) throws NoSuchBeanDefinitionException;

    boolean isPrototype(String var1) throws NoSuchBeanDefinitionException;

    boolean isTypeMatch(String var1, ResolvableType var2) throws NoSuchBeanDefinitionException;

    boolean isTypeMatch(String var1, Class var2) throws NoSuchBeanDefinitionException;

    Class getType(String var1) throws NoSuchBeanDefinitionException;

    String[] getAliases(String var1);
}

是ApplicationContext和ClassPathXmlApplicationContext的父接口，有常用的getBean方法，

BeanFactory文件

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by Fernflower decompiler)
//

package org.springframework.beans.factory;

public interface FactoryBean {
    T getObject() throws Exception;

    Class getObjectType();

    boolean isSingleton();
}

通过自定义类实现BeanFactory接口，实现

getObject

getObjectType

isSingleton

的接口方法，实现工厂bean模式注入，spring工厂bean创建对象