【spring高级49讲】

Spring高级49讲

1. Spring是整个Java体系最核心的框架,没有之一
2. 面试必备
3. 技术、思想提升

一.容器和Bean

第1讲.BeanFactory和ApplicationContext

1.1.BeanFactory

• BeanFactory是ApplicationContext的父接口
• BeanFactory才是Spring的核心容器，ApplicationContext 实现和【组合】了它的功能

注：ctrl alt B 进入方法的实现类 ctrl F12 列出类中所有方法 类图中f4查看方法源码

• (1)获取Springboot中的单例

package com.ttc;

import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.support.DefaultSingletonBeanRegistry;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ConfigurableApplicationContext;

import java.lang.reflect.Field;
import java.util.Map;

@SpringBootApplication
public class Demo1Application {
    

    public static void main(String[] args) throws Exception {
    

        ConfigurableApplicationContext ctx = SpringApplication.run(Demo1Application.class, args);
        System.out.println(ctx);
        Field singletonObjects = DefaultSingletonBeanRegistry.class.getDeclaredField("singletonObjects");
        singletonObjects.setAccessible(true);
        ConfigurableListableBeanFactory beanFactory = ctx.getBeanFactory();
        Map<String, Object> map = (Map<String, Object>) singletonObjects.get(beanFactory);
        map.forEach((k, v) -> {
    
            System.out.println(k + "=" + v);
        });
    }
}

• (2) 指定componet查询单例 componet可任意指定

package com.ttc;

import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.support.DefaultSingletonBeanRegistry;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ConfigurableApplicationContext;

import java.lang.reflect.Field;
import java.util.Map;

@SpringBootApplication
public class Demo1Application {
    

    public static void main(String[] args) throws Exception {
    

        ConfigurableApplicationContext ctx = SpringApplication.run(Demo1Application.class, args);
        System.out.println(ctx);
        Field singletonObjects = DefaultSingletonBeanRegistry.class.getDeclaredField("singletonObjects");
        singletonObjects.setAccessible(true);
        ConfigurableListableBeanFactory beanFactory = ctx.getBeanFactory();
        Map<String, Object> map = (Map<String, Object>) singletonObjects.get(beanFactory);
        map.entrySet().stream().filter(e -> e.getKey().startsWith("componet"))
                .forEach(e -> {
    
                    System.out.println(e.getKey() + "=" + e.getValue());
                });

    }
}

• (3) BeanFactory 能干啥?

• 表面上只有getBean()
• 实际上 控制反转 依赖注入 直至 Bean的生命周期的各种功能，都由它的实现类提供

1.2ApplicationContext

• getMessage 国际化消息功能

package com.ttc;

import org.apache.ibatis.logging.stdout.StdOutImpl;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.support.DefaultSingletonBeanRegistry;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ConfigurableApplicationContext;

import java.lang.reflect.Field;
import java.util.Locale;
import java.util.Map;

@SpringBootApplication
public class Demo1Application {
    

    public static void main(String[] args) throws Exception {
    

        ConfigurableApplicationContext ctx = SpringApplication.run(Demo1Application.class, args);
        System.out.println(ctx);
        Field singletonObjects = DefaultSingletonBeanRegistry.class.getDeclaredField("singletonObjects");
        singletonObjects.setAccessible(true);
        ConfigurableListableBeanFactory beanFactory = ctx.getBeanFactory();
        Map<String, Object> map = (Map<String, Object>) singletonObjects.get(beanFactory);
        map.entrySet().stream().filter(e -> e.getKey().startsWith("componet"))
                .forEach(e -> {
    
                    System.out.println(e.getKey() + "=" + e.getValue());
                });
        System.out.println(ctx.getMessage("hi", null, Locale.CHINA));
        System.out.println(ctx.getMessage("hi", null, Locale.ENGLISH));
        System.out.println(ctx.getMessage("hi", null, Locale.JAPANESE));
    }
}

• getResources

  • classpath 类路径
  • filepath 磁盘路径

  查找文件 classpath* 可以从jar包中寻找

package com.ttc;

import org.apache.ibatis.logging.stdout.StdOutImpl;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.support.DefaultSingletonBeanRegistry;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.core.io.Resource;

import java.lang.reflect.Field;
import java.util.Locale;
import java.util.Map;

@SpringBootApplication
public class Demo1Application {
    

    public static void main(String[] args) throws Exception {
    

        ConfigurableApplicationContext ctx = SpringApplication.run(Demo1Application.class, args);
        System.out.println(ctx);
        Field singletonObjects = DefaultSingletonBeanRegistry.class.getDeclaredField("singletonObjects");
        singletonObjects.setAccessible(true);
        ConfigurableListableBeanFactory beanFactory = ctx.getBeanFactory();
        Map<String, Object> map = (Map<String, Object>) singletonObjects.get(beanFactory);
        map.entrySet().stream().filter(e -> e.getKey().startsWith("componet"))
                .forEach(e -> {
    
                    System.out.println(e.getKey() + "=" + e.getValue());
                });
        System.out.println(ctx.getMessage("hi", null, Locale.CHINA));
        System.out.println(ctx.getMessage("hi", null, Locale.ENGLISH));
        System.out.println(ctx.getMessage("hi", null, Locale.JAPANESE));
        Resource[] resources = ctx.getResources("classpath*:META-INF/spring.factories");
        for (Resource resource : resources) {
    
            System.out.println(resource);
        }

    }
}

• getEnvironment 获取配置信息

  System.out.println(ctx.getEnvironment().getProperty("java_home"));     // 获取 JAVA_HOME 位置 ( jdk 安装目录)
  System.out.println(ctx.getEnvironment().getProperty("server.port"));   // 获取 tomcat访问端口
  

• publishEvent

  #  修改日志级别  可以看到 debug 级别
  logging:
    level:
      com.ttc: trace
  

         // 发送事件
          ctx.publishEvent(new UserReigisteredEvent(ctx));
  

  package com.ttc;
  
  import org.springframework.context.ApplicationEvent;
  
  /** * 设置事件 */
  public class UserReigisteredEvent extends ApplicationEvent {
        
      // source 指代事件源
      public UserReigisteredEvent(Object source) {
        
          super(source);
      }
  }
  
  

  package com.ttc;
  
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.springframework.context.event.EventListener;
  import org.springframework.stereotype.Component;
  
  /** * 监听事件 */
  
  @Component
  public class Componet2 {
        
      private static final Logger log = LoggerFactory.getLogger(Componet2.class);
  
      @EventListener
      public void aaa(UserReigisteredEvent event) {
        
          log.debug("{}", event);
      }
  }
  
  

  注： 任意的类都可以去监听

二.AOP

三.Web MVC

四.Spring boot

五.其他