Spring Boot

前言

Spring Boot启动的时候需要加载许多Bean实现最小化配置，本文将尝试找出Spring启动后加载的所有Bean信息；

通过ApplicationContext 去获取所有的Bean

通过CommandLineRunner接口，可以实现在Spring Boot完全启动后执行一些代码逻辑，本文将执行的逻辑是打印所有Bean的信息；

1. 通过 ApplicationContext.getBeanDefinitionNames() 方法获取所有Bean的名称；
2. 通过 ApplicationContext.getBean(beanName) 获取Bean的详细信息；

具体代码实现如下：

package com.howtodoinjava.app.controller;
 
import java.util.Arrays;
 
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.web.support.SpringBootServletInitializer;
import org.springframework.context.ApplicationContext;
 
@SpringBootApplication
public class SpringBootWebApplication extends SpringBootServletInitializer implements CommandLineRunner {
 
    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
        return application.sources(SpringBootWebApplication.class);
    }
 
    public static void main(String[] args) throws Exception {
        SpringApplication.run(SpringBootWebApplication.class, args);
    }
     
    @Autowired
    private ApplicationContext appContext;
     
    @Override
    public void run(String... args) throws Exception
    {
        String[] beans = appContext.getBeanDefinitionNames();
        Arrays.sort(beans);
        for (String bean : beans)
        {
            System.out.println(bean + " of Type :: " + appContext.getBean(bean).getClass());
        }
    }
}

运行以上程序，控制台将打印如下信息：

2017-03-06 13:22:50 - Tomcat started on port(s): 8080 (http)
 
basicErrorController of Type :: class org.springframework.boot.autoconfigure.web.BasicErrorController
beanNameHandlerMapping of Type :: class org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping
beanNameViewResolver of Type :: class org.springframework.web.servlet.view.BeanNameViewResolver
characterEncodingFilter of Type :: class org.springframework.boot.web.filter.OrderedCharacterEncodingFilter
conventionErrorViewResolver of Type :: class org.springframework.boot.autoconfigure.web.DefaultErrorViewResolver
defaultServletHandlerMapping of Type :: class org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport$EmptyHandlerMapping
defaultViewResolver of Type :: class org.springframework.web.servlet.view.InternalResourceViewResolver
dispatcherServlet of Type :: class org.springframework.web.servlet.DispatcherServlet
dispatcherServletRegistration of Type :: class org.springframework.boot.web.servlet.ServletRegistrationBean
duplicateServerPropertiesDetector of Type :: class org.springframework.boot.autoconfigure.web.ServerPropertiesAutoConfiguration$DuplicateServerPropertiesDetector
embeddedServletContainerCustomizerBeanPostProcessor of Type :: class org.springframework.boot.context.embedded.EmbeddedServletContainerCustomizerBeanPostProcessor
error of Type :: class org.springframework.boot.autoconfigure.web.ErrorMvcAutoConfiguration$SpelView
errorAttributes of Type :: class org.springframework.boot.autoconfigure.web.DefaultErrorAttributes
...
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