SpringBoot---系统启动加载实现的几种方法

柔光的暖阳◎ 2023-10-23 00:42 71阅读 0赞

1.CommandLineRunner

通过实现接口 CommandLineRunner 来实现，来完成项目启动就加载所需要的资源。

import org.springframework.boot.CommandLineRunner;
    import org.springframework.stereotype.Component;
    
    @Component
    public class MyProjectRunner implements CommandLineRunner {
     
        @Override
        public void run(String... args) throws Exception {
           //TODO 业务逻辑
        }
     
    }

多个 CommandLineRunner接口的实例，如果想改变他们的运行顺序可以在实现类上加入 @Order注解

@Order(value=2）

2.ApplicationRunner

通过实现接口 ApplicationRunner来实现，来完成项目启动就加载所需要的资源。

import org.springframework.boot.ApplicationArguments;
    import org.springframework.boot.ApplicationRunner;
    import org.springframework.stereotype.Component;
    
    import java.util.Arrays;
    
    @Component
    public class MyApplicationRunner implements ApplicationRunner{
    
        @Override
        public void run(ApplicationArguments args) throws Exception {
            System.out.println("===MyApplicationRunner==="+ Arrays.asList(args.getSourceArgs()));
            System.out.println("===getOptionNames========"+args.getOptionNames());
            System.out.println("===getOptionValues======="+args.getOptionValues("foo"));
            System.out.println("==getOptionValues========"+args.getOptionValues("developer.name"));
        }
    }

3.在过滤器（Filter）和 监听器（Listener）中加载初始化

Filter

import java.io.IOException;
     
    import javax.servlet.Filter;
    import javax.servlet.FilterChain;
    import javax.servlet.FilterConfig;
    import javax.servlet.ServletException;
    import javax.servlet.ServletRequest;
    import javax.servlet.ServletResponse;
    import javax.servlet.annotation.WebFilter;
     
    /**
     * 使用注解标注过滤器
     * @WebFilter将一个实现了javax.servlet.Filter接口的类定义为过滤器
     * 属性filterName声明过滤器的名称,可选
     * 属性urlPatterns指定要过滤 的URL模式,也可使用属性value来声明.(指定要过滤的URL模式是必选属性)
     */
    @WebFilter(filterName="myFilter",urlPatterns="/*")
    public class MyFilter implements Filter {
     
        @Override
        public void destroy() {
            System.out.println("过滤器销毁");
        }
     
        @Override
        public void doFilter(ServletRequest request, ServletResponse response,
                FilterChain chain) throws IOException, ServletException {
            System.out.println("执行过滤操作");
            chain.doFilter(request, response);
        }
     
        @Override
        public void init(FilterConfig config) throws ServletException {
            System.out.println("过滤器初始化");
        }
     
    }

ServletContext监听器（Listener）文件

使用@WebListener注解，实现ServletContextListener接口
    
    @WebListener
    public class MyServletContextListener implements ServletContextListener {
     
        @Override
        public void contextInitialized(ServletContextEvent sce) {
            System.out.println("ServletContex初始化");
            System.out.println(sce.getServletContext().getServerInfo());
        }
     
        @Override
        public void contextDestroyed(ServletContextEvent sce) {
            System.out.println("ServletContex销毁");
        }
     
    }

监听Session的创建与销毁

@WebListener
    public class MyHttpSessionListener implements HttpSessionListener {
     
        @Override
        public void sessionCreated(HttpSessionEvent se) {
            System.out.println("Session 被创建");
        }
     
        @Override
        public void sessionDestroyed(HttpSessionEvent se) {
            System.out.println("ServletContex初始化");
        }
     
    }

在启动主类上加入@ServletComponentScan 注解

4.在SpringBoot主启动类中嵌套加载初始操作代码

@SpringBootApplication
    @EntityScan("com.xx.entity")
    @EnableTransactionManagement
    @EnableCaching
    //@EnableAsync //开启异步
    public class MaobcMain implements WebMvcConfigurer {
    
        private static final Logger logger= LoggerFactory.getLogger(MaobcMain.class);
    
        public static void main(String[] args) {
            ConfigurableApplicationContext run = SpringApplication.run(MaobcMain.class, args);
            String[] activeProfiles = run.getEnvironment().getActiveProfiles();
            Arrays.stream(activeProfiles).forEach(profile ->logger.warn("Spring Boot 使用profile为:{}",profile));
            SystemInit.init();
        }
    
    }

public class SystemInit {
     
        /** 记录用户每次请求时间:key为userId，value为请求时间毫秒值 */
        private static Map<String, Object> requestTime = new HashMap<String, Object>();
     
        public static Map<String, Object> getRequestTime() {
            return requestTime;
        }
     
        /**
         * 系统初始化
         */
        public static void init() {
            //清空本地用户登陆信息缓存
            RedisUtils.delete(ERedisDomain.TOKEN_LOGIN_USER);
     
            //初始化ES连接池
            ESUtils.initClient();
     
            //启动系统主线程
            SystemThread thread = new SystemThread();
            thread.setDaemon(true);
            thread.start();
        }
    }