咱们都晓得springboot 因为内置tomcat(中间件)间接用启动类就能够启动了。
而且咱们有时想代码给程序设置一些默认参数,所以应用办法Springboot.setDefaultProperties(map)

SpringApplication application = new SpringApplication(startClass);//Map<String, Object> params = new HashMap<>();params.put("lai.ws.test","test");application.setDefaultProperties(params);ApplicationContext context = application.run(startClass,args);

于是启动后发现 lai.ws.test 竟然是null,也就是参数设置不胜利,百思不得其解。为此还断点进入SpringApplication 的源码里。最初发现以下源码

    /**     * Static helper that can be used to run a {@link SpringApplication} from the     * specified sources using default settings and user supplied arguments.     * @param primarySources the primary sources to load     * @param args the application arguments (usually passed from a Java main method)     * @return the running {@link ApplicationContext}     */    public static ConfigurableApplicationContext run(Class<?>[] primarySources,            String[] args) {        return new SpringApplication(primarySources).run(args);    }

各位,发现了没,又new 了一个SpringApplication。到此,问题答案找到了。
如果启动类要设置默认参数,不必应用以下办法去启动

ApplicationContext context = application.run(startClass,args);

应该应用以下

 ApplicationContext context = application.run(args);