Spring MVC Basic Configuration Using Annotations

1. Create a class having the following annotations :

@Configuration
@EnableWebMvc
@ComponentScan("com.XXX")
@EnableAspectJAutoProxy(proxyTargetClass = false)
@PropertySource(value = "classpath:/application.properties")

Below sample class is an example for same :

@Configuration
@EnableWebMvc
@ComponentScan("com.xxx")
@EnableAspectJAutoProxy(proxyTargetClass = false)
@PropertySource(value = "classpath:/application.properties")
public class UtilityServiceConfiguration {

private final static Logger LOG = Logger.getLogger(UtilityServiceConfiguration.class);

@Autowired
private Environment env;

@Value("${application.env}")
private String server;

@Bean
public RestTemplate getRestTemplate() {
RestTemplate restTemplate = new RestTemplate();
return restTemplate;
}

// To resolve ${} in @Value
@Bean
public static PropertySourcesPlaceholderConfigurer propertyConfigInDev() {
return new PropertySourcesPlaceholderConfigurer();
}

@Bean
public CommonsMultipartResolver multipartResolver() {
CommonsMultipartResolver resolver = new CommonsMultipartResolver();
resolver.setDefaultEncoding("utf-8");
resolver.setMaxUploadSize(Integer.parseInt(env.getProperty("multipart.maxFileSize")));
resolver.setMaxInMemorySize(Integer.parseInt(env.getProperty("multipart.maxinMemory")));
return resolver;
}



@Bean
public ThreadPoolTaskExecutor taskExecutor() {
ThreadPoolTaskExecutor pool = new ThreadPoolTaskExecutor();
pool.setCorePoolSize(5);
pool.setMaxPoolSize(10);
pool.setQueueCapacity(200);
pool.setWaitForTasksToCompleteOnShutdown(true);
pool.setRejectedExecutionHandler(new RejectedExecutionHandler() {

@Override
public void rejectedExecution(Runnable r, ThreadPoolExecutor executor) {
LOG.debug("runnable " + r);
executor.execute(r);
}
});

return pool;
}
}


2. Make another class inside the same package and add the following code :

public class XXX extends AbstractAnnotationConfigDispatcherServletInitializer

public class xxx extends AbstractAnnotationConfigDispatcherServletInitializer  {



@Override
protected Class<?>[] getRootConfigClasses() {
return new Class[] { UtilityServiceConfiguration.class };
}

@Override
protected Class<?>[] getServletConfigClasses() {
return null;
}

@Override
protected String[] getServletMappings() {
return new String[] { "/" };
}

@Override
protected Filter[] getServletFilters() {

return new Filter[] {
      new CorsFilter()
    };
}
}

3. For adding  multiple dispatcher servlet use the below config :

public class AppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {

    @Override
    public void onStartup(ServletContext servletContext) throws ServletException {

        servletContext.addListener(MyAppContextLoaderListener.class);

        servletContext.setInitParameter("spring.profiles.active", "dev");
        servletContext.setInitParameter("contextClass", "org.springframework.web.context.support.AnnotationConfigWebApplicationContext");
        servletContext.setInitParameter("contextConfigLocation", "MyAppConfig");

        // dispatcher servlet for restEntryPoint
        AnnotationConfigWebApplicationContext restContext = new AnnotationConfigWebApplicationContext();
        restContext.register(MyRestConfig.class);
        ServletRegistration.Dynamic restEntryPoint = servletContext.addServlet("restEntryPoint", new DispatcherServlet(restContext));
        restEntryPoint.setLoadOnStartup(1);
        restEntryPoint.addMapping("/api/*");

        // dispatcher servlet for webSocketEntryPoint
        AnnotationConfigWebApplicationContext webSocketContext = new AnnotationConfigWebApplicationContext();
        webSocketContext.register(MyWebSocketWebConfig.class);
        ServletRegistration.Dynamic webSocketEntryPoint = servletContext.addServlet("webSocketEntryPoint", new DispatcherServlet(webSocketContext));
        webSocketEntryPoint.setLoadOnStartup(1);
        webSocketEntryPoint.addMapping("/ws/*");

        // dispatcher servlet for webEntryPoint
        AnnotationConfigWebApplicationContext webContext = new AnnotationConfigWebApplicationContext();
        webContext.register(MyWebConfig.class);
        ServletRegistration.Dynamic webEntryPoint = servletContext.addServlet("webEntryPoint", new DispatcherServlet(webContext));
        webEntryPoint.setLoadOnStartup(1);
        webEntryPoint.addMapping("/");

        FilterRegistration.Dynamic validationFilter = servletContext.addFilter("validationFilter", new MyValidationFilter());
        validationFilter.addMappingForUrlPatterns(null, false, "/*");

        FilterRegistration.Dynamic lastFilter = servletContext.addFilter("lastFilter", new MyLastFilter());
        lastFilter.addMappingForUrlPatterns(null, false, "/*");

    }

    @Override
    protected Class<?>[] getRootConfigClasses() {
        // return new Class<?>[] { AppConfig.class };
        return null;
    }

    @Override
    protected Class<?>[] getServletConfigClasses() {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    protected String[] getServletMappings() {
        // TODO Auto-generated method stub
        return null;
    }

}