spring注解驱动开发（servlet）

package com.ldc.servlet;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebServlet("/hello")
public class HelloServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.getWriter().write("hello...");
    }
}

//容器启动的时候会将@HandlesTypes指定的这个类型下面的子类（实现类或者子接口等）传递过来
//传入感兴趣的类型
@HandlesTypes(value = {HelloService.class})
public class MyServletContainerInitializer implements ServletContainerInitializer {
    /**
     * 在应用启动的时候，会运行onStartup方法；
     * Set<Class<?>> ：感兴趣的类型的所有子类型；
     * ServletContext 代表当前的web应用的ServletContext对象，一个web应用相当于是一个ServletContext
     * @throws ServletException
     */
    @Override
    public void onStartup(Set<Class<?>> set, ServletContext servletContext) throws ServletException {
        System.out.println("感兴趣的类型：");
        set.forEach(System.out::println);
    }
}

public class UserServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.getWriter().write("tomcat...");
        System.out.println("UserServlet...doGet...");
    }
}

public class UserFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        //过滤请求
        System.out.println("UserFilter...doFilter...");
        //放行
        filterChain.doFilter(servletRequest,servletResponse);
    }

    @Override
    public void destroy() {

    }
}

/**
 * 监听项目的启动和停止
 */
public class UserListener implements ServletContextListener {
    //监听ServletContextEvent的启动初始化
    @Override
    public void contextInitialized(ServletContextEvent servletContextEvent) {
        System.out.println("UserListener...contextInitialized");
    }
    //监听ServletContextEvent销毁
    @Override
    public void contextDestroyed(ServletContextEvent servletContextEvent) {
        System.out.println("UserListener...contextDestroyed");
    }
}

//容器启动的时候会将@HandlesTypes指定的这个类型下面的子类（实现类或者子接口等）传递过来
//传入感兴趣的类型
@HandlesTypes(value = {HelloService.class})
public class MyServletContainerInitializer implements ServletContainerInitializer {
    /**
     * 在应用启动的时候，会运行onStartup方法；
     * Set<Class<?>> ：感兴趣的类型的所有子类型；
     * ServletContext 代表当前的web应用的ServletContext对象，一个web应用相当于是一个ServletContext
     * 1）、使用ServletContext注册Web组件（Servlet、Filter、Listener）
     * 2）、使用编码的方式，在项目启动的时候给ServletContext添加组件
     * 必须在项目启动的时候来添加
     *  （1）ServletContainerInitializer得到ServletContext对象来注册；
     *  （2）ServletContextListener的方法的参数里面的ServletContextEvent对象可以获取ServletContext对象
     */
    @Override
    public void onStartup(Set<Class<?>> set, ServletContext servletContext) throws ServletException {
        System.out.println("感兴趣的类型：");
        set.forEach(System.out::println);

        //注册组件
        Dynamic servlet = servletContext.addServlet("userServlet", new UserServlet());
        //配置servlet的映射信息
        servlet.addMapping("/user");

        //注册Listener
        servletContext.addListener(UserListener.class);

        //注册Filter
        FilterRegistration.Dynamic filter = servletContext.addFilter("userFilter", UserFilter.class);
        filter.addMappingForUrlPatterns(EnumSet.of(DispatcherType.REQUEST),true,"/*");
    }
}

//Web容器启动的时候创建对象；调用方法来初始化容器以及前端控制器
public class MyWebInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {

    //获取父容器的配置类:（Spring的配置文件） --->作为父容器
    @Override
    protected Class<?>[] getRootConfigClasses() {
        return new Class<?>[]{RootConfig.class};
    }

    //获取web容器的配置类（SpringMVC配置文件） --->作为一个子容器
    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class<?>[]{AppConfig.class};
    }

    //获取DispatcherServlet的映射信息
    //  /:拦截所有请求（包括静态资源（xx.js,xx.png），但是不包括*.jsp）
    //  /*:拦截所有请求，连*.jsp页面都拦截；jsp页面是tomcat引擎解析的
    @Override
    protected String[] getServletMappings() {
        return new String[]{"/"};
    }
}

//Spring的容器不扫描Controller，父容器
@ComponentScan(value = {"com.ldc."},excludeFilters = {
        @Filter(type = FilterType.ANNOTATION,classes = {Controller.class})
})
public class RootConfig {

}

//SpringMVC只扫描Controller，子容器
//useDefaultFilters = false 禁用默认的过滤规则
@ComponentScan(value = {"com.ldc"},includeFilters = {
        @Filter(type = FilterType.ANNOTATION,classes = {Controller.class})
},useDefaultFilters = false)
public class AppConfig {

}

@Controller
public class HelloController {

    @Autowired
    private HelloService helloService;

    @ResponseBody
    @RequestMapping("hello")
    public String hello() {
        String hello = helloService.sayHello("tomcat");
        return hello;
    }

}

@Service
public class HelloService {

    public String sayHello(String name) {
        return "Hello," + name;
    }

}

//SpringMVC只扫描Controller，子容器
//useDefaultFilters = false 禁用默认的过滤规则
@ComponentScan(value = {"com.ldc"},includeFilters = {
        @Filter(type = FilterType.ANNOTATION,classes = {Controller.class})
},useDefaultFilters = false)
@EnableWebMvc
public class AppConfig implements WebMvcConfigurer {

    @Override
    public void configurePathMatch(PathMatchConfigurer pathMatchConfigurer) {

    }

    @Override
    public void configureContentNegotiation(ContentNegotiationConfigurer contentNegotiationConfigurer) {

    }

    @Override
    public void configureAsyncSupport(AsyncSupportConfigurer asyncSupportConfigurer) {

    }

    @Override
    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer defaultServletHandlerConfigurer) {
        //将SpringMVC处理不了的请求交给tomcat，专门针对于静态资源的，这个时候，静态资源就是可以访问的
        defaultServletHandlerConfigurer.enable();
    }

    @Override
    public void addFormatters(FormatterRegistry formatterRegistry) {
        //添加自定义的类型转换器
    }

    @Override
    public void addInterceptors(InterceptorRegistry interceptorRegistry) {

    }

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry resourceHandlerRegistry) {

    }

    @Override
    public void addCorsMappings(CorsRegistry corsRegistry) {

    }

    @Override
    public void addViewControllers(ViewControllerRegistry viewControllerRegistry) {

    }

    @Override
    public void configureViewResolvers(ViewResolverRegistry viewResolverRegistry) {

    }

    @Override
    public void addArgumentResolvers(List<HandlerMethodArgumentResolver> list) {

    }

    @Override
    public void addReturnValueHandlers(List<HandlerMethodReturnValueHandler> list) {

    }

    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> list) {

    }

    @Override
    public void extendMessageConverters(List<HttpMessageConverter<?>> list) {

    }

    @Override
    public void configureHandlerExceptionResolvers(List<HandlerExceptionResolver> list) {

    }

    @Override
    public void extendHandlerExceptionResolvers(List<HandlerExceptionResolver> list) {

    }

    @Override
    public Validator getValidator() {
        return null;
    }

    @Override
    public MessageCodesResolver getMessageCodesResolver() {
        return null;
    }
}

//SpringMVC只扫描Controller，子容器
//useDefaultFilters = false 禁用默认的过滤规则
@ComponentScan(value = {"com.ldc"},includeFilters = {
        @Filter(type = FilterType.ANNOTATION,classes = {Controller.class})
},useDefaultFilters = false)
@EnableWebMvc
public class AppConfig extends WebMvcConfigurerAdapter {
    //定制

    //视图解析器

    @Override
    public void configureViewResolvers(ViewResolverRegistry registry) {
        //默认所有页面都是从/WEB-INF/xxx.jsp
        //registry.jsp();
        //我们也可以自己来写规则
        registry.jsp("/WEB-INF/views/", ".jsp");
    }
}

//SpringMVC只扫描Controller，子容器
//useDefaultFilters = false 禁用默认的过滤规则
@ComponentScan(value = {"com.ldc"},includeFilters = {
        @Filter(type = FilterType.ANNOTATION,classes = {Controller.class})
},useDefaultFilters = false)
@EnableWebMvc
public class AppConfig extends WebMvcConfigurerAdapter {
    //定制

    //视图解析器

    @Override
    public void configureViewResolvers(ViewResolverRegistry registry) {
        //默认所有页面都是从/WEB-INF/xxx.jsp
        //registry.jsp();
        //我们也可以自己来写规则
        registry.jsp("/WEB-INF/views/", ".jsp");
    }

    //静态资源的访问
    @Override
    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
        configurer.enable();
    }
}

public class MyFirstInterceptor implements HandlerInterceptor {
    //在目标方法执行之前执行
    @Override
    public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception {
        System.out.println("preHandle...");
        return true;
    }

    //在目标方法执行之后执行
    @Override
    public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
        System.out.println("postHandle...");
    }

    //页面响应以后执行
    @Override
    public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
        System.out.println("afterCompletion...");
    }
}

//SpringMVC只扫描Controller，子容器
//useDefaultFilters = false 禁用默认的过滤规则
@ComponentScan(value = {"com.ldc"},includeFilters = {
        @Filter(type = FilterType.ANNOTATION,classes = {Controller.class})
},useDefaultFilters = false)
@EnableWebMvc
public class AppConfig extends WebMvcConfigurerAdapter {
    //定制

    //视图解析器

    @Override
    public void configureViewResolvers(ViewResolverRegistry registry) {
        //默认所有页面都是从/WEB-INF/xxx.jsp
        //registry.jsp();
        //我们也可以自己来写规则
        registry.jsp("/WEB-INF/views/", ".jsp");
    }

    //静态资源的访问
    @Override
    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
        configurer.enable();
    }

    //配置拦截器
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        //拦截任意的路径
        registry.addInterceptor(new MyFirstInterceptor()).addPathPatterns("/**");
    }
}

@WebServlet("/hello")
public class HelloServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println(Thread.currentThread()+" start...");
        try {
            sayHello();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        resp.getWriter().write("hello...");
        System.out.println(Thread.currentThread()+" end...");
    }

    private void sayHello() throws InterruptedException {
        System.out.println(Thread.currentThread()+ " processing...");
        Thread.sleep(3000);
    }

}

@WebServlet(value = "/async",asyncSupported = true)
public class HelloAsyncServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //1.支持异步处理:asyncSupported = true

        //2.开启异步模式
        System.out.println("主线程开始..."+Thread.currentThread()+"==>"+ Instant.now().toEpochMilli());
        AsyncContext startAsync = req.startAsync();
        //3.业务逻辑进行异步处理，开始异步处理
        startAsync.start(()-> {
            try {
                System.out.println("副线程开始..."+Thread.currentThread()+"==>"+ Instant.now().toEpochMilli());
                sayHello();
                startAsync.complete();
                //获取异步上下文
                //AsyncContext asyncContext = req.getAsyncContext();
                //4.获取响应
                ServletResponse response = startAsync.getResponse();
                response.getWriter().write("hello async...");
                System.out.println("副线程结束..."+Thread.currentThread()+"==>"+ Instant.now().toEpochMilli());
            } catch (Exception e) {
                e.printStackTrace();
            }
        });
        System.out.println("主线程结束..."+Thread.currentThread()+"==>"+ Instant.now().toEpochMilli());
    }

    private void sayHello() throws InterruptedException {
        System.out.println(Thread.currentThread()+ " processing..."+"==>"+ Instant.now().toEpochMilli());
        Thread.sleep(3000);
    }
}

@Controller
public class AsyncController {
	 /**
     * 1、控制器返回Callable
     * 2、Spring异步处理，将Callable 提交到 TaskExecutor 使用一个隔离的线程进行执行
     * 3、DispatcherServlet和所有的Filter退出web容器的线程，但是response 保持打开状态；
     * 4、Callable返回结果，SpringMVC将请求重新派发给容器，恢复之前的处理；
     * 5、根据Callable返回的结果。SpringMVC继续进行视图渲染流程等（从收请求-视图渲染）。
     *
     * preHandle.../springmvc-annotation/async01
     主线程开始...Thread[http-bio-8081-exec-3,5,main]==>1513932494700
     主线程结束...Thread[http-bio-8081-exec-3,5,main]==>1513932494700
     =========DispatcherServlet及所有的Filter退出线程============================

     ================等待Callable执行==========
     副线程开始...Thread[MvcAsync1,5,main]==>1513932494707
     副线程开始...Thread[MvcAsync1,5,main]==>1513932496708
     ================Callable执行完成==========

     ================再次收到之前重发过来的请求========
     preHandle.../springmvc-annotation/async01
     postHandle...（Callable的之前的返回值就是目标方法的返回值）
     afterCompletion...

     异步的拦截器:
     1）、原生API的AsyncListener
     2）、SpringMVC：实现AsyncHandlerInterceptor；
     * @return
     */
    @ResponseBody
    @RequestMapping("/async01")
    public Callable<String> async01() {
        System.out.println("主线程开始..." + Thread.currentThread() + "==>" + Instant.now().getEpochSecond());
        Callable<String> callable = new Callable<String>() {
            @Override
            public String call() throws Exception {
                System.out.println("副线程开始..." + Thread.currentThread() + "==>" + Instant.now().getEpochSecond());
                Thread.sleep(2000);
                System.out.println("副线程结束..." + Thread.currentThread() + "==>" + Instant.now().getEpochSecond());
                return "Callable<String> async01()";
            }
        };
        System.out.println("主线程结束..." + Thread.currentThread() + "==>" + Instant.now().getEpochSecond());
        return callable;
    }

}

public class DeferredResultQueue {

    private static Queue<DeferredResult<Object>> queue = new ConcurrentLinkedDeque<>();

    public static void save(DeferredResult<Object> deferredResult) {
        queue.add(deferredResult);
    }
    public static DeferredResult<Object> get() {
        return queue.poll();
    }
}

@Controller
public class AsyncController {


    @ResponseBody
    @RequestMapping("/createOrder")
    public DeferredResult<Object> createOrder(){
        DeferredResult<Object> deferredResult = new DeferredResult<>((long)3000, "create fail...");

        DeferredResultQueue.save(deferredResult);

        return deferredResult;
    }


    @ResponseBody
    @RequestMapping("/create")
    public String create(){
        //创建订单
        String order = UUID.randomUUID().toString();
        DeferredResult<Object> deferredResult = DeferredResultQueue.get();
        deferredResult.setResult(order);
        return "success===>"+order;
    }
}