手写tomcat——有线程池化能力的servlet 服务

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public class DiyTomcat {

    private int port = 8080;

    public static final HashMap<String, DiyServlet> SERVLET_MAPPING = new HashMap<>();

    public static final HashMap<String,String> URL_MAPPING = new HashMap<>();

    private static ThreadPoolExecutor threadPoolExecutor;

    static {

        loadServlet();

        initExecutors();

    }

    // 线程池化

    private static void initExecutors() {

        int corePoolSize = 10;

        int maximumPoolSize = 50;

        long keepAliveTime = 100L;

        TimeUnit unit = TimeUnit.SECONDS;

        BlockingQueue<Runnable> workQueue = new ArrayBlockingQueue<>(50);

        ThreadFactory threadFactory = Executors.defaultThreadFactory();

        RejectedExecutionHandler handler = new ThreadPoolExecutor.AbortPolicy();

        threadPoolExecutor = new ThreadPoolExecutor(

                corePoolSize,

                maximumPoolSize,

                keepAliveTime,

                unit,

                workQueue,

                threadFactory,

                handler

        );

    }

    private static void loadServlet() {

        try {

            //获取web.xml目录地址

            String path = DiyTomcat.class.getResource("/").getPath();

            SAXReader reader = new SAXReader();

            //读取web.xml文件

            Document document = reader.read(new File(path + "web.xml"));

            //获取根标签（servlet和servlet-mapping），放在一个List中

            Element rootElement = document.getRootElement();

            List<Element> elements = rootElement.elements();

            //循环将映射写进map映射里

            for(Element element : elements){

                if ("servlet".equalsIgnoreCase(element.getName())){

                    Element servletName = element.element("servlet-name");

                    Element servletClass = element.element("servlet-class");

                    //需要注意的是servletMapping映射的第二个参数，要通过反射的方式进行实例化

                    SERVLET_MAPPING.put(servletName.getText(),

                            (DiyServlet) Class.forName(servletClass.getText().trim()).newInstance());

                }else if ("servlet-mapping".equalsIgnoreCase(element.getName())){

                    Element servletName = element.element("servlet-name");

                    Element urlPattern = element.element("url-pattern");

                    URL_MAPPING.put(urlPattern.getText(), servletName.getText());

                }

            }

        } catch (DocumentException e) {

            e.printStackTrace();

        } catch (MalformedURLException e) {

            e.printStackTrace();

        } catch (ClassNotFoundException e) {

            e.printStackTrace();

        } catch (IllegalAccessException e) {

            e.printStackTrace();

        } catch (InstantiationException e) {

            e.printStackTrace();

        }

    }

    public void start() throws IOException {

        ServerSocket serverSocket = new ServerSocket(port);

        while (true) {

            Socket socket = serverSocket.accept();

            RequestHandler requestHandler = new RequestHandler(socket);

            // 一个 socket 一个线程

            // new Thread(requestHandler).start();

            // 使用线程组干活

            threadPoolExecutor.execute(requestHandler);

        }

    }

}

通过initExecutors方法创建出一个线程池

    private static void initExecutors() {

        // 核心线程数

        int corePoolSize = 10;

       // 最大线程数

        int maximumPoolSize = 50;

       // 空闲线程保活时间

        long keepAliveTime = 100L;

       // 保活单位，当前设置为秒

        TimeUnit unit = TimeUnit.SECONDS;

       // 线程池队列

        BlockingQueue<Runnable> workQueue = new ArrayBlockingQueue<>(50);

       // 线程创建工厂

       ThreadFactory threadFactory = Executors.defaultThreadFactory();

       // 池子满后的拒绝请求处理器

        RejectedExecutionHandler handler = new ThreadPoolExecutor.AbortPolicy();

        threadPoolExecutor = new ThreadPoolExecutor(

                corePoolSize,

                maximumPoolSize,

                keepAliveTime,

                unit,

                workQueue,

                threadFactory,

                handler

        );

    }

accept到socket后直接包装成RequestHandler交由线程池处理

while (true) {

            Socket socket = serverSocket.accept();

            RequestHandler requestHandler = new RequestHandler(socket);

            // 一个 socket 一个线程

            // new Thread(requestHandler).start();

            // 使用线程组干活

            threadPoolExecutor.execute(requestHandler);

        }

代码地址：

https://github.com/ZhongJinHacker/diy-tomcat/tree/pool-tomcat

巴特西

手写tomcat——有线程池化能力的servlet 服务

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