Tomcat学习

1.3 Tomcat目录

bin下，startup.bat, startup.sh, shutdown.bat, shutdown.sh
conf logging.properties 日志相关配置
conf server.xml 需要配置，部署应用端口指定
conf tomcat-users.xml 用户，角色以及功能
conf web.xml 全局的web.xml，局部覆盖全局

1.4 浏览器请求服务器流程

http 只定义了数据的组织各市，数据考TCP/IP 传输

1.5 Tomcat处理请求

http服务器
Tomcat是一个Servlet服务器

1.6 Servlet容器处理请求

Servlet 完成业务逻辑处理

1）Tomcat是一个http服务器

2）Tomcat是一个Servlet容器

加载servlet 就是反射

1.7 总体架构概述

1）和客户端浏览器交互，进行socket通信，将字节流和Request，Response 进行转换

2）Servlet容器处理业务逻辑

1.8 Connector，Coyote

1）封装了网络通信

2）使得容器组件与容器解耦

3）里面有各种IO模型（NIO）和应用层协议（HTTP）

1.10 容器组件Catalina

本质是servlet容器

一个Catalina实例：

一个Server实例
多个Service实例
每个Service有多个Connector 和一个Container

1.11 配置

Connector 可以监听端口

Executor 增加共享线程池

一个服务器可以当做多个虚拟主机用，配置多个站点

1.16 context标签

配置一个Web应用

2.1 手写实现mini版Tomcat。思路分析

1）作为一个服务器，提供服务。接收请求（Socket 通信）。Minicat 1.0版本

package server;

import java.io.IOException;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;

public class Bootstrap {
    //端口号
    private int port = 8080;

    public int getPort() {
        return this.port;
    }

    public void setPort(int port) {
        this.port = port;
    }

    //初始化操作
    public void start() throws IOException {
        // 浏览请求 http://localhost:8080, 返回一个固定的字符串到页面 "Hello Minicat"
        // 必须写好请求体，响应头header
        ServerSocket serverSocket = new ServerSocket(this.port);
        System.out.println("Mini cat start on : " + this.port);
        while (true) {
            Socket socket = serverSocket.accept();
            // 接收到请求
            OutputStream outputStream = socket.getOutputStream();
            String responseText = HttpProtocolUtil.getHttpHeader200("Hello Minicat".getBytes().length) + "Hello Minicat";
            outputStream.write(responseText.getBytes());
            socket.close();
        }
    }

    public static void main(String[] args) {
        Bootstrap bootstrap = new Bootstrap();
        try {
            bootstrap.start();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

package server;

//提供响应头信息，这里提供200 和 400的情况
public class HttpProtocolUtil {
    public static String getHttpHeader200(long length) {
        return "HTTP/1.1 200 OK\n" +
                "Content-Type: text/html \n" +
                "Content-Length: " + length + "\n" +
                "\r\n";
    }

    public static String getHttpHeader404() {
        String str404 = "<h1> 404 not found</h1>";
        return "HTTP/1.1 400 NOT Found\n" +
                "Content-Type: text/html \n" +
                "Content-Length: " + str404.getBytes().length + "\n" +
                "\r\n" + str404;
    }
}

2）请求信息封装成Request对象（Resonpse 对象）Minicat 2.0 版本

返回html静态资源文件

启动：

package server;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;

public class Bootstrap {
    //端口号
    private int port = 8080;

    public int getPort() {
        return this.port;
    }

    public void setPort(int port) {
        this.port = port;
    }

    //初始化操作
    public void start() throws IOException {
        // 浏览请求 http://localhost:8080, 返回一个固定的字符串到页面 "Hello Minicat"
        // 必须写好请求体，响应头header
        ServerSocket serverSocket = new ServerSocket(this.port);
        System.out.println("Mini cat start on : " + this.port);

        while (true) {
            Socket socket = serverSocket.accept();
            InputStream inputStream = socket.getInputStream();
            //从输入流获取请求信息, 网络存在延迟
            Request request = new Request(inputStream);
            Response response = new Response(socket.getOutputStream());
            response.outputHtml(request.getUrl());
            socket.close();
        }
    }

    public static void main(String[] args) {
        Bootstrap bootstrap = new Bootstrap();
        try {
            bootstrap.start();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

package server;

import java.io.IOException;
import java.io.InputStream;

//根据input stream
public class Request {
    private String method; // 请求方式 比如GET/POST

    private String url; // 例如 /,/index.html. 代表资源路径 读出来通过OutputStream输出
    private InputStream inputStream; // 输入流，其他属性，从输入流中解析出来

    public String getMethod() {
        return method;
    }

    public String getUrl() {
        return url;
    }

    public InputStream getInputStream() {
        return inputStream;
    }

    public void setMethod(String method) {
        this.method = method;
    }

    public void setUrl(String url) {
        this.url = url;
    }

    public void setInputStream(InputStream inputStream) {
        this.inputStream = inputStream;
    }

    public Request(InputStream inputStream) throws IOException {
        this.inputStream = inputStream;
        int count = 0;
        while (count == 0) {
            count = inputStream.available();
        }

        byte[] bytes = new byte[count];
        inputStream.read(bytes);
        String inputStr = new String(bytes);
        String [] requests = inputStr.split("\\n");
        String firstLine = requests[0];
        String  [] firstSplit = firstLine.split(" ");
        this.method = firstSplit[0];
        this.url = firstSplit[1];
        // 可以看见请求头
        System.out.println("请求信息 method=" + this.method);
        System.out.println("请求信息 url=" + this.url);
    }
}

package server;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;

//Output Stream
public class Response {
    private OutputStream outPutStream;

    public Response() {
    }

    public Response(OutputStream outputStream) {
        this.outPutStream = outputStream;
    }

    //path url, 根据url 获取静态资源绝对路径 进一步根据绝对路径读取该路径资源文件，最终通过输出流输出
    public void outputHtml(String path) throws IOException {
        // 获取静态资源文件的绝对路径
        String absoluteResourcePath = StaticResourceUtil.getAbsolutePath(path);
        File file = new File(absoluteResourcePath);
        System.out.println("outputHtml absoluteResourcePath=" + absoluteResourcePath);
        if (file.exists() && file.isFile()) {
            System.out.println("here");
            // 读取敬爱资源，输出静态资源, 输出静态资源
            StaticResourceUtil.outputStaticResource(new FileInputStream(file), outPutStream);
        } else {
            // 输出404
            output(HttpProtocolUtil.getHttpHeader404());
        }
    }

    //使用输出流
    public void output(String content) throws IOException {
        outPutStream.write(content.getBytes());
    }

}

package server;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

public class StaticResourceUtil {
    public static String getAbsolutePath(String path) {
        String absolutePath = StaticResourceUtil.class.getResource("/").getPath();
        System.out.println("absolute " + absolutePath);
        return absolutePath.replaceAll("\\\\", "/") + path;
    }

    //读取输入流， 通过输出流
    public static void outputStaticResource(InputStream inputStream, OutputStream outputStream) throws IOException {
        int count = 0;
        while (count == 0) {
            count = inputStream.available();
        }

        int resourceSize = count;
        //输出请求头和内容
        outputStream.write(HttpProtocolUtil.getHttpHeader200(resourceSize).getBytes());
        //读取内容输出
        long written = 0; // 已经读取了内容长度

        while (written < resourceSize) {
            int byteSize = 1024;
            if (written + byteSize > resourceSize) {
                byteSize = (int) (resourceSize - written);
            }
            byte[] bytes = new byte[byteSize];
            inputStream.read(bytes);
            outputStream.write(bytes);
            outputStream.flush();
            written += byteSize;
        }
    }
}

3）客户端请求资源，资源分为静态资源（html）和动态资源（Servlet）

package server;

import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class Bootstrap {
    //端口号
    private int port = 8080;

    private Map<String, HttpServlet> servletMap = new HashMap<>();

    public int getPort() {
        return this.port;
    }

    public void setPort(int port) {
        this.port = port;
    }

    // 加载解析web.xml, 初始化Servlet
    private void loadServlet() {
        InputStream resourcesAsStream = this.getClass().getClassLoader().getResourceAsStream("web.xml");
        SAXReader saxReader = new SAXReader();
        try {
            Document document = saxReader.read(resourcesAsStream);
            Element rootElement = document.getRootElement();

            List<Element> selectNodes = rootElement.selectNodes("//servlet");
            for (Element element : selectNodes) {
                Element servletnameElement = (Element) element.selectSingleNode("servlet-name");
                String servletName = servletnameElement.getStringValue();
                Element servletMapping = (Element) rootElement.selectSingleNode("/web-app/servlet-mapping[servlet-name='" + servletName + "']");
                String urlPattern = servletMapping.selectSingleNode("url-pattern").getStringValue();
                Element servletclassElement = (Element) element.selectSingleNode("servlet-class");
                String servletClass = servletclassElement.getStringValue();
                servletMap.put(urlPattern, (HttpServlet) Class.forName(servletClass).newInstance());
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    //初始化操作
    public void start() throws Exception {
        // 浏览请求 http://localhost:8080, 返回一个固定的字符串到页面 "Hello Minicat"
        // 必须写好请求体，响应头header
        loadServlet();
        ServerSocket serverSocket = new ServerSocket(this.port);
        System.out.println("Mini cat start on : " + this.port);

        while (true) {
            Socket socket = serverSocket.accept();
            InputStream inputStream = socket.getInputStream();
            //从输入流获取请求信息, 网络存在延迟
            Request request = new Request(inputStream);
            Response response = new Response(socket.getOutputStream());
            if (servletMap.get(request.getUrl()) == null) {
                response.outputHtml(request.getUrl());
            } else {
                // 动态资源servlet请求
                HttpServlet httpServlet = servletMap.get(request.getUrl());
                httpServlet.service(request, response);
            }
            socket.close();
        }
    }

    public static void main(String[] args) throws Exception {
        Bootstrap bootstrap = new Bootstrap();
        try {
            bootstrap.start();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

package server;

public class LagouServlet extends HttpServlet {
    @Override
    public void doGet(Request request, Response response) {
        String content = "<h1>LagouServeltGet</h1>";
        try {
            response.output(
                    HttpProtocolUtil.getHttpHeader200(content.getBytes().length) + content
            );
        } catch (Exception e) {
            e.printStackTrace();
        }

    }

    @Override
    public void doPost(Request request, Response response) {

    }

    @Override
    public void init() throws Exception {

    }

    @Override
    public void destroy() throws Exception {

    }
}

package server;

public abstract class HttpServlet implements Servlet {
    public abstract void doGet(Request request, Response response);

    public abstract void doPost(Request request, Response response);

    @Override
    public void service(Request request, Response response) throws Exception {
        if ("GET".equalsIgnoreCase(request.getMethod())) doGet(request, response);
        else doPost(request, response);
    }
}

package server;

interface Servlet {
    void init() throws Exception;

    void destroy() throws Exception;

    void service(Request request, Response response) throws Exception;
}

4) 多线程改造

如果你请求了一个资源阻塞住，那么再有一个请求到你服务器，也同样会阻塞住。可以使用多线程进行改造. 来一个请求，给一个socket处理. 用线程池

package server;

import java.io.InputStream;
import java.net.Socket;
import java.util.Map;

public class RequestProcessor extends Thread {
    private Socket socket;
    private Map<String, HttpServlet> servletMap;

    public RequestProcessor(Socket socket, Map<String, HttpServlet> servletMap) {
        this.socket = socket;
        this.servletMap = servletMap;
    }

    @Override
    public void run() {
        try {
            InputStream inputStream = socket.getInputStream();

            Request request = new Request(inputStream);
            Response response = new Response(socket.getOutputStream());

            // 静态资源处理
            if (servletMap.get(request.getUrl()) == null) {
                response.outputHtml(request.getUrl());
            } else {
                // 动态资源servlet请求
                HttpServlet httpServlet = servletMap.get(request.getUrl());
                httpServlet.service(request, response);
            }

            socket.close();
        } catch (Exception e) {
            e.printStackTrace();
        }

    }
}

package server;

import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadPoolExecutor;

public class Bootstrap {
    //端口号
    private int port = 8080;

    private Map<String, HttpServlet> servletMap = new HashMap<>();

    public int getPort() {
        return this.port;
    }

    public void setPort(int port) {
        this.port = port;
    }

    // 加载解析web.xml, 初始化Servlet
    private void loadServlet() {
        InputStream resourcesAsStream = this.getClass().getClassLoader().getResourceAsStream("web.xml");
        SAXReader saxReader = new SAXReader();
        try {
            Document document = saxReader.read(resourcesAsStream);
            Element rootElement = document.getRootElement();

            List<Element> selectNodes = rootElement.selectNodes("//servlet");
            for (Element element : selectNodes) {
                Element servletnameElement = (Element) element.selectSingleNode("servlet-name");
                String servletName = servletnameElement.getStringValue();
                Element servletMapping = (Element) rootElement.selectSingleNode("/web-app/servlet-mapping[servlet-name='" + servletName + "']");
                String urlPattern = servletMapping.selectSingleNode("url-pattern").getStringValue();
                Element servletclassElement = (Element) element.selectSingleNode("servlet-class");
                String servletClass = servletclassElement.getStringValue();
                servletMap.put(urlPattern, (HttpServlet) Class.forName(servletClass).newInstance());
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    //初始化操作
    public void start() throws Exception {
        // 浏览请求 http://localhost:8080, 返回一个固定的字符串到页面 "Hello Minicat"
        // 必须写好请求体，响应头header
        loadServlet();
        ServerSocket serverSocket = new ServerSocket(this.port);
        System.out.println("Mini cat start on : " + this.port);

        ExecutorService service = Executors.newFixedThreadPool(10);

        while (true) {
            Socket socket = serverSocket.accept();
            RequestProcessor requestProcessor = new RequestProcessor(socket, servletMap);
            service.execute(requestProcessor);
        }
    }

    public static void main(String[] args) throws Exception {
        Bootstrap bootstrap = new Bootstrap();
        try {
            bootstrap.start();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

4）资源返回给客户端浏览器

2,8

posted @ 2024-03-04 11:49 ylxn 阅读(1) 评论(0) 编辑收藏举报

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