手写Tomcat服务器

tip：由于作为调试有一些多余的System.out.println()语句，请忽略。

模拟客户端发送请求，并接收服务器返回的数据：

package com.milk.mytomcat.one;

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

/*
模拟客户端发送请求，并接受服务端传回来的数据
 */
public class TestClient {

    public static void main(String[] args) throws Exception {
        Socket socket = null;
        InputStream inputStream = null;
        OutputStream outputStream = null;

        try {
            socket = new Socket("www.faw.com.cn", 80);
            inputStream = socket.getInputStream();
            outputStream = socket.getOutputStream();
            outputStream.write("GET /fawcn/373694/373706/index.html HTTP/1.1\n".getBytes());
            outputStream.write("HOST:www.faw.com.cn\n".getBytes());
            outputStream.write("\n".getBytes());
            int i = inputStream.read();
            while (i != -1) {
                System.out.print((char)i);
                i = inputStream.read();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            if (null != inputStream) {
                inputStream.close();
                inputStream = null;
            }
            if (null != outputStream) {
                outputStream.close();
                outputStream = null;
            }
            if(null != socket) {
                socket.close();
                socket = null;
            }
        }
    }
}

模拟服务端向客户端响应数据

package com.milk.mytomcat.one;

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

/*
模拟服务端向客户端响应数据
 */
public class TestServer {

    public static void main(String[] args) throws Exception {
        ServerSocket serverSocket = null;
        Socket socket = null;
        OutputStream outputStream = null;

        try {
            serverSocket = new ServerSocket(10086);
            socket = serverSocket.accept();
            outputStream = socket.getOutputStream();
            outputStream.write("HTTP/1.1 200 OK\n".getBytes());
            outputStream.write("Content-Type:text/html;charset=utf-8\n".getBytes());
            outputStream.write("Server:Apache-Coyote/1.1\n".getBytes());
            outputStream.write("\n\n".getBytes());
            StringBuffer buffer = new StringBuffer();
            buffer.append("<html>");
            buffer.append("<head><title>I am Title</title></head>");
            buffer.append("<body>");
            buffer.append("<h1>I am header 1</h1>");
            buffer.append("<a href='http://www.baidu.com'>百度</a>");
            buffer.append("</body>");
            buffer.append("</html>");
            outputStream.write(buffer.toString().getBytes());
            outputStream.flush();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (null != outputStream) {
                outputStream.close();
                outputStream = null;
            }
            if (null != socket) {
                socket.close();
                socket = null;
            }
        }
    }
}

Tomcat版本1:响应静态页面

package com.milk.mytomcat.two;

import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;

/*
Tomcat版本1
 */
public class Tomcat01 {

    public static String WEB_ROOT = System.getProperty("user.dir") + "\\" + "WebContent";

    private static String url = "";

    public static void main(String[] args) throws Exception {
//        System.out.println(WEB_ROOT);
        ServerSocket serverSocket = null;
        Socket socket = null;
        InputStream inputStream = null;
        OutputStream outputStream = null;

        try {
            serverSocket = new ServerSocket(10086);
            while(true) {
                // 接受客户端发送过来的请求
                socket = serverSocket.accept();
                inputStream = socket.getInputStream();
                outputStream = socket.getOutputStream();
                parse(inputStream);
                sendStaticResource(outputStream);
            }

        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if(null != outputStream) {
                outputStream.close();
                outputStream = null;
            }
            if(null != inputStream) {
                inputStream.close();
                inputStream = null;
            }
            if(null != socket) {
                socket.close();
                socket = null;
            }
        }
    }

    // 发送静态资源
    private static void sendStaticResource(OutputStream outputStream) throws Exception {
        byte[] bytes = new byte[2048];
        FileInputStream fileInputStream = null;
        File file = new File(WEB_ROOT, url);
        // 如果文件存在
        System.out.println(file.getAbsoluteFile());
        try {
            if (file.exists()) {
                System.out.println("文件存在");
                outputStream.write("HTTP/1.1 200 OK\n".getBytes());
                outputStream.write("Server:apache-Coyote/1.1\n".getBytes());
                outputStream.write("Content-Type:text/html;charset=utf-8\n".getBytes());
                outputStream.write("\n".getBytes());
                fileInputStream = new FileInputStream(file);
                int ch = fileInputStream.read(bytes);
                while (ch != -1) {
                    outputStream.write(bytes, 0, ch);
                    ch = fileInputStream.read(bytes);
                }
            } else { // 如果文件不存在
                System.out.println("文件不存在");
                outputStream.write("HTTP/1.1 404 not found\n".getBytes());
                outputStream.write("Server:apache-Coyote/1.1\n".getBytes());
                outputStream.write("Content-Type:text/html;charset=utf-8\n".getBytes());
                outputStream.write("\n".getBytes());
                String errorMessage = "file not found";
                outputStream.write(errorMessage.getBytes());
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (null != fileInputStream) {
                fileInputStream.close();
            }
        }
    }

    private static void parse(InputStream inputStream) throws Exception {
//        StringBuffer content = new StringBuffer(2048);
        byte[] buffer = new byte[2048];
        int i = -1;
        i = inputStream.read(buffer);
//        for (int j = 0; j < i; j ++) {
//            content.append((char)buffer[j]);
//        }
        String content = new String(buffer);
        System.out.println(content);
        parseUrl(content.toString());
    }

    private static void parseUrl(String content) {
        int index1,index2;
        index1 = content.indexOf(" ");
        if (index1 != 1) {
            index2 = content.indexOf(" ", index1 + 1);
            if (index2 > index1) {
                url = content.substring(index1 + 2, index2);
            }
        }
        System.out.println(url);
    }
}

Tomcat版本二：响应动态资源

package com.milk.mytomcat.two;

import com.milk.mytomcat.two.servlet.api.Servlet;

import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.*;

/*
扩展内容
查看端口占用进程并关闭
netstat -aon|findstr "8080"
tasklist|findstr "14248"
taskkill /f /t /im node.exe
 */
/*
Tomcat版本2
 */
public class Tomcat02 {

    public static String WEB_ROOT = System.getProperty("user.dir") + "\\" + "WebContent";

    private static String url = "";

    // 用来保存配置文件的映射
    private static Map<String, String> map = new HashMap<>();

    static {
        Properties properties = new Properties();
        try {
            properties.load(new FileInputStream(WEB_ROOT + "\\conf.properties")); // 读取配置文件
            Set<Object> set = properties.keySet();
            Iterator<Object> iterator = set.iterator();
            while (iterator.hasNext()) {
                String key = (String) iterator.next();
                String value = properties.getProperty(key);
                map.put(key, value);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        // 服务器启动的时候就会加载配置文件，读取配置信息
        System.out.println(map);

        ServerSocket serverSocket = null;
        Socket socket = null;
        InputStream inputStream = null;
        OutputStream outputStream = null;

        try {
            serverSocket = new ServerSocket(10086);
            while (true) {
                socket = serverSocket.accept();
                inputStream = socket.getInputStream();
                outputStream = socket.getOutputStream();
                parse(inputStream);
                if (null != url) {
                    if (url.indexOf(".") != -1) {
                        sendStaticResource(outputStream);
                    } else {
                        sendDynamicResource(inputStream, outputStream);
                    }
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private static void parse(InputStream inputStream) throws Exception {
//        StringBuffer content = new StringBuffer(2048);
        byte[] buffer = new byte[2048];
        int i = -1;
        i = inputStream.read(buffer);
//        System.out.println("读取到的i--" + i);
//        for (int j = 0; j < i; j ++) {
//            content.append((char)buffer[j]);
//        }
        String content = new String(buffer);
        System.out.println(content);
        parseUrl(content.toString());
    }

    private static void parseUrl(String content) {
        int index1, index2;
        index1 = content.indexOf(" ");
        if (index1 != 1) {
            index2 = content.indexOf(" ", index1 + 1);
            if (index2 > index1) {
                url = content.substring(index1 + 2, index2);
            }
        }
        System.out.println(url);
    }

    // 发送静态资源
    private static void sendStaticResource(OutputStream outputStream) throws Exception {
        byte[] bytes = new byte[2048];
        FileInputStream fileInputStream = null;
        File file = new File(WEB_ROOT, url);
        // 如果文件存在
        System.out.println(file.getAbsoluteFile());
        try {
            if (file.exists()) {
                System.out.println("文件存在");
                outputStream.write("HTTP/1.1 200 OK\n".getBytes());
                outputStream.write("Server:apache-Coyote/1.1\n".getBytes());
                outputStream.write("Content-Type:text/html;charset=utf-8\n".getBytes());
                outputStream.write("\n".getBytes());
                fileInputStream = new FileInputStream(file);
                int ch = fileInputStream.read(bytes);
                while (ch != -1) {
                    outputStream.write(bytes, 0, ch);
                    ch = fileInputStream.read(bytes);
                }
            } else { // 如果文件不存在
                System.out.println("文件不存在");
                outputStream.write("HTTP/1.1 404 not found\n".getBytes());
                outputStream.write("Server:apache-Coyote/1.1\n".getBytes());
                outputStream.write("Content-Type:text/html;charset=utf-8\n".getBytes());
                outputStream.write("\n".getBytes());
                String errorMessage = "file not found";
                outputStream.write(errorMessage.getBytes());
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (null != fileInputStream) {
                fileInputStream.close();
            }
        }
    }

    // 发送动态内容
    private static void sendDynamicResource(InputStream inputStream, OutputStream outputStream) throws Exception {
        outputStream.write("HTTP/1.1 200 ok\n".getBytes());
        outputStream.write("Server:Apache\n".getBytes());
        outputStream.write("Content-type:text/html;charset=utf-8\n".getBytes());
        outputStream.write("\n".getBytes());

        if (map.containsKey(url)) {
            String value = map.get(url);
            Class clazz = Class.forName(value);
            Servlet servlet = (Servlet) clazz.newInstance();
            servlet.init();
            servlet.Service(inputStream, outputStream);
        }
    }

}

准备两个Servlet作为测试

先准备Servlet接口

package com.milk.mytomcat.two.servlet.api;

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

public interface Servlet {
    void init();
    void Service(InputStream inputStream, OutputStream outputStream);
    void destroy();
}

AAServlet .java

package com.milk.mytomcat.two.servlet.impl;

import com.milk.mytomcat.two.servlet.api.Servlet;

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

public class AAServlet implements Servlet {

    @Override
    public void init() {
        System.out.println("aa...init...");
    }

    @Override
    public void Service(InputStream inputStream, OutputStream outputStream) {
        System.out.println("AA service");
        try {
            outputStream.write("I am from Server..AA".getBytes());
            outputStream.flush();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void destroy() {
        System.out.println("aa.....destroy....");
    }
}

BBServlet .java

package com.milk.mytomcat.two.servlet.impl;

import com.milk.mytomcat.two.servlet.api.Servlet;

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

public class BBServlet implements Servlet {

    @Override
    public void init() {
        System.out.println("bb...init...");
    }

    @Override
    public void Service(InputStream inputStream, OutputStream outputStream) {
        System.out.println("bbServlet...service");
        try {
            outputStream.write("I am from BBServlet".getBytes());
            outputStream.flush();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void destroy() {
        System.out.println("BBServlet Destroy");
    }
}

配置文件

conf.properties，相当于web.xml，作为路径的映射。
当然，这里只是为了简略，也可以换成使用dom4j来解析xml

aa=com.milk.mytomcat.two.servlet.impl.AAServlet
bb=com.milk.mytomcat.two.servlet.impl.BBServlet

最后编辑于：2019.07.13 14:33:16

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手写Tomcat服务器

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