其实编写一个入门级别的JAVA的WEB服务器，很简单，用SOCKET类即可实现。相关内容可以参考：javascript:void(0)

一、首先创建一个目录，目录内结构如下：

@~/study/webserver $ tree
.
├── src
│   └── com
│       └── taobao
│           ├── HttpServer.java
│           ├── Request.java
│           └── Response.java
└── webroot
    └── index.html

二、创建文件：

index.html

<html>
<head>
<title>Hello</title>
</head>
<body>
<br>
World
</body>
</html>

pyrmont目录的三个java文件，分别是：

HttpServer.java

package com.taobao;

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

public class HttpServer {

    public static final String WEB_ROOT = System.getProperty("user.dir") + File.separator + "webroot";

    // shutdown command
    private static final String SHUTDOWN_COMMAND = "/SHUTDOWN";

    // the shutdown command received
    private boolean shutdown = false;

    public static void main(String[] args) {
        HttpServer server = new HttpServer();
        server.await();
    }

    public void await() {
        ServerSocket serverSocket = null;
        int port = 8389;
        try {
            serverSocket = new ServerSocket(port, 1, InetAddress.getByName("127.0.0.1"));
        } catch (IOException e) {
            e.printStackTrace();
            System.exit(1);
        }

        // Loop waiting for a request
        while (!shutdown) {
            Socket socket = null;
            InputStream input = null;
            OutputStream output = null;
            try {
                socket = serverSocket.accept();
                input = socket.getInputStream();
                output = socket.getOutputStream();

                // create Request object and parse
                Request request = new Request(input);
                request.parse();

                // create Response object
                Response response = new Response(output);
                response.setRequest(request);
                response.sendStaticResource();

                // Close the socket
                socket.close();

                // check if the previous URI is a shutdown command
                shutdown = request.getUri().equals(SHUTDOWN_COMMAND);
            } catch (Exception e) {
                e.printStackTrace();
                continue;
            }
        }
    }
}

Request.java

package com.taobao;

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

public class Request {

    private InputStream input;
    private String uri;

    public Request(InputStream input) {
        this.input = input;
    }

    public void parse() {
        // Read a set of characters from the socket
        StringBuffer request = new StringBuffer(2048);
        int i;
        byte[] buffer = new byte[2048];
        try {
            i = input.read(buffer);
        } catch (IOException e) {
            e.printStackTrace();
            i = -1;
        }
        for (int j = 0; j < i; j++) {
            request.append((char) buffer[j]);
        }
        System.out.print("************************");
        System.out.print(request.toString());
        System.out.print("------------------------");
        uri = parseUri(request.toString());
    }

    private String parseUri(String requestString) {
        int index1, index2;
        index1 = requestString.indexOf(' ');
        if (index1 != -1) {
            index2 = requestString.indexOf(' ', index1 + 1);
            if (index2 > index1)
                return requestString.substring(index1 + 1, index2);
        }
        return null;
    }

    public String getUri() {
        return uri;
    }

}

Response.java

package com.taobao;

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

public class Response {

    private static final int BUFFER_SIZE = 1024;
    Request request;
    OutputStream output;

    public Response(OutputStream output) {
        this.output = output;
    }

    public void setRequest(Request request) {
        this.request = request;
    }

    public void sendStaticResource() throws IOException {
        byte[] bytes = new byte[BUFFER_SIZE];
        FileInputStream fis = null;
        try {
            File file = new File(HttpServer.WEB_ROOT, request.getUri());
            if (file.exists()) {
                fis = new FileInputStream(file);
                int ch = fis.read(bytes, 0, BUFFER_SIZE);
                while (ch != -1) {
                    output.write(bytes, 0, ch);
                    ch = fis.read(bytes, 0, BUFFER_SIZE);
                }
            } else {
                // file not found
                String errorMessage = "HTTP/1.1 404 File Not Found\r\n" + "Content-Type: text/html\r\n" + "Content-Length: 23\r\n" + "\r\n"
                        + "<h1>File Not Found</h1>";
                output.write(errorMessage.getBytes());
            }
        } catch (Exception e) {
            // thrown if cannot instantiate a File object
            System.out.println(e.toString());
        } finally {
            if (fis != null)
                fis.close();
        }
    }
}
三、在原始目录编译文件

javac -d . ./src/com/taobao/*.java

@~/study/webserver $ tree

执行成功之后的目录如下：

.
├── com
│   └── taobao
│       ├── HttpServer.class
│       ├── Request.class
│       └── Response.class
├── src
│   └── com
│       └── taobao
│           ├── HttpServer.java
│           ├── Request.java
│           └── Response.java
└── webroot
    └── index.html

6 directories, 7 files
四、执行内容

java com.taobao.HttpServer

五、查看结果

在浏览器输入：http://localhost:8389/index.html

查看的内容是：world