Java Socket实现简单的Http服务器

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小诸葛的博客 2022-09-27 12:01:58 ©著作权

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由于HTTP是在TCP/IP协议之上实现的，因此可以使用Java中的Socket处理HTTP请求，以下为一个简单的实现。

import java.io.FileInputStream;
import java.io.InputStream;
import java.io.PrintStream;
import java.net.ServerSocket;
import java.net.Socket;

public class MyCustomHttpServer {
    public static void main(String[] args) {

        try{
            ServerSocket serverSocket = new ServerSocket(9090);

            while (true){
                Socket accept = serverSocket.accept();
                System.out.println("收到新连接");

                InputStream ins = accept.getInputStream();

                String methoName = getMethodName(ins);
                String url = getUri(ins);

                System.out.println(methoName);
                System.out.println(url);


                PrintStream writer = new PrintStream(accept.getOutputStream());
                writer.println("HTTP/1.0 200 OK");// 返回应答消息,并结束应答

                switch (url){
                    case "text":
                        System.out.println("文本请求");
                        writer.println("Content-Type: text/plain;charset=utf-8");
                        String msg = "你好，小诸葛的博客";
                        writer.println("Content-Length: " + msg.length()*3);
                        writer.println();// 根据 HTTP 协议, 空行将结束头信息
                        writer.write(msg.getBytes("utf-8"));
                        break;
                    case "viewpicture":
                        System.out.println("预览图片请求");
                        InputStream inputStream1 = new FileInputStream("e://bgpic.jpg");
                        writer.println("Content-Type: image/jpeg");
                        writer.println("Content-Length: " + inputStream1.available());// 返回内容字节数
                        writer.println();// 根据 HTTP 协议, 空行将结束头信息

                        byte[] buf1 = new byte[inputStream1.available()];
                        inputStream1.read(buf1);
                        writer.write(buf1);
                        writer.close();
                        inputStream1.close();
                        break;
                    case "downloadpicture":
                        System.out.println("下载图片请求");
                        InputStream inputStream2 = new FileInputStream("e://bgpic.jpg");
                        writer.println("Content-Type: application/binary");
                        writer.println("Content-Length: " + inputStream2.available());// 返回内容字节数
                        writer.println();// 根据 HTTP 协议, 空行将结束头信息

                        byte[] buf2 = new byte[inputStream2.available()];
                        inputStream2.read(buf2);
                        writer.write(buf2);
                        writer.close();
                        inputStream2.close();
                        break;
                    case "html":
                        System.out.println("网页请求");
                        writer.println("Content-Type: text/html;charset=utf-8");
                        String html = "<html><h1 style='color:#3982ff;text-align:center;'>hello,小诸葛的博客!</h1></html>";
                        writer.println("Content-Length: " + html.length());
                        writer.println();// 根据 HTTP 协议, 空行将结束头信息
                        writer.write(html.getBytes("utf-8"));
                    default:
                        System.out.println("无法处理该请求");
                        break;
                }

                accept.close();
                System.out.println("请求结束。。。。。");
            }

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

    }

    //从输入流解析出方法名
    public static String getMethodName(InputStream inputStream){
        try{
            int b = inputStream.read();
            byte[] methodBytes = new byte[10];
            int i = 0;
            while ((b != -1) && ((char)b != ' ') ){
                methodBytes[i] = (byte) b;
                i++;
                b = inputStream.read();
            }
            return new String(methodBytes);
        }catch (Exception e){
            e.printStackTrace();
        }
        return "无";
    }

    //从输入流解析出uri
    public static String getUri(InputStream inputStream){
        try{
            inputStream.read();
            int b = inputStream.read();
            byte[] uriBytes = new byte[24];
            int i = 0;
            while ((b != -1) && ((char)b != ' ') ){
                uriBytes[i] = (byte) b;
                i++;
                b = inputStream.read();
            }

            byte[] realUri = new byte[i];

            System.arraycopy(uriBytes,0, realUri,0, i);

            return new String(realUri);
        }catch (Exception e){
            e.printStackTrace();
        }
        return "无";
    }
}