56 | JAVA_编写HTTPserver


编写HTTP Server

我们来看一下如何编写HTTP Server。一个HTTP Server本质上是一个TCP服务器,我们先用TCP编程的多线程实现的服务器端框架:

public class Server {
    public static void main(String[] args) throws IOException {
        ServerSocket ss = new ServerSocket(8080); // 监听指定端口
        System.out.println("server is running...");
        for (;;) {
            Socket sock = ss.accept();
            System.out.println("connected from " + sock.getRemoteSocketAddress());
            Thread t = new Handler(sock);
            t.start();
        }
    }
}

class Handler extends Thread {
    Socket sock;

    public Handler(Socket sock) {
        this.sock = sock;
    }

    public void run() {
        try (InputStream input = this.sock.getInputStream()) {
            try (OutputStream output = this.sock.getOutputStream()) {
                handle(input, output);
            }
        } catch (Exception e) {
            try {
                this.sock.close();
            } catch (IOException ioe) {
            }
            System.out.println("client disconnected.");
        }
    }

    private void handle(InputStream input, OutputStream output) throws IOException {
        var reader = new BufferedReader(new InputStreamReader(input, StandardCharsets.UTF_8));
        var writer = new BufferedWriter(new OutputStreamWriter(output, StandardCharsets.UTF_8));
        // TODO: 处理HTTP请求
    }
}

只需要在handle()方法中,用Reader读取HTTP请求,用Writer发送HTTP响应,即可实现一个最简单的HTTP服务器。编写代码如下:

private void handle(InputStream input, OutputStream output) throws IOException {
    System.out.println("Process new http request...");
    var reader = new BufferedReader(new InputStreamReader(input, StandardCharsets.UTF_8));
    var writer = new BufferedWriter(new OutputStreamWriter(output, StandardCharsets.UTF_8));
    // 读取HTTP请求:
    boolean requestOk = false;
    String first = reader.readLine();
    if (first.startsWith("GET / HTTP/1.")) {
        requestOk = true;
    }
    for (;;) {
        String header = reader.readLine();
        if (header.isEmpty()) { // 读取到空行时, HTTP Header读取完毕
            break;
        }
        System.out.println(header);
    }
    System.out.println(requestOk ? "Response OK" : "Response Error");
    if (!requestOk) {
        // 发送错误响应:
        writer.write("HTTP/1.0 404 Not Found/r/n");
        writer.write("Content-Length: 0/r/n");
        writer.write("/r/n");
        writer.flush();
    } else {
        // 发送成功响应:
        String data = "<html><body><h1>Hello, world!</h1></body></html>";
        int length = data.getBytes(StandardCharsets.UTF_8).length;
        writer.write("HTTP/1.0 200 OK/r/n");
        writer.write("Connection: close/r/n");
        writer.write("Content-Type: text/html/r/n");
        writer.write("Content-Length: " + length + "/r/n");
        writer.write("/r/n"); // 空行标识Header和Body的分隔
        writer.write(data);
        writer.flush();
    }
}

原创文章,作者:ItWorker,如若转载,请注明出处:https://blog.ytso.com/287666.html

(0)
上一篇 2022年9月5日
下一篇 2022年9月5日

相关推荐

发表回复

登录后才能评论