java - 编写一个简单的 HTTP 服务器来接受 GET 请求

Question

我正在尝试创建一个简单的服务器来接受请求，然后将文件的内容写入发送请求的浏览器。服务器连接并写入套接字。但是我的浏览器显示

no data received

并且不显示任何内容。

public class Main {

/**
 * @param args
 */
public static void main(String[] args) throws IOException{

    while(true){
        ServerSocket serverSock = new ServerSocket(6789);
        Socket sock = serverSock.accept();

        System.out.println("connected");

        InputStream sis = sock.getInputStream();
        BufferedReader br = new BufferedReader(new InputStreamReader(sis));
        String request = br.readLine(); // Now you get GET index.html HTTP/1.1`
        String[] requestParam = request.split(" ");
        String path = requestParam[1];

        System.out.println(path);

        PrintWriter out = new PrintWriter(sock.getOutputStream(), true);
        File file = new File(path);
        BufferedReader bfr = null;
        String s = "Hi";

        if (!file.exists() || !file.isFile()) {
            System.out.println("writing not found...");
             out.write("HTTP/1.0 200 OK\r\n");
             out.write(new Date() + "\r\n");
             out.write("Content-Type: text/html");
             out.write("Content length: " + s.length() + "\r\n");
             out.write(s);
        }else{
            FileReader fr = new FileReader(file);
            bfr = new BufferedReader(fr);
            String line;
            while ((line = bfr.readLine()) != null) {
                out.write(line);
            }
        }
        if(bfr != null){
            bfr.close();
        }
        br.close();
        out.close();
        serverSock.close();
    }
}

}

Answer 1

如果我使用，你的代码对我有用(数据显示在浏览器中)

http://localhost:6789/etc/hosts

还有一个文件 /etc/hosts(Linux 文件系统符号)。

---

如果文件不存在，则这段代码

out.write("HTTP/1.0 200 OK\r\n");
out.write(new Date() + "\r\n");
out.write("Content-Type: text/html\r\n");
out.write("\r\n");
out.write("File " + file + " not found\r\n");
out.flush();

将返回显示在浏览器中的数据:请注意，我已在此处明确添加了对 flush() 的调用。确保 out 在其他情况下也被刷新。

另一种可能性是重新排列您的close 语句。引用 EJP 在 How to close a socket 上的回答:

You should close the outermost output stream you have created from the socket. That will flush it.

如果最外层的输出流是(同一来源的另一引述)，情况尤其如此:

a buffered output stream, or a stream wrapped around one. If you don't close that, it won't be flushed.

所以 out.close() 应该在 br.close() 之前调用。