我正在尝试手动构建一个HTTP请求字符串并通过TCP套接字发送它,这就是我要做的事情:
但无论选择哪个URL,我都会收到这个响应消息:
为什么?
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.MalformedURLException;
import java.net.Socket;
import java.net.URL;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* SimpleHttpClient.java (UTF-8)
*
* Mar 27, 2014
*
* @author tarrsalah.org
*/
public class SimpleHttpClient {
private static final String StackOverflow = "http://stackoverflow.com/";
public static void main(String[] args) {
// if (args.length < 1) {
// System.out.println("Usage : SimpleHttpClient <url>");
// return;
// }
try {
URL url = new URL(StackOverflow);
String host = url.getHost();
String path = url.getPath();
int port = url.getPort();
if (port < 80) {
port = 80;
}
//Construct and send the HTTP request
String request = "GET" + path + "HTTP/1.1\n";
request += "host: " + host;
request += "\n\n";
// Open a TCP connection
Socket socket = new Socket(host, port);
// Send the request over the socket
PrintWriter writer = new PrintWriter(socket.getOutputStream());
writer.print(request);
writer.flush();
// Read the response
BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
String next_record = null;
while ((next_record = reader.readLine()) != null) {
System.out.println(next_record);
}
socket.close();
} catch (MalformedURLException ex) {
Logger.getLogger(SimpleHttpClient.class.getName()).log(Level.SEVERE, null, ex);
} catch (IOException ex) {
Logger.getLogger(SimpleHttpClient.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
但无论选择哪个URL,我都会收到这个响应消息:
HTTP/1.0 400 Bad request
Cache-Control: no-cache
Connection: close
Content-Type: text/html
<html><body><h1>400 Bad request</h1>
Your browser sent an invalid request.
</body></html>
为什么?