Question

我正在尝试了解HTTP客户端如何在Java中工作。我正在尝试构建自己的客户端，该客户端将向Web服务器请求php文件。

目前，当我发出请求时，服务器会给我以下错误：

HTTP / 1.1 400错误请求

但是，我能够在浏览器中访问该文件没问题。我不知道我做错了什么，但我无法理解。下面是我的HTTP Client类的代码：

public class MyHttpClient {

MyHttpRequest request;
String host;

public MyHttpResponse execute(MyHttpRequest request) throws IOException {

    //Creating the response object
    MyHttpResponse response = new MyHttpResponse();

    //Get web server host and port from request.
    String host = request.getHost();
    int port = request.getPort();

    //Check 1: HOST AND PORT NAME CORRECT!
    System.out.println("host: " + host + " port: " + String.valueOf(port));

    //Get resource path on web server from requests.
    String path = request.getPath();

    //Check 2: ENSURE PATH IS CORRECT!
    System.out.println("path: " + path);

    //Open connection to the web server
    Socket s = new Socket(host, port);

    //Get Socket input stream and wrap it in Buffered Reader so it can be read line by line.
    BufferedReader inFromServer = new BufferedReader(new InputStreamReader(s.getInputStream()));

    //Get Socket output stream and wrap it in a Buffered Writer so it can be written to line by line.
    PrintWriter outToServer = new PrintWriter(s.getOutputStream(),true);

    //Get request method
    String method = request.getMethod();

    //Check 3: ENSURE REQUEST IS CORRECT GET/POST!
    System.out.println("Method: " + method);

    //GET REQUEST
    if(method.equalsIgnoreCase("GET")){
        //Send request to server
        outToServer.println("GET " + path + " HTTP/1.1 " + "\r\n");
        String line = inFromServer.readLine();
        System.out.println("Line: " + line);
    }

    //Returning the response
    return response;
}

}

如果有人能对这个问题有所了解，我会非常感激！感谢。

对服务器的新请求：

outToServer.print("GET " + path+ " HTTP/1.1" + "\r\n");
outToServer.print("Host: " + host + "\r\n");
outToServer.print("\r\n");

响应：

方法：GET

line: <!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
line: <html><head>
line: <title>400 Bad Request</title>
line: </head><body>
line: <h1>Bad Request</h1>
line: <p>Your browser sent a request that this server could not understand.<br />
line: </p>
line: <hr>
line: <address>Apache Server at default.secureserver.net Port 80</address>
line: </body></html>
line: null

Answer 1

不要使用PrintWriter。你必须写ascii字符。

 s.getOutputStream().write(("GET " + path + " HTTP/1.1\r\n\r\n").getBytes("ASCII"));

Answer 2

我认为您至少需要在请求中添加Host标头。

取自http://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol

的示例

GET /index.html HTTP/1.1
Host: www.example.com

标题完成后，您还需要传输额外的\r\n，以便服务器知道请求已完成。

请勿使用println，print。 println为每一行添加了另一个\n，导致这些行以\r\n\n终止。

HTTP客户端错误请求400

2 个答案: