Java：使用TCP套接字的简单http GET请求 [英] Java: Simple http GET request using TCP sockets
问题描述
我在本地托管一个简单的PHP echo服务器。
我试图用Java向服务器发送消息，并使用GET请求打印响应但是收到'格式错误的HTTP请求'错误。谁能告诉我如何正确格式化GET请求？
I am hosting a simple PHP echo server locally. I am trying to send a message to the server in Java, and use a GET request to print the response but am getting a 'malformed HTTP request' error. Can anyone tell me how to correctly format the GET request?
//客户代码：
import java.io.*;
import java.net.*;
public class TCPclient {
public static void main(String argv[]) throws Exception {
String sentence, modifiedSentence;
BufferedReader inFromUser = new BufferedReader(new InputStreamReader(System.in));
Socket clientSocket = new Socket("localhost", 8000);
DataOutputStream outToServer = new DataOutputStream(clientSocket.getOutputStream());
BufferedReader inFromServer = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
sentence = inFromUser.readLine();
outToServer.writeBytes(sentence + "\n");
outToServer.writeChars("GET /echo.php HTTP/1.1" +"\n");
modifiedSentence = inFromServer.readLine();
System.out.println("FROM SERVER: " + modifiedSentence);
inFromServer.close();
outToServer.close();
inFromUser.close();
clientSocket.close();
}
}
//PHP Server code:
<?php
/* Simple php echo page
*/
// ini_set('display_errors', 'On');
// error_reporting(E_ALL | E_STRICT);
if(isset($_GET['source'])) {
if ($_GET['source'] == "raw")
echo file_get_contents(basename($_SERVER['PHP_SELF']));
else
echo "<pre>" . htmlspecialchars(file_get_contents(basename($_SERVER['PHP_SELF']))) . "</pre>";
} else if (isset($_GET['message'])){
echo strtoupper( htmlspecialchars($_GET['message'])) . '\n';
} else {
?>
<html>
<head>
<title>Error: No input message</title>
</head>
<body>
<h1> No message</h1>
<p>Echo server called without sending parameter</p>
</body>
</html>
<?php
}
?>
推荐答案
http服务器理解GET，POST，PUT等字样，删除。所以这是一个问题：
An http server understand words like GET, POST, PUT, DELETE. So here's a problem:
outToServer.writeBytes(sentence + "\n");
outToServer.writeChars("GET /echo.php HTTP/1.1" +"\n");
第一个语句告诉http服务器它不理解：句子。注释掉该行和您的请求是否有效，您将收到回复。
The first statement there is telling something to the http server that it doesn't understand: the sentence. Comment out that line and your request becomes valid, and you will get a response.
我想您要将该句子作为参数发布到echo服务。你可以把它放在查询字符串中：
I guess you want to post the sentence as a parameter to the echo service. You can put it in the query string:
outToServer.writeChars("GET /echo.php?message=" + sentence + " HTTP/1.0\n\n");
我还更改了HTTP版本并附加了额外的\ n，正如Steffen的评论所指出的那样Ullrich：
I also changed the HTTP version and appended an extra \n as pointed out by the comment of Steffen Ullrich:
此外，您必须添加空行以标记标题的结尾。并且行结尾必须是\\ n而不是\ n。你应该更好地做HTTP / 1.0请求而不是HTTP / 1.1，因为你的代码既不能处理HTTP keep-alive也不能处理HTTP chunked编码
Also you must add empty line to mark the end of the header. And the line ending must be \r\n not \n. And you should better do a HTTP/1.0 request not HTTP/1.1 since your code is neither able to deal with HTTP keep-alive nor with HTTP chunked encoding
然而，这还不够。您还需要编码一些字符，例如空格。必须对get请求中的URL进行编码，如@zapl在评论中所指出的那样。
However, this is not quite enough. You also need to encode some characters, such as spaces. The URL in the get request must be encoded, as pointed out by @zapl in a comment.
我还建议首先使用简单的telnet测试你的echo服务：
I also recommend to test your echo service first using simple telnet:
telnet localhost 8000
在那里，您可以输入消息GET /echo.php?message=something并验证其是否有效。一旦找到符合预期的东西，就可以相应地更新Java代码。
There, you can type your message, "GET /echo.php?message=something" and verify it works. Once you find something that works as intended, you can update the Java code accordingly.
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