HttpURLConnection sends a POST request even though

问题:

Here is my code:

String addr = "http://172.26.41.18:8080/domain/list";

URL url = new URL(addr);
HttpURLConnection httpCon = (HttpURLConnection) url.openConnection();
httpCon.setDoOutput(true);
httpCon.setDoInput(true);
httpCon.setUseCaches(false);
httpCon.setAllowUserInteraction(false);
httpCon.setRequestMethod("GET");
httpCon.addRequestProperty("Authorization", "Basic YWRtaW4fYFgjkl5463");

httpCon.connect();

OutputStreamWriter out = new OutputStreamWriter(httpCon.getOutputStream());

System.out.println(httpCon.getResponseCode());
System.out.println(httpCon.getResponseMessage());

out.close();

What I see in response:

500 Server error

I open my httpCon var, and what I see:

POST /rest/platform/domain/list HTTP/1.1

Why is it set to POST even though I have used httpCon.setRequestMethod("GET"); to set it to GET?

回答1:

The httpCon.setDoOutput(true); implicitly set the request method to POST because that's the default method whenever you want to send a request body.

If you want to use GET, remove that line and remove the OutputStreamWriter out = new OutputStreamWriter(httpCon.getOutputStream()); line. You don't need to send a request body for GET requests.

The following should do for a simple GET request:

String addr = "http://172.26.41.18:8080/domain/list";
URL url = new URL(addr);
HttpURLConnection httpCon = (HttpURLConnection) url.openConnection();
httpCon.setUseCaches(false);
httpCon.setAllowUserInteraction(false);
httpCon.addRequestProperty("Authorization", "Basic YWRtaW4fYFgjkl5463");
System.out.println(httpCon.getResponseCode());
System.out.println(httpCon.getResponseMessage());

See also:

• Using java.net.URLConnection to fire and handle HTTP requests

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Unrelated to the concrete problem, the password part of your Authorization header value doesn't seem to be properly Base64-encoded. Perhaps it's scrambled because it was examplary, but even if it wasn't I'd fix your Base64 encoding approach.