Java HttpURLConnectionはリダイレクトの例に従います
HttpURLConnection
のフォローリダイレクトは単なる指標であり、実際には「実際の」httpリダイレクトを行うのに役立ちません。それでも、手動で処理する必要があります。
URL obj = new URL(url); HttpURLConnection conn = (HttpURLConnection) obj.openConnection(); conn.setInstanceFollowRedirects(true); //you still need to handle redirect manully. HttpURLConnection.setFollowRedirects(true);
1. Java Httpリダイレクトの例
サーバーが元のURLから別のURLにリダイレクトされる場合、応答コードは301: Moved Permanentlyまたは302: Temporary Redirectである必要があります。 And you can get the new redirected url by reading the “Location” header of the HTTP response header.
たとえば、通常のHTTP Twitter Webサイト–http://www.twitter.comにアクセスすると、HTTPS Twitter Webサイト–https://www.twitter.comに自動的にリダイレクトされます。
HttpRedirectExample –完全なJavaはリダイレクトの例に従います。説明はコメントを参照してください。
package com.example.http; import java.io.BufferedReader; import java.io.InputStreamReader; import java.net.HttpURLConnection; import java.net.URL; public class HttpRedirectExample { public static void main(String[] args) { try { String url = "http://www.twitter.com"; URL obj = new URL(url); HttpURLConnection conn = (HttpURLConnection) obj.openConnection(); conn.setReadTimeout(5000); conn.addRequestProperty("Accept-Language", "en-US,en;q=0.8"); conn.addRequestProperty("User-Agent", "Mozilla"); conn.addRequestProperty("Referer", "google.com"); System.out.println("Request URL ... " + url); boolean redirect = false; // normally, 3xx is redirect int status = conn.getResponseCode(); if (status != HttpURLConnection.HTTP_OK) { if (status == HttpURLConnection.HTTP_MOVED_TEMP || status == HttpURLConnection.HTTP_MOVED_PERM || status == HttpURLConnection.HTTP_SEE_OTHER) redirect = true; } System.out.println("Response Code ... " + status); if (redirect) { // get redirect url from "location" header field String newUrl = conn.getHeaderField("Location"); // get the cookie if need, for login String cookies = conn.getHeaderField("Set-Cookie"); // open the new connnection again conn = (HttpURLConnection) new URL(newUrl).openConnection(); conn.setRequestProperty("Cookie", cookies); conn.addRequestProperty("Accept-Language", "en-US,en;q=0.8"); conn.addRequestProperty("User-Agent", "Mozilla"); conn.addRequestProperty("Referer", "google.com"); System.out.println("Redirect to URL : " + newUrl); } BufferedReader in = new BufferedReader( new InputStreamReader(conn.getInputStream())); String inputLine; StringBuffer html = new StringBuffer(); while ((inputLine = in.readLine()) != null) { html.append(inputLine); } in.close(); System.out.println("URL Content... \n" + html.toString()); System.out.println("Done"); } catch (Exception e) { e.printStackTrace(); } } }
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