Web 瀏覽器成功時Java 程序收到403 禁止錯誤
問題：
一個Java旨在檢索給定Google 搜尋查詢的結果計數的程式返回403 Forbidden錯誤，而相同的查詢在 Web 瀏覽器中會產生結果。程式碼片段：
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URL;
public class DataGetter {
public static void main(String[] args) throws IOException {
getResultAmount("test");
}
private static int getResultAmount(String query) throws IOException {
BufferedReader r = new BufferedReader(new InputStreamReader(new URL("https://www.google.com/search?q=" + query).openConnection()
.getInputStream()));
String line;
String src = "";
while ((line = r.readLine()) != null) {
src += line;
}
System.out.println(src);
return 1;
}
}錯誤：
Exception in thread "main" java.io.IOException: Server returned HTTP response code: 403 for URL: https://www.google.com/search?q=test
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source)
at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(Unknown Source)
at DataGetter.getResultAmount(DataGetter.java:15)
at DataGetter.main(DataGetter.java:10)解決方案：
出現此問題是因為Java的URLConnection 類別預設不會偽造實際的用戶代理程式。修改程式碼以設定使用者代理程式標頭可以解決此問題：
URLConnection connection = new URL("https://www.google.com/search?q=" + query).openConnection();
connection.setRequestProperty("User-Agent", "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.95 Safari/537.11");
connection.connect();
BufferedReader r = new BufferedReader(new InputStreamReader(connection.getInputStream(), Charset.forName("UTF-8")));此外，SSL 處理是透明的，如異常堆疊追蹤所示。
其他注意事項：
檢索結果計數涉及進一步的步驟，包括透過取得cookie 來偽造瀏覽器解析重定向令牌連結：
String cookie = connection.getHeaderField("Set-Cookie").split(";")[0];
Pattern pattern = Pattern.compile("content=\\"0;url=(.*?)\\"");
Matcher m = pattern.matcher(response);
if (m.find()) {
String url = m.group(1);
connection = new URL(url).openConnection();
connection.setRequestProperty("User-Agent", "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.95 Safari/537.11");
connection.setRequestProperty("Cookie", cookie);
connection.connect();
r = new BufferedReader(new InputStreamReader(connection.getInputStream(), Charset.forName("UTF-8")));
sb = new StringBuilder();
while ((line = r.readLine()) != null) {
sb.append(line);
}
response = sb.toString();
pattern = Pattern.compile("<div>執行此完整程式碼會產生2930000000L 的結果。
以上是為什麼我的 Java 程式在抓取 Google 搜尋結果時會出現 403 禁止錯誤，而我的瀏覽器卻不會？的詳細內容。更多資訊請關注PHP中文網其他相關文章！
