问题描述
我正在尝试使用以下代码获取标题字段:
import java.net.URL;
import java.net.URLConnection;
public class Main {
public static void main() {
try {
URL url = new URL("URL");
URLConnection con = url.openConnection();
con.setRequestMethod("HEAD");
con.setRequestProperty("property","name");
System.out.println("\nGetting Response Header By Key ...\n");
String userToken = con.getHeaderField("parameter");
if (userToken == null) {
System.out.println("Key 'userToken' is not found!");
} else {
System.out.println("userToken - " + userToken);
}
System.out.println("\n Done");
} catch (Exception e) {
e.printStackTrace();
}
}
}
但我收到以下错误:
Main.java:14:错误:找不到符号 con.setRequestMethod("HEAD"); ^ 符号:方法 setRequestMethod(String) 位置:URLConnection 类型的变量 con 1 个错误
解决方法
您正在尝试对 URLConnection
变量使用 HttpURLConnection.setRequestMethod(String)。幸运的是,url.openConnection();
实际上会返回一个 HttpURLConnection
,因此您可以转换为 HttpURLConnection
:
HttpURLConnection con = (HttpURLConnection) url.openConnection();
con.setRequestMethod("HEAD");