java - java中的HTTPS和HTTP连接

Question

我知道 HTTPS 扩展了 http。那么这是否意味着我可以做到这一点？

HttpUrlConnection connect = passmyurl.openconnection(url);

和

HttpsUrlConnection connect = passmyurl.openconnection(url);



public static HttpsURLConnection passmyurl(URL url) throws IOException {
        HttpsURLConnection connection = (HttpsURLConnection) url.openConnection();
        return connection;
    }

这是否意味着两者都可以工作？由于HTTPps扩展了HTTP，这意味着我也可以将HTTP url传递给这个函数？

Answer 1

在您的代码中:

public static HttpsURLConnection passmyurl(URL url) throws IOException {
    HttpsURLConnection connection = (HttpsURLConnection) url.openConnection();
    return connection;
}

您应该将返回类型 HttpsURLConnection 更改为 URLConnection。因为 url.openConnection() 结果的类型是 URLConnection 的子类型，具体类型取决于参数url的协议(protocol)。URL类中openConnection()的实现文档:

If for the URL's protocol (such as HTTP or JAR), there exists a public, specialized URLConnection subclass belonging to one of the following packages or one of their subpackages: java.lang, java.io, java.util, java.net, the connection returned will be of that subclass. For example, for HTTP an HttpURLConnection will be returned, and for JAR a JarURLConnection will be returned.

因此，您可以将 Http url 或 Https url 传递给您的方法。

请参阅以下代码:

    URLConnection httpConnection = new URL("http://test").openConnection();
    System.out.println(httpConnection.getClass());
    URLConnection httpsConnection = new URL("https://test").openConnection();
    System.out.println(httpsConnection.getClass());
    URLConnection ftpConnection = new URL("ftp://test").openConnection();
    System.out.println(ftpConnection.getClass());`

打印内容是:

class sun.net.www.protocol.http.HttpURLConnection
class sun.net.www.protocol.https.HttpsURLConnectionImpl
class sun.net.www.protocol.ftp.FtpURLConnection