HttpUrlConnection.connect 失败

Question

我一直在尝试创建一个连接到editText中的url并返回状态码的小应用程序。

这里是 onCreate 代码：

 override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)
    button.setOnClickListener {
        val url = editText.text.toString()
        var connection: HttpURLConnection? = null
        if (URLUtil.isValidUrl(url)) {
            connection = URL(url).openConnection() as HttpURLConnection
            var thr = Thread {
                connection.connect()
                val code = connection.responseCode
                runOnUiThread {
                    if (code != 404 && code != 500) {
                        textView.text = "Ok"
                    } else {
                        textView.text = "Failed"
                    }
                }

            }
            thr.start()
            thr.join()
        } else {
            textView.text = "Failed"
        }
    }

问题是只要 URL 有效，.connect() 方法中就会出现运行时错误。上网权限是在 android manifest 中设置的。是什么导致了这个问题？

E/AndroidRuntime: FATAL EXCEPTION: Thread-2
Process: com.example.company.myapplication, PID: 27183
java.net.SocketException: socket failed: EPERM (Operation not permitted)
    at java.net.Socket.createImpl(Socket.java:492)
    at java.net.Socket.getImpl(Socket.java:552)
    at java.net.Socket.setSoTimeout(Socket.java:1180)
    at com.android.okhttp.internal.io.RealConnection.connectSocket(RealConnection.java:143)
    at com.android.okhttp.internal.io.RealConnection.connect(RealConnection.java:116)
    at com.android.okhttp.internal.http.StreamAllocation.findConnection(StreamAllocation.java:186)
    at com.android.okhttp.internal.http.StreamAllocation.findHealthyConnection(StreamAllocation.java:128)
    at com.android.okhttp.internal.http.StreamAllocation.newStream(StreamAllocation.java:97)
    at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:289)
    at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:232)
    at com.android.okhttp.internal.huc.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:465)
    at com.android.okhttp.internal.huc.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:131)
    at com.android.okhttp.internal.huc.DelegatingHttpsURLConnection.connect(DelegatingHttpsURLConnection.java:90)
    at com.android.okhttp.internal.huc.HttpsURLConnectionImpl.connect(HttpsURLConnectionImpl.java:30)
    at com.example.company.myapplication.MainActivity$onCreate$1$thr$1.run(MainActivity.kt:25)
    at java.lang.Thread.run(Thread.java:919)

Answer 1

对于那些没有阅读聊天的人：

URLUtil.isValidUrl(url) 不检查有问题的 url 实际上可以解析到网站/服务器。这意味着当在不存在的网站/服务器上调用 connect 时，会引发异常，因为没有可连接的内容。

Answer 2

您好，请检查您是否在清单中提供了互联网许可，

<manifest >
 <uses-permission android:name="android.permission.INTERNET" />
 <application> 
  ...
 </application> 
</manifest>