在非常有限的情况下允许来自Android App的明文HTTP流量

解决方法

OkhttpClient client = new OkhttpClient.builder() 
.connectionSpecs(Arrays.asList(ConnectionSpec.MODERN_TLS,ConnectionSpec.COMPATIBLE_TLS))
.build();

这只允许通过httpS连接.那么,您可以使用您的第三个选项(android：usesCleartextTraffic =“true”),当您通过此客户端进行明文连接时,它将失败.

最后,您可以创建一个标准的Okhttp客户端：

OkhttpClient client = new OkhttpClient.builder().build()

当你想使用明文连接时.

编辑：使用httpUrlConnection,您可以简单地检查返回的连接是否是httpsUrlConnection,如：

try {
    URL my_url = new URL(path);
    httpUrlConnection urlConnection = (httpURLConnection) my_url.openConnection();
    if(!(urlConnection instanceof httpsURLConnection)) {
        // cleartext connection,throw error
        throw new NothttpsException();
    }
    // the connection is secure,do normal stuff here
    urlConnection.setrequestMethod("POST");
    urlConnection.setConnectTimeout(1500);
    urlConnection.setReadTimeout(1500);
    result = IoUtil.readFully(urlConnection.geTinputStream());
} catch(Exception E) {
    e.printStackTrace()
} finally {
    if(urlConnection != null) urlConnection.disconnect();
}