Android 9.0 Java.net.URL

Question

Android 9.0 Java.net.URL

3

我一直在想，如果没有java.net.URL，Android 9.0上的网络是如何工作的（因为我的应用程序在Android Pie上崩溃，说找不到类java.net.url）。在浏览网页时，我发现有些帖子说我应该使用URI，但无论我在哪里查看，它总是使用.toURL()。

我能否得到一些示例来下载图像并获取输入流，而不使用java.net.url?

提前感谢！

编辑：这里是我承诺的堆栈跟踪：

12/17 17:24:37: Launching app
$ adb shell am start -n "xyz.mglolenstine.nekoslife/xyz.mglolenstine.nekoslife.MainActivity" -a android.intent.action.MAIN -c android.intent.category.LAUNCHER
Client not ready yet..Waiting for process to come online
Connected to process 14213 on device xiaomi-pocophone_f1-8e0cf863
Capturing and displaying logcat messages from application. This behavior can be disabled in the "Logcat output" section of the "Debugger" settings page.
W/stine.nekoslif: JIT profile information will not be recorded: profile file does not exits.
I/chatty: uid=10172(xyz.mglolenstine.nekoslife) identical 10 lines
W/stine.nekoslif: JIT profile information will not be recorded: profile file does not exits.
I/Perf: Connecting to perf service.
I/InstantRun: starting instant run server: is main process
W/stine.nekoslif: Accessing hidden method Landroid/view/View;->computeFitSystemWindows(Landroid/graphics/Rect;Landroid/graphics/Rect;)Z (light greylist, reflection)
W/stine.nekoslif: Accessing hidden method Landroid/view/ViewGroup;->makeOptionalFitsSystemWindows()V (light greylist, reflection)
W/stine.nekoslif: Accessing hidden field Ljava/net/URL;->host:Ljava/lang/String; (dark greylist, reflection)
W/stine.nekoslif: Accessing hidden field Ljava/net/URL;->host:Ljava/lang/String; (dark greylist, reflection)
W/stine.nekoslif: Accessing hidden field Ljava/net/URL;->host:Ljava/lang/String; (dark greylist, reflection)
W/stine.nekoslif: Accessing hidden field Ljava/net/URL;->host:Ljava/lang/String; (dark greylist, reflection)
E/AndroidRuntime: FATAL EXCEPTION: pool-1-thread-3
    Process: xyz.mglolenstine.nekoslife, PID: 14213
    java.lang.Error: java.lang.NoSuchFieldException: No field host in class Ljava/net/URL; (declaration of 'java.net.URL' appears in /system/framework/core-oj.jar)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1173)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
        at java.lang.Thread.run(Thread.java:764)
     Caused by: java.lang.NoSuchFieldException: No field host in class Ljava/net/URL; (declaration of 'java.net.URL' appears in /system/framework/core-oj.jar)
        at java.lang.Class.getDeclaredField(Native Method)
        at khttp.requests.GenericRequest.toIDN(GenericRequest.kt:198)
        at khttp.requests.GenericRequest.makeRoute(GenericRequest.kt:208)
        at khttp.requests.GenericRequest.<init>(GenericRequest.kt:132)
        at khttp.KHttp.request(KHttp.kt:60)
        at khttp.KHttp.get(KHttp.kt:30)
        at khttp.KHttp.get$default(KHttp.kt:29)
        at xyz.mglolenstine.nekoslife.MainActivity$addImage$1.run(MainActivity.kt:426)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641) 
        at java.lang.Thread.run(Thread.java:764) 
E/AndroidRuntime: FATAL EXCEPTION: pool-1-thread-4
    Process: xyz.mglolenstine.nekoslife, PID: 14213
    java.lang.Error: java.lang.NoSuchFieldException: No field host in class Ljava/net/URL; (declaration of 'java.net.URL' appears in /system/framework/core-oj.jar)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1173)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
        at java.lang.Thread.run(Thread.java:764)
     Caused by: java.lang.NoSuchFieldException: No field host in class Ljava/net/URL; (declaration of 'java.net.URL' appears in /system/framework/core-oj.jar)
        at java.lang.Class.getDeclaredField(Native Method)
        at khttp.requests.GenericRequest.toIDN(GenericRequest.kt:198)
        at khttp.requests.GenericRequest.makeRoute(GenericRequest.kt:208)
        at khttp.requests.GenericRequest.<init>(GenericRequest.kt:132)
        at khttp.KHttp.request(KHttp.kt:60)
        at khttp.KHttp.get(KHttp.kt:30)
        at khttp.KHttp.get$default(KHttp.kt:29)
        at xyz.mglolenstine.nekoslife.MainActivity$addImage$1.run(MainActivity.kt:426)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641) 
        at java.lang.Thread.run(Thread.java:764) 
E/AndroidRuntime: FATAL EXCEPTION: pool-1-thread-1
    Process: xyz.mglolenstine.nekoslife, PID: 14213
    java.lang.Error: java.lang.NoSuchFieldException: No field host in class Ljava/net/URL; (declaration of 'java.net.URL' appears in /system/framework/core-oj.jar)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1173)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
        at java.lang.Thread.run(Thread.java:764)
     Caused by: java.lang.NoSuchFieldException: No field host in class Ljava/net/URL; (declaration of 'java.net.URL' appears in /system/framework/core-oj.jar)
        at java.lang.Class.getDeclaredField(Native Method)
        at khttp.requests.GenericRequest.toIDN(GenericRequest.kt:198)
        at khttp.requests.GenericRequest.makeRoute(GenericRequest.kt:208)
        at khttp.requests.GenericRequest.<init>(GenericRequest.kt:132)
        at khttp.KHttp.request(KHttp.kt:60)
        at khttp.KHttp.get(KHttp.kt:30)
        at khttp.KHttp.get$default(KHttp.kt:29)
        at xyz.mglolenstine.nekoslife.MainActivity$addImage$1.run(MainActivity.kt:426)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641) 
        at java.lang.Thread.run(Thread.java:764) 
E/AndroidRuntime: FATAL EXCEPTION: pool-1-thread-2
    Process: xyz.mglolenstine.nekoslife, PID: 14213
    java.lang.Error: java.lang.NoSuchFieldException: No field host in class Ljava/net/URL; (declaration of 'java.net.URL' appears in /system/framework/core-oj.jar)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1173)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
        at java.lang.Thread.run(Thread.java:764)
     Caused by: java.lang.NoSuchFieldException: No field host in class Ljava/net/URL; (declaration of 'java.net.URL' appears in /system/framework/core-oj.jar)
        at java.lang.Class.getDeclaredField(Native Method)
        at khttp.requests.GenericRequest.toIDN(GenericRequest.kt:198)
        at khttp.requests.GenericRequest.makeRoute(GenericRequest.kt:208)
        at khttp.requests.GenericRequest.<init>(GenericRequest.kt:132)
        at khttp.KHttp.request(KHttp.kt:60)
        at khttp.KHttp.get(KHttp.kt:30)
        at khttp.KHttp.get$default(KHttp.kt:29)
        at xyz.mglolenstine.nekoslife.MainActivity$addImage$1.run(MainActivity.kt:426)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641) 
        at java.lang.Thread.run(Thread.java:764) 
I/Process: Sending signal. PID: 14213 SIG: 9
I/Process: Sending signal. PID: 14213 SIG: 9
I/Process: Sending signal. PID: 14213 SIG: 9
Application terminated.

再次强调，此问题仅在Android 9.0(API 28)中出现，但在低版本中可以完美运行。

- MG lolenstine

我不知道你为什么遇到麻烦，因为java.net.url是Android 9的一部分。它没有被弃用。请发布您的代码和实际堆栈跟踪。 - Gabe Sechan

我正在使用khttp，将在一个小时内发布堆栈跟踪。 - MG lolenstine

我已经更新了我的问题并附上了堆栈跟踪。 - MG lolenstine

错误似乎是自我解释的：“java.lang.NoSuchFieldException: No field host in class Ljava/net/URL”。看起来变量“host”在Android 9的“java.net.URL”类中不再存在。这是因为“kHTTP”似乎使用反射来获取隐藏变量。 - emandt

嗯，有点奇怪...我会去看看的，谢谢！ - MG lolenstine

公正的观点，你是正确的，而我是盲目的。感谢您的帮助，我不得不编写自己的函数来处理GET请求和图像下载，现在它可以工作了！谢谢。 - MG lolenstine

1个回答

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原文链接

- MG lolenstine · Answer 1

我之前瞎了，显然Java的新版本在Android 9.0中有所改变，'java.net.URL'中没有名为“host”的字段，而khttp正试图访问它。

感谢@emandt，我弄清楚了，并编写了自己的函数来完成完全相同的操作，而无需反射。

编辑： 一个承诺的示例，以与khttp非常相似的方式工作，但仅适用于get，并使用Kotlin编写。如果您愿意，我也可以发布Java版本。

    fun get(url: String): String {
        try {
            val connection = URI(url).toURL().openConnection() as HttpURLConnection
            connection.connect()
            val text = connection.inputStream.use { it.reader().use { reader -> reader.readText() } }
            return text
        } catch (e: IOException) {
            Log.e("Error: ", "" + e)
        }
        return ""
    }

    fun getImage(url: String): InputStream? {
        try {
            val connection = URI(url).toURL().openConnection() as HttpURLConnection
            connection.connect()
            return BufferedInputStream(connection.inputStream)
        }catch(e: FileNotFoundException){
            e.printStackTrace()
        }
        return null
    }