![](/img/trans.png)
[英]Error While Uploading in JAVA “message[java.lang.IllegalArgumentException: im == null!]”
[英]java.lang.IllegalArgumentException: im == null! error
我刚刚学会了如何使用线程,我正在尝试使用线程编码一些图像,但我会得到这个错误java.lang.IllegalArgumentException:im == null!
我尝试没有线程做同样的事情,它只是慢慢地工作,不是因为图像io,而是因为编码图像所需的时间。 WinDef.HDC是我从JNA库获得的变量类型。 当我没有线程尝试它时,我可以很容易地写出1000张图像(约60mb)。
//The thread class
public class imageEncoderThread extends Thread {
HDC originalImage;
BufferedImage image;
public imageProcessThread (HDC rI) {
originalImage = rI'
}
@Override
public void run() {
//returns a buffered image
image = process(rawImage);
try {
ImageIO.write(image, "jpg", new File (filePath));
} catch (IOException e) {
}
}
}
//full stack trace
Exception in thread "Thread-5" java.lang.IllegalArgumentException: im == null!
at javax.imageio.ImageIO.write(Unknown Source)
at javax.imageio.ImageIO.write(Unknown Source)
at com.capture.SingleImageEncoderThread.run(Thread.java:33)
Exception in thread "Thread-7" java.lang.IllegalArgumentException: im == null!
at javax.imageio.ImageIO.write(Unknown Source)
at javax.imageio.ImageIO.write(Unknown Source)
at com.capture.SingleImageEncoderThread.run(Thread.java:33)
Exception in thread "Thread-6" java.lang.IllegalArgumentException: im == null!
at javax.imageio.ImageIO.write(Unknown Source)
at javax.imageio.ImageIO.write(Unknown Source)
//and so on with the same exception
几乎可以肯定你不能打电话:
image = JNAScreenShot.encodeRawWindow(rawImage, bounds);
从主ui线程以外的任何线程。 请参阅: http ://social.msdn.microsoft.com/Forums/en-US/vclanguage/thread/6398cda5-5393-4b16-b8dc-5bbf8902033f/(具体来说,我认为HDC不能在主ui线程之外使用) 。
因此,您需要首先创建屏幕截图,然后将其传递给您的线程以执行IO(无论如何,这可能是缓慢的部分)。
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.