将图像绘制到 jframe 时出现空异常错误。我调试代码并检查图像和框架不为空，但在将图像绘制到框架时仍然抛出 NULL 异常。
请看一看 ：
public void run(){
try{
ObjectInputStream objVideoIn = new ObjectInputStream(serVideoIn);
byte[] imgbytes=null;
ByteArrayInputStream barrin=null;
JFrame jf = new JFrame();
Graphics ga=jf.getGraphics(); //Getting null exception
//Thread.sleep(10000);
jf.setVisible(true);
jf.setSize(400, 400);
while(true){
int index=0;
//Thread.sleep(300);
int size= (int)objVideoIn.readObject();
imgbytes = new byte[size];
barrin = new ByteArrayInputStream(imgbytes);
System.out.println("image size" + size);
//Thread.sleep(200);
while(index<size)
{
System.out.println("reading image");
int bytesread = objVideoIn.read(imgbytes, index, size-index);
if(bytesread<0){
System.out.println("error in receiving bytes yar");
}
index+=bytesread;
}
//barrin.read(imgbytes, 0, imgbytes.length);
barrin = new ByteArrayInputStream(imgbytes);
buffImg = ImageIO.read(barrin);
if(buffImg==null)
{
System.out.println("null received");
}
else {
System.out.println("image received");
**ga.drawImage(buffImg, 0, 0, null);**
}
}
}
}
catch(Exception ex)
{
System.out.println("error reading video" +ex.getMessage());
}
}