What is the fastest way to read Images from a File into a BufferedImage in Java/Grails?
What is the fastest way to write Images from a BufferedImage into a File in Java/Grails?
my variant (read):
byte [] imageByteArray = new File(basePath+imageSource).readBytes()
InputStream inStream = new ByteArrayInputStream(imageByteArray)
BufferedImage bufferedImage = ImageIO.read(inStream)
my variant (write):
BufferedImage bufferedImage = // some image
def fullPath = // image page + file name
byte [] currentImage
try{
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ImageIO.write( bufferedImage, "jpg", baos );
baos.flush();
currentImage = baos.toByteArray();
baos.close();
}catch(IOException e){
System.out.println(e.getMessage());
}
}
def newFile = new FileOutputStream(fullPath)
newFile.write(currentImage)
newFile.close()
解决方案
Your solution to read is basically reading the bytes twice, once from the file and once from the ByteArrayInputStream. Don't do that
With Java 7 to read
BufferedImage bufferedImage = ImageIO.read(Files.newInputStream(Paths.get(basePath + imageSource)));
With Java 7 to write
ImageIO.write(bufferedImage, "jpg", Files.newOutputStream(Paths.get(fullPath)));
The call to Files.newInputStream will return a ChannelInputStream which (AFAIK) is not buffered. You'll want to wrap it
new BufferedInputStream(Files.newInputStream(...));
So that there are less IO calls to disk, depending on how you use it.
