从文件读取/写入图像到BufferedImage的最快方法？ [英] Fastest way to read/write Images from a File into a BufferedImage?

问题描述

在Java / Grails中将图像从文件读取到BufferedImage中的最快方式是什么？ 使用Java / Grails将BufferedImage转换为文件？

my variant（read）：

  byte []图像字节数组= （inStream）
  

我的变体（写）：

  BufferedImage bufferedImage = //某图像
 def fullPath = //图像页面+文件名称
字节[] currentImage 
 
尝试{
 
 ByteArrayOutputStream baos = new ByteArrayOutputStream（）; 
 ImageIO.write（bufferedImage，jpg，baos）; 
 baos.flush（）; 
 currentImage = baos.toByteArray（）; 
 baos.close（）; 
 
} catch（IOException e）{
 System.out.println（e.getMessage（））; 
 
 
 
 $ b def newFile = new FileOutputStream（fullPath）
 newFile.write（currentImage）
 newFile.close（）
  

解决方案

您的解决方案是基本读取两次字节从文件中，一次从 ByteArrayInputStream 。不要这样做

使用Java 7读取

  BufferedImage bufferedImage = ImageIO.read（Files.newInputStream（Paths.get（basePath + imageSource）））; 
  

使用Java 7编写

<$ p $ ImageIO.write（bufferedImage，jpg，Files.newOutputStream（Paths.get（fullPath）））;

调用 Files.newInputStream 将会返回一个 ChannelInputStream 其中（AFAIK）未被缓冲。你需要包装它

  new BufferedInputStream（Files.newInputStream（...））; 
  

这样可以减少对磁盘的IO调用，具体取决于您如何使用它。

1. What is the fastest way to read Images from a File into a BufferedImage in Java/Grails?
2. 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.

这篇关于从文件读取/写入图像到BufferedImage的最快方法？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！