blocks|key|3034196|text|java.io.FileInputStream就是您要找的:-)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3034197|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

java.io.FileInputStream is what you're looking for :-)

blocks|key|3248389|text|查看javax.imageio，特别是ImageReader和ImageWriter，它是用于读取和写入图像文件的抽象。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3248390|BufferedImage.getRGB(int+x,+int+y)则允许您获取给定像素上的RGB值，这些值可以分成字节。|3248391|注意:我认为您不希望读取原始字节，因为这样您就必须处理所有的压缩/解压缩。|3248392|entityMap^0|2|D|J|B|V|B|0|0|Y|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@$9|M|A|N|B|C]|$9|O|A|P|B|C]|$9|Q|A|R|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@]|E|$]]|$1|H|3|I|5|6|7|V|8|@]|D|@]|E|$]]|$1|J|3|-4|5|6|7|W|8|@]|D|@]|E|$]]]|K|$]]

Check out <code>javax.imageio</code>, especially <code>ImageReader</code> and <code>ImageWriter</code> as an abstraction for reading and writing image files.

<code>BufferedImage.getRGB(int x, int y)</code> than allows you to get RGB values on the given pixel, which can be chunked into bytes.

Note: I think you don't want to read the raw bytes, because then you have to deal with all the compression/decompression.

blocks|key|303704|text|我认为最好的方法是首先将文件读入字节数组，然后使用ImageIO.read()将数组转换为图像|type|unstyled|depth|inlineStyleRanges|entityRanges|data|303705|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

I think the best way to do that is to first read the file into a byte array, then convert the array to an image with ImageIO.read()

blocks|key|3248399|text|尝试此代码片段|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3248400|BufferedImage+image+=+ImageIO.read(new+File("filename.jpg"));

//+Process+image

ImageIO.write(image,+"jpg",+new+File("output.jpg"));|code-block|syntax|javascript|3248401|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Try this code snippet

<pre><code>BufferedImage image = ImageIO.read(new File("filename.jpg"));

// Process image

ImageIO.write(image, "jpg", new File("output.jpg"));
</code></pre>

blocks|key|303710|text|File+fnew=new+File("/tmp/rose.jpg");
BufferedImage+originalImage=ImageIO.read(fnew);
ByteArrayOutputStream+baos=new+ByteArrayOutputStream();
ImageIO.write(originalImage,+"jpg",+baos+);
byte[]+imageInByte=baos.toByteArray();|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|303711|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>File fnew=new File("/tmp/rose.jpg");
BufferedImage originalImage=ImageIO.read(fnew);
ByteArrayOutputStream baos=new ByteArrayOutputStream();
ImageIO.write(originalImage, "jpg", baos );
byte[] imageInByte=baos.toByteArray();
</code></pre>

blocks|key|3034271|text|如果您使用的是JDK+7，则可以使用以下代码。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3034272|import+java.nio.file.Files;
import+java.io.File;

File+fi+=+new+File("myfile.jpg");
byte[]+fileContent+=+Files.readAllBytes(fi.toPath())|code-block|syntax|javascript|3034273|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

If you are using JDK 7 you can use the following code..

<pre><code>import java.nio.file.Files;
import java.io.File;

File fi = new File("myfile.jpg");
byte[] fileContent = Files.readAllBytes(fi.toPath())
</code></pre>

blocks|key|302827|text|以下是完成此操作的代码的完整版本。我已经测试过了。BufferedImage和Base64类主要完成此任务。另外，还需要正确设置一些参数。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|302828|public+class+SimpleConvertImage+{
++++public+static+void+main(String[]+args)+throws+IOException{
++++++++String+dirName="C:\\";
++++++++ByteArrayOutputStream+baos=new+ByteArrayOutputStream(1000);
++++++++BufferedImage+img=ImageIO.read(new+File(dirName,"rose.jpg"));
++++++++ImageIO.write(img,+"jpg",+baos);
++++++++baos.flush();

++++++++String+base64String=Base64.encode(baos.toByteArray());
++++++++baos.close();

++++++++byte[]+bytearray+=+Base64.decode(base64String);

++++++++BufferedImage+imag=ImageIO.read(new+ByteArrayInputStream(bytearray));
++++++++ImageIO.write(imag,+"jpg",+new+File(dirName,"snap.jpg"));
++++}
}|code-block|syntax|javascript|302829|Reference+link|302830|entityMap|0|LINK|mutability|MUTABLE|url|http://www.programcreek.com/2009/02/java-convert-image-to-byte-array-convert-byte-array-to-image/^0|P|D|13|6|0|0|0|E|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]|$9|X|A|Y|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|Z|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|10|8|@]|D|@$9|11|A|12|1|13]]|E|$]]|$1|M|3|-4|5|6|7|14|8|@]|D|@]|E|$]]]|N|$O|$5|P|Q|R|E|$S|T]]]]

Here is a complete version of code for doing this. I have tested it. The <code>BufferedImage</code> and <code>Base64</code> class do the trick mainly. Also some parameter needs to be set correctly. 

<pre><code>public class SimpleConvertImage {
 public static void main(String[] args) throws IOException{
 String dirName="C:\\";
 ByteArrayOutputStream baos=new ByteArrayOutputStream(1000);
 BufferedImage img=ImageIO.read(new File(dirName,"rose.jpg"));
 ImageIO.write(img, "jpg", baos);
 baos.flush();

 String base64String=Base64.encode(baos.toByteArray());
 baos.close();

 byte[] bytearray = Base64.decode(base64String);

 BufferedImage imag=ImageIO.read(new ByteArrayInputStream(bytearray));
 ImageIO.write(imag, "jpg", new File(dirName,"snap.jpg"));
 }
}
</code></pre>

<a href="http://www.programcreek.com/2009/02/java-convert-image-to-byte-array-convert-byte-array-to-image/" rel="noreferrer">Reference link</a>

blocks|key|305806|text|使用RandomAccessFile将是简单和方便的。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|305807|RandomAccessFile+f+=+new+RandomAccessFile(filepath,+"r");
byte[]+bytes+=+new+byte[(int)+f.length()];
f.read(bytes);
f.close();|code-block|syntax|javascript|305808|entityMap^0|2|G|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

Using <code>RandomAccessFile</code> would be simple and handy.

<pre><code>RandomAccessFile f = new RandomAccessFile(filepath, "r");
byte[] bytes = new byte[(int) f.length()];
f.read(bytes);
f.close();
</code></pre>

I want to convert an image to byte array and vice versa. Here, the user will enter the name of the image (<code>.jpg</code>) and program will read it from the file and will convert it to a byte array.

how to convert image to byte array in java?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我想要将图像转换为字节数组，反之亦然。在这里，用户将输入图像的名称(.jpg)，程序将从文件中读取它，并将其转换为字节数组。

问如何在java中将图像转换为字节数组？
EN

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问如何在java中将图像转换为字节数组？EN