java实现图片转化为字节流，字节流还原成图片

╰+攻爆jí腚メ 2022-08-19 09:01 293阅读 0赞

最近，在研究图片转化为字节流以及字节流还原成图片的，

项目下载地址：[http://download.csdn.net/detail/u010627840/9397506][http_download.csdn.net_detail_u010627840_9397506]

代码如下：

package com.mybatis.test;
    
    import java.io.File;
    import java.io.FileInputStream;
    import java.io.FileOutputStream;
    
    public class TestImage {
    	
    	 public static void main(String[] args) throws Exception
    	    {
    	        //先模拟一个图形byte[]
    	        byte[] b1 =image2Bytes("d:\\1.jpg");
    	        //存为文件
    	        buff2Image(b1,"d:\\test.jpg");
    	 
    	        System.out.println("Hello World!");
    	    }
    	 
    	 static void buff2Image(byte[] b,String tagSrc) throws Exception
    	    {
    	        FileOutputStream fout = new FileOutputStream(tagSrc);
    	        //将字节写入文件
    	        fout.write(b);
    	        fout.close();
    	    }
    	 
    	 static byte[] image2Bytes(String imgSrc) throws Exception
    	    {
    	        FileInputStream fin = new FileInputStream(new File(imgSrc));
    	        //可能溢出,简单起见就不考虑太多,如果太大就要另外想办法，比如一次传入固定长度byte[]
    	        byte[] bytes  = new byte[fin.available()];
    	        //将文件内容写入字节数组，提供测试的case
    	        fin.read(bytes);
    	        
    	        fin.close();
    	        return bytes;
    }
    	 
    }

如何判断图片类型

>     import javax.imageio.ImageIO;
>     import javax.imageio.ImageReader;
>     import javax.imageio.stream.MemoryCacheImageInputStream;
>     import javax.swing.*;
>     import java.awt.image.BufferedImage;
>     import java.io.*;
>     import java.util.Iterator;

>     /**
>      *  根据字节流获取图片类型
>      * */
>     public static String getImageType(byte[] imageBytes) {
>         try {
>             MemoryCacheImageInputStream memoryCacheImageInputStream = new MemoryCacheImageInputStream(new ByteArrayInputStream(imageBytes));
>             Iterator<ImageReader> itr = ImageIO.getImageReaders(memoryCacheImageInputStream);
>             while (itr.hasNext()) {
>                 ImageReader reader = itr.next();
>                 String imageName = reader.getClass().getSimpleName();
>                 if (imageName != null) {
>                     if ("JPEGImageReader".equalsIgnoreCase(imageName)){
>                         return "jpeg";
>                     }
>                     if ("JPGImageReader".equalsIgnoreCase(imageName)) {
>                         return "jpg";
>                     }
>                     if ("pngImageReader".equalsIgnoreCase(imageName)) {
>                         return "png";
>                     }
>                 }
>             }
>         } catch (Exception e) {
>             // TODO: handle exception
>             e.printStackTrace();
>         }
>         return null;
>     }

如何改变图片格式

>     //把这个jpg图像写到这个流中去,这里可以转变图片的编码格式
>     boolean resultWrite = ImageIO.write(bu, "jpg", imageStream);

[http_download.csdn.net_detail_u010627840_9397506]: http://download.csdn.net/detail/u010627840/9397506