ImageIO 先read再write 文件变小了

傷城~ 2021-11-06 01:04 622阅读 0赞

ImageIO 先read再write 图片文件变小了以及处理办法：

public static void testImageIo(){ 
            try { 
                InputStream inputStream =  FileUtils.openInputStream(new File("/Users/mac/Desktop/B612/a.jpg"));
                BufferedImage bImage = ImageIO.read(inputStream);
                // 此处直接write会导致图片被压缩处理，失真
    // ImageIO.write(bImage,"jpg",new File("/Users/mac/Desktop/B612/a-copy.jpg"));
    
                // 所以经过以下处理，可以调整相应的参数，甚至可以生成大于原图的图片
                Iterator<ImageWriter> iter = ImageIO.getImageWritersByFormatName("jpg");
                if (iter.hasNext()) { 
                    ImageWriter writer = iter.next();
                    ImageWriteParam param = writer.getDefaultWriteParam();
    
                    param.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);
                    // 该参数在0.92～0.93左右是最接近原图大小的，最大是1
                    param.setCompressionQuality(0.92f);
                    FileImageOutputStream out = new FileImageOutputStream(new File(
                            "/Users/mac/Desktop/B612/a-copy01.jpg"));
                    writer.setOutput(out);
                    // writer.write(bi);
                    writer.write(null, new IIOImage(bImage, null, null), param);
                    out.close();
                    writer.dispose();
                }
            }catch (Exception e){ 
                e.printStackTrace();
            }
        }

参考：[https://www.iteye.com/problems/72994][https_www.iteye.com_problems_72994]  
[https://blog.csdn.net/liuxiaoshuang002/article/details/89680313][https_blog.csdn.net_liuxiaoshuang002_article_details_89680313]

[https_www.iteye.com_problems_72994]: https://www.iteye.com/problems/72994
[https_blog.csdn.net_liuxiaoshuang002_article_details_89680313]: https://blog.csdn.net/liuxiaoshuang002/article/details/89680313