Java中图片的常用操作代码总结

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2023-06-21
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目录
  • 前言
  • 一、获取系统支持图片格式
  • 二、生成自定义图片
  • 三、获取图片格式
  • 四、图片裁剪
  • 五、图片压缩
  • 六、图片水印
  • 七、Thumbnails工具类

前言

本文主要使用Java对图片各种操作进行处理。

一、获取系统支持图片格式

代码：

System.out.println(Arrays.asList(ImageIO.getReaderFormatNames()));
System.out.println(Arrays.asList(ImageIO.getReaderFileSuffixes()));
System.out.println(Arrays.asList(ImageIO.getReaderMIMETypes()));
 
String[] writerFormatName = ImageIO.getWriterFormatNames();
String[] writerSuffixName = ImageIO.getWriterFileSuffixes();
String[] writerMIMEType = ImageIO.getWriterMIMETypes();

输出：

[JPG, jpg, tiff, pcx, PCX, bmp, BMP, gif, GIF, WBMP, png, PNG, raw, RAW, JPEG, pnm, PNM, tif, TIF, TIFF, wbmp, jpeg]
[, jpg, tiff, pcx, bmp, gif, png, ppm, tif, pgm, wbmp, jpeg, pbm]
[, image/vnd.wap.wbmp, image/png, image/jpeg, image/x-portable-graymap, image/pcx, image/bmp, image/gif, image/x-windows-pcx, image/x-windows-bmp, image/x-pc-paintbrush, image/x-pcx, image/x-bmp, image/x-png, image/x-portable-bitmap, image/x-portable-pixmap, image/tiff, image/x-portable-anymap]

二、生成自定义图片

代码：

@SneakyThrows
public static void main(String[] args) {
    BufferedImage bufferedImage = new BufferedImage(, 400, BufferedImage.TYPE_INT_BGR);
    Graphics g = bufferedImage.getGraphics();
    try {
        g.fillRect(, 40, 400, 400);
        g.setColor(new Color(, 120, 120));
        g.setFont(new Font("隶书", Font.BOLD,));
        g.drawString("自定义图片",, 200);
        ImageIO.write(bufferedImage, "jpg", new File("D:/test.jpg"));
    } finally {
        g.dispose();//释放画笔
    }
}

输出：

三、获取图片格式

代码：

 public static String getImageFormatName(File file) throws IOException {
     String formatName = null;
     ImageInputStream iis = ImageIO.createImageInputStream(file);
     Iterator<ImageReader> imageReader = ImageIO.getImageReaders(iis);
     if (imageReader.hasNext()) {
         ImageReader reader = imageReader.next();
         formatName = reader.getFormatName();
     }
     return formatName;
 }

四、图片裁剪

public static String cutImage(String sourcePath, String targetPath, int x, int y, int width, int height) throws IOException {
        File file = new File(sourcePath);
        if (!file.exists()) {
            throw new IOException("not found the image：" + sourcePath);
        }
        if (null == targetPath || targetPath.isEmpty()) {
            targetPath = sourcePath;
        }
 
        String formatName = getImageFormatName(file);
        if (null == formatName) {
            return targetPath;
        }
        formatName = formatName.toLowerCase();
 
        // 防止图片后缀与图片本身类型不一致的情况
        String pathPrefix = getPathWithoutSuffix(targetPath);
        targetPath = pathPrefix + formatName;
 
        // GIF需要特殊处理
        if (IMAGE_FORMAT.GIF.getValue() == formatName) {
            GifDecoder decoder = new GifDecoder();
            int status = decoder.read(sourcePath);
            if (status != GifDecoder.STATUS_OK) {
                throw new IOException("read image " + sourcePath + " error!");
            }
 
            AnimatedGifEncoder encoder = new AnimatedGifEncoder();
            encoder.start(targetPath);
            encoder.setRepeat(decoder.getLoopCount());
            for (int i =; i < decoder.getFrameCount(); i++) {
                encoder.setDelay(decoder.getDelay(i));
                BufferedImage childImage = decoder.getFrame(i);
                BufferedImage image = childImage.getSubimage(x, y, width, height);
                encoder.addFrame(image);
            }
            encoder.finish();
        } else {
            BufferedImage image = ImageIO.read(file);
            image = image.getSubimage(x, y, width, height);
            ImageIO.write(image, formatName, new File(targetPath));
        }
        return targetPath;
    }

五、图片压缩

 public static String zoom(String sourcePath, String targetPath, int width, int height) throws IOException {
        File file = new File(sourcePath);
        if (!file.exists()) {
            throw new IOException("not found the image ：" + sourcePath);
        }
        if (null == targetPath || targetPath.isEmpty()) {
            targetPath = sourcePath;
        }
        String formatName = getImageFormatName(file);
        if (null == formatName) {
            return targetPath;
        }
        formatName = formatName.toLowerCase();
        String pathPrefix = getPathWithoutSuffix(targetPath);
        targetPath = pathPrefix + formatName;
 
        // GIF处理
        if (IMAGE_FORMAT.GIF.getValue() == formatName) {
            GifDecoder decoder = new GifDecoder();
            int status = decoder.read(sourcePath);
            if (status != GifDecoder.STATUS_OK) {
                throw new IOException("read image " + sourcePath + " error!");
            }
            AnimatedGifEncoder encoder = new AnimatedGifEncoder();
            encoder.start(targetPath);
            encoder.setRepeat(decoder.getLoopCount());
            for (int i =; i < decoder.getFrameCount(); i++) {
                encoder.setDelay(decoder.getDelay(i));
                BufferedImage image = zoom(decoder.getFrame(i), width, height);
                encoder.addFrame(image);
            }
            encoder.finish();
        } else {
            BufferedImage image = ImageIO.read(file);
            BufferedImage zoomImage = zoom(image, width, height);
            ImageIO.write(zoomImage, formatName, new File(targetPath));
        }
        return targetPath;
    }

六、图片水印

  private static void waterMark(Image srcImg, String path) throws IOException {
        int srcImgWidth = srcImg.getWidth(null);
        int srcImgHeight = srcImg.getHeight(null);
/*
        //网络图片
        URL url = new URL("url");
        //将URL对象输入流转化为图片对象 (url.openStream()方法，获得一个输入流)
        Image srcImg = ImageIO.read(url.openStream());
        //获取图片的宽
        int srcImgWidth = srcImg.getWidth(null);
        //获取图片的高
        int srcImgHeight = srcImg.getHeight(null);
        System.out.println("图片的宽:"+srcImgWidth);
        System.out.println("图片的高:"+srcImgHeight);
*/
        BufferedImage bufImg = new BufferedImage(srcImgWidth, srcImgHeight, BufferedImage.TYPE_INT_RGB);
        // 加水印
        //创建画笔
        GraphicsD g = bufImg.createGraphics();
        //绘制原始图片
        g.drawImage(srcImg,, 0, srcImgWidth, srcImgHeight, null);
/*
        //文字水印
        //根据图片的背景设置水印颜色
        g.setColor(new Color(, 255, 255, 128));
        //设置字体  画笔字体样式为微软雅黑，加粗，文字大小为pt
        g.setFont(new Font("微软雅黑", Font.BOLD,));
        String waterMarkContent = "自定义水印";
        //设置水印的坐标(为原图片中间位置)
        int x = srcImgWidth /;
        int y = srcImgHeight /;
        //画出水印 第一个参数是水印内容，第二个参数是x轴坐标，第三个参数是y轴坐标
        g.drawString(waterMarkContent, x, y);
        g.dispose();*/
 
        //图片水印
        // 水印文件
        String waterMarkImage = "D:/print.jpg";
        Image srcWaterMark = ImageIO.read(new File(waterMarkImage));
        //获取水印图片的宽度
        int widthWaterMark = srcWaterMark.getWidth(null);
        //获取水印图片的高度
        int heightWaterMark = srcWaterMark.getHeight(null);
        //设置 alpha 透明度：alpha 必须是范围 [.0, 1.0] 之内（包含边界值）的一个浮点数字
        g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP,.9f));
        //绘制水印图片
        g.drawImage(srcWaterMark, (srcImgWidth - widthWaterMark) /,
                (srcImgHeight - heightWaterMark) /, widthWaterMark, heightWaterMark, null);
        // 水印文件结束
        g.dispose();
 
        //文件输出地址
        String tarImgPath = path;
        // 输出图片
        FileOutputStream outImgStream = new FileOutputStream(tarImgPath);
        ImageIO.write(bufImg, "png", outImgStream);
        outImgStream.flush();
        outImgStream.close();
    }

七、Thumbnails工具类

通过以上对图片的各种操作，还是需要对流进行转化，那是不是已经有成型的工具类了呢？对，Thumbnails工具类就能对以上各种情况处理。

主要有以下功能处理：

  • 旋转
  • 水印
  • 裁剪
  • 指定大小进行缩放
  • 按照比例进行缩放
  • 不按照比例，指定大小进行缩放
  • 转化图片格式
  • 输出到OutputStream
  • 输出到BufferedImage

代码示例如下：

依赖

<dependency>
        <groupId>net.coobird</groupId>
        <artifactId>thumbnailator</artifactId>
        <version>.4.17</version>
</dependency>

代码

 @SneakyThrows
    public static void main(String[] args) {
        //指定大小进行缩放
        Thumbnails.of("D:/test.jpg").size(, 100).toFile("D:/test.jpg.jpg");
 
        //按照比例进行缩放
        // scale 图片的压缩比例 值在-1之间，1f就是原图，0.5就是原图的一半大小
        // outputQuality 图片压缩的质量 值在-1 之间，越接近1质量越好，越接近0 质量越差
        Thumbnails.of("D:/test.jpg").scale(.75f).outputQuality(0.8f).toFile("D:/test.jpg");
 
        //不按照比例，指定大小进行缩放 keepAspectRatio(false) 默认是按照比例缩放的
        Thumbnails.of("D:/test.jpg").size(, 100).keepAspectRatio(false).toFile("D:/test.jpg");
 
        //旋转  rotate(角度),正数：顺时针 负数：逆时针
        Thumbnails.of("D:/test.jpg").size(, 1024).rotate(90).toFile("C:/image+90.jpg");
 
        //水印 watermark(位置，水印图，透明度)
        Thumbnails.of("D:/test.jpg").size(, 1024)
                .watermark(Positions.BOTTOM_RIGHT, ImageIO.read(new File("水印地址")),.5f)
                .outputQuality(.4f).toFile("输出地址");
 
        //裁剪
        Thumbnails.of("D:/test.jpg").sourceRegion(Positions.CENTER,, 400).size(200, 200).keepAspectRatio(false)
                .toFile("输出地址");
 
        //转化图片格式
        Thumbnails.of("D:/test.jpg").size(, 666).outputFormat("png").toFile("D:/test.png");
 
        // 输出到OutputStream
        OutputStream os = new FileOutputStream("D:/test.jpg");
        Thumbnails.of("test.jpg").size(, 666).toOutputStream(os);
 
        //输出到BufferedImage
        BufferedImage thumbnail = Thumbnails.of("D:/test.jpg").size(, 666).asBufferedImage();
        ImageIO.write(thumbnail, "jpg", new File("test.jpg"));
    }
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