Java修改图片大小尺寸图片缩放（URL图片和本地图片） |
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方式一：使用Image.getScaledInstance
使用jdk的awt包下的Image.getScaledInstance实现图片的缩放。好处是无需引入第三方jar，缺点是会稍微有点模糊。 工具类ImageUtils： package utils; import javax.imageio.ImageIO; import java.awt.*; import java.awt.image.BufferedImage; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.IOException; public class ImageUtils { /** * 通过BufferedImage图片流调整图片大小 */ public static BufferedImage resizeImage(BufferedImage originalImage, int targetWidth, int targetHeight) throws IOException { Image resultingImage = originalImage.getScaledInstance(targetWidth, targetHeight, Image.SCALE_AREA_AVERAGING); BufferedImage outputImage = new BufferedImage(targetWidth, targetHeight, BufferedImage.TYPE_INT_RGB); outputImage.getGraphics().drawImage(resultingImage, 0, 0, null); return outputImage; } /** * BufferedImage图片流转byte[]数组 */ public static byte[] imageToBytes(BufferedImage bImage) { ByteArrayOutputStream out = new ByteArrayOutputStream(); try { ImageIO.write(bImage, "jpg", out); } catch (IOException e) { e.printStackTrace(); } return out.toByteArray(); } /** * byte[]数组转BufferedImage图片流 */ private static BufferedImage bytesToBufferedImage(byte[] ImageByte) { ByteArrayInputStream in = new ByteArrayInputStream(ImageByte); BufferedImage image = null; try { image = ImageIO.read(in); } catch (IOException e) { e.printStackTrace(); } return image; } } 测试：1.通过 url 获取图片并调整大小后保存： import utils.ImageUtils; import javax.imageio.ImageIO; import java.awt.image.BufferedImage; import java.io.File; import java.io.IOException; import java.net.URL; public class Test { public static void main(String[] args) { try { //通过url获取BufferedImage图像缓冲区 URL img = new URL("https://img1.360buyimg.com/image/jfs/t1/38591/20/3737/314695/5cc69c01E1838df09/dd6dce681bd23031.jpg"); BufferedImage image = ImageIO.read(img); //获取图片的宽、高 System.out.println("Width: " + image.getWidth()); System.out.println("Height: " + image.getHeight()); //调整图片大小为 400X400尺寸 BufferedImage newImage = ImageUtils.resizeImage(image,400,400); //将缓冲区图片保存到 F:/test/pic1.jpg (文件不存在会自动创建文件保存，文件存在会覆盖原文件保存) ImageIO.write(newImage, "jpg", new File("F:/test/pic1.jpg")); } catch (IOException e) { e.printStackTrace(); } } }2、通过读取图片文件调整大小再保存： import utils.ImageUtils; import javax.imageio.ImageIO; import java.awt.image.BufferedImage; import java.io.File; import java.io.FileInputStream; import java.io.IOException; public class Test { public static void main(String[] args) { try { //读取原始图片 BufferedImage image = ImageIO.read(new FileInputStream("F:/test/pic1.jpg")); System.out.println("Width: " + image.getWidth()); System.out.println("Height: " + image.getHeight()); //调整图片大小 BufferedImage newImage = ImageUtils.resizeImage(image,200,200); //图像缓冲区图片保存为图片文件(文件不存在会自动创建文件保存，文件存在会覆盖原文件保存) ImageIO.write(newImage, "jpg", new File("F:/test/pic2.jpg")); } catch (IOException e) { e.printStackTrace(); } } }3、MultipartFile类型的图片文件调整大小再保存： public JSONObject imageSizeAdjustment(MultipartFile file) { JSONObject result = new JSONObject(); try { //从MultipartFile 中获取 byte[] byte[] bytes = file.getBytes(); //byte[]转 InputStream InputStream in = new ByteArrayInputStream(bytes); //读取图片输入流为 BufferedImage BufferedImage image = ImageIO.read(in); System.out.println("Width: " + image.getWidth()); System.out.println("Height: " + image.getHeight()); //调整图片大小 BufferedImage newImage = ImageUtils.resizeImage(image, 200, 200); //图像缓冲区图片保存为图片文件(文件不存在会自动创建文件保存，文件存在会覆盖原文件保存) ImageIO.write(newImage, "jpg", new File("F:/test/pic2.jpg")); } catch (IOException e) { e.printStackTrace(); } result.put("code", 1); result.put("note", "成功"); return result; } 方式二：使用ThumbnailatorThumbnailator是Java的开源图像大小调整库，它使用渐进式双线性缩放。它支持JPG，BMP，JPEG，WBMP，PNG和GIF。 通过将以下Maven依赖项添加到我们的pom.xml中，将其包括在我们的项目中： net.coobird thumbnailator 0.4.11工具类ThumbnailsUtils： import net.coobird.thumbnailator.Thumbnails; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import javax.imageio.ImageIO; import java.awt.image.BufferedImage; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.IOException; public class ThumbnailsUtils{ private static final Logger logger = LoggerFactory.getLogger(ThumbnailsUtils.class); /** * 通过BufferedImage图片流调整图片大小 */ public static BufferedImage resizeImageOne(BufferedImage originalImage, int targetWidth, int targetHeight) throws Exception { ByteArrayOutputStream outputStream = new ByteArrayOutputStream(); Thumbnails.of(originalImage) .size(targetWidth, targetHeight) .outputFormat("JPEG") .outputQuality(1) .toOutputStream(outputStream); byte[] data = outputStream.toByteArray(); ByteArrayInputStream inputStream = new ByteArrayInputStream(data); return ImageIO.read(inputStream); } /** * BufferedImage图片流转byte[]数组 */ public static byte[] imageToBytes(BufferedImage bImage) { ByteArrayOutputStream out = new ByteArrayOutputStream(); try { ImageIO.write(bImage, "jpg", out); } catch (IOException e) { logger.error("错误信息: ", e); } return out.toByteArray(); } /** * byte[]数组转BufferedImage图片流 */ private static BufferedImage bytesToBufferedImage(byte[] ImageByte) { ByteArrayInputStream in = new ByteArrayInputStream(ImageByte); BufferedImage image = null; try { image = ImageIO.read(in); } catch (IOException e) { logger.error("错误信息: ", e); } return image; } } 测试：和上面测试基本一样只不过 ImageUtils.resizeImage换成 ThumbnailsUtils.resizeImageOne即可。 不修改尺寸直接将Url图片下载并转化为File /** * 将Url转换为File * @param url 图片在线链接 * @param pathUrl 下载到本地路径 * @return * @throws Exception */ public static File urltoFile(String url,String pathUrl) throws Exception { HttpURLConnection httpUrl = (HttpURLConnection) new URL(url).openConnection(); httpUrl.connect(); InputStream ins=httpUrl.getInputStream(); // 获取文件后缀 String prefix = url.substring(url.lastIndexOf(".")); String fileUrl = pathUrl + UUIDUtil.get32UUID()+prefix; File file = new File(fileUrl);//System.getProperty("java.io.tmpdir")缓存 if (file.exists()) { file.delete();//如果缓存中存在该文件就删除 } OutputStream os = new FileOutputStream(file); int bytesRead; int len = 8192; byte[] buffer = new byte[len]; while ((bytesRead = ins.read(buffer, 0, len)) != -1) { os.write(buffer, 0, bytesRead); } os.close(); ins.close(); return file; } |
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