图片分页

src/main/java/com/example/sso/dao/ThumbnailCompressor.java

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+package com.example.sso.dao;
+
+import net.coobird.thumbnailator.Thumbnails;
+import net.coobird.thumbnailator.geometry.Positions;
+import javax.imageio.ImageIO;
+import java.awt.image.BufferedImage;
+import java.io.*;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+
+public class ThumbnailCompressor {
+
+    private static final long MAX_SIZE = 300 * 1024; // 500KB
+
+    /**
+     * 使用Thumbnailator压缩图片
+     */
+    public static long compressWithThumbnailator(String inputPath, String outputPath) throws IOException {
+        File inputFile = new File(inputPath);
+        long fileSize = inputFile.length();
+
+        System.out.println("原始大小: " + formatFileSize(fileSize));
+
+        // 如果小于500KB，直接复制
+        if (fileSize <= MAX_SIZE) {
+            Files.copy(inputFile.toPath(), Paths.get(outputPath));
+            return fileSize;
+        }
+
+        // 获取图片尺寸
+        BufferedImage originalImage = ImageIO.read(inputFile);
+        int width = originalImage.getWidth();
+        int height = originalImage.getHeight();
+
+        // 计算缩放比例
+        float scale = 1.0f;
+        if (width > 1920 || height > 1080) {
+            float widthRatio = 1920f / width;
+            float heightRatio = 1080f / height;
+            scale = Math.min(widthRatio, heightRatio);
+        }
+
+        // 逐步压缩
+        float quality = 0.9f;
+        long compressedSize = Long.MAX_VALUE;
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+
+        while (quality > 0.1f && compressedSize > MAX_SIZE) {
+            baos.reset();
+
+            Thumbnails.of(inputFile)
+                    .scale(scale)
+                    .outputQuality(quality)
+                    .outputFormat("jpg")
+                    .toOutputStream(baos);
+
+            compressedSize = baos.size();
+            System.out.println("质量: " + quality + ", 大小: " + formatFileSize(compressedSize));
+
+            quality -= 0.1f;
+        }
+
+        // 保存文件
+        try (FileOutputStream fos = new FileOutputStream(outputPath)) {
+            fos.write(baos.toByteArray());
+        }
+
+        return compressedSize;
+    }
+
+    /**
+     * 批量压缩
+     */
+    public static void batchCompress(String inputDir, String outputDir, long maxSize) throws IOException {
+        File dir = new File(inputDir);
+        File[] imageFiles = dir.listFiles((d, name) ->
+                name.toLowerCase().endsWith(".jpg") ||
+                        name.toLowerCase().endsWith(".jpeg") ||
+                        name.toLowerCase().endsWith(".png") ||
+                        name.toLowerCase().endsWith(".bmp")
+        );
+
+        if (imageFiles == null) return;
+
+        for (File imageFile : imageFiles) {
+            String outputPath = outputDir + File.separator + "compressed_" + imageFile.getName();
+            long compressedSize = compressWithThumbnailator(imageFile.getPath(), outputPath);
+
+            System.out.println(imageFile.getName() +
+                    " 压缩后: " + formatFileSize(compressedSize));
+        }
+    }
+
+    private static String formatFileSize(long size) {
+        if (size < 1024) return size + " B";
+        if (size < 1024 * 1024) return String.format("%.2f KB", size / 1024.0);
+        if (size < 1024 * 1024 * 1024) return String.format("%.2f MB", size / (1024.0 * 1024.0));
+        return String.format("%.2f GB", size / (1024.0 * 1024.0 * 1024.0));
+    }
+
+    public static void main(String[] args) {
+        try {
+            // 压缩单个图片
+            long size = compressWithThumbnailator("D:\\下载模板\\微信图片_20251224111834_4_27.jpg", "D:\\下载模板\\微信图片_20251224111834_4_27.jpg");
+            System.out.println("最终大小: " + formatFileSize(size));
+
+            // 批量压缩
+            // batchCompress("input_images", "output_images", 500 * 1024);
+
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+}