java上传图片并压缩 java图片压缩到指定大小

1、maven引入jar包

<dependency>
			<groupId>net.coobird</groupId>
			<artifactId>thumbnailator</artifactId>
			<version>0.4.8</version>
		</dependency>

2、处理图片util

public static void main(String[] args) {

        CompressPicture.commpressPicForScale("D:\\001.jpg",
                "D:\\001.jpg", 400, 0.8); // 图片小于400kb
    }

    /**
     * @param srcPath     原地址
     * @param desPath     压缩后的地址
     * @param desFileSize 指定大小
     * @param accuracy
     * @return
     */
    public static String commpressPicForScale(String srcPath, String desPath,
                                              long desFileSize, double accuracy) {
        if (StringUtils.isEmpty(srcPath) || StringUtils.isEmpty(srcPath)) {
            return null;
        }
        if (!new File(srcPath).exists()) {
            return null;
        }
        try {
            File srcFile = new File(srcPath);
            long srcFileSize = srcFile.length();
            System.out.println("源图片：" + srcPath + "，大小：" + srcFileSize / 1024
                    + "kb");

// 1、先转换成jpg
            Thumbnails.of(srcPath).scale(1f).toFile(desPath);
// 递归压缩，直到目标文件大小小于desFileSize
            commpressPicCycle(desPath, desFileSize, accuracy);

            File desFile = new File(desPath);
            System.out.println("目标图片：" + desPath + "，大小" + desFile.length()
                    / 1024 + "kb");
            System.out.println("图片压缩完成！");
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
        return desPath;
    }


    private static void commpressPicCycle(String desPath, long desFileSize,
                                          double accuracy) throws IOException {
        File srcFileJPG = new File(desPath);
        long srcFileSizeJPG = srcFileJPG.length();
// 2、判断大小，如果小于500kb，不压缩；如果大于等于500kb，压缩
        if (srcFileSizeJPG <= desFileSize * 1024) {
            return;
        }
// 计算宽高
        BufferedImage bim = ImageIO.read(srcFileJPG);
        int srcWdith = bim.getWidth();
        int srcHeigth = bim.getHeight();
        int desWidth = new BigDecimal(srcWdith).multiply(
                new BigDecimal(accuracy)).intValue();
        int desHeight = new BigDecimal(srcHeigth).multiply(
                new BigDecimal(accuracy)).intValue();

        Thumbnails.of(desPath).size(desWidth, desHeight)
                .outputQuality(accuracy).toFile(desPath);
        commpressPicCycle(desPath, desFileSize, accuracy);
    }