图片指定压缩大小

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.UUID;

/**
 * 图片压缩
 */
public class ImageCompressUtil {


    private static String path = "C:\\Users\\Administrator\\Pictures\\";

    public static void main(String[] args) throws IOException {
        File imageFile = new File(path + "反.jpg");
        BufferedImage inputImage = ImageIO.read(imageFile);

        //通过比例压缩
        float scale = 0.5f;
        BufferedImage outputImage = compress(inputImage, scale);

        //图片输出路径，以及图片名
        File outputFile = new File(path + UUID.randomUUID() + "." + getImageType(inputImage.getType()));
        ImageIO.write(outputImage, getImageType(inputImage.getType()), outputFile);

    }

    /**
     * 压缩图片
     */
    public static BufferedImage compress(BufferedImage inputImage, float scale) {
        //压缩之后的长度和宽度
        int outputHeight = (int) (inputImage.getHeight() * scale);
        int outputWidth = (int) (inputImage.getWidth() * scale);

        BufferedImage outputImage = new BufferedImage(outputWidth, outputHeight, inputImage.getType());

        outputImage.getGraphics().drawImage(
                inputImage.getScaledInstance(outputWidth, outputHeight, Image.SCALE_SMOOTH), 0, 0, null);

        return outputImage;
    }

    public static String getImageType(int imageType) {
        switch (imageType) {
//            case 5:
//                return "jpg";
            case 6:
                return "png";
            case 13:
                return "gif";
            default:
                return "jpg";
        }
    }