实际开发之图片按比例压缩

import com.lufax.g.media.utils.Logger;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.*;

/**
 * 压缩图片
 * Created by shazhipeng880 on 19-10-11.
 */
@Service
public class CompressImgService {

    public InputStream compressImgByWidth(InputStream inputStream, Integer width){

        OutputStream os = null;
        InputStream is = null;
        String fileName = "1.jpg";

        //保存图片到临时路径
        savePic(inputStream, fileName);

        //缩略后图片临时存放地址
        String destination = System.getProperty("java.io.tmpdir") + File.separator + fileName;

        try {
            BufferedImage image = ImageIO.read(new FileInputStream(destination));

            os = new FileOutputStream(destination);

            //原图宽度
            int srcWidth = image.getWidth();
            //原图高度
            int srcHeight = image.getHeight();
            //缩略后宽度
            int compressWidth = width.intValue();
            //缩略比例
            int rate = srcWidth/compressWidth;

            //计算缩略后高度
            int compressHeight = srcHeight/rate;

            BufferedImage bufferedImage = new BufferedImage(compressWidth, compressHeight, BufferedImage.TYPE_INT_RGB);
            bufferedImage.getGraphics().drawImage(image.getScaledInstance(compressWidth, compressHeight, image.SCALE_SMOOTH), 0, 0, null);

            String imageType = "jpg";
            ImageIO.write(bufferedImage, imageType, os);

            //缩略后图片的流
            is = new FileInputStream(destination);

        } catch (FileNotFoundException e) {
            
        } catch (IOException e) {
            
        } finally {
            if(null != os){
                try {
                    os.close();
                } catch (IOException e) {
                    
                }
            }

            //删除临时文件
            deleteFile(destination);

            return is;
        }
    }

    public void savePic(InputStream inputStream, String fileName) {
        OutputStream os = null;
        try {
            String path = System.getProperty("java.io.tmpdir");
            // 2、保存到临时文件
            // 1K的数据缓冲
            byte[] bs = new byte[1024];
            // 读取到的数据长度
            int len;
            // 输出的文件流保存到本地文件

            File tempFile = new File(path);
            if (!tempFile.exists()) {
                tempFile.mkdirs();
            }
            os = new FileOutputStream(tempFile.getPath() + File.separator + fileName);
            int available = inputStream.available();
            // 开始读取
            while ((len = inputStream.read(bs)) != -1) {
                os.write(bs, 0, len);
            }

        } catch (IOException e) {
            
        } catch (Exception e) {
            
        } finally {
            // 完毕，关闭所有链接
            if(null != inputStream){
                try {
                    inputStream.close();
                    os.close();
                } catch (IOException e) {
                    
                }
            }
        }
    }

public boolean deleteFile(String fileName) {
    File file = new File(fileName);
    // 如果文件路径所对应的文件存在，并且是一个文件，则直接删除
    if (file.exists() && file.isFile()) {
        if (file.delete()) {
            System.out.println("删除单个文件" + fileName + "成功！");
            return true;
        } else {
            System.out.println("删除单个文件" + fileName + "失败！");
            return false;
        }
    } else {
        System.out.println("删除单个文件失败：" + fileName + "不存在！");
        return false;
    }
}

}