java 图片压缩稳定版本

package com.liaoin.smart.property.provider.service.provider.helper;

import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
import net.coobird.thumbnailator.Thumbnails;
import org.apache.commons.collections.CollectionUtils;
import org.springframework.web.multipart.MultipartFile;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.*;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Date;

public class FileTest {



    public static void main(String[] args) {
        File srcfile = new File("D:\\45678.jpg");
        File distfile = new File("D:\\123456.jpg");


      compressPicForScale(srcfile,200);



    }

    /**
     * 根据byte数组，生成文件
     */
    public static void getFile(File file,byte[] bfile) {
        BufferedOutputStream bos = null;
        FileOutputStream fos = null;
        try {
            fos = new FileOutputStream(file);
            bos = new BufferedOutputStream(fos);
            bos.write(bfile);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (bos != null) {
                try {
                    bos.close();
                } catch (IOException e1) {
                    e1.printStackTrace();
                }
            }
            if (fos != null) {
                try {
                    fos.close();
                } catch (IOException e1) {
                    e1.printStackTrace();
                }
            }
        }
    }

    private static byte[] getBytes(File file){
        byte[] buffer = null;
        try {
            FileInputStream fis = new FileInputStream(file);
            ByteArrayOutputStream bos = new ByteArrayOutputStream(1000);
            byte[] b = new byte[1000];
            int n;
            while ((n = fis.read(b)) != -1) {
                bos.write(b, 0, n);
            }
            fis.close();
            bos.close();
            buffer = bos.toByteArray();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return buffer;
    }

    /**
     * 根据指定大小压缩图片
     *
     * @param desFileSize 指定图片大小，单位kb
     * @return 压缩质量后的图片字节数组
     */
    public static void compressPicForScale(File file, long desFileSize) {
        byte[] imageBytes=getBytes(file);

        if (imageBytes == null || imageBytes.length <= 0 || imageBytes.length < desFileSize * 1024) {
            return ;
        }
        long srcSize = imageBytes.length;
        double accuracy = getAccuracy(srcSize / 1024);
        try {
            while (imageBytes.length > desFileSize * 1024) {
                ByteArrayInputStream inputStream = new ByteArrayInputStream(imageBytes);
                ByteArrayOutputStream outputStream = new ByteArrayOutputStream(imageBytes.length);
                Thumbnails.of(inputStream)
                        .scale(accuracy)
                        .outputQuality(accuracy)
                        .toOutputStream(outputStream);
                imageBytes = outputStream.toByteArray();
            }
            System.out.printf("【图片压缩】| 图片原大小={}kb | 压缩后大小={}kb",
                     srcSize / 1024, imageBytes.length / 1024);
        } catch (Exception e) {
            System.out.printf("【图片压缩】msg=图片压缩失败!", e);

        }
        getFile(file,imageBytes);
        System.out.printf("图片转换完成");
    }

    /**
     * 自动调节精度(经验数值)
     *
     * @param size 源图片大小
     * @return 图片压缩质量比
     */
    private static double getAccuracy(long size) {
        double accuracy;
        if (size < 900) {
            accuracy = 0.85;
        } else if (size < 2047) {
            accuracy = 0.6;
        } else if (size < 3275) {
            accuracy = 0.44;
        } else {
            accuracy = 0.4;
        }
        return accuracy;
    }






}