使用Thumbnails工具对图片进行缩放，压缩

Thumbnails是Google公司开源的图片处理工具

一、将Thumbnails引入到maven工程

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

二、关键代码

String filePathName = "需要压缩的图片根路径";
String thumbnailFilePathName = "压缩之后的图片路径";
double scale = 1d;//图片缩小倍数0~1),1代表保持原有的大小
double quality = 1d;//压缩的质量,1代表保持原有的大小默认1)

Thumbnails.offilePathName).scalescale).outputQualityquality).outputFormat"jpg").toFilethumbnailFilePathName);

Thumbnails.offilePathName).scalescale).outputFormat"jpg").toFilethumbnailFilePathName);

Thumbnails.offilePathName).size400,500).toFilethumbnailFilePathName);//变为400*500,遵循原图比例缩或放到400*某个高度

三、Spring-boot的例子

package com.example.atlogging.controller;

import com.alibaba.fastjson.JSONObject;
import net.coobird.thumbnailator.Thumbnails;
import org.apache.commons.io.FilenameUtils;
import org.apache.commons.io.IOUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;

import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletRequest;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.UUID;

@RestController
@RequestMappingpath = "/thumb", produces = "application/json;charset=UTF-8")
public class TestThumbnails {
    /**
     * @Description:保存图片并且生成缩略图
     * @param imageFile 图片文件
     * @param request 请求对象
     * @param uploadPath 上传目录
     * @return
     */
    private static Logger log = LoggerFactory.getLoggerTestThumbnails.class);

    @RequestMapping"/up")
    public String testThumbMultipartFile imageFile, HttpServletRequest request) {
        String res = this.uploadFileAndCreateThumbnailimageFile, request, "");
        return res;
    }

    public static String uploadFileAndCreateThumbnailMultipartFile imageFile, HttpServletRequest request, String uploadPath) {

        JSONObject result = new JSONObject);
        int maxWidth = 1200;//压缩之后的图片最大宽度
        if imageFile == null) {
            result.put"msg", "imageFile不能为空");
            return result.toJSONString);
        }

        if imageFile.getSize) >= 10 * 1024 * 1024) {
            result.put"msg", "文件不能大于10M");
            return result.toJSONString);
        }
        String uuid = UUID.randomUUID).toString);

        String fileDirectory = new SimpleDateFormat"yyyyMMdd").formatnew Date));//设置日期格式

        //拼接后台文件名称
        String pathName = fileDirectory + File.separator + uuid + "."
                + FilenameUtils.getExtensionimageFile.getOriginalFilename));
        //构建保存文件路径
        //修改上传路径为服务器上
        String realPath = "F:/桌面temp/ys";//request.getServletContext).getRealPath"uploadPath");
        //获取服务器绝对路径 linux 服务器地址  获取当前使用的配置文件配置
        //String urlString=PropertiesUtil.getInstance).getSysPro"uploadPath");
        //拼接文件路径
        String filePathName = realPath + File.separator + pathName;
        log.info"图片上传路径：" + filePathName);
        //判断文件保存是否存在
        File file = new FilefilePathName);
        if file.getParentFile) != null || !file.getParentFile).isDirectory)) {
            //创建文件
            file.getParentFile).mkdirs);
        }

        InputStream inputStream = null;
        FileOutputStream fileOutputStream = null;
        try {
            inputStream = imageFile.getInputStream);
            fileOutputStream = new FileOutputStreamfile);
            //写出文件
//            IOUtils.copyinputStream, fileOutputStream);
            byte[] buffer = new byte[2048];
            IOUtils.copyLargeinputStream, fileOutputStream, buffer);
            buffer = null;

        } catch IOException e) {
            filePathName = null;
            result.put"msg", "操作失败");
            return result.toJSONString);
        } finally {
            try {
                if inputStream != null) {
                    inputStream.close);
                }
                if fileOutputStream != null) {
                    fileOutputStream.flush);
                    fileOutputStream.close);
                }
            } catch IOException e) {
                filePathName = null;
                result.put"msg", "操作失败");
                return result.toJSONString);

            }
        }

        //拼接后台文件名称
        String thumbnailPathName = fileDirectory + File.separator + uuid + "small."
                + FilenameUtils.getExtensionimageFile.getOriginalFilename));
        if thumbnailPathName.contains".png")) {
            thumbnailPathName = thumbnailPathName.replace".png", ".jpg");
        }
        long size = imageFile.getSize);

        double scale = 1d;
        double quality = 1d;
        if size >= 200 * 1024) {//当图片超过200kb的时候进行压缩处理
            if size > 0) {
                quality = 200 * 1024f) / size;
            }
        }

        //图片信息
        double width = 0;
        double height = 0;
        try {
            BufferedImage bufferedImage = ImageIO.readimageFile.getInputStream)); //获取图片流
            if bufferedImage == null) {
                // 证明上传的文件不是图片，获取图片流失败，不进行下面的操作
            }
            width = bufferedImage.getWidth); // 通过图片流获取图片宽度
            height = bufferedImage.getHeight); // 通过图片流获取图片高度
            // 省略逻辑判断
        } catch Exception e) {
            // 省略异常操作
        }
        System.out.printlnwidth);
        while width * scale > maxWidth) {//处理图片像素宽度（当像素大于1200时进行图片等比缩放宽度）
            scale -= 0.1;
        }

        //拼接文件路径
        String thumbnailFilePathName = realPath + File.separator + thumbnailPathName;
        System.out.printlnscale);
        System.out.printlnquality);
        System.out.printlnint) width * scale);
        /*iftrue){
            return result.toJSONString);
        }*/
        try {
            //注释掉之前长宽的方式，改用大小
//          Thumbnails.offilePathName).sizewidth, height).toFilethumbnailFilePathName);
            if size < 200 * 1024) {
                Thumbnails.offilePathName).scalescale).outputFormat"jpg").toFilethumbnailFilePathName);
            } else {
                Thumbnails.offilePathName).scalescale).outputQualityquality).outputFormat"jpg").toFilethumbnailFilePathName);//thumbnailFilePathName + "l.");
            }

        } catch Exception e1) {
            result.put"msg", "操作失败");
            return result.toJSONString);
        }
        /**
         * 缩略图end
         */

        //原图地址
        result.put"originalUrl", pathName);
        //缩略图地址
        result.put"thumbnailUrl", thumbnailPathName);
        //缩略图地址
        result.put"msg", "操作成功");
        result.put"status", 200);
        return result.toJSONString);
    }
}