Get几个非常实用技能——常用文件操作工具类、图片视频操作

目录

  • 文件工具类
  • 获取图片响应流操作
  • 获取视频响应流操作
  • 获取视频响应流(断点传输)
  • 截取视频某帧图片
  • 在获取的视频缩略图中间添加暂停按钮
  • 压缩图片
    • 1. 按图片的比例进行压缩
    • 2. 直接设置图片压缩后的输出大小进行压缩
    • 3. 按设置宽高对图片进行压缩

文件工具类

导入坐标:


        <dependency>
            <groupId>cn.hutoolgroupId>
            <artifactId>hutool-allartifactId>
            <version>${hutool.version}version>
        dependency>
        <dependency>
            <groupId>commons-iogroupId>
            <artifactId>commons-ioartifactId>
            <version>2.6version>
        dependency>

工具类中的方法

  1. toFile:MultipartFile转File
    参数:MultipartFile multipartFile
  2. getExtensionName:获取文件扩展名,不带 .
    参数:String filename
  3. getFileNameNoEx:Java文件操作 获取不带扩展名的文件名
    参数:String filename
  4. getSize:文件大小转换
    参数:long size
  5. inputStreamToFile:inputStream 转 File
    参数:InputStream ins, String name
  6. upload:将文件名解析成文件的上传路径
    MultipartFile file, String filePath
  7. downloadExcel:导出excel
    参数:List> list, HttpServletResponse response
  8. getFileType:获取文件类型
    参数:String type
  9. getTransferFileType:获取文件类型英文名
    参数:String type
  10. checkSize:检测文件是否超出允许范围
    参数:long maxSize, long size
  11. check:判断两个文件是否相同
    参数:File file1, File file2
  12. getByte:获取文件字节长度
    参数:File file
  13. getMd5:将字节数组转换为16进制字符
    参数:byte[] bytes
  14. downloadFile:下载文件
    参数:HttpServletRequest request, HttpServletResponse response, File file, boolean deleteOnExit

代码如下:

/*
 *  Copyright 2019-2020 Zheng Jie
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package com.team.utils;

import cn.hutool.core.io.IoUtil;
import cn.hutool.core.util.IdUtil;
import cn.hutool.poi.excel.BigExcelWriter;
import cn.hutool.poi.excel.ExcelUtil;
import com.team.exception.BadRequestException;
import org.apache.poi.util.IOUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.security.MessageDigest;
import java.text.DecimalFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;
import java.util.Map;

/**
 * File工具类,扩展 hutool 工具包
 *
 */
public class FileUtil extends cn.hutool.core.io.FileUtil {
    private static final Logger log = LoggerFactory.getLogger(FileUtil.class);
    /**
     * 系统临时目录
     * 
* windows 包含路径分割符,但Linux 不包含, * 在windows \\==\ 前提下, * 为安全起见 同意拼装 路径分割符, *
     *       java.io.tmpdir
     *       windows : C:\Users/xxx\AppData\Local\Temp\
     *       linux: /temp
     * 
*/
public static final String SYS_TEM_DIR = System.getProperty("java.io.tmpdir") + File.separator; /** * 定义GB的计算常量 */ private static final int GB = 1024 * 1024 * 1024; /** * 定义MB的计算常量 */ private static final int MB = 1024 * 1024; /** * 定义KB的计算常量 */ private static final int KB = 1024; /** * 格式化小数 */ private static final DecimalFormat DF = new DecimalFormat("0.00"); /** * MultipartFile转File */ public static File toFile(MultipartFile multipartFile) { // 获取文件名 String fileName = multipartFile.getOriginalFilename(); // 获取文件后缀 String prefix = "." + getExtensionName(fileName); File file = null; try { // 用uuid作为文件名,防止生成的临时文件重复 file = File.createTempFile(IdUtil.simpleUUID(), prefix); // MultipartFile to File multipartFile.transferTo(file); } catch (IOException e) { log.error(e.getMessage(), e); } return file; } /** * 获取文件扩展名,不带 . */ public static String getExtensionName(String filename) { if ((filename != null) && (filename.length() > 0)) { int dot = filename.lastIndexOf('.'); if ((dot > -1) && (dot < (filename.length() - 1))) { return filename.substring(dot + 1); } } return filename; } /** * Java文件操作 获取不带扩展名的文件名 */ public static String getFileNameNoEx(String filename) { if ((filename != null) && (filename.length() > 0)) { int dot = filename.lastIndexOf('.'); if ((dot > -1) && (dot < (filename.length()))) { return filename.substring(0, dot); } } return filename; } /** * 文件大小转换 */ public static String getSize(long size) { String resultSize; if (size / GB >= 1) { //如果当前Byte的值大于等于1GB resultSize = DF.format(size / (float) GB) + "GB "; } else if (size / MB >= 1) { //如果当前Byte的值大于等于1MB resultSize = DF.format(size / (float) MB) + "MB "; } else if (size / KB >= 1) { //如果当前Byte的值大于等于1KB resultSize = DF.format(size / (float) KB) + "KB "; } else { resultSize = size + "B "; } return resultSize; } /** * inputStream 转 File */ static File inputStreamToFile(InputStream ins, String name) throws Exception { File file = new File(SYS_TEM_DIR + name); if (file.exists()) { return file; } OutputStream os = new FileOutputStream(file); int bytesRead; int len = 8192; byte[] buffer = new byte[len]; while ((bytesRead = ins.read(buffer, 0, len)) != -1) { os.write(buffer, 0, bytesRead); } os.close(); ins.close(); return file; } /** * 将文件名解析成文件的上传路径 */ public static File upload(MultipartFile file, String filePath) { Date date = new Date(); SimpleDateFormat format = new SimpleDateFormat("yyyyMMddhhmmssS"); String name = getFileNameNoEx(file.getOriginalFilename()); String suffix = getExtensionName(file.getOriginalFilename()); String nowStr = "-" + format.format(date); try { String fileName = name + nowStr + "." + suffix; String path = filePath + fileName; // getCanonicalFile 可解析正确各种路径 File dest = new File(path).getCanonicalFile(); // 检测是否存在目录 if (!dest.getParentFile().exists()) { if (!dest.getParentFile().mkdirs()) { System.out.println("was not successful."); } } // 文件写入 file.transferTo(dest); return dest; } catch (Exception e) { log.error(e.getMessage(), e); } return null; } /** * 导出excel */ public static void downloadExcel(List<Map<String, Object>> list, HttpServletResponse response) throws IOException { String tempPath = SYS_TEM_DIR + IdUtil.fastSimpleUUID() + ".xlsx"; File file = new File(tempPath); BigExcelWriter writer = ExcelUtil.getBigWriter(file); // 一次性写出内容,使用默认样式,强制输出标题 writer.write(list, true); //response为HttpServletResponse对象 response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet;charset=utf-8"); //test.xls是弹出下载对话框的文件名,不能为中文,中文请自行编码 response.setHeader("Content-Disposition", "attachment;filename=file.xlsx"); ServletOutputStream out = response.getOutputStream(); // 终止后删除临时文件 file.deleteOnExit(); writer.flush(out, true); //此处记得关闭输出Servlet流 IoUtil.close(out); } public static String getFileType(String type) { String documents = "txt pdf pps wps doc docx ppt pptx xls xlsx"; String music = "mp3 wav wma mpa ram ra aac aif m4a"; String video = "avi mpg mpe mpeg asf wmv mov qt rm mp4 flv m4v webm ogv ogg"; String image = "bmp dib pcp dif wmf gif jpg tif eps psd cdr iff tga pcd mpt png jpeg"; if (image.contains(type)) { return "图片"; } else if (documents.contains(type)) { return "文档"; } else if (music.contains(type)) { return "音乐"; } else if (video.contains(type)) { return "视频"; } else { return "其他"; } } public static String getTransferFileType(String type) { String documents = "txt pdf pps wps doc docx ppt pptx xls xlsx"; String music = "mp3 wav wma mpa ram ra aac aif m4a"; String video = "avi mpg mpe mpeg asf wmv mov qt rm mp4 flv m4v webm ogv ogg"; String image = "bmp dib pcp dif wmf gif jpg tif eps psd cdr iff tga pcd mpt png jpeg"; if (image.contains(type)) { return "image"; } else if (documents.contains(type)) { return "documents"; } else if (music.contains(type)) { return "music"; } else if (video.contains(type)) { return "video"; } else { return "other"; } } public static void checkSize(long maxSize, long size) { // 1M int len = 1024 * 1024; if (size > (maxSize * len)) { throw new BadRequestException("文件超出规定大小"); } } /** * 判断两个文件是否相同 */ public static boolean check(File file1, File file2) { String img1Md5 = getMd5(file1); String img2Md5 = getMd5(file2); return img1Md5.equals(img2Md5); } /** * 判断两个文件是否相同 */ public static boolean check(String file1Md5, String file2Md5) { return file1Md5.equals(file2Md5); } private static byte[] getByte(File file) { // 得到文件长度 byte[] b = new byte[(int) file.length()]; try { InputStream in = new FileInputStream(file); try { System.out.println(in.read(b)); } catch (IOException e) { log.error(e.getMessage(), e); } } catch (FileNotFoundException e) { log.error(e.getMessage(), e); return null; } return b; } private static String getMd5(byte[] bytes) { // 16进制字符 char[] hexDigits = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'}; try { MessageDigest mdTemp = MessageDigest.getInstance("MD5"); mdTemp.update(bytes); byte[] md = mdTemp.digest(); int j = md.length; char[] str = new char[j * 2]; int k = 0; // 移位 输出字符串 for (byte byte0 : md) { str[k++] = hexDigits[byte0 >>> 4 & 0xf]; str[k++] = hexDigits[byte0 & 0xf]; } return new String(str); } catch (Exception e) { log.error(e.getMessage(), e); } return null; } /** * 下载文件 * * @param request / * @param response / * @param file / */ public static void downloadFile(HttpServletRequest request, HttpServletResponse response, File file, boolean deleteOnExit) { response.setCharacterEncoding(request.getCharacterEncoding()); response.setContentType("application/octet-stream"); FileInputStream fis = null; try { fis = new FileInputStream(file); response.setHeader("Content-Disposition", "attachment; filename=" + file.getName()); IOUtils.copy(fis, response.getOutputStream()); response.flushBuffer(); } catch (Exception e) { log.error(e.getMessage(), e); } finally { if (fis != null) { try { fis.close(); if (deleteOnExit) { file.deleteOnExit(); } } catch (IOException e) { log.error(e.getMessage(), e); } } } } public static String getMd5(File file) { return getMd5(getByte(file)); } }

获取图片响应流操作

流操作
传入参数:

  1. src:本地图片路径
  2. response:HttpServletResponse对象
/**
     * @param src
     * @param response
     *
     */
    //获取图片
    public static void getImageSteam(String src, HttpServletResponse response) {

        File file = new File(src);
        //System.out.println("文件名---" + file.getName());

        //获取文件后缀名
        String extensionName = FileUtil.getExtensionName(file.getName());
        //System.out.println("后缀名---" + extensionName);

        //设置响应数据类型(后缀名)
        response.setContentType("image/" + extensionName);
        FileInputStream in = null;
        ServletOutputStream out = null;

        try {
            in = new FileInputStream(file);
            out = response.getOutputStream();
            byte[] bytes = new byte[1024 * 10];
            int len = 0;

            while ((len = in.read(bytes)) != -1) {
                out.write(bytes, 0, len);
            }
            out.flush();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                in.close();
                out.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }


 /**
     * @param fileName
     * @param response 获取图片的方法
     */
    @GetMapping("/getImage")
    @AnonymousAccess
    @Transactional
    public void getImage(@RequestParam String fileName, HttpServletResponse response) {
        System.out.println("文件名---" + fileName);
        FeedbackImages image = feedbackService.findImageByName(fileName);
        String src = image.getSrc();
        System.out.println("文件路径---" + src);

        /*使用ImageUtil的封装方法*/
        ImageUtil.getImageSteam(src, response);
    }

获取视频响应流操作

传入参数:

  1. src:本地图片路径
  2. response:HttpServletResponse对象
/**
     * @param src
     * @param response
     *
     */
    //获取图片
    public static void getImageSteam(String src, HttpServletResponse response) {

        File file = new File(src);
        //System.out.println("文件名---" + file.getName());

        //获取文件后缀名
        String extensionName = FileUtil.getExtensionName(file.getName());
        //System.out.println("后缀名---" + extensionName);

        //设置响应数据类型(后缀名)
        response.setContentType("video/" + extensionName);
        FileInputStream in = null;
        ServletOutputStream out = null;

        try {
            in = new FileInputStream(file);
            out = response.getOutputStream();
            byte[] bytes = new byte[1024 * 10];
            int len = 0;

            while ((len = in.read(bytes)) != -1) {
                out.write(bytes, 0, len);
            }
            out.flush();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                in.close();
                out.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

/**
     * @param fileName
     * @param response 获取视频的方法
     */
    @GetMapping("/getVideo")
    @AnonymousAccess
    @Transactional
    public void getVideo(@RequestParam String fileName, HttpServletRequest request, HttpServletResponse response) throws UnsupportedEncodingException {

        response.setHeader("Content-Type", "video/mp4");

        System.out.println("文件名---" + fileName);
        FeedbackImages image = feedbackService.findImageByName(fileName);
        String src = image.getSrc();
        System.out.println("文件路径---" + src);

        /*使用ImageUtil的封装方法*/
        ImageUtil.getVideoSteam(src, response);
    }

获取视频响应流(断点传输)

特别注意:如果使用上述的方法直接对视频进行流传输,会出现一个问题:在前端使用video标签读取视频时,视频无法拖动进度条,只能一直从头播放到尾,缺少了断点续传。(移动端好像不会)
因此在响应视频的文件流时,需要对文件进行字节切割,实现单点续传。

传入参数:
src:本地图片路径
response:HttpServletResponse对象

 //获取视频
    public static void getVideoSteam(String src, HttpServletRequest request, HttpServletResponse response) {
    BufferedInputStream bis = null;
        try {
            File file = new File(src);
            if (file.exists()) {
                long p = 0L;
                long toLength = 0L;
                long contentLength = 0L;
                int rangeSwitch = 0; // 0,从头开始的全文下载;1,从某字节开始的下载(bytes=27000-);2,从某字节开始到某字节结束的下载(bytes=27000-39000)
                long fileLength;
                String rangBytes = "";
                fileLength = file.length();

                // get file content
                InputStream ins = new FileInputStream(file);
                bis = new BufferedInputStream(ins);

                // tell the client to allow accept-ranges
                response.reset();
                response.setHeader("Accept-Ranges", "bytes");

                // client requests a file block download start byte
                String range = request.getHeader("Range");
                if (range != null && range.trim().length() > 0 && !"null".equals(range)) {
                    response.setStatus(javax.servlet.http.HttpServletResponse.SC_PARTIAL_CONTENT);
                    rangBytes = range.replaceAll("bytes=", "");
                    if (rangBytes.endsWith("-")) { // bytes=270000-
                        rangeSwitch = 1;
                        p = Long.parseLong(rangBytes.substring(0, rangBytes.indexOf("-")));
                        contentLength = fileLength - p; // 客户端请求的是270000之后的字节(包括bytes下标索引为270000的字节)
                    } else { // bytes=270000-320000
                        rangeSwitch = 2;
                        String temp1 = rangBytes.substring(0, rangBytes.indexOf("-"));
                        String temp2 = rangBytes.substring(rangBytes.indexOf("-") + 1, rangBytes.length());
                        p = Long.parseLong(temp1);
                        toLength = Long.parseLong(temp2);
                        contentLength = toLength - p + 1; // 客户端请求的是 270000-320000 之间的字节
                    }
                } else {
                    contentLength = fileLength;
                }

                // 如果设设置了Content-Length,则客户端会自动进行多线程下载。如果不希望支持多线程,则不要设置这个参数。
                // Content-Length: [文件的总大小] - [客户端请求的下载的文件块的开始字节]
                response.setHeader("Content-Length", new Long(contentLength).toString());

                // 断点开始
                // 响应的格式是:
                // Content-Range: bytes [文件块的开始字节]-[文件的总大小 - 1]/[文件的总大小]
                if (rangeSwitch == 1) {
                    String contentRange = new StringBuffer("bytes ").append(new Long(p).toString()).append("-")
                            .append(new Long(fileLength - 1).toString()).append("/")
                            .append(new Long(fileLength).toString()).toString();
                    response.setHeader("Content-Range", contentRange);
                    bis.skip(p);
                } else if (rangeSwitch == 2) {
                    String contentRange = range.replace("=", " ") + "/" + new Long(fileLength).toString();
                    response.setHeader("Content-Range", contentRange);
                    bis.skip(p);
                } else {
                    String contentRange = new StringBuffer("bytes ").append("0-").append(fileLength - 1).append("/")
                            .append(fileLength).toString();
                    response.setHeader("Content-Range", contentRange);
                }

                String fileName = file.getName();
                response.setContentType("application/octet-stream");
                response.addHeader("Content-Disposition", "attachment;filename=" + fileName);

                OutputStream out = response.getOutputStream();
                int n = 0;
                long readLength = 0;
                int bsize = 1024;
                byte[] bytes = new byte[bsize];
                if (rangeSwitch == 2) {
                    // 针对 bytes=27000-39000 的请求,从27000开始写数据
                    while (readLength <= contentLength - bsize) {
                        n = bis.read(bytes);
                        readLength += n;
                        out.write(bytes, 0, n);
                    }
                    if (readLength <= contentLength) {
                        n = bis.read(bytes, 0, (int) (contentLength - readLength));
                        out.write(bytes, 0, n);
                    }
                } else {
                    while ((n = bis.read(bytes)) != -1) {
                        out.write(bytes, 0, n);
                    }
                }
                out.flush();
                out.close();
                bis.close();
            }
        } catch (IOException ie) {
            // 忽略 ClientAbortException 之类的异常
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

截取视频某帧图片

1、使用工具:ffmpeg,
官网下载地址:http://ffmpeg.org/download.html
自己提供的下载地址:
链接:https://pan.baidu.com/s/1x03SItqFfhl0LHGypxDqRA
提取码:obun

测试:
进入含有ffmpeg.exe的bin目录(也可以配置环境变量)
ffmpeg -i xxx.mp4 -y -f image2 -t 0.001 -s 125x125 xxx.jpg
运行成功后,将截取xxx.mp4的第0.0001秒的图片生成125*125的xxx.jpg图片
注意视频、图片名称要带路径,否则当前目录
其他f fmpeg 工具命令可以参考:https://blog.csdn.net/YZ099/article/details/108082980

使用java编写代码实现
获取成功返回true,获取失败返回false
传入参数:

  1. ffmpegPath:ffmpeg.exe存放的路径
  2. path:视频文件的存放路径
  3. outImagePath:输出缩略图的保存路径
 /**
     * 获得视频缩略图,获取成功返回true,获取失败返回false
     *
     * @param ffmpegPath   是ffmpeg.exe存放的路径
     * @param path         是视频文件的存放路径
     * @param outImagePath 输出缩略图的保存路径
     * @return
     */
    public static boolean SaveVideoThumbnail(String ffmpegPath, String path, String outImagePath) throws Exception {
        boolean flag = true;
        try {
            File file = new File(path);
            if (!file.exists()) {    //判断视频文件是否存在
                return false;
            }
            //设置参数
            List<String> commands = new java.util.ArrayList<String>();
            commands.add(ffmpegPath);//这里设置ffmpeg.exe存放的路径
            commands.add("-i");
            commands.add(path);//这里是设置要截取缩略图的视频的路径
            commands.add("-y");
            commands.add("-f");
            commands.add("image2");
            commands.add("-ss");
            commands.add("1");//这里设置的是要截取视频开始播放多少秒后的图,可以自己设置时间
            commands.add("-t");
            commands.add("0.001");
            //commands.add("-s");
            //commands.add("660x660");//这里设置输出图片的大小
            commands.add(outImagePath);//这里设置输出的截图的保存路径
            //截取缩略图并保存
            ProcessBuilder builder = new ProcessBuilder();
            builder.command(commands);
            builder.start();
        } catch (Exception e) {
            e.printStackTrace();
            flag = false;
            System.out.println("获取视频缩略图失败");
        }
        return flag;
    }

在获取的视频缩略图中间添加暂停按钮

思路:使用java GPU绘图工具Graphics2D,先将截取的视频图片绘画出来,然后再获取该图片的正中间位置,接着绘画出准备好的暂停按钮的图标图片,最后使用文件流导出图片。

传入参数:

  1. bigPath:大图片的路径
  2. smallPath:小图片的路径
/**
     * 在获取的视频缩略图中间添加暂停按钮
     *
     * @param bigPath
     * @param smallPath
     * @throws IOException
     */
    public static void mergeImage(String bigPath, String smallPath) throws IOException {

        try {
            BufferedImage small;
            BufferedImage big = ImageIO.read(new File(bigPath));
            if (smallPath.contains("http")) {

                URL url = new URL(smallPath);
                small = ImageIO.read(url);
            } else {
                small = ImageIO.read(new File(smallPath));
            }

            Graphics2D g = big.createGraphics();

            int width = big.getWidth() - small.getWidth();
            int height = big.getHeight() - small.getHeight();
            float fx = width / 2;
            float fy = height / 2;
            int x_i = (int) fx;
            int y_i = (int) fy;
//            g.drawImage(small, x_i, y_i, small.getWidth(), small.getHeight(), null);
            g.drawImage(small, x_i, y_i, null);
            g.dispose();
            ImageIO.write(big, "png", new File(bigPath));

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

执行结果输出的图片
Get几个非常实用技能——常用文件操作工具类、图片视频操作_第1张图片

压缩图片

压缩一般分为三种情况:

  1. 按图片的比例进行压缩
  2. 直接设置图片压缩后的输出大小进行压缩
  3. 按设置宽高对图片进行压缩

1. 按图片的比例进行压缩

思路:获取传进来的图片,获取该图片的宽高,计算出比例,然后根据传进来的要压缩结果宽度/比例得到要压缩结果的高度,接着按照要压缩结果的宽高进行对图片进行压缩,最后文件流输出图片。

传入参数:

  1. srcImgPath:原图片路径
  2. distImgPath: 转换大小后图片路径
  3. width0:压缩结果的目标宽度
 /***
     * 功能 :调整图片大小
     * @param srcImgPath 原图片路径
     * @param distImgPath  转换大小后图片路径
     * @param width0  按比例压缩图片,压缩后宽度为width0
     */
    public static void resizeImage(String srcImgPath, String distImgPath,
                                   int width0) throws IOException {

        File srcFile = new File(srcImgPath);
        Image srcImg = ImageIO.read(srcFile);
        BufferedImage buffImg = null;
        float width = ((BufferedImage) srcImg).getWidth();
        float height = ((BufferedImage) srcImg).getHeight();
        float scale = width / height;
        int height0 = (int) (width0 / scale);
        System.out.println(scale + ":" + width0 + "---" + height0);
        buffImg = new BufferedImage(width0, height0, BufferedImage.TYPE_INT_RGB);
        buffImg.getGraphics().drawImage(
                srcImg.getScaledInstance(width0, height0, Image.SCALE_SMOOTH), 0,
                0, null);

        ImageIO.write(buffImg, "JPG", new File(distImgPath));

    }


    public static void main(String[] args) {
        try {
            resizeImage("D:\\projects\\TS_Admin\\trunk\\team-system\\src\\main\\resources\\static\\images\\pause.png", "D:\\projects\\TS_Admin\\trunk\\team-system\\src\\main\\resources\\static\\images\\pause_100_100.png", 100);
        } catch (IOException e) {
            System.out.println("图片转换出现异常!");
        }

    }

2. 直接设置图片压缩后的输出大小进行压缩

传入参数:

  1. imageBytes:源图片字节数组
  2. desFileSize: 指定图片大小,单位kb
  3. imageId:影像编号
    return: 压缩质量后的图片字节数组

代码如下:

/**
 * Created by tao.
 * Date: 2021/3/12 17:45
 * 描述:
 */

public class PicUtils {

    private static Logger logger = LoggerFactory.getLogger(PicUtils.class);

    public static void main(String[] args) throws IOException {
        byte[] bytes = FileUtils.readFileToByteArray(new File("C:\\teamadmin\\file\\图片\\3a6372e3cfefec8144de4fc0585105dd.jpg"));
        long l = System.currentTimeMillis();
        bytes = PicUtils.compressPicForScale(bytes, 50, "x");// 图片小于300kb
        System.out.println(System.currentTimeMillis() - l);
        FileUtils.writeByteArrayToFile(new File("C:\\teamadmin\\file\\图片\\3a6372e3cfefec8144de4fc0585105dd.jpg"), bytes);
    }

    /**
     * 根据指定大小压缩图片
     *
     * @param imageBytes  源图片字节数组
     * @param desFileSize 指定图片大小,单位kb
     * @param imageId     影像编号
     * @return 压缩质量后的图片字节数组
     */
    public static byte[] compressPicForScale(byte[] imageBytes, long desFileSize, String imageId) {
        if (imageBytes == null || imageBytes.length <= 0 || imageBytes.length < desFileSize * 1024) {
            return imageBytes;
        }
        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();
            }
            logger.info("【图片压缩】imageId={} | 图片原大小={}kb | 压缩后大小={}kb",
                    imageId, srcSize / 1024, imageBytes.length / 1024);
        } catch (Exception e) {
            logger.error("【图片压缩】msg=图片压缩失败!", e);
        }
        return imageBytes;
    }

    /**
     * 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;
    }
}

3. 按设置宽高对图片进行压缩

传入参数:

  1. srcImgPath:原图片路径
  2. distImgPath: 转换大小后图片路径
  3. width:压缩结果的目标宽度
  4. height:压缩结果的目标高度
/***
     * 功能 :调整图片大小
     * @param srcImgPath 原图片路径
     * @param distImgPath  转换大小后图片路径
     */
    public static void resizeImage(String srcImgPath, String distImgPath,
                                   int width,int height) throws IOException {

        File srcFile = new File(srcImgPath);
        Image srcImg = ImageIO.read(srcFile);
        BufferedImage buffImg = null;
        buffImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        buffImg.getGraphics().drawImage(
                srcImg.getScaledInstance(width, height, Image.SCALE_SMOOTH), 0,
                0, null);
        ImageIO.write(buffImg, "JPG", new File(distImgPath));
    }

压缩结果
Get几个非常实用技能——常用文件操作工具类、图片视频操作_第2张图片

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