243 lines
9.1 KiB
Markdown
243 lines
9.1 KiB
Markdown
---
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title: 视频压缩
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date: 2026-01-29
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---
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# 一、简介
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  视频码率（Bit Rate），指的是视频文件在单位时间内（通常是每秒）所包含的数据量。单位通常是 Mbps（兆比特每秒）或 Kbps（千比特每秒）。
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  码率越高：视频中包含的细节信息越多，画面越清晰、色彩越丰富、动态画面（如快速运动、爆炸等）越流畅，不容易出现马赛克或模糊。但代价是文件体积越大，传输所需的网络带宽也越高。码率越低：视频文件更小，传输更快，但在复杂画面中容易产生压缩瑕疵（如马赛克、模糊、色带等）。
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  如果不压缩，原始视频数据量极其庞大，一部2小时的未压缩1080p电影可能占用数TB的存储空间，普通硬盘无法承受，家庭宽带或移动网络无法实时传输如此巨大的数据量，视频播放会不断卡顿。
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  如果服务器的带宽为10M，适合 720p，勉强支持低码率 1080p。
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# 二、引入依赖
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```xml
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<!-- Jave 2 视频处理库 -->
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<dependency>
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<groupId>ws.schild</groupId>
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<artifactId>jave-all-deps</artifactId>
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<version>3.5.0</version>
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</dependency>
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```
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# 三、工具类
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```java
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import lombok.extern.slf4j.Slf4j;
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import ws.schild.jave.Encoder;
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import ws.schild.jave.MultimediaObject;
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import ws.schild.jave.encode.AudioAttributes;
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import ws.schild.jave.encode.EncodingAttributes;
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import ws.schild.jave.encode.VideoAttributes;
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import ws.schild.jave.info.VideoSize;
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import java.io.File;
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/**
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* 视频压缩工具类
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* 提供将视频压缩到720p的静态方法
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*/
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@Slf4j
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public class VideoCompressor {
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// 支持的视频格式
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private static final String[] SUPPORTED_FORMATS = {
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".mp4", ".avi", ".mov", ".mkv", ".flv",
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".wmv", ".webm", ".mpeg", ".mpg", ".3gp"
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};
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// 压缩参数常量
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private static final int TARGET_WIDTH = 1280;
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private static final int TARGET_HEIGHT = 720;
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private static final int VIDEO_BITRATE = 1500000; // 1.5 Mbps
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private static final int AUDIO_BITRATE = 128000; // 128 kbps
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private static final String VIDEO_CODEC = "libx264";
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private static final String AUDIO_CODEC = "aac";
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private static final String OUTPUT_FORMAT = "mp4";
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private static final String OUTPUT_SUFFIX = "_720p.mp4";
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private static final int MAX_BITRATE = 2500; // 2.5 Mbps
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private static final int MIN_BITRATE = 1000; // 1 Mbps
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/**
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* 压缩视频到720p，统一输出为MP4格式
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*
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* @param inputFile 输入视频文件
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* @return 压缩后的视频文件，如果不需要压缩则返回原文件
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* @throws Exception 压缩过程中可能出现的异常
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*/
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public static File compressTo720p(File inputFile) throws Exception {
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if (!isSupportedVideoFile(inputFile)) {
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log.info("文件格式不支持或文件不存在，直接返回源文件");
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return inputFile;
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}
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// 判断是否需要压缩
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if (!needCompression(inputFile)) {
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return inputFile;
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}
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File outputFile = createOutputFile(inputFile);
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Encoder encoder = new Encoder();
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// 配置编码参数
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EncodingAttributes encodingAttributes = createEncodingAttributes();
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log.info("开始压缩视频: {} -> {}", inputFile.getName(), outputFile.getName());
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encoder.encode(new MultimediaObject(inputFile), outputFile, encodingAttributes);
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log.info("视频压缩完成: {}", outputFile.getName());
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return outputFile;
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}
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/**
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* 智能判断视频是否需要压缩
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* 基于分辨率、码率、数据密度等多维度综合判断
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*/
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public static boolean needCompression(File videoFile) throws Exception {
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MultimediaObject media = new MultimediaObject(videoFile);
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// 获取视频基本信息
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double fileSizeMB = videoFile.length() / 1048576.0; // 转换为MB
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double duration = media.getInfo().getDuration() / 1000.0;
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int bitRateKbps = media.getInfo().getVideo().getBitRate() / 1000; // 转换为kbps
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// 获取视频分辨率
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int width = media.getInfo().getVideo().getSize().getWidth();
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int height = media.getInfo().getVideo().getSize().getHeight();
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log.info("视频分析: 分辨率 {}x{}, 大小 {}MB, 时长 {}秒, 码率约 {}kbps", width, height, fileSizeMB, duration, bitRateKbps);
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// 判断逻辑：基于分辨率和码率的智能判断
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boolean needsCompression = false;
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// 1. 如果分辨率已经<=720p，检查码率是否过高
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if (height <= TARGET_HEIGHT && width <= TARGET_WIDTH) {
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if (bitRateKbps > MAX_BITRATE) {
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log.info("视频分辨率达标但码率({}kbps)过高，需要压缩", bitRateKbps);
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needsCompression = true;
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} else {
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log.info("视频分辨率已达720p或以下，且码率合理，无需压缩");
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}
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}
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// 2. 如果分辨率>720p，但码率很低，说明已是优化过的视频，无需压缩
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else if (height > TARGET_HEIGHT && bitRateKbps < MIN_BITRATE) {
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log.info("视频虽为{}p高分辨率，但码率({}kbps)已优化，无需压缩", height, bitRateKbps);
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}
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// 3. 高分辨率+高码率，需要压缩
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else if (height > TARGET_HEIGHT && bitRateKbps >= MAX_BITRATE) {
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log.info("视频为{}p高分辨率且码率较高({}kbps)，需要压缩至720p", height, bitRateKbps);
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needsCompression = true;
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}
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// 4. 其他情况（如异常数据）默认不压缩
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else {
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log.info("视频参数异常，保守处理：不进行压缩");
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}
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return needsCompression;
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}
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/**
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* 检查文件是否为支持的视频格式
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*/
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private static boolean isSupportedVideoFile(File file) {
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if (file == null || !file.exists()) {
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return false;
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}
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String filename = file.getName().toLowerCase();
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for (String format : SUPPORTED_FORMATS) {
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if (filename.endsWith(format)) {
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return true;
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}
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}
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return false;
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}
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/**
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* 创建输出文件对象
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*/
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private static File createOutputFile(File inputFile) {
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String baseName = getFileBaseName(inputFile.getName());
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String outputFilename = baseName + OUTPUT_SUFFIX;
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return new File(inputFile.getParent(), outputFilename);
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}
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/**
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* 获取文件名（不含扩展名）
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*/
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private static String getFileBaseName(String filename) {
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int dotIndex = filename.lastIndexOf('.');
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return (dotIndex == -1) ? filename : filename.substring(0, dotIndex);
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}
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/**
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* 创建编码配置参数
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*/
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private static EncodingAttributes createEncodingAttributes() {
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// 音频配置
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AudioAttributes audio = new AudioAttributes();
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audio.setCodec(AUDIO_CODEC);
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audio.setBitRate(AUDIO_BITRATE);
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// 视频配置
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VideoAttributes video = new VideoAttributes();
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video.setCodec(VIDEO_CODEC);
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video.setBitRate(VIDEO_BITRATE);
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video.setSize(new VideoSize(TARGET_WIDTH, TARGET_HEIGHT));
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// 编码设置
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EncodingAttributes attributes = new EncodingAttributes();
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attributes.setOutputFormat(OUTPUT_FORMAT);
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attributes.setAudioAttributes(audio);
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attributes.setVideoAttributes(video);
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return attributes;
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}
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}
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```
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  通过分辨率和码率的双重判断，确定是否需要压缩。
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# 四、使用
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```java
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public void uploadFile(MultipartFile file, String filePath) {
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try {
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MultiValueMap<String, Object> body = new LinkedMultiValueMap<>();
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File tempFile = convertMultipartFileToFile(file);
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log.info("临时文件地址：{}", tempFile.toPath());
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log.info("开始压缩文件：{}", tempFile.getName());
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File compressFile = VideoCompressor.compressTo720p(tempFile);
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log.info("完成压缩文件：{}", tempFile.getName());
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log.info("压缩文件地址：{}", tempFile.toPath());
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body.add("file", new FileSystemResource(compressFile));
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aListClient.put()
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.uri("api/fs/form")
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.header(HttpHeaders.AUTHORIZATION, token)
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.header("File-Path", filePath)
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.contentType(MediaType.MULTIPART_FORM_DATA)
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.body(body)
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.retrieve()
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.body(Map.class);
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Files.deleteIfExists(compressFile.toPath());
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Files.deleteIfExists(tempFile.toPath());
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} catch (Exception e) {
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log.error("文件上传失败{}", e.getMessage());
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throw new RuntimeException("文件上传失败", e);
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}
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}
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private File convertMultipartFileToFile(MultipartFile file) throws IOException {
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String suffix = (file.getOriginalFilename() != null && file.getOriginalFilename().contains("."))
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? file.getOriginalFilename().substring(file.getOriginalFilename().lastIndexOf("."))
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: ".tmp";
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Path tempFile = Files.createTempFile(System.currentTimeMillis() + "", suffix);
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file.transferTo(tempFile);
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return tempFile.toFile();
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}
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``` |