为 Spring Boot 实现字节服务

Question

我想使用 Spring Boot Rest API 在 Angular 中实现视频播放器。我可以播放视频，但我无法进行视频搜索。每次当我使用 Chrome 或 Edge 时，视频都会一遍又一遍地播放。

我试过这个端点：

@RequestMapping(value = "/play_video/{video_id}", method = RequestMethod.GET)
    @ResponseBody public ResponseEntity<byte[]> getPreview1(@PathVariable("video_id") String video_id, HttpServletResponse response) {
        ResponseEntity<byte[]> result = null;
        try {
            String file = "/opt/videos/" + video_id + ".mp4";
            Path path = Paths.get(file);
            byte[] image = Files.readAllBytes(path);

            response.setStatus(HttpStatus.OK.value());
            HttpHeaders headers = new HttpHeaders();
            headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
            headers.setContentLength(image.length);
            result = new ResponseEntity<byte[]>(image, headers, HttpStatus.OK);
        } catch (java.nio.file.NoSuchFileException e) {
            response.setStatus(HttpStatus.NOT_FOUND.value());
        } catch (Exception e) {
            response.setStatus(HttpStatus.INTERNAL_SERVER_ERROR.value());
        }
        return result;
    }

我发现这篇文章给出了一些想法：如何在 Spring MVC 中实现 HTTP 字节范围请求

但目前它不起作用。当我尝试移动位置时，视频又从头开始播放。

我用这个播放器：https : //github.com/smnbbrv/ngx-plyr

我是这样配置的：

<div class="media">
        <div
          class="class-video mr-3 mb-1"
          plyr
          [plyrPlaysInline]="true"
          [plyrSources]="gymClass.video"
          (plyrInit)="player = $event"
          (plyrPlay)="played($event)">
        </div>
        <div class="media-body">
          {{ gymClass.description }}
        </div>
      </div>

你知道我该如何解决这个问题吗？

Answer 1

第一个解决方案：使用 FileSystemResource

FileSystemResource 内部处理字节范围标头支持，读取和写入适当的标头。

这种方法有两个问题。

1. 它在FileInputStream内部用于读取文件。这适用于小文件，但不适用于通过字节范围请求提供服务的大文件。FileInputStream将从头开始读取文件并丢弃不需要的内容，直到它重新获得请求的起始偏移量。这可能会导致较大文件的速度变慢。

2. 它设置"application/json"为"Content-Type"响应头。所以，我提供了我自己的"Content-Type"标题。看到这个线程

import java.nio.file.Path;
import java.nio.file.Paths;
import org.springframework.core.io.FileSystemResource;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
public class Stream3 {
    @GetMapping(value = "/play_video/{video_id}")
    @ResponseBody
    public ResponseEntity<FileSystemResource> stream(@PathVariable("video_id") String video_id) {
        String filePathString = "/opt/videos/" + video_id + ".mp4";        
        final HttpHeaders responseHeaders = new HttpHeaders();
        responseHeaders.add("Content-Type", "video/mp4");
        return new ResponseEntity<>(new FileSystemResource(filePathString), responseHeaders, HttpStatus.OK);
    }
}

第二种解决方案：使用HttpServletResponse和RandomAccessFile

有了RandomAccessFile可以实现的字节范围请求支持。与 , 相比的优势FileInputStream在于，每次有新的范围请求时，您都不需要从头开始读取文件，这使得此方法也可用于较大的文件。RandomAccessFile有一个seek(long)调用 C 方法的方法fseek()，该方法直接将文件的指针移动到请求的偏移量。

import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.OutputStream;
import java.io.RandomAccessFile;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import javax.servlet.http.HttpServletResponse;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestHeader;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
public class Stream {
    @GetMapping(value = "/play_video/{video_id}")
    @ResponseBody
    public void stream(        
            @PathVariable("video_id") String video_id,
            @RequestHeader(value = "Range", required = false) String rangeHeader,
            HttpServletResponse response) {

        try {
            OutputStream os = response.getOutputStream();
            long rangeStart = 0;
            long rangeEnd;
            String filePathString = "/opt/videos/" + video_id + ".mp4";
            Path filePath = Paths.get(filePathString);
            Long fileSize = Files.size(filePath);
            byte[] buffer = new byte[1024];
            RandomAccessFile file = new RandomAccessFile(filePathString, "r");
            try (file) {
                if (rangeHeader == null) {
                    response.setHeader("Content-Type", "video/mp4");
                    response.setHeader("Content-Length", fileSize.toString());
                    response.setStatus(HttpStatus.OK.value());
                    long pos = rangeStart;
                    file.seek(pos);
                    while (pos < fileSize - 1) {                        
                        file.read(buffer);
                        os.write(buffer);
                        pos += buffer.length;
                    }
                    os.flush();
                    return;
                }

                String[] ranges = rangeHeader.split("-");
                rangeStart = Long.parseLong(ranges[0].substring(6));
                if (ranges.length > 1) {
                    rangeEnd = Long.parseLong(ranges[1]);
                } else {
                    rangeEnd = fileSize - 1;
                }
                if (fileSize < rangeEnd) {
                    rangeEnd = fileSize - 1;
                }

                String contentLength = String.valueOf((rangeEnd - rangeStart) + 1);
                response.setHeader("Content-Type", "video/mp4");
                response.setHeader("Content-Length", contentLength);
                response.setHeader("Accept-Ranges", "bytes");
                response.setHeader("Content-Range", "bytes" + " " + rangeStart + "-" + rangeEnd + "/" + fileSize);
                response.setStatus(HttpStatus.PARTIAL_CONTENT.value());
                long pos = rangeStart;
                file.seek(pos);
                while (pos < rangeEnd) {                    
                    file.read(buffer);
                    os.write(buffer);
                    pos += buffer.length;
                }
                os.flush();

            }

        } catch (FileNotFoundException e) {
            response.setStatus(HttpStatus.NOT_FOUND.value());
        } catch (IOException e) {
            response.setStatus(HttpStatus.INTERNAL_SERVER_ERROR.value());
        }

    }

}

第三种解决方案：也使用RandomAccessFile, 但StreamingResponseBody代替HttpServletResponse

import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestHeader;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.servlet.mvc.method.annotation.StreamingResponseBody;

@Controller
public class Stream2 {
    @GetMapping(value = "/play_video/{video_id}")
    @ResponseBody
    public ResponseEntity<StreamingResponseBody> stream(
            @PathVariable("video_id") String video_id,
            @RequestHeader(value = "Range", required = false) String rangeHeader) {        
        try {
            StreamingResponseBody responseStream;
            String filePathString = "/opt/videos/" + video_id + ".mp4";
            Path filePath = Paths.get(filePathString);
            Long fileSize = Files.size(filePath);
            byte[] buffer = new byte[1024];      
            final HttpHeaders responseHeaders = new HttpHeaders();

            if (rangeHeader == null) {
                responseHeaders.add("Content-Type", "video/mp4");
                responseHeaders.add("Content-Length", fileSize.toString());
                responseStream = os -> {
                    RandomAccessFile file = new RandomAccessFile(filePathString, "r");
                    try (file) {
                        long pos = 0;
                        file.seek(pos);
                        while (pos < fileSize - 1) {                            
                            file.read(buffer);
                            os.write(buffer);
                            pos += buffer.length;
                        }
                        os.flush();
                    } catch (Exception e) {}
                };
                return new ResponseEntity<>(responseStream, responseHeaders, HttpStatus.OK);
            }

            String[] ranges = rangeHeader.split("-");
            Long rangeStart = Long.parseLong(ranges[0].substring(6));
            Long rangeEnd;
            if (ranges.length > 1) {
                rangeEnd = Long.parseLong(ranges[1]);
            } else {
                rangeEnd = fileSize - 1;
            }
            if (fileSize < rangeEnd) {
                rangeEnd = fileSize - 1;
            }

            String contentLength = String.valueOf((rangeEnd - rangeStart) + 1);
            responseHeaders.add("Content-Type", "video/mp4");
            responseHeaders.add("Content-Length", contentLength);
            responseHeaders.add("Accept-Ranges", "bytes");
            responseHeaders.add("Content-Range", "bytes" + " " + rangeStart + "-" + rangeEnd + "/" + fileSize);
            final Long _rangeEnd = rangeEnd;
            responseStream = os -> {
                RandomAccessFile file = new RandomAccessFile(filePathString, "r");
                try (file) {
                    long pos = rangeStart;
                    file.seek(pos);
                    while (pos < _rangeEnd) {                        
                        file.read(buffer);
                        os.write(buffer);
                        pos += buffer.length;
                    }
                    os.flush();
                } catch (Exception e) {}
            };
            return new ResponseEntity<>(responseStream, responseHeaders, HttpStatus.PARTIAL_CONTENT);

        } catch (FileNotFoundException e) {
            return new ResponseEntity<>(HttpStatus.NOT_FOUND);
        } catch (IOException e) {
            return new ResponseEntity<>(HttpStatus.INTERNAL_SERVER_ERROR);
        }
    }
}

在你的 component.ts 中：

您可以使用 playVideoFile() 更改当前显示的视频

export class AppComponent implements OnInit {
  videoSources: Plyr.Source[];
  ngOnInit(): void {
    const fileName = 'sample';
    this.playVideoFile(fileName);
  }

  playVideoFile(fileName: string) {
    this.videoSources = [
      {
        src: `http://localhost:8080/play_video/${fileName}`,
      },
    ];
  }
}

和 html：

<div
  #plyr
  plyr
  [plyrPlaysInline]="false"
  [plyrSources]="videoSources"
></div>