如何在 Spring MVC 中实现 HTTP 字节范围请求

Question

我的网站上的视频倒带有问题。

我发现了 http 标头的问题。

我当前返回视频的控制器方法：

@RequestMapping(method = RequestMethod.GET, value = "/testVideo")
@ResponseBody
public FileSystemResource testVideo(Principal principal) throws IOException {
   return new FileSystemResource(new File("D:\\oceans.mp4"));
}

如何在支持字节范围的情况下重写以下代码？

附言

我看过下面的例子http://balusc.blogspot.in/2009/02/fileservlet-supporting-resume-and.html

但是这段代码对我来说看起来很难，我无法理解。我希望在 spring mvc 中存在的方式更简单。

Answer 1

在提供此答案时，支持 http 字节范围的请求已打开，但在 Spring 4.2.RC1 中已修复。检查 jira SPR-10805 或 PR here。

但根据您在问题中链接的代码，Davin Kevin 构建了一个 solution 可以满足您的要求。

MultipartFileSender 的代码：

import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.attribute.FileTime;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.ZoneOffset;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

/**
 * Created by kevin on 10/02/15.
 * See full code here : https://github.com/davinkevin/Podcast-Server/blob/d927d9b8cb9ea1268af74316cd20b7192ca92da7/src/main/java/lan/dk/podcastserver/utils/multipart/MultipartFileSender.java
 */
public class MultipartFileSender {

    protected final Logger logger = LoggerFactory.getLogger(this.getClass());

    private static final int DEFAULT_BUFFER_SIZE = 20480; // ..bytes = 20KB.
    private static final long DEFAULT_EXPIRE_TIME = 604800000L; // ..ms = 1 week.
    private static final String MULTIPART_BOUNDARY = "MULTIPART_BYTERANGES";

    Path filepath;
    HttpServletRequest request;
    HttpServletResponse response;

    public MultipartFileSender() {
    }

    public static MultipartFileSender fromPath(Path path) {
        return new MultipartFileSender().setFilepath(path);
    }

    public static MultipartFileSender fromFile(File file) {
        return new MultipartFileSender().setFilepath(file.toPath());
    }

    public static MultipartFileSender fromURIString(String uri) {
        return new MultipartFileSender().setFilepath(Paths.get(uri));
    }

    //** internal setter **//
    private MultipartFileSender setFilepath(Path filepath) {
        this.filepath = filepath;
        return this;
    }

    public MultipartFileSender with(HttpServletRequest httpRequest) {
        request = httpRequest;
        return this;
    }

    public MultipartFileSender with(HttpServletResponse httpResponse) {
        response = httpResponse;
        return this;
    }

    public void serveResource() throws Exception {
        if (response == null || request == null) {
            return;
        }

        if (!Files.exists(filepath)) {
            logger.error("File doesn't exist at URI : {}", filepath.toAbsolutePath().toString());
            response.sendError(HttpServletResponse.SC_NOT_FOUND);
            return;
        }

        Long length = Files.size(filepath);
        String fileName = filepath.getFileName().toString();
        FileTime lastModifiedObj = Files.getLastModifiedTime(filepath);

        if (StringUtils.isEmpty(fileName) || lastModifiedObj == null) {
            response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
            return;
        }
        long lastModified = LocalDateTime.ofInstant(lastModifiedObj.toInstant(), ZoneId.of(ZoneOffset.systemDefault().getId())).toEpochSecond(ZoneOffset.UTC);
        String contentType = "video/mp4";

        // Validate request headers for caching ---------------------------------------------------

        // If-None-Match header should contain "*" or ETag. If so, then return 304.
        String ifNoneMatch = request.getHeader("If-None-Match");
        if (ifNoneMatch != null && HttpUtils.matches(ifNoneMatch, fileName)) {
            response.setHeader("ETag", fileName); // Required in 304.
            response.sendError(HttpServletResponse.SC_NOT_MODIFIED);
            return;
        }

        // If-Modified-Since header should be greater than LastModified. If so, then return 304.
        // This header is ignored if any If-None-Match header is specified.
        long ifModifiedSince = request.getDateHeader("If-Modified-Since");
        if (ifNoneMatch == null && ifModifiedSince != -1 && ifModifiedSince + 1000 > lastModified) {
            response.setHeader("ETag", fileName); // Required in 304.
            response.sendError(HttpServletResponse.SC_NOT_MODIFIED);
            return;
        }

        // Validate request headers for resume ----------------------------------------------------

        // If-Match header should contain "*" or ETag. If not, then return 412.
        String ifMatch = request.getHeader("If-Match");
        if (ifMatch != null && !HttpUtils.matches(ifMatch, fileName)) {
            response.sendError(HttpServletResponse.SC_PRECONDITION_FAILED);
            return;
        }

        // If-Unmodified-Since header should be greater than LastModified. If not, then return 412.
        long ifUnmodifiedSince = request.getDateHeader("If-Unmodified-Since");
        if (ifUnmodifiedSince != -1 && ifUnmodifiedSince + 1000 <= lastModified) {
            response.sendError(HttpServletResponse.SC_PRECONDITION_FAILED);
            return;
        }

        // Validate and process range -------------------------------------------------------------

        // Prepare some variables. The full Range represents the complete file.
        Range full = new Range(0, length - 1, length);
        List<Range> ranges = new ArrayList<>();

        // Validate and process Range and If-Range headers.
        String range = request.getHeader("Range");
        if (range != null) {

            // Range header should match format "bytes=n-n,n-n,n-n...". If not, then return 416.
            if (!range.matches("^bytes=\\d*-\\d*(,\\d*-\\d*)*$")) {
                response.setHeader("Content-Range", "bytes */" + length); // Required in 416.
                response.sendError(HttpServletResponse.SC_REQUESTED_RANGE_NOT_SATISFIABLE);
                return;
            }

            String ifRange = request.getHeader("If-Range");
            if (ifRange != null && !ifRange.equals(fileName)) {
                try {
                    long ifRangeTime = request.getDateHeader("If-Range"); // Throws IAE if invalid.
                    if (ifRangeTime != -1) {
                        ranges.add(full);
                    }
                } catch (IllegalArgumentException ignore) {
                    ranges.add(full);
                }
            }

            // If any valid If-Range header, then process each part of byte range.
            if (ranges.isEmpty()) {
                for (String part : range.substring(6).split(",")) {
                    // Assuming a file with length of 100, the following examples returns bytes at:
                    // 50-80 (50 to 80), 40- (40 to length=100), -20 (length-20=80 to length=100).
                    long start = Range.sublong(part, 0, part.indexOf("-"));
                    long end = Range.sublong(part, part.indexOf("-") + 1, part.length());

                    if (start == -1) {
                        start = length - end;
                        end = length - 1;
                    } else if (end == -1 || end > length - 1) {
                        end = length - 1;
                    }

                    // Check if Range is syntactically valid. If not, then return 416.
                    if (start > end) {
                        response.setHeader("Content-Range", "bytes */" + length); // Required in 416.
                        response.sendError(HttpServletResponse.SC_REQUESTED_RANGE_NOT_SATISFIABLE);
                        return;
                    }

                    // Add range.                    
                    ranges.add(new Range(start, end, length));
                }
            }
        }

        // Prepare and initialize response --------------------------------------------------------

        // Get content type by file name and set content disposition.
        String disposition = "inline";

        // If content type is unknown, then set the default value.
        // For all content types, see: http://www.w3schools.com/media/media_mimeref.asp
        // To add new content types, add new mime-mapping entry in web.xml.
        if (contentType == null) {
            contentType = "application/octet-stream";
        } else if (!contentType.startsWith("image")) {
            // Else, expect for images, determine content disposition. If content type is supported by
            // the browser, then set to inline, else attachment which will pop a 'save as' dialogue.
            String accept = request.getHeader("Accept");
            disposition = accept != null && HttpUtils.accepts(accept, contentType) ? "inline" : "attachment";
        }
        logger.debug("Content-Type : {}", contentType);
        // Initialize response.
        response.reset();
        response.setBufferSize(DEFAULT_BUFFER_SIZE);
        response.setHeader("Content-Type", contentType);
        response.setHeader("Content-Disposition", disposition + ";filename=\"" + fileName + "\"");
        logger.debug("Content-Disposition : {}", disposition);
        response.setHeader("Accept-Ranges", "bytes");
        response.setHeader("ETag", fileName);
        response.setDateHeader("Last-Modified", lastModified);
        response.setDateHeader("Expires", System.currentTimeMillis() + DEFAULT_EXPIRE_TIME);

        // Send requested file (part(s)) to client ------------------------------------------------

        // Prepare streams.
        try (InputStream input = new BufferedInputStream(Files.newInputStream(filepath));
             OutputStream output = response.getOutputStream()) {

            if (ranges.isEmpty() || ranges.get(0) == full) {

                // Return full file.
                logger.info("Return full file");
                response.setContentType(contentType);
                response.setHeader("Content-Range", "bytes " + full.start + "-" + full.end + "/" + full.total);
                response.setHeader("Content-Length", String.valueOf(full.length));
                Range.copy(input, output, length, full.start, full.length);

            } else if (ranges.size() == 1) {

                // Return single part of file.
                Range r = ranges.get(0);
                logger.info("Return 1 part of file : from ({}) to ({})", r.start, r.end);
                response.setContentType(contentType);
                response.setHeader("Content-Range", "bytes " + r.start + "-" + r.end + "/" + r.total);
                response.setHeader("Content-Length", String.valueOf(r.length));
                response.setStatus(HttpServletResponse.SC_PARTIAL_CONTENT); // 206.

                // Copy single part range.
                Range.copy(input, output, length, r.start, r.length);

            } else {

                // Return multiple parts of file.
                response.setContentType("multipart/byteranges; boundary=" + MULTIPART_BOUNDARY);
                response.setStatus(HttpServletResponse.SC_PARTIAL_CONTENT); // 206.

                // Cast back to ServletOutputStream to get the easy println methods.
                ServletOutputStream sos = (ServletOutputStream) output;

                // Copy multi part range.
                for (Range r : ranges) {
                    logger.info("Return multi part of file : from ({}) to ({})", r.start, r.end);
                    // Add multipart boundary and header fields for every range.
                    sos.println();
                    sos.println("--" + MULTIPART_BOUNDARY);
                    sos.println("Content-Type: " + contentType);
                    sos.println("Content-Range: bytes " + r.start + "-" + r.end + "/" + r.total);

                    // Copy single part range of multi part range.
                    Range.copy(input, output, length, r.start, r.length);
                }

                // End with multipart boundary.
                sos.println();
                sos.println("--" + MULTIPART_BOUNDARY + "--");
            }
        }

    }

    private static class Range {
        long start;
        long end;
        long length;
        long total;

        /**
         * Construct a byte range.
         * @param start Start of the byte range.
         * @param end End of the byte range.
         * @param total Total length of the byte source.
         */
        public Range(long start, long end, long total) {
            this.start = start;
            this.end = end;
            this.length = end - start + 1;
            this.total = total;
        }

        public static long sublong(String value, int beginIndex, int endIndex) {
            String substring = value.substring(beginIndex, endIndex);
            return (substring.length() > 0) ? Long.parseLong(substring) : -1;
        }

        private static void copy(InputStream input, OutputStream output, long inputSize, long start, long length) throws IOException {
            byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
            int read;

            if (inputSize == length) {
                // Write full range.
                while ((read = input.read(buffer)) > 0) {
                    output.write(buffer, 0, read);
                    output.flush();
                }
            } else {
                input.skip(start);
                long toRead = length;

                while ((read = input.read(buffer)) > 0) {
                    if ((toRead -= read) > 0) {
                        output.write(buffer, 0, read);
                        output.flush();
                    } else {
                        output.write(buffer, 0, (int) toRead + read);
                        output.flush();
                        break;
                    }
                }
            }
        }
    }
    private static class HttpUtils {

        /**
         * Returns true if the given accept header accepts the given value.
         * @param acceptHeader The accept header.
         * @param toAccept The value to be accepted.
         * @return True if the given accept header accepts the given value.
         */
        public static boolean accepts(String acceptHeader, String toAccept) {
            String[] acceptValues = acceptHeader.split("\\s*(,|;)\\s*");
            Arrays.sort(acceptValues);

            return Arrays.binarySearch(acceptValues, toAccept) > -1
                    || Arrays.binarySearch(acceptValues, toAccept.replaceAll("/.*$", "/*")) > -1
                    || Arrays.binarySearch(acceptValues, "*/*") > -1;
        }

        /**
         * Returns true if the given match header matches the given value.
         * @param matchHeader The match header.
         * @param toMatch The value to be matched.
         * @return True if the given match header matches the given value.
         */
        public static boolean matches(String matchHeader, String toMatch) {
            String[] matchValues = matchHeader.split("\\s*,\\s*");
            Arrays.sort(matchValues);
            return Arrays.binarySearch(matchValues, toMatch) > -1
                    || Arrays.binarySearch(matchValues, "*") > -1;
        }
    }
}

在控制器中使用：

MultipartFileSender.fromPath(pathtofile)
                .with(httprequest)
                .with(httpresponse)
                .serveResource();

Answer 2

现在是 2020 年。

部分范围默认在 Spring 中实现（我使用的是 Spring Boot 2.2.4）。我的控制器代码看起来类似于下面的代码，它适用于范围标头。

return ResponseEntity.ok().body(new FileSystemResource(file))

注意事项（详见The Almighty Source Code）：

• Spring 要求将响应设置为 200，并且在内部（如果请求中存在范围标头）将其替换为 206 Partial Content。
• Spring 还要求响应是资源实例 except InputStreamResource 失败。对于文件，FileSystemResource 似乎是最佳选择。

Answer 3

如果你想避开MimeTypeUtils，你可以使用Files.probeContentType(Path path)。这将使用系统的默认实现。

Answer 4

根据您要实现的目标，将请求映射到容器的默认 servlet 可能是有意义的。

即在初始化期间：

ServletContext container = ...

// Map *.mp4 to the default servlet to support range requests

ServletRegistration servletRegistration = container.getServletRegistration("default");
servletRegistration.addMapping("*.mp4");

Answer 5

Leandro 的回答非常适合我。我只用 RandomAccessFile 更改了 InputStream，访问文件内的随机点性能更好。

这里是 MultipartFileSender 类

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.StringUtils;

import java.io.*;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.attribute.FileTime;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.ZoneOffset;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class MultipartFileSender {

    protected final Logger logger = LoggerFactory.getLogger(this.getClass());

    private static final int DEFAULT_BUFFER_SIZE = 20480; // ..bytes = 20KB.
    private static final long DEFAULT_EXPIRE_TIME = 604800000L; // ..ms = 1 week.
    private static final String MULTIPART_BOUNDARY = "MULTIPART_BYTERANGES";

    Path filepath;
    HttpServletRequest request;
    HttpServletResponse response;

    public MultipartFileSender() {
    }

    public static MultipartFileSender fromPath(Path path) {
        return new MultipartFileSender().setFilepath(path);
    }

    public static MultipartFileSender fromFile(File file) {
        return new MultipartFileSender().setFilepath(file.toPath());
    }

    public static MultipartFileSender fromURIString(String uri) {
        return new MultipartFileSender().setFilepath(Paths.get(uri));
    }

    //** internal setter **//
    private MultipartFileSender setFilepath(Path filepath) {
        this.filepath = filepath;
        return this;
    }

    public MultipartFileSender with(HttpServletRequest httpRequest) {
        request = httpRequest;
        return this;
    }

    public MultipartFileSender with(HttpServletResponse httpResponse) {
        response = httpResponse;
        return this;
    }

    public void serveResource() throws Exception {
        if (response == null || request == null) {
            return;
        }

        if (!Files.exists(filepath)) {
            logger.error("File doesn't exist at URI : {}", filepath.toAbsolutePath().toString());
            response.sendError(HttpServletResponse.SC_NOT_FOUND);
            return;
        }

        Long length = Files.size(filepath);
        String fileName = filepath.getFileName().toString();
        FileTime lastModifiedObj = Files.getLastModifiedTime(filepath);

        if (StringUtils.isEmpty(fileName) || lastModifiedObj == null) {
            response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
            return;
        }
    long lastModified = LocalDateTime.ofInstant(lastModifiedObj.toInstant(), ZoneId.of(ZoneOffset.systemDefault().getId())).toEpochSecond(ZoneOffset.UTC);
    String contentType = "video/mp4";

    // Validate request headers for caching ---------------------------------------------------

    // If-None-Match header should contain "*" or ETag. If so, then return 304.
    String ifNoneMatch = request.getHeader("If-None-Match");
    if (ifNoneMatch != null && HttpUtils.matches(ifNoneMatch, fileName)) {
        response.setHeader("ETag", fileName); // Required in 304.
        response.sendError(HttpServletResponse.SC_NOT_MODIFIED);
        return;
    }

    // If-Modified-Since header should be greater than LastModified. If so, then return 304.
    // This header is ignored if any If-None-Match header is specified.
    long ifModifiedSince = request.getDateHeader("If-Modified-Since");
    if (ifNoneMatch == null && ifModifiedSince != -1 && ifModifiedSince + 1000 > lastModified) {
        response.setHeader("ETag", fileName); // Required in 304.
        response.sendError(HttpServletResponse.SC_NOT_MODIFIED);
        return;
    }

    // Validate request headers for resume ----------------------------------------------------

    // If-Match header should contain "*" or ETag. If not, then return 412.
    String ifMatch = request.getHeader("If-Match");
    if (ifMatch != null && !HttpUtils.matches(ifMatch, fileName)) {
        response.sendError(HttpServletResponse.SC_PRECONDITION_FAILED);
        return;
    }

    // If-Unmodified-Since header should be greater than LastModified. If not, then return 412.
    long ifUnmodifiedSince = request.getDateHeader("If-Unmodified-Since");
    if (ifUnmodifiedSince != -1 && ifUnmodifiedSince + 1000 <= lastModified) {
        response.sendError(HttpServletResponse.SC_PRECONDITION_FAILED);
        return;
    }

    // Validate and process range -------------------------------------------------------------

    // Prepare some variables. The full Range represents the complete file.
    Range full = new Range(0, length - 1, length);
    List<Range> ranges = new ArrayList<>();

    // Validate and process Range and If-Range headers.
    String range = request.getHeader("Range");
    if (range != null) {

        // Range header should match format "bytes=n-n,n-n,n-n...". If not, then return 416.
        if (!range.matches("^bytes=\\d*-\\d*(,\\d*-\\d*)*$")) {
            response.setHeader("Content-Range", "bytes */" + length); // Required in 416.
            response.sendError(HttpServletResponse.SC_REQUESTED_RANGE_NOT_SATISFIABLE);
            return;
        }

        String ifRange = request.getHeader("If-Range");
        if (ifRange != null && !ifRange.equals(fileName)) {
            try {
                long ifRangeTime = request.getDateHeader("If-Range"); // Throws IAE if invalid.
                if (ifRangeTime != -1) {
                    ranges.add(full);
                }
            } catch (IllegalArgumentException ignore) {
                ranges.add(full);
            }
        }

        // If any valid If-Range header, then process each part of byte range.
        if (ranges.isEmpty()) {
            for (String part : range.substring(6).split(",")) {
                // Assuming a file with length of 100, the following examples returns bytes at:
                // 50-80 (50 to 80), 40- (40 to length=100), -20 (length-20=80 to length=100).
                long start = Range.sublong(part, 0, part.indexOf("-"));
                long end = Range.sublong(part, part.indexOf("-") + 1, part.length());

                if (start == -1) {
                    start = length - end;
                    end = length - 1;
                } else if (end == -1 || end > length - 1) {
                    end = length - 1;
                }

                // Check if Range is syntactically valid. If not, then return 416.
                if (start > end) {
                    response.setHeader("Content-Range", "bytes */" + length); // Required in 416.
                    response.sendError(HttpServletResponse.SC_REQUESTED_RANGE_NOT_SATISFIABLE);
                    return;
                }

                // Add range.                    
                ranges.add(new Range(start, end, length));
            }
        }
    }

    // Prepare and initialize response --------------------------------------------------------

    // Get content type by file name and set content disposition.
    String disposition = "inline";

    // If content type is unknown, then set the default value.
    // For all content types, see: http://www.w3schools.com/media/media_mimeref.asp
    // To add new content types, add new mime-mapping entry in web.xml.
    if (contentType == null) {
        contentType = "application/octet-stream";
    } else if (!contentType.startsWith("image")) {
        // Else, expect for images, determine content disposition. If content type is supported by
        // the browser, then set to inline, else attachment which will pop a 'save as' dialogue.
        String accept = request.getHeader("Accept");
        disposition = accept != null && HttpUtils.accepts(accept, contentType) ? "inline" : "attachment";
    }
    logger.debug("Content-Type : {}", contentType);
    // Initialize response.
    response.reset();
    response.setBufferSize(DEFAULT_BUFFER_SIZE);
    response.setHeader("Content-Type", contentType);
    response.setHeader("Content-Disposition", disposition + ";filename=\"" + fileName + "\"");
    logger.debug("Content-Disposition : {}", disposition);
    response.setHeader("Accept-Ranges", "bytes");
    response.setHeader("ETag", fileName);
    response.setDateHeader("Last-Modified", lastModified);
    response.setDateHeader("Expires", System.currentTimeMillis() + DEFAULT_EXPIRE_TIME);

    // Send requested file (part(s)) to client ------------------------------------------------

    // Prepare streams.
    try (RandomAccessFile input = new RandomAccessFile(filepath.toFile(), "r");
         OutputStream output = response.getOutputStream()) {

        if (ranges.isEmpty() || ranges.get(0) == full) {
            // Return full file.
            logger.info("Return full file");
            response.setContentType(contentType);
            response.setHeader("Content-Range", "bytes " + full.start + "-" + full.end + "/" + full.total);
            response.setHeader("Content-Length", String.valueOf(full.length));
            Range.copy(input, output, length, full.start, full.length);

        } else if (ranges.size() == 1) {

            // Return single part of file.
            Range r = ranges.get(0);
            logger.info("Return 1 part of file : from ({}) to ({})", r.start, r.end);
            response.setContentType(contentType);
            response.setHeader("Content-Range", "bytes " + r.start + "-" + r.end + "/" + r.total);
            response.setHeader("Content-Length", String.valueOf(r.length));
            response.setStatus(HttpServletResponse.SC_PARTIAL_CONTENT); // 206.
            // Copy single part range.
            Range.copy(input, output, length, r.start, r.length);

        } else {

            // Return multiple parts of file.
            response.setContentType("multipart/byteranges; boundary=" + MULTIPART_BOUNDARY);
            response.setStatus(HttpServletResponse.SC_PARTIAL_CONTENT); // 206.

            // Cast back to ServletOutputStream to get the easy println methods.
            ServletOutputStream sos = (ServletOutputStream) output;

            // Copy multi part range.
            for (Range r : ranges) {
                logger.info("Return multi part of file : from ({}) to ({})", r.start, r.end);
                // Add multipart boundary and header fields for every range.
                sos.println();
                sos.println("--" + MULTIPART_BOUNDARY);
                sos.println("Content-Type: " + contentType);
                sos.println("Content-Range: bytes " + r.start + "-" + r.end + "/" + r.total);
                // Copy single part range of multi part range.
                Range.copy(input, output, length, r.start, r.length);
            }

            // End with multipart boundary.
            sos.println();
            sos.println("--" + MULTIPART_BOUNDARY + "--");
        }
    }

}

private static class Range {
    long start;
    long end;
    long length;
    long total;

    /**
     * Construct a byte range.
     * @param start Start of the byte range.
     * @param end End of the byte range.
     * @param total Total length of the byte source.
     */
    public Range(long start, long end, long total) {
        this.start = start;
        this.end = end;
        this.length = end - start + 1;
        this.total = total;
    }

    public static long sublong(String value, int beginIndex, int endIndex) {
        String substring = value.substring(beginIndex, endIndex);
        return (substring.length() > 0) ? Long.parseLong(substring) : -1;
    }

    private static void copy(RandomAccessFile input, OutputStream output, long inputSize, long start, long length) throws IOException {
        byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
        int read;

        if (inputSize == length) {
            // Write full range.
            while ((read = input.read(buffer)) > 0) {
                output.write(buffer, 0, read);
                output.flush();
            }
        } else {
            input.seek(start);
            long toRead = length;

            while ((read = input.read(buffer)) > 0) {
                if ((toRead -= read) > 0) {
                    output.write(buffer, 0, read);
                    output.flush();
                } else {
                    output.write(buffer, 0, (int) toRead + read);
                    output.flush();
                    break;
                }
            }
        }
    }
    }
    private static class HttpUtils {

    /**
     * Returns true if the given accept header accepts the given value.
     * @param acceptHeader The accept header.
     * @param toAccept The value to be accepted.
     * @return True if the given accept header accepts the given value.
     */
        public static boolean accepts(String acceptHeader, String toAccept) {
            String[] acceptValues = acceptHeader.split("\\s*(,|;)\\s*");
            Arrays.sort(acceptValues);

            return Arrays.binarySearch(acceptValues, toAccept) > -1
                || Arrays.binarySearch(acceptValues, toAccept.replaceAll("/.*$", "/*")) > -1
                || Arrays.binarySearch(acceptValues, "*/*") > -1;
        }

    /**
     * Returns true if the given match header matches the given value.
     * @param matchHeader The match header.
     * @param toMatch The value to be matched.
     * @return True if the given match header matches the given value.
     */
        public static boolean matches(String matchHeader, String toMatch) {
            String[] matchValues = matchHeader.split("\\s*,\\s*");
            Arrays.sort(matchValues);
            return Arrays.binarySearch(matchValues, toMatch) > -1
                || Arrays.binarySearch(matchValues, "*") > -1;
        }
    }
}

Answer 6

哇，Leandro 的回答太精彩了。只需创建服务文件跟随他 并在控制器中使用。在这里我遵循他的指导方针

@RequestMapping(value = [(SKConstant.URL_PROJECT_API + "/video/{token}")], method = arrayOf(RequestMethod.GET)
fun getVideo(@PathVariable("token") token: String, response: HttpServletResponse, request: HttpServletRequest): Any?{
         val file = baseService.getByToken(token)
         if(file != null) {
           return MultipartFileSender.fromFile(File(fileService.getUploadFileRealPath(file.uniqueName!!)))
                              .with(request)
                              .with(response)
                              .serveResource()
 }

Answer 7

试试这个简单的代码。

@GET
@Produces({"application/octet-stream"})
public Response getFile() {
  File file = ... 
  return Response.ok(file, MediaType.APPLICATION_OCTET_STREAM)
      .header("Content-Disposition", "attachment; filename=\"" + file.getName() + "\"" ) .build();
}

更新：

它使用 spring MVC 包装 Spring Jersey jersey.java.net RESTful 实现。

对于纯 Spring mvc，请使用以下代码。

@RequestMapping("/video") public ResponseEntity<byte[]> getvideo() throws IOException { 
    InputStream in = ... 
    final HttpHeaders headers = new HttpHeaders(); 
    headers.setContentType(MediaType.APPLICATION_OCTET_STREAM); 
    return new ResponseEntity<byte[]>IOUtils.toByteArray(in),headers,HttpStatus.CREATED); 
}

IOUtils 来自 apache common jar