SpringBoot下载文件的实现及速度对比

InputStream in = new FileInputStream(System.getProperty("user.dir") + filePath);

@Service
@Slf4j
public class MongoConfig extends AbstractMongoConfiguration {
 
    @Autowired
    private MongoTemplate mongoTemplate;
    @Autowired
    private GridFSBucket gridFSBucket;
 
    @Override
    public MongoClient mongoClient() {
        MongoClient mongoClient = getMongoClient();
        return mongoClient;
    }
 
    public MongoClient getMongoClient() {
        // mongoDB地址列表
        List<ServerAddress> serverAddresses = new ArrayList<>();
        serverAddresses.add(new ServerAddress("10.1.61.101:27017"));
        // 连接认证
        MongoCredential credential = MongoCredential.createCredential("root", "admin", "Root_123".toCharArray());
        MongoClientOptions.Builder builder = MongoClientOptions.builder();
 
        //最大连接数
        builder.connectionsPerHost(10);
        //最小连接数
        builder.minConnectionsPerHost(0);
        //超时时间
        builder.connectTimeout(1000*3);
        // 一个线程成功获取到一个可用数据库之前的最大等待时间
        builder.maxWaitTime(5000);
        //此参数跟connectionsPerHost的乘机为一个线程变为可用的最大阻塞数，超过此乘机数之后的所有线程将及时获取一个异常.eg.connectionsPerHost=10 and threadsAllowedToBlockForConnectionMultiplier=5,最多50个线程等级一个链接，推荐配置为5
        builder.threadsAllowedToBlockForConnectionMultiplier(5);
        //最大空闲时间
        builder.maxConnectionIdleTime(1000*10);
        //设置池连接的最大生命时间。
        builder.maxConnectionLifeTime(1000*10);
        //连接超时时间
        builder.SocketTimeout(1000*10);
 
        MongoClientOptions myOptions = builder.build();
        MongoClient mongoClient = new MongoClient(serverAddresses, credential, myOptions);
        return mongoClient;
    }
 
    @Override
    protected String getDatabaseName() {
        return "notifyTest";
    }
 
    
    public String getFilesDataBaseName() {
        return "notifyFiles";
    }
 
    
    public MongoDbFactory getDbFactory(String dataBaseName) {
        MongoDbFactory dbFactory = null;
        try {
            dbFactory = new SimpleMongoDbFactory(getMongoClient(), dataBaseName);
        } catch (Exception e) {
            log.error("Get mongo client have an error, please check reason...", e.getMessage());
        }
        return dbFactory;
    }
 
    
    public GridFsTemplate getGridFS() {
        return new GridFsTemplate(getDbFactory(getFilesDataBaseName()), mongoTemplate.getConverter());
    }
 
    @Bean
    public GridFSBucket getGridFSBuckets() {
        MongoDatabase db = getDbFactory(getFilesDataBaseName()).getDb();
        return GridFSBuckets.create(db);
    }
 
    
    public GridFsResource convertGridFSFile2Resource(GridFSFile gridFsFile) {
        GridFSDownloadStream gridFSDownloadStream = gridFSBucket.openDownloadStream(gridFsFile.getObjectId());
        return new GridFsResource(gridFsFile, gridFSDownloadStream);
    }
}

    @RequestMapping(value = "/download2", method = RequestMethod.GET)
    public void downLoad2(httpservletResponse response, String id) {
        userService.download2(response, id);
    }

    
    @Override
    public void download2(HttpServletResponse response, String id) {
        GridFsTemplate gridFsTemplate = new GridFsTemplate(mongoConfig.getDbFactory(mongoConfig.getFilesDataBaseName()), mongoTemplate.getConverter());
        // 由于springBoot升级到2.x 之后 findOne方法返回由 GridFSDBFile 变为 GridFSFile 了，导致下载变得稍微有点繁琐
        GridFSFile gridFSFile = gridFsTemplate.findOne(new Query(Criteria.where("_id").is(id)));
        String fileName = gridFSFile.getFilename();
        GridFsResource gridFsResource = mongoConfig.convertGridFSFile2Resource(gridFSFile);
        // 从此处开始计时
        long startTime = System.currentTimeMillis();
        InputStream in = null;
        OutputStream out = null;
        try {
            // 这里需对中文进行转码处理
            fileName = new String(fileName.getBytes("utf-8"), "ISO-8859-1");
            // 告诉浏览器弹出下载对话框
            response.setHeader("Content-Disposition", "attachment;filename=" + fileName);
            byte[] buffer = new byte[1024];
            int len;
            // 获得输出流
            out = response.getOutputStream();
            in = gridFsResource.getInputStream();
            while ((len = in.read(buffer)) > 0) {
               out.write(buffer, 0 ,len);
            }
        } catch (IOException e) {
            log.error("transfer in error .");
        } finally {
            try {
                if (null != in)
                    in.close();
                if (null != out)
                    out.close();
                log.info("download file with stream total time : {}", System.currentTimeMillis() - startTime);
            } catch (IOException e){
                log.error("close IO error .");
            }
        }
    }

    @RequestMapping(value = "/download", method = RequestMethod.GET, produces = MediaType.APPLICATION_OCTET_STREAM_VALUE)
    public Object downLoad(String id) {
        return userService.download(id);
    }

    
    @Override
    public ResponseEntity<byte[]> download(String id) {
        GridFsTemplate gridFsTemplate = new GridFsTemplate(mongoConfig.getDbFactory(mongoConfig.getFilesDataBaseName()), mongoTemplate.getConverter());
        // 由于springBoot升级到2.x 之后 findOne方法返回由 GridFSDBFile 变为 GridFSFile 了，导致下载变得稍微有点繁琐
        GridFSFile gridFSFile = gridFsTemplate.findOne(new Query(Criteria.where("_id").is(id)));
        String fileName = gridFSFile.getFilename();
        GridFsResource gridFsResource = mongoConfig.convertGridFSFile2Resource(gridFSFile);
        // 从此处开始计时
        long startTime = System.currentTimeMillis();
        try {
            InputStream in = gridFsResource.getInputStream();
            // 请求体
            byte[] body = IOUtils.toByteArray(in);
            // 请求头
            HttpHeaders httpHeaders = new HttpHeaders();
            // 这里需对中文进行转码处理
            fileName = new String(fileName.getBytes("utf-8"), "ISO-8859-1");
            // 告诉浏览器弹出下载对话框
            httpHeaders.add("Content-Disposition", "attachment;filename=" + fileName);
            ResponseEntity<byte[]> responseEntity = new ResponseEntity<>(body, httpHeaders, HttpStatus.OK);
            log.info("download file total with ResponseEntity time : {}", System.currentTimeMillis() - startTime);
            return responseEntity;
        } catch (IOException e) {
            log.error("transfer in error .");
        }
        return null;
    }

<dependency>
    <groupId>commons-io</groupId>
    <artifactId>commons-io</artifactId>
    <version>2.4</version>
</dependency>

    @RequestMapping(value = "/application/file/show", method = RequestMethod.GET, produces = MediaType.IMAGE_PNG_VALUE)
    public Object downloadFile(@RequestParam("path") String filePath) {
        try {
            InputStream in = new FileInputStream(System.getProperty("user.dir") + filePath);
            byte[] bytes = new byte[in.available()];
            in.read(bytes);
            return bytes;
        } catch (IOException e) {
            log.error("transfer byte error");
            return buildMessage(ResultModel.FAIL, "show pic error");
        }
    }