1.上传文件

		String result="";
        PostMethod post = new PostMethod(url);
        Part[] parts = { new StringPart("token", "1F019648B56CF2C2A380248ED6F4A650"),  
        						new StringPart("key", "111111111111111"),
                   			    new FilePart("file",new file(filePath)};
        try {
            HttpClient httpclient = new HttpClient();
            MultipartRequestEntity entity = new MultipartRequestEntity( parts, post.getParams());
            post.setRequestEntity(entity);
            int code = httpclient.executeMethod(post);
            //拿到响应结果
            result = new String(post.getResponseBody(), "UTF-8");
        }catch (Exception e){
            logger.error("post请求出现异常:"+e);
        }finally {
            if (post!=null){
                //可释放连接
                post.releaseConnection();
            }
        }
        return result;

2.上传文件二进制流

Part[] parts = { new StringPart("token", "1F019648B56CF2C2A380248ED6F4A650"),  
        		 new StringPart("key", customerNo),
                 new FilePart("file",new ByteArrayPartSource("file",bytes))}

我使用 Node.js 的 request 工具库，请求服务器端的视频文件，保存到本地之后，发现了问题。

我把 url 输入到浏览器里，手动下载视频文件后，文件大小为 70 多 KB：

然而使用 Node.js 代码请求文件数据并保存到本地，发现文件尺寸变成 100 多 KB 了，显然不正确：

经过研究发现，需要使用 request 在发起数据请求之前，添加如下一行语句：

request.defaults({ encoding: null });

完整的数据请求的代码：

var requestC = request.defaults({ encoding: null });
        
        console.log("get video via url: " + url );
        const fileName = getVideoPartNameByUrl(url);

        requestC(getVideoOptions,function(error,response,body){
            if(error){
                console.log("error occurred: " + error);
                reject(error);
            }
            resolve({
                fileName: fileName,
                fileContent: body
            });
        }); 

文件写入的代码：

fs.writeFile(oVideo.fileName, oVideo.fileContent, "binary", function (error) {
        if(error)
            console.log("file writes error");
        else{
            console.log("File: ", oVideo.fileName, " writes ok");
        }
    });

之后问题消失。

更多Jerry的原创文章，尽在：“汪子熙”:

声明：根据http请求图片的url下载文件到本地

public void  downLoadPhoto(String photoUrl)throws Exception{
         
        //获取照片返回二进制流
            RestTemplate restTemplate = new RestTemplate();
            HttpHeaders headers = new HttpHeaders();
            ResponseEntity<byte[]> entity = restTemplate.exchange(photoUrl, HttpMethod.GET,new HttpEntity<>(headers), byte[].class);
            byte[] body = entity.getBody();
            InputStream sbs = new ByteArrayInputStream(body);

            File dest = new File("/Users/qixin/Desktop/a.jpg");
            if(!dest.exists()) {
                dest.createNewFile();
            }

            InputStream in = null;
            OutputStream out = null;

            in = new ByteArrayInputStream(body);
            out = new FileOutputStream(dest);

            byte []bt = new byte[1024];
            int length=0;
            while(	(length = in.read(bt)) !=-1) {
                //一次性写入文件a中
                out.write(bt,0,length);
            }

            if(null!=out) {
                out.close();
            }



 }