Java模拟http上传文件请求（HttpURLConnection,HttpClient4.4,RestTemplate）

先上代码：

    public void uploadToUrl(String fileId, String fileSetId, String formUrl) throws Throwable {
        String urlStr = MyServiceConfig.getUrl() + UPLOAD_URL;
        String fileName = FileUtils.getFileName(formUrl);
        long fileSize = getFileSize(formUrl);
        String uri = UriComponentsBuilder.fromUriString(urlStr).queryParam("fileId", fileId).build().encode().toString();

        logger.debug("文件上传请求路径：{}", uri);

        // 获取文件输入流
        InputStream in = getFileInputString(formUrl);
        if (null != in) {
            URL urlObj = new URL(uri);
            HttpURLConnection con = (HttpURLConnection) urlObj.openConnection();
            con.setRequestMethod("POST"); // 设置关键值,以Post方式提交表单，默认get方式
            con.setDoInput(true);
            con.setDoOutput(true);
            con.setUseCaches(false); // post方式不能使用缓存
            // 设置请求头信息
            con.setRequestProperty("Connection", "Keep-Alive");
            con.setRequestProperty("Charset", "UTF-8");
            // 设置边界
            String BOUNDARY = "----------" + System.currentTimeMillis();
            con.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + BOUNDARY);
            // 请求正文信息
            // 第一部分：
            StringBuilder sb = new StringBuilder();
            sb.append("--"); // 必须多两道线
            sb.append(BOUNDARY);
            sb.append("\r\n");
            sb.append("Content-Disposition: form-data;name=\"file\";filename=\"" + fileName + "\"\r\n");
            if(!fileName.endsWith("mp4")){
                sb.append("Content-Type:image/jpeg\r\n\r\n");
            }else if(){
                sb.append("Content-Type:video/mp4\r\n\r\n");
            }
//未知文件类型，以流的方式上传
//sb.append("Content-Type:application/octet-stream\r\n\r\n");
            byte[] head = sb.toString().getBytes("utf-8");
            // 获得输出流
            OutputStream out = new DataOutputStream(con.getOutputStream());
            // 输出表头
            out.write(head);
            // 文件正文部分
            // 把文件已流文件的方式 推入到url中
            DataInputStream dataIn = new DataInputStream(in);
            int bytes = 0;
            byte[] bufferOut = new byte[1024];
            while ((bytes = dataIn.read(bufferOut)) != -1) {
                out.write(bufferOut, 0, bytes);
            }
            in.close();
            // 结尾部分
            byte[] foot = ("\r\n--" + BOUNDARY + "--\r\n").getBytes("utf-8");// 定义最后数据分隔线
            out.write(foot);
            out.flush();
            out.close();

            // 读取返回数据
            StringBuffer strBuf = new StringBuffer();
            BufferedReader reader = new BufferedReader(new InputStreamReader(con.getInputStream()));
            String line = null;
            while ((line = reader.readLine()) != null) {
                strBuf.append(line).append("\n");
            }
            logger.debug("文件上传返回信息{}",strBuf.toString());
            reader.close();
            con.disconnect();
            con = null;
        } else {
            throw new Throwable("获取文件流失败,文件下载地址url=" + formUrl);
        }

    }

    // 获取文件大小
    public InputStream getFileInputString(String formUrl) throws Throwable {
        URL urlPath = new URL(formUrl);
        HttpURLConnection conn = (HttpURLConnection) urlPath.openConnection();
        conn.setConnectTimeout(5000);
        conn.setRequestMethod("GET");
        int status = conn.getResponseCode();
        if (status == 200) {
            return conn.getInputStream();
        }
        return null;
    }

    //获取文件大小
        public long getFileSize(String formUrl) throws Throwable{
              URL urlPath = new URL(formUrl);
              HttpURLConnection conn = (HttpURLConnection)urlPath.openConnection();
              conn.setConnectTimeout(downloadTimeout);
              conn.setRequestMethod("GET");
              int status = conn.getResponseCode();
              if(status==200){
                  return conn.getContentLengthLong();
              }
              return 0;
        }

　　　　

public static String getFileName(String fileFullPath) {
fileFullPath = fileFullPath.replace("/", "\\");
return fileFullPath.substring(fileFullPath.lastIndexOf("\\") + 1,
fileFullPath.length());
}

public static String getFileNameWithoutSuffix(String fileFullPath) {
fileFullPath = fileFullPath.replace("/", "\\");
return fileFullPath.substring(fileFullPath.lastIndexOf("\\") + 1,
fileFullPath.lastIndexOf("."));
}

代码逻辑：

1、从访问文件的url中获取文件流和文件大小；

2、模拟http上传文件post请求；

1》.打开httpurlconnection连接，设置关键值：重点是设置请求方法post和设置不缓存；

2》.设置请求头，设置边界；重点是Content-Type；

3》.设置请求正文，比较复杂，参照代码；

4》.获取返回值；

二、使用httpClient4.4上传文件：

//上传实体文件
    public static void upload(String url,String filePath) throws Exception{
        HttpPost httpPost = new HttpPost(url);
        httpPost.setHeader("User-Agent","Mozilla/5.0 (Windows NT 10.0; Win64; x64) "
                + "AppleWebKit/537.36 (KHTML, like Gecko) "
                + "Chrome/62.0.3202.89 Safari/537.36");
        httpPost.setHeader("Accept-Language","zh-cn,zh;q=0.5");
        httpPost.setHeader("Accept-Charset","GBK,utf-8;q=0.7,*;q=0.7");
        httpPost.setHeader("Connection","keep-alive");

        MultipartEntityBuilder mutiEntity = MultipartEntityBuilder.create();
        File file = new File(filePath);
        //File file = new File("C:\\Users\\\\Desktop\\20171002中士.mp4");
        //mutiEntity.addTextBody("filename","1问题.mp4");
        mutiEntity.addPart("file", new FileBody(file));

        CloseableHttpClient httpClient = HttpClients.createDefault();
        httpPost.setEntity(mutiEntity.build());
        HttpResponse  httpResponse = httpClient.execute(httpPost);
        HttpEntity httpEntity =  httpResponse.getEntity();
        String content = EntityUtils.toString(httpEntity);
        System.out.println(content);

    }

上传文件流： 重点是mode的设置，这里卡了半天；

    //上传文件流
    public static void upload(String url,InputStream in) throws Exception{
        HttpPost httpPost = new HttpPost(url);
        httpPost.setHeader("User-Agent","Mozilla/5.0 (Windows NT 10.0; Win64; x64) "
                + "AppleWebKit/537.36 (KHTML, like Gecko) "
                + "Chrome/62.0.3202.89 Safari/537.36");
        httpPost.setHeader("Accept-Language","zh-cn,zh;q=0.5");
        httpPost.setHeader("Accept-Charset","GBK,utf-8;q=0.7,*;q=0.7");
        httpPost.setHeader("Connection","keep-alive");

        MultipartEntityBuilder mutiEntity = MultipartEntityBuilder.create();
        //mutiEntity.addTextBody("filename","16有问题.mp4");
        mutiEntity.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);
        mutiEntity.addBinaryBody("uploadFile", in, ContentType.create("multipart/form-data"), "16有问题.mp4"); 

        CloseableHttpClient httpClient = HttpClients.createDefault();
        httpPost.setEntity(mutiEntity.build());
        HttpResponse  httpResponse = httpClient.execute(httpPost);
        HttpEntity httpEntity =  httpResponse.getEntity();
        String content = EntityUtils.toString(httpEntity);
        System.out.println(content);

    }

使用RestTemplate:

public static void uploadFile(String url,File file){
        RestTemplate template = new RestTemplate();
        ClientHttpRequestFactory clientFactory = new HttpComponentsClientHttpRequestFactory();
        template.setRequestFactory(clientFactory);

        URI uri = UriComponentsBuilder.fromUriString(url).build().encode().toUri();

        FileSystemResource resource = new FileSystemResource(file);
        MultiValueMap<String, Object> param = new LinkedMultiValueMap<>();
        param.add("file", resource);
        //param.add("fileName", "问题.mp4");
        org.springframework.http.HttpEntity<MultiValueMap<String, Object>> httpEntity = new org.springframework.http.HttpEntity<MultiValueMap<String, Object>>(param);
        ResponseEntity<String> responseEntity = template.exchange(uri, HttpMethod.POST, httpEntity, String.class);
        System.out.println("文件上传成功，返回：" + responseEntity.getBody());
    }

RestTemplate上传文件流：不建议用

这个比较麻烦，先看代码吧；

    public static void uploadFile(String url,InputStream in){
        RestTemplate template = new RestTemplate();
        ClientHttpRequestFactory clientFactory = new HttpComponentsClientHttpRequestFactory();
        template.setRequestFactory(clientFactory);

        URI uri = UriComponentsBuilder.fromUriString(url).build().encode().toUri();

//        InputStreamResource resource = new InputStreamResource(in);

        MultiValueMap<String, Object> param = new LinkedMultiValueMap<>();
        param.add("file", new MultipartFileResource(in, "test"));
        //param.add("fileName", "问题.mp4");
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.MULTIPART_FORM_DATA);

        org.springframework.http.HttpEntity<MultiValueMap<String, Object>> httpEntity =
                new org.springframework.http.HttpEntity<MultiValueMap<String, Object>>(param,headers);

         List<HttpMessageConverter<?>> messageConverters = template.getMessageConverters();
            for (int i = 0; i < messageConverters.size(); i++) {
                HttpMessageConverter<?> messageConverter = messageConverters.get(i);
                if ( messageConverter.getClass().equals(ResourceHttpMessageConverter.class) )
                    messageConverters.set(i, new ResourceHttpMessageConverterHandlingInputStreams());
            }

        ResponseEntity<String> responseEntity = template.exchange(uri, HttpMethod.POST, httpEntity, String.class);

        System.out.println("文件上传成功，返回：" + responseEntity.getBody());
    }
        

这是修改后的，添加了转换器，因为添加之前会报错，文件流读了两次，其中一次是读取文件大小contentLength;

package com.my.upload;

import java.io.IOException;
import java.io.InputStream;

import org.springframework.core.io.InputStreamResource;

public class MultipartFileResource extends InputStreamResource {

     private final String filename;

     public MultipartFileResource(InputStream inputStream, String filename) {
         super(inputStream);
         this.filename = filename;
     }
     @Override
     public String getFilename() {
         return this.filename;
     }

     @Override
     public long contentLength() throws IOException {
         return -1; // we do not want to generally read the whole stream into memory ...
     }
}

package com.my.upload;

import java.io.IOException;

import org.springframework.core.io.Resource;
import org.springframework.http.MediaType;
import org.springframework.http.converter.ResourceHttpMessageConverter;

public class ResourceHttpMessageConverterHandlingInputStreams extends ResourceHttpMessageConverter {

    @Override
    protected Long getContentLength(Resource resource, MediaType contentType) throws IOException {
        Long contentLength = super.getContentLength(resource, contentType);

        return contentLength == null || contentLength < 0 ? null : contentLength;
    }
}

以上！