java后台以流的形式上传图片(类似form表单提交),以base64字符串上传图片

现在很多借口调用如果要上传图片,都是采用的图片流上传,(有些会使用base64字符串),这里记录一下自己使用的方法,以备再用.

 

一,流形式:

  /**
   * 测试上传png图片
   * 
   */
  public static void testUploadImage() {
    String url = "";//这里填写访问接口url
    String fileName = "";//这里为了简单测试,所以图片直接使用的是本地的图片,也可以使用页面上传的方式
    Map textMap = new HashMap();
    // 可以设置多个input的name，value
    textMap.put(name, value);
    // 设置file的name，路径
    Map fileMap = new HashMap();
    fileMap.put("file", fileName);
    String contentType = "";// image/png
    String ret = formUpload(url, textMap, fileMap, contentType);
    System.out.println(ret);
  }

  /**
   * @param urlStr
   * @param textMap
   * @param fileMap
   * @param contentType 没有传入文件类型默认采用application/octet-stream contentType非空采用filename匹配默认的图片类型
   * @return 返回response数据
   */
  @SuppressWarnings("rawtypes")
  public static String formUpload(String urlStr, Map textMap,
      Map fileMap, String contentType) {
    String res = "";
    HttpURLConnection conn = null;
    // boundary就是request头和上传文件内容的分隔符
    String BOUNDARY = "---------------------------123821742118716";
    try {
      URL url = new URL(urlStr);
      conn = (HttpURLConnection) url.openConnection();
      conn.setConnectTimeout(5000);
      conn.setReadTimeout(30000);
      conn.setDoOutput(true);
      conn.setDoInput(true);
      conn.setUseCaches(false);
      conn.setRequestMethod("POST");
      conn.setRequestProperty("Connection", "Keep-Alive");
      conn.setRequestProperty("User-Agent",
          "Mozilla/5.0 (Windows; U; Windows NT 6.1; zh-CN; rv:1.9.2.6)");
      conn.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + BOUNDARY);
      OutputStream out = new DataOutputStream(conn.getOutputStream());
      // text
      if (textMap != null) {
        StringBuffer strBuf = new StringBuffer();
        Iterator iter = textMap.entrySet().iterator();
        while (iter.hasNext()) {
          Map.Entry entry = (Map.Entry) iter.next();
          String inputName = (String) entry.getKey();
          String inputValue = (String) entry.getValue();
          if (inputValue == null) {
            continue;
          }
          strBuf.append("\r\n").append("--").append(BOUNDARY).append("\r\n");
          strBuf.append("Content-Disposition: form-data; name=\"" + inputName + "\"\r\n\r\n");
          strBuf.append(inputValue);
        }
        out.write(strBuf.toString().getBytes());
      }
      // file
      if (fileMap != null) {
        Iterator iter = fileMap.entrySet().iterator();
        while (iter.hasNext()) {
          Map.Entry entry = (Map.Entry) iter.next();
          String inputName = (String) entry.getKey();
          String inputValue = (String) entry.getValue();
          if (inputValue == null) {
            continue;
          }
          File file = new File(inputValue);
          String filename = file.getName();

          // 没有传入文件类型，同时根据文件获取不到类型，默认采用application/octet-stream
          contentType = new MimetypesFileTypeMap().getContentType(file);
          // contentType非空采用filename匹配默认的图片类型
          if (!"".equals(contentType)) {
            if (filename.endsWith(".png")) {
              contentType = "image/png";
            } else if (filename.endsWith(".jpg") || filename.endsWith(".jpeg")
                || filename.endsWith(".jpe")) {
              contentType = "image/jpeg";
            } else if (filename.endsWith(".gif")) {
              contentType = "image/gif";
            } else if (filename.endsWith(".ico")) {
              contentType = "image/image/x-icon";
            }
          }
          if (contentType == null || "".equals(contentType)) {
            contentType = "application/octet-stream";
          }
          StringBuffer strBuf = new StringBuffer();
          strBuf.append("\r\n").append("--").append(BOUNDARY).append("\r\n");
          strBuf.append("Content-Disposition: form-data; name=\"" + inputName + "\"; filename=\""
              + filename + "\"\r\n");
          strBuf.append("Content-Type:" + contentType + "\r\n\r\n");
          out.write(strBuf.toString().getBytes());
          DataInputStream in = new DataInputStream(new FileInputStream(file));
          int bytes = 0;
          byte[] bufferOut = new byte[1024];
          while ((bytes = in.read(bufferOut)) != -1) {
            out.write(bufferOut, 0, bytes);
          }
          in.close();
        }
      }
      byte[] endData = ("\r\n--" + BOUNDARY + "--\r\n").getBytes();
      out.write(endData);
      out.flush();
      out.close();
      // 读取返回数据
      StringBuffer strBuf = new StringBuffer();
      BufferedReader reader = new BufferedReader(new         
      InputStreamReader(conn.getInputStream()));
      String line = null;
      while ((line = reader.readLine()) != null) {
        strBuf.append(line).append("\n");
      }
      res = strBuf.toString();
      reader.close();
      reader = null;
    } catch (Exception e) {
      System.out.println("发送POST请求出错。" + urlStr);
      e.printStackTrace();
    } finally {
      if (conn != null) {
        conn.disconnect();
        conn = null;
      }
    }
    return res;
  }

这是网络上的一种写法,测试过,能走通.

第二种:  以base64字符串形式

    URL url;
    ByteArrayOutputStream outputStream = null;//这里使用ByteArrayOutputStream ,我尝试过使用outputStream,但上传后都提示错误,也不知道为什么.以为只要把图片读取成byte[]就行,但好像不是那么简单.
    try {
      url = new URL(imgFile);
      try {
        BufferedImage bufferedImage = ImageIO.read(url);
        outputStream = new ByteArrayOutputStream();
        ImageIO.write(bufferedImage, "png", outputStream);
      } catch (MalformedURLException e1) {
        e1.printStackTrace();
      } catch (IOException e) {
        e.printStackTrace();
      }
    } catch (MalformedURLException e2) {
      // TODO Auto-generated catch block
      e2.printStackTrace();
    }
    // 对字节数组Base64编码
    BASE64Encoder encoder = new BASE64Encoder();
    String result = encoder.encode(outputStream.toByteArray());
    //result就是图片转码base64的字符串