java发送post请求，使用multipart/form-data的方式传递参数--《优化》
/** * 测试上传图片 * */ public static void testUploadImage(){ String url = "http://xxxtest/Api/testUploadModelBaking"; String fileName = "e:/username/textures/antimap_0017.png"; Map<String, String> textMap = new HashMap<String, String>(); //可以设置多个input的name，value textMap.put("name", "testname"); textMap.put("type", "2"); //设置file的name，路径 Map<String, String> fileMap = new HashMap<String, String>(); fileMap.put("upfile", fileName); String contentType = "";//image/png String ret = formUpload(url, textMap, fileMap,contentType); System.out.println(ret); //{"status":"0","message":"add succeed","baking_url":"group1\/M00\/00\/A8\/CgACJ1Zo-LuAN207AAQA3nlGY5k151.png"} } /** * 上传图片 * @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<String, String> textMap, Map<String, String> 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; }
以上是网上可以搜到显示最多的代码：
实际使用中发现有部分接口无法调通，后来发现是在
strBuf.append("\r\n").append("--").append(BOUNDARY).append("\r\n");
多了换行符，应改为：
strBuf.append("--").append(BOUNDARY).append("\r\n");
完整代码如下：
OutputStream out = new DataOutputStream(conn.getOutputStream()); if (fileMap != null) { String filename = fileMap.get("filename"); String upload = fileMap.get("upload"); StringBuffer strBuf = new StringBuffer(); strBuf.append("--").append(BOUNDARY).append("\r\n"); strBuf.append("Content-Disposition: form-data;name=\"filename\"\r\n\r\n" + filename + "\r\n"); strBuf.append("--").append(BOUNDARY).append("\r\n"); strBuf.append("Content-Disposition: form-data;name=\"upload\";filename=\"" + upload + "\"\r\n"); strBuf.append("\r\n"); // strBuf.append("test:ai\n"); out.write(strBuf.toString().getBytes()); logger.debug(strBuf.toString()); 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; logger.info("上传完成:"+res);
这个要根据接收者的接收协议来确定使用哪一种方式。
