废话少说，直接上代码：

 　　/**

     * 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;

    }