Java模拟表单post提交，可支持图片上传

/**
* 模拟表单post
*
* @param textMap 文本域
* @param fileMap 文件
*
*/

public static String postForm(String urlStr, Map<String, String> textMap, Map<String, String> fileMap) throws IOException {
    String res = "";
    HttpURLConnection conn = null;
    InputStream inS = null;
    OutputStream out = null;
    String BOUNDARY = "---------------------------123821742118716"; //boundary就是request头和上传文件内容的分隔符
    try {
        URL url = new URL(urlStr);
        conn = (HttpURLConnection) url.openConnection();
        if (conn instanceof HttpsURLConnection) {
            ((HttpsURLConnection) conn).setSSLSocketFactory(sslSocketFactory);
            ((HttpsURLConnection) conn).setHostnameVerifier(trustAnyHostnameVerifier);
        }

        conn.setConnectTimeout(19000);
        conn.setReadTimeout(19000);
        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);

        out = new DataOutputStream(conn.getOutputStream());
        // text value
        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();
                String contentType = new MimetypesFileTypeMap().getContentType(file);
                if (filename.endsWith(".png")) {
                    contentType = "image/png";
                } else if (filename.endsWith(".gif")) {
                    contentType = "image/gif";
                } else if (filename.endsWith(".jpg")) {
                    contentType = "image/jpeg";
                }
                if (contentType == null || contentType.equals("")) {
                    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);
                }
            }
        }

        byte[] endData = ("\r\n--" + BOUNDARY + "--\r\n").getBytes();
        out.write(endData);
        out.flush();

        // 读取返回数据
        StringBuffer strBuf = new StringBuffer();
        inS = conn.getInputStream();
        BufferedReader reader = new BufferedReader(new InputStreamReader(inS));
        String line = null;
        while ((line = reader.readLine()) != null) {
            strBuf.append(line).append("\n");
        }
        res = strBuf.toString();
        reader.close();
        reader = null;
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        if (out != null) {
            out.close();
        }
        if (inS != null) {
            inS.close();
        }
        if (conn != null) {
            conn.disconnect();
            conn = null;
        }
    }
    return res;
}