HttpUtil

1、发送doPost请求，在web那边使用request.setCharacterEncoding("UTF-8");保证中文不乱码，不需要第三方jar包

 public static String sendPost(String url, String param) {
 PrintWriter out = null;
 BufferedReader in = null;
 String result = "";
 try {
     URL realUrl = new URL(url);
     // 打开和URL之间的连接
     URLConnection conn = realUrl.openConnection();
     // 设置通用的请求属性
     conn.setRequestProperty("accept", "*/*");
     conn.setRequestProperty("connection", "Keep-Alive");
     conn.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
     conn.setRequestProperty("charset", "utf-8");
     // 发送POST请求必须设置如下两行
     conn.setDoOutput(true);
     conn.setDoInput(true);
     // 获取URLConnection对象对应的输出流
     out = new PrintWriter(new OutputStreamWriter(conn.getOutputStream(), "utf-8"));
     // 发送请求参数
     out.print(param);
     // flush输出流的缓冲
     out.flush();
     // 定义BufferedReader输入流来读取URL的响应
     in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
     String line;
     while ((line = in.readLine()) != null) {
         result += line;
     }
 } catch (Exception e) {
     System.out.println("发送 POST 请求出现异常！" + e);
     e.printStackTrace();
 }
 // 使用finally块来关闭输出流、输入流
 finally {
     try {
         if (out != null) {
             out.close();
         }
         if (in != null) {
             in.close();
         }
     } catch (IOException ex) {
         ex.printStackTrace();
     }
 }
 return result;
 }

2、拼装URL参数信息

 public static String buildQueryStr(Map<String, Object> params) {
     if (CheckNull.isNull(params)) {
         return "";
     }
     StringBuffer sb = new StringBuffer();
     for (String k : params.keySet()) {
         sb.append(k);
         sb.append("=");
         sb.append(params.get(k).toString());
         sb.append("&");
     }
     return sb.toString().substring(0, sb.length() - 1);
 }