title: How to convert javabean to post param string?
body: <p>example:</p>
  
  <pre><code>public class User{
      private String name;
      private String age;
      private String address;
      .... set and get methods....
  }
  
  User user = new User();
  user.setName("albert");
  user.setAge("22");
  </code></pre>
  
  <p>i want convert user object to this string<br>
  <code>name=albert&amp;address=&amp;age=22</code><br>
  Because i use <code>new URL()</code> to post this string.</p>
  
  <p>I have much other object to convert to like this string,so i want a tool method<br>
  Is any good way to do?  </p>
  
  <p>Thanks in advance</p>