方法1：

 String str="http://www.baidu.com/api/?action=s2s_install&a={appsunion}&b=3&c=300294cf2fb33ab47691cde6fed03836";       
 URL url = new URL(str);
 URI uri = new URI(url.getProtocol(), url.getHost(), url.getPath(), url.getQuery(), null);
System.out.println("*********" + uri.toString());

str = UrlEscapers.urlFragmentEscaper().escape(str);
System.out.println("*********" + str);