HashMap转JsonObj

public String toJson (HashMap params) {

String url ="";

String urls ="";

if(params !=null) {

Iterator it = params.keySet().iterator();

StringBuffer sb =null;

while(it.hasNext()) {

String key = it.next();

String value = params.get(key);

if(sb ==null) {

sb =newStringBuffer();

sb.append("{");

}else{

sb.append(",");

}

sb.append("\"");

sb.append(key);

sb.append("\"");

sb.append(":");

sb.append("\"");

sb.append(value);

sb.append("\"");

}

url += sb.toString();

}

urls=url+"}";

returnurls;

}