除null。
try:String str=request.getParameter("type")==null?"":(request.getParameter("type").equals("null")?"":request.getParameter("type").trim()) ;
try:String str=request.getParameter("type")==null?"":(request.getParameter("type").equals("null")?"":request.getParameter("type").trim()) ;
try:String str=request.getParameter("type")==null?"":(request.getParameter("type").equals("null")?"":request.getParameter("type").trim()) ;
if (str==null){ return;}
else
{str=str.trim();if (""equals(str)) {return;}
else
...
}