Java Good habit 2

1. The spelling of this parameter

Learn, when Keys.length-1 is added "&" and is behind the puzzle

 Public StaticString Map2content (Mapparams) {StringBuilder StringBuilder=NewStringBuilder (); Try{Set KeySet=params. KeySet (); Object[] Keys=Keyset.toarray ();  for(intI=0; i < keys.length; i++{stringbuilder.append (Encode (), keys[i].tostring (),"UTF-8"). Append ("="). Append (Encode (params.Get(Keys[i]). ToString (),"UTF-8")); if (i < (keys.length-1)) {stringbuilder.append ("&"); }    }  } Catch(Exception e) {Throw NewHttpException ("failed to generate content from map", E); }  returnstringbuilder.tostring ();}

2. Delete the file if it exists, and then create a new file

Private voidSaveusers (set<string>set,string FileName) {File F=NewFile (Getdatafolder (), fileName); if (f.exists ()) {f.delete (); } Try {f.createnewfile (); BufferedWriter Bwriter=NewBufferedWriter (NewFileWriter (f)); intCount=0;  for(String name:set) {bwriter.write (name+ System.getproperty ("Line.separator")); Count++; } consoleutils.printinfo (NAME,"Saved" + Count + "users in" + filename+ "'!");    Bwriter.flush ();  Bwriter.close (); } Catch(Exception e) {consoleutils.printexception (E,name,"Error while saving file '" + fileName + "'!"); }}

3.if (widget instanceof Checkbox) {

CheckBox cb = (checkbox) Widget If this is the case, strong turn into this class, commonly used in the wording

}

@Override PublicSet<activity>GE
Tinstitutionactivities () {Set<Activity> activities=NewHashset<activity>();  for(inti=0; I < Institutionactivities.getwidgetcount (); i++) {Widget widget=Institutionactivities.getwidget (i); if (widget instanceof checkbox) {checkbox cb= (checkbox) widget; if(Cb.getvalue ()) {Activity Activity=NewActivity ();        Activity.setid (Integer.parseint (Cb.getformvalue ()));        Activity.setname (Cb.gettext ());      Activities.add (activity); }    }  }  returnactivities;}

Add elements in 4.set and do not repeat

Private Object createstringset (String ... strings) {  Set<String> stringset=new hashset<string >();    for (  string string:strings) {    stringset.add (string);  }   return Stringset;}

5. The exception can return null, empty can return null

 Public Staticstring getsearchenginequerystring (httpservletrequest request,string referrer) {string queryString=NULL; String HostName=NULL; if(Referrer! =NULL) {URL refererurl; try {refererurl=new URL (referrer); } catch (Malformedurlexception e) {return null; } hostName=Refererurl.gethost (); QueryString=Refererurl.getquery (); if (Strings.isempty (queryString)) {return null; } Set<String> keys=Separams.keyset ();  for(String se:keys) {if(Hostname.tolowercase (). Contains (SE)) {queryString=getquerystringparameter (Querystring,separams.get (SE)); }    }    returnqueryString; }  return NULL;}

6.

Java Good habit 2