APEX LIB

{!IF(x.A_Type__c = 'abc','this is true','this is false')} 


<!-- date format --> 
<apex:outputText value="{0,date,MM/dd/yyyy}"> 
<apex:param value="{!d.Start_Date__c}" /> 
</apex:outputText> 

DateTime myDateTime = system.now(); 
String method1= myDateTime .format('MM/dd/yyyy'); 
Sting method2= myDateTime .month()+'/'+myDateTime .day()+'/'+myDateTime .year(); 


String abc = 'a,b,c'; 
abc.split('\\,');  //记得就加 \\ 


http://www.salesforce.com/us/developer/docs/pages/Content/pages_compref_outputText.htm