java - Difference between the two methods of creating class objects in JSP -

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i'm learning jsp came across 2 methods of creating class object in jsp

method 1: 

<jsp:usebean id = "obj" class = "classname" /> <%  obj.method(); %>

method 2:

<%  classname obj = new classname();  obj.method(); %>
  • can 1 please explain difference?
  • which practice?
  • in context method 1/method 2 relevant , not

thank in advance

method 1:

the <jsp:usebean> standard action element used locate or instantiate javabean component. firstly <jsp: usebean> tries locate instance of bean class if found fine, if not instantiate class mentioned in class attribute. default object in page scope if scope attribute not specified.the name of bean same have given in id attribute of <jsp:usebean>. if object reference doesn't exist name have specify create instance , find scope of variable, class attributes defines bean class , type attribute defines parent class or interface of bean class.

you can access bean style properties of java bean using <jsp:usebean>:

<jsp:usebean id = "obj" class = "classname" /> <jsp:getproperty name="obj" property="someproperty"/>

the above code looks java bean stored obj in page, if doesn't finds 1 tries create new bean using class definition specified class attribute , sets newly created bean page scope. try access someproperty attribute of obj bean . someproperty attribute should have bean style getter. go through oracle tutorial more.

method 2 :

you creating local object within service() method of generated servlet. not setting scope.

note:

scriptlets , <jsp:usebean> not advisable . please use jstl , el expressions.


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