Getting null if i do not do an explicit new TestBean() in Action Class .....

[Rohit Rai]

Hi,

In my action class e.g. A

      public class A extends ActionSupport
    {
          private TestBean tb = new TestBean();// If I do this then everything is working fine

          public String execute(){
               System.out.println(tb.getName());
               System.out.println(tb.getRoll());
          }

         public void setTb(TestBean tb){
            this.tb = tb;
        }
   
       public TestBean getTb(){
         return this.tb;
      }
    }
   

if in the JSP i have some code like

  <s:form action="saveAction">
     <s:textfield name="name" label="Enter Name"/>
     <s:textfield name="age" label="Enter Age" />
  </s:form>

And if the TestBean is as follows

   public class TestBean{
  private String name;
  private int age;

  public void setName(){
     this.name = name;
 }

 public String getName(){
  return this.name
 }

 public void setAge(int age){
     this.age = age;
 }

 public int getAge(){
  return this.age;
 }
  }

However if I remove then i get a NUll Pointer @

      public class A extends ActionSupport
    {
          private TestBean tb;//If i remove the new TestBean() as done previousely the it gives a null pointer 

          public String execute(){
               System.out.println(tb.getName());
               System.out.println(tb.getRoll());
          }

       public String saveAction(){
           System.out.println("tb ---> "+tb);//This goves a null i.e. tb is null
    return SUCCESS;
 }

         public void setTb(TestBean tb){
            this.tb = tb;
        }
   
       public TestBean getTb(){
         return this.tb;
      }
    }
   

if in the JSP i have some code like

  <s:form action="saveAction">
     <s:textfield name="name" label="Enter Name"/>
     <s:textfield name="age" label="Enter Age" />
  </s:form>

And if the TestBean is as follows

   public class TestBean{
  private String name;
  private int age;

  public void setName(){
     this.name = name;
 }

 public String getName(){
  return this.name
 }

 public void setAge(int age){
     this.age = age;
 }

 public int getAge(){
  return this.age;
 }
  }

Whats wrong with the above code .... m missing something but i do not know what ??? Helpppp

[David Newton]

What's missing is any link from the form element names on the JSP to action properties: if you're not implementing ModelDriven and providing the TestBean as the model, "name" and "roll" (I think you mean "role", by the way, unless it's specifically a bakery ordering system) there's no properties available on the stack named "name" and "roll".

[Rohit Rai]

Hi David,
Thanks a lot for the reply ... it was a silly mistake on my part there were two getters and setters with the same name in diferrent beans. e.g.

   class A{
   private  int testValue;
    public void setTest(int val){
         testValue=val;
    }

   public int getTest(){
    return testValue;
  }
}

   class B{
   private int test;
   public void setTest(int test){
   this.test= test;
  }
  
  public int getTest(){
  return test;
 }
  }

as soon as i renamed the getters and setters appropriately it started working fine.

One thing though i am confused as to why this happens .. its in a diferrent after all .. is struts not able to figure out which getter or setter to call ?

[David Newton]

Unless there's a direct path to the method, how could it?

[Rohit Rai]

Not sure what you mean by - a direct path to method

[David Newton]

How would Struts know which test() method to call unless it's explicitly stated somehow?