How to dynamically call methods of Java Bean in for loop

Question

How to dynamically call methods of Java Bean.

I have the following methods in a class of Java:

public class Bean {
   public String column1val;
   public String column2val;
   public String column2val;

}

I need to access these methods from for loop like the below:

for(int i=0;i<2;i++) { 
    String s = Bean.get column+i+val;
}

How can we achieve this scenario ?

I think there is already answer for use of **Java Reflection** then no need to provide the same.. :-) — user370305, Dec 13 '12 at 10:17

score 2 · Answer 1 · answered Dec 13 '12 at 10:12

Hi you can use Java Reflections for this purpose...

   //Obtain the Class instance
    Class beanClass = Bean.class;

    //Get the methods
    Method[] methods = beanClass.getMethods();

    //Loop through the methods and print out their names
    for (Method method : methods) {
        System.out.println(method.getName());
    }

score 2 · Accepted Answer · answered Dec 13 '12 at 10:16

Sample Code.

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

public class Bean {
    public String getMethod1(String a) {
        return a;
    }

    public String getMethod2(String a) {
        return a;
    }

    public static void main(String[] args) throws SecurityException,
            NoSuchMethodException, IllegalArgumentException,
            IllegalAccessException, InvocationTargetException {
        Bean bean = new Bean();
        for (int i = 1; i <= 2; i++) {
            Method method = Bean.class.getMethod("getMethod" + i, String.class);
            System.out.println(method.invoke(bean, "Simple"));
        }

    }
}

score 1 · Answer 3 · edited May 23 '17 at 12:06

1

You can't as Java needs the pre-qualified method names to executes. Its not a String so you can append it.

This question helps you for your better understanding Array of function pointers in Java

Or You can use Java Reflection as Other Suggest..

edited May 23 '17 at 12:06

Community

1
1

answered Dec 13 '12 at 10:08

user370305

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score 1 · Answer 4 · answered Dec 13 '12 at 10:11

1

try as:

Bean beanobj=new Bean();
for(int i=0;i<2;i++) { 

   Method method= beanobj.getClass().getMethod("getMethod"+
                                   String.valueOf(i), new Class[]{});
    String s=(String)method.invoke(beanobj,"aaa");

}

answered Dec 13 '12 at 10:11

ρяσѕρєя K

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score 1 · Answer 5 · answered Dec 13 '12 at 10:14

1

You have use Reflection:

              MyBean m = new MyBean();
          Method[] methods =  m.getClass().getMethods();
          for(Method methid: methods){
              methid.invoke(m, "abc");
          }

answered Dec 13 '12 at 10:14

PermGenError

45,977
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score 1 · Answer 6 · answered Dec 13 '12 at 10:15

1

You can try this:

Bean b = new Bean();
for(int i=0;i<2;i++) { 
    String s = (String) Bean.getClass().getMethod("getMethod" + i, String.class).invoke(b, "aaa");
}

answered Dec 13 '12 at 10:15

Waqas Ilyas

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score 0 · Answer 7 · answered Dec 13 '12 at 10:11

0

You can use reflection to get the list of methods and call them in a loop, if that's what is your requirement. As rightly said above you can not dynamically form the method names at run time.

answered Dec 13 '12 at 10:11

Swagatika

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score 0 · Answer 8 · answered Dec 13 '12 at 10:16

Using reflection it can be possible - But it is not really good way to call method -

Class<Bean> class1 =Bean.class;
for(int i=1;i<=2;i++) { 
    Method s = class1.getMethod("getMethod"+i, String.class);
    Object invoke = s.invoke(new Bean(),"Str");
    System.out.println(invoke);
}

How to dynamically call methods of Java Bean in for loop

8 Answers8