We start with basic transfer object:
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Code listing 10.1: DummyTo.java
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package com.test;
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public class DummyTo {
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private String name;
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private String address;
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public String getName() {
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return name;
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}
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public void setName(String name) {
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this.name = name;
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}
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public String getAddress() {
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return address;
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}
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public void setAddress(String address) {
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this.address = address;
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}
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public DummyTo(String name, String address) {
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this.name = name;
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this.address = address;
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}
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public DummyTo() {
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this.name = new String();
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this.address = new String();
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}
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public String toString(String appendBefore) {
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return appendBefore + " " + name + ", " + address;
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}
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}
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Following is the example for invoking method from the above mentioned to dynamically. Code is self explanatory.
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Code listing 10.2: ReflectTest.java
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package com.test;
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import java.lang.reflect.Constructor;
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import java.lang.reflect.InvocationTargetException;
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import java.lang.reflect.Method;
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public class ReflectTest {
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public static void main(String[] args) {
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try {
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Class<?> dummyClass = Class.forName("com.test.DummyTo");
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// parameter types for methods
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Class<?>[] partypes = new Class[]{String.class};
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// Create method object. methodname and parameter types
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Method meth = dummyClass.getMethod("toString", partypes);
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// parameter types for constructor
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Class<?>[] constrpartypes = new Class[]{String.class, String.class};
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//Create constructor object. parameter types
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Constructor<?> constr = dummyClass.getConstructor(constrpartypes);
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// create instance
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Object dummyto = constr.newInstance(new Object[]{"Java Programmer", "India"});
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// Arguments to be passed into method
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Object[] arglist = new Object[]{"I am"};
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// invoke method!!
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String output = (String) meth.invoke(dummyto, arglist);
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System.out.println(output);
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} catch (ClassNotFoundException e) {
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e.printStackTrace();
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} catch (SecurityException e) {
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e.printStackTrace();
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} catch (NoSuchMethodException e) {
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e.printStackTrace();
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} catch (IllegalArgumentException e) {
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e.printStackTrace();
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} catch (IllegalAccessException e) {
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e.printStackTrace();
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} catch (InvocationTargetException e) {
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e.printStackTrace();
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} catch (InstantiationException e) {
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e.printStackTrace();
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}
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}
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}
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Console for Code listing 10.2
I am Java Programmer, India
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Conclusion: Above examples demonstrate the invocation of method dynamically using reflection.
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To do:
Add some exercises like the ones in Variables
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