objectcreator.java

一个非常好的FRAMWRK!是一个外国组织做的!不!

package com.jdon.util;

import java.lang.reflect.*;

/**
 * Creates instance of any object, given its full qualified class name is given
 * and it has a public accessable constructor. This class is a static class it
 * can not be instantiated
 * @author Nadia Nashi
 */

public final class ObjectCreator {
  /**
   * Private constructor. This class can not be instantiated
   */
  private ObjectCreator() {
  }

  /**
   * Instantaite an Object from a given class name
   * @param className full qualified name of the class
   * @return the instantaited Object
   * @exception java.lang.Exception if instantiation failed
   */
  public static Object createObject(String className) throws Exception {
    return createObject(Class.forName(className));
  }

  /**
   * Instantaite an Object instance
   * @param classObject Class object representing the object type to be instantiated
   * @return the instantaied Object
   * @exception java.lang.Exception if instantiation failed
   */
  public static Object createObject(Class classObject) throws Exception {
    Object object = null;
    return classObject.newInstance();
  }

  /**
   * Instantaite an Object instance, requires a constructor with parameters
   * @param className full qualified name of the class
   * @param params an array including the required parameters to instantaite the object
   * @return the instantaited Object
   * @exception java.lang.Exception if instantiation failed
   */
  public static Object createObject(String className, Object[] params) throws
      Exception {
    return createObject(Class.forName(className), params);
  }

  /**
   * Instantaite an Object instance, requires a constractor with parameters
   * @param classObject, Class object representing the object type to be instantiated
   * @param params an array including the required parameters to instantaite the object
   * @return the instantaied Object
   * @exception java.lang.Exception if instantiation failed
   */
  public static Object createObject(Class classObject, Object[] params) throws
      Exception {
    Constructor[] constructors = classObject.getConstructors();
    Object object = null;
    for (int counter = 0; counter < constructors.length; counter++) {
      try {
        object = constructors[counter].newInstance(params);
      } catch (Exception e) {
        if (e instanceof InvocationTargetException)
          ( (InvocationTargetException) e).getTargetException().printStackTrace();
        //do nothing, try the next constructor
      }
    }
    if (object == null)
      throw new InstantiationException();
    return object;
  }
}