通过反射获取类的实例

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Properties;



/**
* 该类的功能：通过反射获取类的实例
*
*/
public class ClassLoaderFactory {

public ClassLoaderFactory() {
super();

}

/**
* 功能：通过一般方法（有参数）获取实例（私有构造方法--单例）
*
* @param methodName：方法名
* @param className：类名
* @param pro：参数值
* @return
*/
public static Object loadClassByMethod(String methodName, String className,
Properties pro) {
Class c = null;

try {
c = Class.forName(className);
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

Method method = null;

try {
method = c.getMethod(methodName, new Class[] { Properties.class });// 方法参数的类型为：Properties
} catch (SecurityException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (NoSuchMethodException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

Object o = null;

try {
// o=method.invoke(c,null);
o = method.invoke(c, new Object[] { pro });// 方法参数的值为：pro
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InvocationTargetException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

return o;
}

/**
* 功能：通过一般方法（无参数）获取实例（私有构造方法--单例）
*
* @param methodName：方法名
* @param className：类名
* @return
*/
public static Object loadClassByMethod(String methodName, String className) {
Class c = null;

try {
c = Class.forName(className);
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

Method method = null;

try {
method = c.getMethod(methodName, new Class[] { });
} catch (SecurityException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (NoSuchMethodException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

Object o = null;

try {
//o=method.invoke(c,null);
o=method.invoke(c,new Object[] { });
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InvocationTargetException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

return o;
}

/**
* 功能：通过构造方法获取实例（有参数的构造方法）
*
* @param className：类名
* @param pro：参数值
* @return
*/
//public static Object loadClassByConstructor(String className, Properties pro) {
public static Object loadClassByConstructor(String className, String beanId) {
Class c = null;

try {
//c = Class.forName(pro.getProperty(className));
c = Class.forName(className);
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

Constructor ct = null;

try {
//ct = c.getConstructor(new Class[] { Properties.class });// 构造方法的参数类型为：Properties
ct = c.getConstructor(new Class[] { String.class });
} catch (SecurityException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (NoSuchMethodException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

Object o = null;

try {
//o = ct.newInstance(new Object[] { pro });// 构造方法的参数值为：Properties
o = ct.newInstance(new Object[] { beanId });
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InstantiationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InvocationTargetException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

return o;
}

/**
* 功能：通过空构造方法获取实例
*
* @param className
* @return
*/
public static Object loadClass(String className) {
Class c = null;

try {
c = Class.forName(className);
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

Object o = null;

try {
o = c.newInstance();
} catch (InstantiationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

return o;
}

}