java反射机制(工厂模式)

http://www.phpddt.com/dhtml/338.html

java里面没有typeof，js有。

我终于实现了用反射机制编写的工厂模式。java反射在工厂模式可以体现。

包含产品接口类，具体产品实现类，工厂类，这三种不同的类型

http://wenku.baidu.com/view/8899ecfff705cc175527094d.html

http://wenku.baidu.com/view/8ceb39c52cc58bd63186bd87.html

http://blog.csdn.net/justinavril/article/details/2873664

http://bbs.csdn.net/topics/60429890

http://www.cnblogs.com/pricks/archive/2009/08/11/1543855.html

http://www.cnblogs.com/bingoidea/archive/2009/06/21/1507889.html

http://www.cnblogs.com/octobershiner/archive/2012/03/18/2404751.html

具体java代码三种实现如下：

1、接口实现

/**
 * 
 */
package factory.realize1;

/**
 * @author wangjian2
 * 接口
 */
public interface Product {
    public String getProductName(String type,int id);
}

package factory.realize1;

public class Route implements Product {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub

    }

    @Override
    public String getProductName(String type, int id) {
        return "RouteNameupdate";
    }

}

/**
 * 
 */
package factory.realize1;

/**
 * @author wangjian2
 *
 */
public class Package implements Product {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub

    }

    @Override
    public String getProductName(String type, int id) {
        return "PackageName";
    }

}

/**
 * 
 */
package factory.realize1;

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

/**
 * @author wangjian2
 *
 */
public class Factory {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub

    }

    public void getName(String type,int id){
        if("跟团".equals(type)){
            Product prd = new Route();
            System.out.println(prd.getProductName("", 0));
        }else if ("自助游".equals(type)){
            Product prd = new Package();
            System.out.println(prd.getProductName("", 0));
        }
    }
    
    /**
     * 通过反射将参数传给函数并返回结果
     * @param type
     * @param id
     */
    public void getNameByreflect(String type,int id){
        Class<?> cls = null;
        try {
            //获取指定的任意type的所需类的完全限定名(包名+类名)相关联的class对象
            cls = Class.forName("factory.realize1."+type);
            //获取类对应的任意方法对象
            Method getProductName = cls.getMethod("getProductName", new Class[]{String.class,int.class});
            //使用该方法
            Object result = getProductName.invoke(cls.newInstance(), new Object[]{new String(type),0});
            System.out.println(result);
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (SecurityException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (NoSuchMethodException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } 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();
        } catch (InstantiationException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

/**
 * 
 */
package factory.realize1;


/**
 * @author wangjian2
 * 
 */
public class TestExample {

    /**
     * @param args
     */
    public static void main(String[] args) {
        Factory factory = new Factory();
        factory.getName("跟团", 0);
        //反射实现
        factory.getNameByreflect("Route", 0);
    }

    
}

2、抽象类实现

/**
 * 
 */
package factory.realize2;

/**
 * @author wangjian2
 * 抽象类
 */
public abstract class Product {
    public abstract String getProductName(String type,int id);
}

package factory.realize2;

public class Route extends Product {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub

    }

    @Override
    public String getProductName(String type, int id) {
        return "RouteNameupdate";
    }

}

/**
 * 
 */
package factory.realize2;

/**
 * @author wangjian2
 *
 */
public class Package extends Product {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub

    }

    @Override
    public String getProductName(String type, int id) {
        return "PackageName";
    }

}

/**
 * 
 */
package factory.realize2;

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

/**
 * @author wangjian2
 *
 */
public class Factory {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub

    }

    public void getName(String type,int id){
        if("跟团".equals(type)){
            Product prd = new Route();
            System.out.println(prd.getProductName("", 0));
        }else if ("自助游".equals(type)){
            Product prd = new Package();
            System.out.println(prd.getProductName("", 0));
        }
    }
    
    /**
     * 通过反射将参数传给函数并返回结果
     * @param type
     * @param id
     */
    public void getNameByreflect(String type,int id){
        Class<?> cls = null;
        try {
            cls = Class.forName("factory.realize1."+type);
            Method getProductName = cls.getMethod("getProductName", new Class[]{String.class,int.class});
            Object result = getProductName.invoke(cls.newInstance(), new Object[]{new String(type),0});
            System.out.println(result);
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (SecurityException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (NoSuchMethodException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } 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();
        } catch (InstantiationException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

/**
 * 
 */
package factory.realize2;


/**
 * @author wangjian2
 * 
 */
public class TestExample {

    /**
     * @param args
     */
    public static void main(String[] args) {
        Factory factory = new Factory();
        factory.getName("跟团", 0);
        factory.getNameByreflect("Route", 0);
    }

    
}

3、继承类重写（覆盖）

/**
 * 
 */
package factory.realize3;

/**
 * @author wangjian2
 * 继承类重写（覆盖）
 */
public class Product {
    public String getProductName(String type,int id) {
        return null;
    }
}

package factory.realize3;

public class Route extends Product {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub

    }

    @Override
    public String getProductName(String type, int id) {
        return "RouteNameupdate";
    }

}

/**
 * 
 */
package factory.realize3;

/**
 * @author wangjian2
 *
 */
public class Package extends Product {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub

    }

    @Override
    public String getProductName(String type, int id) {
        return "PackageName";
    }

}

/**
 * 
 */
package factory.realize3;

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

/**
 * @author wangjian2
 *
 */
public class Factory {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub

    }

    public void getName(String type,int id){
        if("跟团".equals(type)){
            Product prd = new Route();
            System.out.println(prd.getProductName("", 0));
        }else if ("自助游".equals(type)){
            Product prd = new Package();
            System.out.println(prd.getProductName("", 0));
        }
    }
    
    /**
     * 通过反射将参数传给函数并返回结果
     * @param type
     * @param id
     */
    public void getNameByreflect(String type,int id){
        Class<?> cls = null;
        try {
            cls = Class.forName("factory.realize1."+type);
            Method getProductName = cls.getMethod("getProductName", new Class[]{String.class,int.class});
            Object result = getProductName.invoke(cls.newInstance(), new Object[]{new String(type),0});
            System.out.println(result);
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (SecurityException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (NoSuchMethodException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } 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();
        } catch (InstantiationException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

/**
 * 
 */
package factory.realize3;


/**
 * @author wangjian2
 * 
 */
public class TestExample {

    /**
     * @param args
     */
    public static void main(String[] args) {
        Factory factory = new Factory();
        factory.getName("跟团", 0);
        factory.getNameByreflect("Route", 0);
        
    }

    
}

 个人理解反射机制是为了开发者方便，减少开发量。

http://www.cnblogs.com/rollenholt/archive/2011/09/02/2163758.html

java反射在工厂模式可以体现

http://blog.csdn.net/ritterliu/article/details/7764849