jdk6.0从入门到精通-----chapter16反射机制---javabean

javabean就是简单的java类

package Beans;

import java.util.ArrayList;
import java.util.List;
import java.util.Date;

public class TestBean
{
    public int id;
    public String name;
    public boolean joined;
    public Date birthday;
    
    public int getId()
    {
    	  return id;
    }
    
    public void setId(int id)
    {
    	  this.id=id;
    }
    
    public String getName()
    {
    	  return name;
    }
    
    public void setName(String name)
    {
    	  this.name=name;
    }

    public boolean isJoined()//也可以是getJoined()
    {
    	  return joined;
    }
    
    public void setJoined(boolean joined)
    {
    	  this.joined=joined;
    }
    
    public Date getBirthday()
    {
    	  return birthday;
    }
    
    public void setBirthday(Date birthday)
    {
    	  this.birthday=birthday;
    }        
    
    public String getGreeting()
    {
    	  return "Hello "+this.name; 
    }
    
    public List<TestBean> getTestBeans()
    {
    	  List<TestBean> testBeanList=new ArrayList<TestBean>();
    	  return testBeanList;
    }
}

package Beans;

import java.beans.IntrospectionException;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Method;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;

public class TestBeansUtil {
	public static Class findPropertyType(String propertyName, Class clazz)
			throws IntrospectionException {
		PropertyDescriptor pd = new PropertyDescriptor(propertyName, clazz);

		System.out.println("		getter=" + pd.getReadMethod());
		System.out.println("		setter=" + pd.getWriteMethod());

		if (pd != null)
			return pd.getPropertyType();
		else
			return Object.class;
	}

	public static Class getMethodType(Method method) {
		Class clazz = method.getReturnType();
		return clazz;
	}

	public static Class getMethodGenericType(Method method) {

		Type type = method.getGenericReturnType();

		if (type instanceof ParameterizedType) {
			ParameterizedType ptype = (ParameterizedType) type;
			return (Class) ptype.getActualTypeArguments()[0];
		}

		return Object.class;
	}

	public static void main(String[] args) throws IntrospectionException,
			ClassNotFoundException, IllegalAccessException,
			NoSuchMethodException {
		// 获取id属性的类型
		System.out.println(TestBeansUtil.findPropertyType("id", TestBean.class)
				.getName());
		// 获取name属性的类型
		System.out.println(TestBeansUtil.findPropertyType("name",
				TestBean.class).getName());
		// 获取joined属性的类型
		System.out.println(TestBeansUtil.findPropertyType("joined",
				TestBean.class).getName());
		// 获取birthday属性的类型
		System.out.println(TestBeansUtil.findPropertyType("birthday",
				TestBean.class).getName());
		// 获取getGreeting()方法的返回值类型
		Method method1 = Class.forName("TestBean").getMethod("getGreeting",
				new Class[] {});
		System.out.println(TestBeansUtil.getMethodType(method1).getName());
		// 获取getTestBeans()方法的返回值类型和泛型
		Method method2 = Class.forName("TestBean").getMethod("getTestBeans",
				new Class[] {});
		System.out.println(TestBeansUtil.getMethodType(method2).getName());
		System.out.println(TestBeansUtil.getMethodGenericType(method2)
				.getName());
	}
}

执行结果

		getter=public int Beans.TestBean.getId()
		setter=public void Beans.TestBean.setId(int)
int
		getter=public java.lang.String Beans.TestBean.getName()
		setter=public void Beans.TestBean.setName(java.lang.String)
java.lang.String
		getter=public boolean Beans.TestBean.isJoined()
		setter=public void Beans.TestBean.setJoined(boolean)
boolean
		getter=public java.util.Date Beans.TestBean.getBirthday()
		setter=public void Beans.TestBean.setBirthday(java.util.Date)
java.util.Date
java.lang.String
java.util.List
Beans.TestBean