<dependency>

            <groupId>cglib</groupId>

            <artifactId>cglib</artifactId>

            <version>3.2.4</version>

        </dependency>

import java.io.Serializable;

import java.lang.reflect.Method;

import java.text.SimpleDateFormat;

import java.util.Date;

import net.sf.cglib.core.Signature;

import net.sf.cglib.proxy.Enhancer;

import net.sf.cglib.proxy.InterfaceMaker;

import net.sf.cglib.proxy.MethodInterceptor;

import net.sf.cglib.proxy.MethodProxy;

import org.objectweb.asm.Type;

public class CGLibExample {  

    @SuppressWarnings("rawtypes")

    public static void main(String[] args) {  

        // 定义一个参数是字符串类型的setCreatedAt方法

        InterfaceMaker im = new InterfaceMaker();

        im.add(new Signature("setCreatedAt", Type.VOID_TYPE,

                new Type[] { Type.getType(String.class) }), null);  

        Class myInterface = im.create();  

        Enhancer enhancer = new Enhancer();

        enhancer.setSuperclass(ExampleBean.class);

        enhancer.setInterfaces(new Class[] { myInterface });

        enhancer.setCallback(new MethodInterceptor() {

            @Override

            public Object intercept(Object obj, Method method, Object[] args,

                    MethodProxy proxy) throws Throwable {

                ExampleBean bean = (ExampleBean) obj;  

                // 调用字符串类型的setCreatedAt方法时，转换成Date型后调用Setter

                if (method.getName().startsWith("setCreatedAt")

                        && args[0] != null && args[0] instanceof String) {  

                    SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd");

                    Date date = null;

                    try {

                        date = sdf.parse((String) args[0]);

                    } catch (final Exception e) { /* nop */ }

                    bean.setCreatedAt(date);

                    return null;  

                }

                return proxy.invokeSuper(obj, args);  

            }

        });  

        // 生成一个Bean

        ExampleBean bean = (ExampleBean) enhancer.create();

        bean.setId(999);  

        try {

            Method method = bean.getClass().getMethod("setCreatedAt", new Class[] {String.class});

            method.invoke(bean, new Object[]{"20160531"});

        } catch (final Exception e) {

            e.printStackTrace();

        }  

        System.out.printf("id : [%d] createdAt : [%s]\n", bean.getId(), bean.getCreatedAt());

    }

}  

class ExampleBean implements Serializable {

    private static final long serialVersionUID = -8121418052209958014L;  

    private int id;

    private Date createdAt;  

    public int getId() {

        return id;

    }  

    public void setId(int id) {

        this.id = id;

    }  

    public Date getCreatedAt() {

        return createdAt;

    }  

    public void setCreatedAt(Date createdAt) {

        this.createdAt = createdAt;

    }

}