cglib动态新增类方法

<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]
", 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;  
    }  
}