固定的Proxy.newProxyInstance()方法

package shejimoshi.dongtaidaili;

import java.lang.reflect.Proxy;

public class JDKProxyFactory {

    public Object getProxy(Object target) {
        Object proxy = Proxy.newProxyInstance(target.getClass().getClassLoader(),target.getClass().getInterfaces(),new MyInvocationHandler(target));
        return  proxy;
    }

}

主要想增强的代码逻辑在这里写

package shejimoshi.dongtaidaili;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;

public class MyInvocationHandler implements InvocationHandler {

    private Object target;

    public MyInvocationHandler(Object object) {
        this.target = object;
    }
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        //增强代码逻辑(执行代码前)
        System.out.println("执行方法前");
        //xxx
        Object returnValue = method.invoke(target, args);
        //增强代码逻辑(执行代码后)
        //xxx
        System.out.println("执行方法后xxxxxxx");
        return returnValue;
    }
}

使用示例

前提准备接口

package shejimoshi.dongtaidaili.demo;

public interface StudentService {

    public void sayHello();
}

前提接口实现类

package shejimoshi.dongtaidaili.demo;

public class StudentServiceImpl implements StudentService{
    public void sayHello() {
        System.out.println("说 hello");
    }
}

测试类

package shejimoshi.dongtaidaili.demo;

import shejimoshi.dongtaidaili.JDKProxyFactory;

public class UseDemo {

    public static void main(String[] args) {
        StudentService studentService = new StudentServiceImpl();
        JDKProxyFactory proxy = new JDKProxyFactory();
        StudentService proxyService = (StudentService) proxy.getProxy(studentService);
        proxyService.sayHello();

    }
}

输出

执行方法前
说 hello
执行方法后xxxxxxx