模拟spring，Aop（JDK与CGLib两种方式实现）

「爱情、让人受尽委屈。」 2024-02-18 15:43 61阅读 0赞

**一、AOP以JDK版实现**

1.定义接口

package cn.hq.service;
    
    public interface StudentService {
    	public String getUser() throws Exception;
    	public void save(String name) throws Exception;
    	public void update(String name) throws Exception;
    }

2.接口实现

package cn.hq.service.impl;
    
    import cn.hq.service.StudentService;
    
    public class StudentServiceImpl implements StudentService {
    	
    	private String user;
    	public String getUser() {
    		return user;
    	}
    	
    	public StudentServiceImpl() {}
    	
    	public StudentServiceImpl(String user) {
    		this.user = user;
    	}
    	
    	public void save(String name) throws Exception {
    		System.out.println("save()==>" + name);
    	}
    	
    	public void update(String name) {
    		System.err.println("update()==>" + name);
    	}
    
    
    }

3.代理类工厂

package cn.hq.aop;
    
    import java.lang.reflect.InvocationHandler;
    import java.lang.reflect.Method;
    import java.lang.reflect.Proxy;
    
    import cn.hq.service.StudentService;
    
    
    public class JDKProxyFactory implements InvocationHandler{
    	private Object targetObject;
    	public JDKProxyFactory() {}
    	
    	
    	public Object createProxyInstance(Object targetObject) {
    		this.targetObject = targetObject;
    		return Proxy.newProxyInstance(
    				this.targetObject.getClass().getClassLoader(),  //类加载器
    				this.targetObject.getClass().getInterfaces(), 	//类中的所有接口
    				this); //当前对象   此处较为重要  通过此处回调 invoke函数 
    	}
    
    	@Override
    	public Object invoke(Object proxy, Method method, Object[] args) 
    			throws Throwable { //--环绕通知
    		
    		StudentService bean = (StudentService)this.targetObject;
    		Object result = null;
    		if(bean.getUser() != null) {
    			//---spring中的advice()---前置通知
    			try {
    				result = method.invoke(targetObject, args);
    				//afterAdivice()-----后置通知
    			} catch (Exception e) {
    				// exceptionAdivce()---异常通知
    			}finally {
    				//finallyAdive()----后置通知
    			}
    			
    			
    			
    		}
    		
    		return result;
    	}
    }

4.测试

@Test
    	public void proxyTest() {
    		JDKProxyFactory factory =new JDKProxyFactory();
    		StudentService studentService = (StudentService) factory.createProxyInstance(new StudentServiceImpl("zzz"));
    		try {
    			
    			if(studentService.getUser() != null && !"".equals(studentService.getUser())) {
    				studentService.save("dddd");
    			}
    			
    		} catch (Exception e) {
    			e.printStackTrace();
    		}finally {
    			
    		}
    	}

**二、AOP以CGLib实现**

1.定义方法类

package cn.hq.service.impl;
    
    public class TeacherServiceBean {
    	
    	private String user;
    	public String getUser() {
    		return user;
    	}
    
    	public void setUser(String user) {
    		this.user = user;
    	}
    	
    	public void save() throws Exception{
    		System.out.println(this.getClass().getName() + "====>save()");
    	}
    }

2.代理类工厂

package cn.hq.aop;
    
    import java.lang.reflect.Method;
    
    import cn.hq.service.impl.TeacherServiceBean;
    import net.sf.cglib.proxy.Enhancer;
    import net.sf.cglib.proxy.MethodInterceptor;
    import net.sf.cglib.proxy.MethodProxy;
    
    public class CGlibProxyFactory implements MethodInterceptor{
    
    	private Object targetObject;
    	public Object createProxyInstance(Object targetObject) {
    		this.targetObject = targetObject;
    		
    		Enhancer enhancer = new Enhancer();
    		enhancer.setSuperclass(this.targetObject.getClass()); //非Final
    		enhancer.setCallback(this);
    		return enhancer.create();
    	}
    	
    	@Override
    	public Object intercept(Object proxy, Method method, Object[] args, MethodProxy methodProxy) 
    			throws Throwable { //--环绕通知
    		TeacherServiceBean teacherServiceBean = (TeacherServiceBean)this.targetObject;
    		Object result = null;
    		if(teacherServiceBean.getUser() != null) {
    			//---spring中的advice()---前置通知
    			try {
    				result = methodProxy.invoke(targetObject, args);
    				//afterAdivice()-----后置通知
    			} catch (Exception e) {
    				// exceptionAdivce()---异常通知
    			}finally {
    				//finallyAdive()----后置通知
    			}
    			
    		}
    		
    		return result;
    	}
    }

3.测试

@Test
    	public void cglibProxyTest() {
    		CGlibProxyFactory factory =new CGlibProxyFactory();
    		TeacherServiceBean bean = (TeacherServiceBean) factory.createProxyInstance(new TeacherServiceBean());
    		try {
    			bean.save();
    		} catch (Exception e) {
    			e.printStackTrace();
    		}finally{
    			
    		}
    	}

4.注，CGLib实现需要添加jar包

asm-3.3.1.jar

cglib-2.2.2.jar

**三、两者的区别**

JDK版的代理实现，方法类必须要有接口实现。。采用的动态代理的方式

CGLib不需要实现接口。。具体是使用继承的重载的方式