學習設計模式3--代理模式

阿新 • • 發佈：2020-12-20

代理模式

結構

Subject介面

package 結構;

/**
 * @Program: 設計模式
 * @Description: Subject類定義了 RealSubject和Proxy的共用介面，
 *               這樣就能在任何能夠使用RealSubject的地方使用Proxy了
 * @Author Mokairui
 * @Date 2020/12/5 11:46
 */
public interface Subject {

    void request();

}

RealSubject具體實現類

package 結構;

/**
 * @Program: 設計模式
 * @Description: 定義了Proxy所代表的真實實體
 * @Author Mokairui
 * @Date 2020/12/5 11:48
 */
public class RealSubject implements Subject {

    @Override
    public void request() {
        System.out.println("真實的請求");
    }
}

代理物件

package 結構;

/**
 * @Program: 設計模式
 * @Description: 儲存一個引用使得代理可以訪問實體，並提供一個於Subject的介面相同的介面，
 *               這樣代理就可以用來替代實體
 * @Author Mokairui
 * @Date 2020/12/5 11:50
 */
public class Proxy implements Subject {

    private RealSubject realSubject;

    @Override
    public void request() {
        if (realSubject == null) {
            realSubject = new RealSubject();
        }
        // 呼叫方法，但是在這裡就可以就可以新增你想要的額外功能等
        realSubject.request();
    }
}

測試

package 結構;

/**
 * @Program: 設計模式
 * @Description: 測試類
 * @Author Mokairui
 * @Date 2020/12/5 12:22
 */
public class Demo {

    public static void main(String[] args) {
        Proxy proxy = new Proxy();
        proxy.request();
    }

}

靜態代理

禮物介面

package example.靜態;

/**
 * @Program: 設計模式
 * @Description: 送禮物的介面
 * @Author Mokairui
 * @Date 2020/12/5 13:43
 */
public interface IGiveGift {

    void GiveDolls();

    void GiveFlowers();

    void GiveChocolate();

}

被追求者

package example.靜態;

/**
 * @Program: 設計模式
 * @Description: 被追求者
 * @Author Mokairui
 * @Date 2020/12/5 14:29
 */
public class SchoolGirl {

    private String name;

    public SchoolGirl() {
    }

    public SchoolGirl(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

}

追求者

package example.靜態;

/**
 * @Program: 設計模式
 * @Description: 追求者
 * @Author Mokairui
 * @Date 2020/12/5 13:44
 */
public class Pursuit implements IGiveGift {

    private SchoolGirl schoolGirl;

    public void setSchoolGirl(SchoolGirl schoolGirl) {
        this.schoolGirl = schoolGirl;
    }

    @Override
    public void GiveDolls() {
        System.out.println(schoolGirl.getName() + "送你洋娃娃");
    }

    @Override
    public void GiveFlowers() {
        System.out.println(schoolGirl.getName() + "送你鮮花");
    }

    @Override
    public void GiveChocolate() {
        System.out.println(schoolGirl.getName() + "送你巧克力");
    }
}

代理類

package example.靜態;

/**
 * @Program: 設計模式
 * @Description: 代理類
 * @Author Mokairui
 * @Date 2020/12/5 14:33
 */
public class Proxy implements IGiveGift {

    private Pursuit pursuit;

    public void setPursuit(Pursuit pursuit) {
        this.pursuit = pursuit;
    }

    @Override
    public void GiveDolls() {
        System.out.println("我是代理了送洋娃娃,我可以在這裡加額外需求");
        pursuit.GiveDolls();

    }

    @Override
    public void GiveFlowers() {
        System.out.println("我是代理了送鮮花，我可以在這裡加額外需求");
        pursuit.GiveFlowers();
    }

    @Override
    public void GiveChocolate() {
        System.out.println("我是代理了送巧克力，我可以再這裡加額外需求");
        pursuit.GiveChocolate();
    }
}

測試

package example.靜態;

/**
 * @Program: 設計模式
 * @Description: 測試類
 * @Author Mokairui
 * @Date 2020/12/5 14:36
 */
public class Demo {
    public static void main(String[] args) {
        SchoolGirl schoolGirl = new SchoolGirl("yanzi");
        Pursuit pursuit = new Pursuit();
        pursuit.setSchoolGirl(schoolGirl);

        Proxy proxy = new Proxy();
        proxy.setPursuit(pursuit);

        proxy.GiveDolls();
        System.out.println("-----------------");
        proxy.GiveFlowers();
        System.out.println("------------------");
        proxy.GiveChocolate();
    }
}

動態代理

JDK代理

追求者和被追求者，送禮物的介面這裡就不重複寫了

DynamicProxyHandler類

package example.動態.jdk;

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

/**
 * @Program: 設計模式
 * @Description: 動態代理物件
 * @Author Mokairui
 * @Date 2020/12/5 13:08
 */
public class DynamicProxyHandler implements InvocationHandler {

    private Pursuit pursuit;

    public DynamicProxyHandler(Pursuit pursuit) {
        this.pursuit = pursuit;
    }

    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        Object result = null;
        if ("GiveDolls".equals(method.getName())) {
            // 用來區別增強的不同方法
            System.out.print("最最可愛的");
        }

        if ("GiveFlowers".equals(method.getName())) {
            // 針對不同的方法，增強不同的內容
            System.out.println("五顏六色的哦");
        }
        result = method.invoke(this.pursuit, args);

        return result;
    }

}

測試類

package example.動態.jdk;

import java.lang.reflect.Proxy;

/**
 * @Program: 設計模式
 * @Description: 測試類
 * @Author Mokairui
 * @Date 2020/12/5 13:11
 */
public class Demo {
    public static void main(String[] args) {
        Pursuit pursuit = new Pursuit();
        pursuit.setSchoolGirl(new SchoolGirl("yanzi"));

        IGiveGift proxy = (IGiveGift) Proxy.newProxyInstance(pursuit.getClass().getClassLoader()
                , pursuit.getClass().getInterfaces()
                , new DynamicProxyHandler(pursuit));

        proxy.GiveDolls();
        System.out.println("---------------------");
        proxy.GiveFlowers();
        System.out.println("---------------------");
        proxy.GiveChocolate();
    }
}

CGLIB代理

追求者的類，本來是實現介面，這裡就變成了一個普通的類

package example.動態.cglib;

/**
 * @Program: 設計模式
 * @Description:
 * @Author Mokairui
 * @Date 2020/12/14 22:15
 */
public class Pursuit {

    private SchoolGift schoolGift;


    public void setSchoolGift(SchoolGift schoolGift) {
        this.schoolGift = schoolGift;
    }


    public void giveDolls() {
        System.out.println("追求者送" + schoolGift.getName() + "娃娃");
    }

    public void giveFlowers() {
        System.out.println("追求者送" + schoolGift.getName() + "鮮花");
    }

    public void giveChocolate() {
        System.out.println("追求者送" + schoolGift.getName() + "巧克力");
    }
}

代理類

package example.動態.cglib;

import net.sf.cglib.proxy.MethodInterceptor;
import net.sf.cglib.proxy.MethodProxy;

import java.lang.reflect.Method;

/**
 * @Program: 設計模式
 * @Description:
 * @Author Mokairui
 * @Date 2020/12/14 22:26
 */
public class DynamicProxyCglibHandler implements MethodInterceptor {

    // 需要代理的物件
    private Pursuit pursuit;

    public DynamicProxyCglibHandler(Pursuit pursuit) {
        this.pursuit = pursuit;
    }

    /**
     * 代理的核心方法
     * @param proxy
     * @param method
     * @param args
     * @param methodProxy
     * @return
     * @throws Throwable
     */
    @Override
    public Object intercept(Object proxy, Method method, Object[] args, MethodProxy methodProxy) throws Throwable {
        Object obj = null;
        System.out.println("代理方法前");
        method.invoke(pursuit, args);
        System.out.println("代理方法後");
        return obj;
    }
}

測試類

package example.動態.cglib;


import net.sf.cglib.proxy.Enhancer;


/**
 * @Program: 設計模式
 * @Description:
 * @Author Mokairui
 * @Date 2020/12/14 22:10
 */
public class Demo {

    public static void main(String[] args) {
        SchoolGift schoolGift = new SchoolGift();
        schoolGift.setName("燕子");
        Pursuit pursuit = new Pursuit();

        pursuit.setSchoolGift(schoolGift);

        Pursuit proxy = (Pursuit) Enhancer.create(pursuit.getClass(),
                new DynamicProxyCglibHandler(pursuit));

        proxy.giveDolls();
        System.out.println("-----------------");
        proxy.giveFlowers();
        System.out.println("----------------");
        proxy.giveChocolate();

    }

}