设计模式-策略模式

项目中用策略模式往往启到事半功倍的效果。

第一步：

package com.example.myapp.strategy2;

/**
 * Created by mike.
 * Created on 2020/4/1.
 */
public interface Strategy {
    int doOperate(int num1,int num2);
}

第二步：

package com.example.myapp.strategy2;

/**
 * Created by mike.
 * Created on 2020/4/1.
 */
public class OperateAdd implements Strategy {
    @Override
    public int doOperate(int num1, int num2) {
        return num1 + num2;
    }
}

package com.example.myapp.strategy2;

/**
 * Created by mike.
 * Created on 2020/4/1.
 */
public class OperateSubstract implements Strategy {
    @Override
    public int doOperate(int num1, int num2) {
        return num1 - num2;
    }
}

package com.example.myapp.strategy2;

/**
 * Created by mike.
 * Created on 2020/4/1.
 */
public class OperateMulpity implements Strategy {
    @Override
    public int doOperate(int num1, int num2) {
        return num1 * num2;
    }
}

第三步：

package com.example.myapp.strategy2;

/**
 * Created by mike.
 * Created on 2020/4/1.
 */
public class Context {
    private Strategy strategy;

    public Context(Strategy strategy) {
        this.strategy = strategy;
    }

    public int executeOperate(int num1, int num2){
        return strategy.doOperate(num1, num2);
    }
}

第四步：

package com.example.myapp.strategy2;

import org.junit.Test;

/**
 * Created by mike.
 * Created on 2020/4/1.
 */
public class StrategyDemo {
    @Test
    public void main() {
        Context context = new Context(new OperateAdd());
        System.out.println(context.executeOperate(5, 10));
        context = new Context(new OperateSubstract());
        System.out.println(context.executeOperate(5, 10));
        context = new Context(new OperateMulpity());
        System.out.println(context.executeOperate(5, 10));
    }
}

 

输出结果：

15
-5
50