Java设计模式之策略模式详解

public class Test3 { 
 public static void main(String[] args) { 
    
  //声明一个具体的策略 
   Strategy strategy = new ConcreteStrategy1(); 
   //声明上下文对象 
   Context context = new Context(strategy); 
   //执行封装后的方法 
   context.doAnythinig(); 
 
 
   
 } 
} 
 
interface Strategy { 
 //策略模式的运算法则 
 public void doSomething(); 
} 
 
class ConcreteStrategy1 implements Strategy { 
  
 public void doSomething() { 
   System.out.println("具体策略1的运算法则"); 
 } 
} 
class ConcreteStrategy2 implements Strategy {  
  
 public void doSomething() { 
   System.out.println("具体策略2的运算法则"); 
 } 
} 
 
class Context { 
 //抽象策略 
 private Strategy strategy; 
 //构造函数设置具体策略 
 public Context(Strategy _strategy){ 
   this.strategy = _strategy; 
 } 
 //封装后的策略方法 
 public void doAnythinig(){ 
   this.strategy.doSomething(); 
 } 
} 

import java.util.Arrays; 
 
 
public class Test3 { 
 public static void main(String[] args) { 
    
  //输入的两个参数是数字 
  int a = Integer.parseInt(args[0]); 
  String symbol = args[1]; //符号 
  int b = Integer.parseInt(args[2]); 
  System.out.println("输入的参数为："+Arrays.toString(args)); 
  System.out.println("运行结果为："+a+symbol+b+"="+Calculator.ADD.exec(a,b)); 
 
 
 
   
 } 
} 
enum Calculator { 
 //加法运算 
 ADD("+"){ 
   public int exec(int a,int b){ 
     return a+b; 
   } 
 }, 
 //减法运算 
 SUB("-"){ 
   public int exec(int a,int b){ 
     return a - b; 
   } 
 }; 
 String value = ""; 
  
 //定义成员值类型 
 private Calculator(String _value){ 
   this.value = _value; 
 }  
  
 //获得枚举成员的值 
 public String getValue(){ 
   return this.value; 
 } 
 //声明一个抽象函数 
 public abstract int exec(int a,int b); 
}