drools6入门例子(二)

﹏ヽ暗。殇╰゛Y 2022-08-04 05:24 213阅读 0赞

产品规则如下：  
1：单个产品数量超过2个，该产品打9折

2：总价格超过1000，立减50

新建maven项目，加入drools的依赖

<dependency>
    	<groupId>org.drools</groupId>
    	<artifactId>drools-core</artifactId>
    	<version>6.2.0.Final</version>
    </dependency>
    <dependency>
    	<groupId>org.drools</groupId>
    	<artifactId>drools-compiler</artifactId>
    	<version>6.2.0.Final</version>
    </dependency>

创建Fact

package com.lala.bean;
    
    /**
     * 产品
     */
    public class Product 
    {
    	private String name;
    	private Integer count = 1; //数量
    	private double price; //价格
    	private double discount = 1;	//折扣
    	public Product(String name, double price)
    	{
    		this.name = name;
    		this.price = price;
    	}
    	public Product(String name, double price, Integer count)
    	{
    		this.name = name;
    		this.price = price;
    		this.count = count;
    	}
    	public String getName()
    	{
    		return name;
    	}
    	public void setName(String name)
    	{
    		this.name = name;
    	}
    	public Integer getCount()
    	{
    		return count;
    	}
    	public void setCount(Integer count) 
    	{
    		this.count = count;
    	}
    	public double getPrice() 
    	{
    		return price;
    	}
    	public void setPrice(double price) 
    	{
    		this.price = price;
    	}
    	public double getDiscount() 
    	{
    		return discount;
    	}
    	public void setDiscount(double discount)
    	{
    		this.discount = discount;
    	}
    	/**
    	 * 金额
    	 */
    	public double getPay()
    	{
    		return price * count * discount;
    	}
    	public String toString()
    	{
    		return "[name="+name+",price="+price+",count="+count+",discount="+discount+",getPay()="+getPay()+"]";
    	}
    }

package com.lala.bean;
    
    import java.util.List;
    
    /**
     * 订单
     */
    public class Order 
    {
    	private Integer id;
    	private List<Product> products;
    	private double cash = 0;	//返现
    	public Integer getId()
    	{
    		return id;
    	}
    	public void setId(Integer id)
    	{
    		this.id = id;
    	}
    	public List<Product> getProducts() 
    	{
    		return products;
    	}
    	public void setProducts(List<Product> products)
    	{
    		this.products = products;
    	}
    	/**
    	 * 总金额
    	 */
    	public double getTotal()
    	{
    		double total = 0;
    		for(Product product : products)
    		{
    			total += product.getPay();
    		}
    		return total;
    	}
    	/**
    	 * 实际支付金额
    	 */
    	public double getPay()
    	{
    		return getTotal() - cash;
    	}
    	public double getCash() 
    	{
    		return cash;
    	}
    	public void setCash(double cash) 
    	{
    		this.cash = cash;
    	}
    }

drools规则：

package com.order;
    
    import com.lala.bean.Product;
    import com.lala.bean.Order;
    
    rule "products"
    	salience 2
        when
        	$order : Order();
        	$product : Product(count >= 3) from $order.products;//从list中取出每个product
        then
        	$product.setDiscount(0.9);//产品数量超过2个，则该产品打9折
    end
    
    rule "order"
    	salience 1
        when
        	order:Order(getTotal() > 1000);
        then
        	order.setCash(50);//总价钱超过1000，立减50
    end

测试：

package com.lala.mydrools;
    
    import java.util.ArrayList;
    import java.util.List;
    
    import org.kie.api.KieServices;
    import org.kie.api.runtime.KieContainer;
    import org.kie.api.runtime.KieSession;
    
    import com.lala.bean.Order;
    import com.lala.bean.Product;
    
    public class OrderTest 
    {
    	static KieSession getSession()
        {
            KieServices ks = KieServices.Factory.get();
             
            KieContainer kc = ks.getKieClasspathContainer();
     
            return kc.newKieSession("simpleRuleKSession");
        }
        public static void main(String[] args)
        {
            KieSession ks = getSession();
    
            Order order = new Order();
            
            List<Product> products = new ArrayList<>();
            products.add(new Product("MP3", 120, 2));
            products.add(new Product("MP4", 200));
            products.add(new Product("TCL电视", 3000));
            products.add(new Product("红米note2", 799, 5));
            
            order.setProducts(products);
           
            ks.insert(order);
            int count = ks.fireAllRules();
            System.out.println("总执行了"+count+"条规则");
            System.out.println("实际需要支付：" + order.getPay());
            ks.dispose();
        }
    }

最后输出结果为：

总执行了2条规则  
实际需要支付：6985.5