业务代表模式

基本介绍

1.对表示层和业务层解耦，用来减少通信或对表示层代码中的业务层代码的远程查询功能

2.角色

（1）Client：客户端的表示层代码可以是 JSP、servlet 或 UI java 代码

（2）Business Delegate：业务代表，一个为 Client 提供的入口类，提供了对业务服务方法的访问

（3）LookUp Service：查询服务，查找服务对象负责获取相关的业务实现，并提供业务对象对业务代表对象的访问

（4）Business Service：业务服务，实现了该业务服务的实体类，提供了实际的业务实现逻辑

 

代码示例

public class Client {//客户端
    public static void main(String[] args) {
        BusinessDelegate businessDelegate = new BusinessDelegate();
        businessDelegate.setServiceType("EJB");
        businessDelegate.doTask();
        businessDelegate.setServiceType("JMS");
        businessDelegate.doTask();
    }
}

class BusinessDelegate {//业务代表
    //依赖查询服务、业务服务
    private BusinessLookUp lookupService = new BusinessLookUp();
    private BusinessService businessService;
    private String serviceType;

    public void setServiceType(String serviceType) {
        this.serviceType = serviceType;
    }

    public void doTask() {
        businessService = lookupService.getBusinessService(serviceType);
        businessService.doProcessing();
    }
}

interface BusinessService {//业务服务

    void doProcessing();
}

class EJBService implements BusinessService {

    @Override
    public void doProcessing() {
        System.out.println("Processing task by invoking EJB Service");
    }
}

class JMSService implements BusinessService {

    @Override
    public void doProcessing() {
        System.out.println("Processing task by invoking JMS Service");
    }
}

class BusinessLookUp {//查询服务

    public BusinessService getBusinessService(String serviceType) {
        if (serviceType.equalsIgnoreCase("EJB")) {
            return new EJBService();
        } else {
            return new JMSService();
        }
    }
}