java通过服务名动态实例化

java通过服务名动态实例化对象并调用指定方法
第一步:定义服务的配置文件(指定服务名和服务路径)

 <? xml version = " 1.0 "  encoding = " gb2312 " ?>
 <!-- DOCTYPE service - config SYSTEM  " service.dtd " -->
 < service - config >
     <!--  用户服务  -->
     < service name = " UserService "   class = " com.xainfor.service.UserService "  template = " normal "   />
     < service name = " GnmkService "   class = " com.xainfor.service.GnmkService "  template = " normal "   />
 </ service - config >  
第二步:系统初始化是将所有服务名和路径加载到一个静态的HashMap中

  public   class  ServiceConfig   {
   
     public   static  HashMap serviceMap  =   new  HashMap();
   
     public   static  String getService(String serviceName)   {
        String serviceClass  =   "" ;
        serviceClass  =  ServiceConfig.serviceMap.get(serviceName).toString();
         return  serviceClass;
    }
}

第三步:定义一个接口类

  public   interface  Service   {
  public   void  execute();
} 第四步:服务实例化类
public class ServiceExecuteHelper {
   
    /** *//**
     * 日志处理
     */
    private static final MsgLogger logger = MsgLogger.getLogger();
   
     public static void execute(String servicename) {
         try {
            //验证服务是否存在
            String servicClass = ServiceConfig.getService(servicename);
            //如果服务存在就加载服务信息
            if (servicClass != null && !servicClass.equals("")) {
                Class classObject = Class.forName(servicClass);
                Service service = (Service) classObject.newInstance();
                service.execute();                           
            } else {
                logger.info("服务["+servicename+"]未定义");
            }
        } catch(Exception e) {
            logger.info("服务["+servicename+"]不存在!");
        }
     }
}第五步:定义接具体服务并实现接口类
public class GnmkService implements Service {

    /**//* (non-Javadoc)
     * @see com.xainfor.service.Service#println()
     */
    public void execute() {
        // TODO Auto-generated method stub
        System.out.println("执行的是GnmkService");
    }

}public class UserService implements Service {
   
    public void execute() {
        // TODO Auto-generated method stub
        System.out.println("执行的是UserService");
       
    }
}第六步:测试类
public class testService {
  
    public static void main(String [] temp) {
      ServiceExecuteHelper.execute("UserService");
   }
}