单例模式

class Singelton {
private static singleton instance;
//构造方法让其private，这就封住了外界利用new创建实例的可能
private Singleton(){}

//该方法是活的哥本类实例的唯一全局访问点
public static Singleton GetInstance(){

//若实例不存在，则new一个新实例，否则返回已有的实例
if (instance == null){
instance=new Singleton()
}

return instance ;

}
}

//实现赖式单态类
private static ControlConfigurationFiles object = null;

public static synchronized ControlConfigurationFiles getInstance(ServletContext context) {
//获取web项目中ccs的配置文件
ControlConfigurationFiles.filePath = context.getRealPath("/WEB-INF/classes/ccs.properties");

if (object == null) {
object = new ControlConfigurationFiles(ControlConfigurationFiles.filePath);
}

return object;
}