Spring.NET教程（五）

Spring.NET教程（五）——容器中对象的作用域(基础篇)

2018年05月23日 10:43:41 Wang Jianguo 阅读数：84

        容器中对象的部署分为两种方式：singleton和非singleton(java里叫prototype)。这里的singleton指的是“单例模式”，就是说当一个对象被定义为singleton时，容器中就只会有一个共享的实例，任何时候通过id或别名请求该对象都会返回这个共享实例的引用（也就是说这个对象只会被创建一次）。当使用非singleton，或者说原型模式布署时，每次请求对象都会创建新的实例。在某些场合，如果需要为每个用户返回单独的用户对象或其它对象，非singlton布署模式就比较理想。Spring.NET默认为singleton模式。每次调用GetObject方法时得到的都是同样的实例；当singleton="false"时，每次调用GetObject方法时得到的则是不同的实例。

<?xml version="1.0" encoding="utf-8" ?>
<objects xmlns="http://www.">
  <!--单例模式-->
  <object id="personDao" type="SpringNetScopes.PersonDao,　SpringNetScopes"/>
  <!--非单例模式-->
  <object id="person" type="SpringNetScopes.Person,　SpringNetScopes" singleton="false" />
  <!--调用时加载-->
  <object id="personServer" type="SpringNetScopes.PersonServer,　SpringNetScopes" lazy-init="true"/>
</objects>

namespace SpringNetScopes
{
    public class PersonDao : IPersonDao
    {
        public PersonDao()
        {
            Console.WriteLine("PersonDao被实例");
        }
        public override string ToString()
        {
            return "我是PersonDao";
        }
        ~PersonDao()
        {
            Console.WriteLine("PersonDao被销毁");
        }
        public void Save()
        {
            Console.WriteLine("保存　Person");
        }
    }
    public class Person
    {
        public Person()
        {
            Console.WriteLine("Person被实例");
        }
        public override string ToString()
        {
            return "我是Person";
        }
        ~Person()
        {
            Console.WriteLine("Person被销毁");
        }
    }
    public class PersonServer
    {
        public PersonServer()
        {
            Console.WriteLine("PersonServer被实例");
        }
        public override string ToString()
        {
            return "我是PersonServer";
        }
        ~PersonServer()
        {
            Console.WriteLine("PersonServer被销毁");
        }
    }
}
        [TestMethod]
        public void CreateWithSingleton()
        {
            string[] xmlFiles = new string[]
            {
                "assembly://SpringNetScopes/SpringNetScopes/Objects.xml"
            };
            IApplicationContext context = new XmlApplicationContext(xmlFiles);
            IObjectFactory factory = (IObjectFactory)context;
            object obj1 = factory.GetObject("personDao");
            object obj2 = factory.GetObject("personDao");
            Assert.AreEqual(obj1, obj2);
        }
        [TestMethod]
        public void CreateWithOutSingleton()
        {
            string[] xmlFiles = new string[]
            {
                "assembly://SpringNetScopes/SpringNetScopes/Objects.xml"
            };
            IApplicationContext context = new XmlApplicationContext(xmlFiles);
            IObjectFactory factory = (IObjectFactory)context;
            object obj1 = factory.GetObject("person");
            object obj2 = factory.GetObject("person");
            Assert.AreNotEqual(obj1, obj2);
        }
        [TestMethod]
        public void CreateWithLazy()
        {
            string[] xmlFiles = new string[]
            {
                "assembly://SpringNetScopes/SpringNetScopes/Objects.xml"
            };
            IApplicationContext context = new XmlApplicationContext(xmlFiles);
            IObjectFactory factory = (IObjectFactory)context;
            object dao = factory.GetObject("personDao");
            Console.WriteLine(dao.ToString());
            object server = factory.GetObject("personServer");
            Console.WriteLine(server.ToString());
        }