Spring -10 -<bean>的 scope 属性 -singleton 默认值/prototype 多例 /request /session /application /global session

1.<bean>的属性;

2.作用:控制对象有效范围(单例,多例等)
3.<bean/>标签对应的对象默认是单例的.
　　3.1无论获取多少次,都是同一个对象
　

Teacher t1 = ac.getBean("teacher1",Teacher.class);
System.out.println(t1);

Teacher t2 = ac.getBean("teacher1",Teacher.class);
System.out.println(t2);

System.out.println(t1==t2);

3.3输出结果如下:
3.4com.test.Teacher@5b275dab
3.5com.test.Teacher@5b275dab
3.6true

3.7
4.scope 可取值
4.1singleton 默认值,单例--所有同一对象使用同一地址!

<bean id="teacher1" class="com.test.Teacher" scope="singleton"></bean> 
等价于下面的:
<bean id="teacher1" class="com.test.Teacher" ></bean>

4.4prototype 多例,每次获取重新实例化该Class !

<bean id="teacher1" class="com.test.Teacher" scope="prototype"></bean>

Teacher t1 = ac.getBean("teacher1",Teacher.class);
t1.setCnt(2);
System.out.println(t1); //Teacher{cnt=2}

Teacher t2 = ac.getBean("teacher1",Teacher.class);
System.out.println(t2); //Teacher{cnt=2}

System.out.println(t1==t2);

输出结果: Teacher{cnt=2} ,Teacher{cnt=0} , false

4.8  request 在每次请求时,重新new() / 实例化;
4.9  session 每个会话对象内,对象是单例的. (依赖于Spring0MVC架构)
4.10  application 在application 对象内是单例;
4.11   global session, spring 推 出 的 一 个 对 象 , 依 赖 于 spring-webmvc-portlet ,类似于session