Spring IOC容器对Bean管理

一.bean实例化

1.通过构造方法（默认）

2.通过工厂方法

3.通过静态工厂方法

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd"><!--===========================beans的实例化==============================--><!--===========================beans的构造方法==============================--><bean id="student" class="com.pojo.Student"></bean><!--===========================beans的工厂方法==============================--><bean id="student" class="com.pojo.Student" factory-bean="factory" factory-method="createstu"></bean><bean id="factory" class="com.Factory.BeansFactory"></bean><!--===========================beans的工厂方法==============================--><bean id="student" class="com.Factory.StaticBeansFactory" factory-method="createstu" ></bean></beans>

public class BeansFactory {public Student createstu(){System.out.println("===>student的普通工厂方法");return new Student();}
}

public class StaticBeansFactory {public static Student createstu(){System.out.println("===>student的静态工厂方法");return new Student();}
}

public class Student {public Student() {System.out.println("===>student构造方法");}
}

二.bean作用域

含义：spring对于创建javaBean实例的方式

语法：<bean scope="属性值"></bean>

属性值：

singleton=====>单例（默认）

prototype=====>多例

request=======>一个请求创建一个

session=======>一个会话创建一个

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd"><!--===========================beans的作用域================================--><bean id="student" class="com.Factory.StaticBeansFactory" factory-method="createstu" scope="prototype"></bean></beans>

public class test01 {public static void main(String[] args) {ClassPathXmlApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationcontext.xml");Student student1 = (Student)applicationContext.getBean("student");System.out.println(student1);Student student2 = (Student)applicationContext.getBean("student");System.out.println(student2);System.out.println(student1==student2);}
}

三.bean生命周期

1.实例化

2.属性赋值(DI)

3.初始化

3.1接口 InitializingBean

3.2属性 init-method=“”

4.操作使用

5.销毁了

5.1接口 DisposableBean

5.2属性 destory-method=“”

<!--===========================beans的生命周期================================--><bean id="teacher" class="com.pojo.Teacher" init-method="doinit" destroy-method="dodel"><property name="name" value="张三"></property></bean>

public class Teacher implements InitializingBean, DisposableBean {public Teacher() {System.out.println("===>teacher的实例化");}public String name;public void setName(String name) {System.out.println("===>teacher的属性赋值");this.name = name;}@Overridepublic void afterPropertiesSet() throws Exception {System.out.println("===>teacher的初始化（接口）");}public void doinit(){System.out.println("===>teacher的初始化（属性）");}@Overridepublic void destroy() throws Exception {System.out.println("===>teacher的销毁（接口）");}public void dodel(){System.out.println("===>teacher的销毁（属性）");}
}

public class test02 {public static void main(String[] args) {ClassPathXmlApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationcontext.xml");Teacher teacher = applicationContext.getBean(Teacher.class);System.out.println(teacher);applicationContext.close();}
}