bean管理(xml)
(一)spring的工厂类
FileSystemXmlApplicationContext 读取磁盘配置文件
(二)bean实例化的三种方式
(1)使用类构造器实例化(默认无参数)
1.Bean01.java
package demo01;public class Bean01 {//无参构造函数 public Bean01() { System.out.println("bean1被实例化了..."); }}
2.applicationContext.xml
3.DemoTest.java
package Test;import demo01.Bean01;import org.junit.Test;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class DemoTest { @Test public void demo01(){ //创建工厂 ApplicationContext applicationContext=new ClassPathXmlApplicationContext("applicationContext.xml"); //通过工厂创建类 Bean01 bean01=(Bean01)applicationContext.getBean("bean01"); }}
(2)使用静态工厂方法实例化(简单工厂模式)
1.Bean02.java
package demo01;public class Bean02 {}
2.Bean02Factory.java
package demo01;public class Bean02Factory { public static Bean02 bean2(){ System.out.println("bean02被实例化了..."); return new Bean02(); }}
3.applicationContext.xml
4.DemoTest.java
@Testpublic void demo02(){ //创建工厂 ApplicationContext applicationContext=new ClassPathXmlApplicationContext("applicationContext.xml"); //通过工厂创建类 Bean02 bean02=(Bean02) applicationContext.getBean("bean02");}
(3)使用实例工厂方法实例化(工厂方法模式)
1.Bean03.java
package demo01;public class Bean03 {}
2.Bean03Factory.java
package demo01;public class Bean03Factory { public Bean03 bean3(){ System.out.println("bean03被实例化了..."); return new Bean03(); }}
3.applicationContext.xml
4.DemoTest.java
@Testpublic void demo03(){ //创建工厂 ApplicationContext applicationContext=new ClassPathXmlApplicationContext("applicationContext.xml"); //通过工厂创建类 Bean03 bean03=(Bean03) applicationContext.getBean("bean03");}
(三)bean的常用配置
(1)bean的配置
(2)bean的作用域
(四)bean的生命周期