从头认识Spring-1.6 Bean的创建与销毁操作
Posted 李灵晖
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这一章节我们来介绍一下Bean的创建与销毁操作。
在xml的配置里面,我们可以配置Bean的创建与销毁操作。
(1)domain
package com.raylee.my_new_spring.my_new_spring.ch01.topic_1_6;
public class Chief {
private final int id = index++;
public int getId() {
return id;
}
public void create() {
System.out.println("chief created");
}
public void destroy() {
System.out.println("chief destroy");
}
private static int index = 0;
}
除了定义每一个对象的id之外,还定义了创建和销毁操作的相应的方法create和destroy
(2)配置xml里面的Bean时,我们需要配置init-method="create" destroy-method="destroy"
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:aop="http://www.springframework.org/schema/aop"
xsi:schemaLocation="
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.1.xsd
http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.1.xsd
http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.0.xsd
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd">
<bean id="chief"
class="com.raylee.my_new_spring.my_new_spring.ch01.topic_1_6.Chief"
init-method="create" destroy-method="destroy" />
</beans>
(3)测试类,只是简单的geiId
package com.raylee.my_new_spring.my_new_spring.ch01.topic_1_6;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = {
"/com/raylee/my_new_spring/my_new_spring/ch01/topic_1_6/ApplicationContext-test.xml" })
public class ChiefTest {
@Autowired
private ApplicationContext applicationContext;
@Test
public void testChief() {
Chief chief = applicationContext.getBean(Chief.class);
System.out.println("chief id:" + chief.getId());
}
}
输出:
chief created
chief id:0
chief destroy
创建操作发生在对象的创建之后,销毁操作发生在对象的销毁之后。
(4)我们修改一下测试类和domain,让上面的结果更加突出
domain:
package com.raylee.my_new_spring.my_new_spring.ch01.topic_1_6;
public class Chief {
static {
System.out.println("before chief create");
}
public Chief() {
System.out.println("chief construtor");
}
private final int id = index++;
public int getId() {
return id;
}
public void create() {
System.out.println("chief created");
}
public void destroy() {
System.out.println("chief destroy");
}
private static int index = 0;
}
我们在domain里面增加了优先执行的静态代码块,以及在构造器里面增加了输出
测试类:
package com.raylee.my_new_spring.my_new_spring.ch01.topic_1_6;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = {
"/com/raylee/my_new_spring/my_new_spring/ch01/topic_1_6/ApplicationContext-test.xml" })
public class ChiefTest {
@Autowired
private ApplicationContext applicationContext;
@Test
public void testChief() {
for (int i = 0; i < 3; i++) {
Chief chief = applicationContext.getBean(Chief.class);
System.out.println("chief id:" + chief.getId());
}
}
}
在测试类里面我们增加了循环取id的操作。
测试输出:
before chief create
chief construtor
chief created
chief id:0
chief id:0
chief id:0
chief destroy
有输出可以看出,执行顺序是:
(1)静态代码块
(2)构造函数,创建对象
(3)创建操作
(4)执行业务操作
(5)销毁操作
总结:这一章节简单介绍了Bean的创建与销毁操作。
目录:http://blog.csdn.net/raylee2007/article/details/50611627
我的github:https://github.com/raylee2015/my_new_spring
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