spring---生命周期

spring---生命周期

1.lazy-init="true/false/default";

2.init-method=" "//对象创建时调用

destroy-method=" "

问题：对象是什么时候创建的呢？

lazy-init="true/false/default";

配置文件：applicationContext.xml

<?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">
   <bean id="p" class="com.Person" ></bean>
   <bean id="s" class="com.student" lazy-init="true"></bean>
   <bean id="w" class="com.Worker" lazy-init="false"></bean>
</beans>

测试：

package com.life;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.Person;

public class TestlifeDemo {
   @Test
   public void test01() {
       //启动spring容器，读取src文件下的applicationContext.xml
      ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
      
   }
}

测试结果：

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由测试结果知：

当lazy-init=“false” 或默认不写时

对象实在spring容器启动时创建的

测试：

package com.life;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.Person;
import com.Worker;
import com.student;

public class TestlifeDemo {
   @Test
   public void test01() {
       //启动spring容器，读取src文件下的applicationContext.xml
      ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
      Person p = (Person) ac.getBean("p");
      student s = (student) ac.getBean("s");
      Worker w = (Worker) ac.getBean("w");
   }
}

测试结果：

由测试结果知：

当lazy-init=“true” 时，调用spring容器调用getBean方法时，对象才创建出来

init-method=" " destroy-method=" "

配置文件：applicationContext.xml

<?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">
   <bean id="p" class="com.Person" init-method="init" destroy-method="destroy"></bean>
</beans>

person.java

package com;

public class Person {

    public Person() {
        System.out.println("Person对象已创建完毕。。。");
    }
    public void init() {
        System.out.println("初始化方法");
    }
    public void destroy() {
        System.out.println("销毁方法");
    }

    public void say() {
        System.out.println("hello world....");
    }
  
}

测试：

package com.life;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.Person;
import com.Worker;
import com.student;

public class TestlifeDemo {
   @Test
   public void test01() {
       //启动spring容器，读取src文件下的applicationContext.xml
      ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
      Person p = (Person) ac.getBean("p");
      p.say();
   }
}

测试结果：

总结：

bean对象什么时候创建出来的呢?

1.首先spring容器通过默认的构造函数创建对象

2. init-method="init" 调用初始化方法

3. talk()
4. destroy-method="destroy"调用销毁方法

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