spring framework 4 原始碼閱讀(2)---從ClassPathXmlApplicationContext開始
阿新 • • 發佈：2019-01-08
Application初始化日誌
15:23:12.790 [main] DEBUG o.s.core.env.StandardEnvironment - Adding [systemProperties] PropertySource with lowest search precedence
15:23:12.797 [main] DEBUG o.s.core.env.StandardEnvironment - Adding [systemEnvironment] PropertySource with lowest search precedence
15:23:12.797 [main] DEBUG o.s.core.env.StandardEnvironment - Initialized StandardEnvironment with PropertySources [systemProperties,systemEnvironment]
//初始化Environment
15:23:12.803 [main] INFO o.s.c.s.ClassPathXmlApplicationContext - Refreshing org 一些bean的初始化
一個簡單的bean，裡面有個屬性property,以及test方法和需要進行屬性注入的setProperty/**
* 基本的bean方便測試
* Created by zhangya on 2014/8/13.
*/
public class SimpleBean
{
private static final Logger LOGGER = LoggerFactory.getLogger(SimpleBean.class);
private SimpleBeanProperty property;
/**
* 簡單測試方法
*/
public void test()
{
LOGGER.info("SimpleBean is loading.");
property.propertyTest();
}
/**
* 設定屬性 property
* <p>記錄日誌
* @param property
*/
public void setProperty(SimpleBeanProperty property)
{
LOGGER.info("Property is setting.");
this.property = property;
}
}作為屬性賦值的bean，裡面包含初始化方法
/**
* 作為屬性初始化的bean
* Created by zhangya on 2014/8/13.
*/
public class SimpleBeanProperty
{
private static final Logger LOGGER = LoggerFactory.getLogger(SimpleBeanProperty.class);
private String simpleVariable = "test567";
public SimpleBeanProperty()
{
LOGGER.info("SimpleBeanProperty is loading.");
}
/**
* property的test方法
*/
public void propertyTest()
{
LOGGER.info("propertyTest method is invoking.{}",this);
}
/**
* 設定變數
* @param simpleVariable
*/
public void setSimpleVariable(String simpleVariable)
{
this.simpleVariable = simpleVariable;
}
/**
* 獲取變數的值
* @return 變數的值
*/
public String getSimpleVariable()
{
return simpleVariable;
}
@Override
public String toString()
{
return "SimpleBeanProperty{" +
"simpleVariable='" + simpleVariable + '\'' +
'}';
}
}另外一個
/**
* 用於初始化的另外一個bean
* @author zhangya
* @category com.letume.spring.study.init
* @since 2014/8/24
*/
public class SimpleAnotherBean
{
private static final Logger LOGGER = LoggerFactory.getLogger(SimpleBeanProperty.class);
private String simpleVariable = "test123";
public SimpleAnotherBean()
{
LOGGER.info("SimpleAnotherBean is loading.");
}
/**
* property的test方法
*/
public void test()
{
LOGGER.info("test method is invoking.{}",this);
}
/**
* 設定變數
* @param simpleVariable
*/
public void setSimpleVariable(String simpleVariable)
{
this.simpleVariable = simpleVariable;
}
@Override
public String toString()
{
return "SimpleAnotherBean{" +
"simpleVariable='" + simpleVariable + '\'' +
'}';
}
}simpleContext.xml applicationContext的配置檔案，這裡使用xml形式對bean進行配置
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN 2.0//EN"
"http://www.springframework.org/dtd/spring-beans-2.0.dtd">
<beans>
<bean name="simpleBean"
class="com.letume.spring.study.init.SimpleBean">
<property name="property"><ref local="property"/> </property>
</bean>
<bean id="property" name="property"
class="com.letume.spring.study.init.SimpleBeanProperty" scope="prototype"/>
<bean name="anotherBean"
class="com.letume.spring.study.init.SimpleAnotherBean" scope="prototype"/>
</beans>下面是main函式，
例1 普通的bean初始化呼叫過程
/**
* 簡單的spring類載入的方法
* <pre>
* ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(PATH+RESOURCE_CONTEXT);
* SimpleBean simpleBean = context.getBean(SimpleBean.class)
* simpleLoaderSimpleBean.test();
* </pre>
* Created by mitchz on 2014/8/13.
*/
public class SimpleInit
{
private static final String PATH = "";
private static final String RESOURCE_CONTEXT = "simpleContext.xml";
public static void main(String[] args) throws InterruptedException
{
ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(
PATH + RESOURCE_CONTEXT);
//獲取simpleBean
SimpleBean simpleBean = context
.getBean("simpleBean", SimpleBean.class);
simpleBean.test();
//context.registerShutdownHook();
}
}---執行單例的初始化（為什麼會使用單例）
14:36:48.766 [main] DEBUG o.s.b.f.s.DefaultListableBeanFactory - Pre-instantiating singletons in org.s[email protected]29d8a2c5: defining beans [simpleBean,property,anotherBean]; root of factory hierarchy
14:36:48.767 [main] DEBUG o.s.b.f.s.DefaultListableBeanFactory - Creating shared instance of singleton bean 'simpleBean'
---建立bean例項
14:36:48.767 [main] DEBUG o.s.b.f.s.DefaultListableBeanFactory - Creating instance of bean 'simpleBean'
14:36:48.786 [main] DEBUG o.s.b.f.s.DefaultListableBeanFactory - Eagerly caching bean 'simpleBean' to allow for resolving potential circular references
---建立屬性的例項
14:36:48.799 [main] DEBUG o.s.b.f.s.DefaultListableBeanFactory - Creating instance of bean 'property'
14:36:48.799 [main] INFO c.l.s.study.init.SimpleBeanProperty - SimpleBeanProperty is loading.
14:36:48.799 [main] DEBUG o.s.b.f.s.DefaultListableBeanFactory - Finished creating instance of bean 'property'
---賦值
14:36:48.838 [main] INFO c.l.spring.study.init.SimpleBean - Property is setting.
14:36:48.840 [main] DEBUG o.s.b.f.s.DefaultListableBeanFactory - Finished creating instance of bean 'simpleBean'
....
---getBean的方法執行時，則直接從cache中取，之前初始化的例項
14:36:48.847 [main] DEBUG o.s.b.f.s.DefaultListableBeanFactory - Returning cached instance of singleton bean 'simpleBean'
14:36:48.847 [main] INFO c.l.spring.study.init.SimpleBean - SimpleBean is loading.SimpleBean{property=SimpleBeanProperty{simpleVariable='test567'}}
14:36:48.849 [main] INFO c.l.s.study.init.SimpleBeanProperty - propertyTest method is invoking.SimpleBeanProperty{simpleVariable='test567'}
從日誌中可以看出bean在沒有設定scope的時候，預設值為singletone的。另外即使屬性類是protetype的時候，也會在父bean初始化將其填充。不會在呼叫父bean的時候，重新初始化屬性所關聯的bean。詳細見例2
例2，在執行過程中，增加屬性修改，咱們再來執行下看看
//修改property bean例項中的變數simpleVariable
simpleBean.getProperty().setSimpleVariable("aaaaa");
//重新獲取simpleBean例項
simpleBean = context
.getBean("simpleBean", SimpleBean.class);
//再次執行test方法
simpleBean.test();15:14:58.447 [main] INFO c.l.spring.study.init.SimpleBean - SimpleBean is loading.SimpleBean{property=SimpleBeanProperty{simpleVariable='aaaaa'}}
15:14:58.447 [main] INFO c.l.s.study.init.SimpleBeanProperty - propertyTest method is invoking.SimpleBeanProperty{simpleVariable='aaaaa'}第一、bean的scope預設為SingleTone的
第二、bean的lazyInit為false的
第三、即使屬性為prototype也不會再父bean為SingleTone的時重新初始化
例3、再增加兩行
//獲取property例項
SimpleBeanProperty property = context
.getBean("property", SimpleBeanProperty.class);
//測試propertyTest方法
property.propertyTest();再看下執行後新增的日誌：
15:19:10.331 [main] DEBUG o.s.b.f.s.DefaultListableBeanFactory - Creating instance of bean 'property'
15:19:10.331 [main] INFO c.l.s.study.init.SimpleBeanProperty - SimpleBeanProperty is loading.
15:19:10.331 [main] DEBUG o.s.b.f.s.DefaultListableBeanFactory - Finished creating instance of bean 'property'
15:19:10.331 [main] INFO c.l.s.study.init.SimpleBeanProperty - propertyTest method is invoking.SimpleBeanProperty{simpleVariable='test567'}例4、再增加四行：
//獲取anotherBean例項
SimpleAnotherBean anotherBean = context
.getBean("anotherBean", SimpleAnotherBean.class);
anotherBean.test();
//設定變數的值
anotherBean.setSimpleVariable("bbbbb");
//重新獲取anotherBean例項
anotherBean = context
.getBean("anotherBean", SimpleAnotherBean.class);
anotherBean.test();大家在看下執行日誌：
15:23:13.130 [main] DEBUG o.s.b.f.s.DefaultListableBeanFactory - Creating instance of bean 'anotherBean'
15:23:13.130 [main] INFO c.l.s.study.init.SimpleBeanProperty - SimpleAnotherBean is loading.
15:23:13.130 [main] DEBUG o.s.b.f.s.DefaultListableBeanFactory - Finished creating instance of bean 'anotherBean'
15:23:13.130 [main] INFO c.l.s.study.init.SimpleBeanProperty - test method is invoking.SimpleAnotherBean{simpleVariable='test123'}
15:23:13.131 [main] DEBUG o.s.b.f.s.DefaultListableBeanFactory - Creating instance of bean 'anotherBean'
15:23:13.131 [main] INFO c.l.s.study.init.SimpleBeanProperty - SimpleAnotherBean is loading.
15:23:13.131 [main] DEBUG o.s.b.f.s.DefaultListableBeanFactory - Finished creating instance of bean 'anotherBean'
15:23:13.131 [main] INFO c.l.s.study.init.SimpleBeanProperty - test method is invoking.SimpleAnotherBean{simpleVariable='test123'}通過日誌的內容，梳理一下大概初始化邏輯
可以看出主要針對beans context 還有core包。
具體怎麼相互協作的，下一篇會進一步介紹。