fastcampus java 온라인 강의를 들으면서 정리한 내용입니다.
Customizing the Nature of a Bean
- Lifecycle Callbacks
- ApplicationContextAware and BeanNameAware
LifeCycle
객체들을 관리 , 객체를 만들때(new), 객체를 없앨 때(destroy)
new라는 객체를 만들기 전
특정 빈에 대해서 자원 없앨때 close에 대한 함수
- InitializingBean
- DisposableBean
- xml -init method / destroy
실행
ApplicationContext context = new ClassPathXmlApplicationContext("dao.xml");
ConnectionFactory connectionFactory = context.getBean("connectionFactory",ConnectionFactory.class);
log.info("result : "+connectionFactory.getConnection());
-
Initializing Bean (Interface)
bean이 생성 될때 미리 생성됨 : 컨테이너가 빈에 필요한 모든 속성을 설정 한 후 빈 초기화 작업을 수행
InitializingBean 인터페이스는 afterPropertiesSet 하나의 메서드를 가진다.
void afterPropertiesSet() throws Exception;
예제 dao.xml
<bean id="connectionFactory" class="kr.co.fastcampus.cli.ConnectionFactory" >
<constructor-arg name="driverClass" value="org.h2.Driver"/>
<constructor-arg name="url" value="jdbc:h2:mem:test"/>
<constructor-arg name="user" value="sa"/>
<constructor-arg name="password" value=""/>
</bean>
<bean id = "connection" class="java.sql.Connection"
factory-bean = "connectionFactory"
factory-method="createConnection"
/>
<bean id="dao" class="kr.co.fastcampus.cli.Dao">
<constructor-arg ref="connection"></constructor-arg>
</bean>
ConnectionFactory.java
public class ConnectionFactory implements InitializingBean {
private String driverClass;
private String url;
private String user;
private String password;
//bean을 만들지면서 Connection을 미리 생성 하기
@Getter
private Connection connection=null;
public ConnectionFactory(String driverClass,String url, String user, String password) {
this.driverClass = driverClass;
this.url = url;
this.user = user;
this.password = password;
}
public Connection createConnection() throws SQLException {
try {
Class.forName("org.h2.Driver");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
String url = "jdbc:h2:mem:test;MODE=MySQL;";
return DriverManager.getConnection(this.url,this.user,this.password);
}
@Override
public void afterPropertiesSet() throws Exception {
this.connection = createConnection();
}
}
-
Initializing Bean (xml)
init-method 에 는 빈 팩토리를 불러올 때 실행될 메서드이름을 지정해서 사용할 수 있다.
dao.xml
<bean id="connectionFactory" class="kr.co.fastcampus.cli.ConnectionFactory" init-method="init" >
ConnectionFactory.java
public class ConnectionFactory {
private String driverClass;
private String url;
private String user;
private String password;
//bean을 만들지면서 Connection을 미리 생성 하기
@Getter
private Connection connection=null;
public ConnectionFactory( String driverClass,String url, String user, String password) {
this.driverClass = driverClass;
this.url = url;
this.user = user;
this.password = password;
}
//bean 메서드(xml)의 init의 메서드를 지정해주면 bean이 초기화될때 생성된다.
public void init() throws Exception {
this.connection = createConnection();
}
public Connection createConnection() throws SQLException {
try {
Class.forName("org.h2.Driver");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
String url = "jdbc:h2:mem:test;MODE=MySQL;";
return DriverManager.getConnection(this.url,this.user,this.password);
}
}
###DisposableBean
Bean을 포함하는 컨테이너가 소멸 될 때 Bean이 콜백을 얻을 수 있습니다.
1.Disposable Bean (Interface)
DisposableBean 인터페이스는 destroy 메서드를 가진다.
void destroy() throws Exception;
ConnectionFactory.java
@Slf4j
public class ConnectionFactory implements DisposableBean {
private String driverClass;
private String url;
private String user;
private String password;
//bean을 만들지면서 Connection을 미리 생성 하기
@Getter
private Connection connection=null;
public ConnectionFactory( String driverClass,String url, String user, String password) {
this.driverClass = driverClass;
this.url = url;
this.user = user;
this.password = password;
}
//bean 메서드(xml)의 init의 메서드를 지정해주면 bean이 초기화될때 생성된다.
public void init() throws Exception {
this.connection = createConnection();
}
public Connection createConnection() throws SQLException {
try {
Class.forName("org.h2.Driver");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
String url = "jdbc:h2:mem:test;MODE=MySQL;";
return DriverManager.getConnection(this.url,this.user,this.password);
}
@Override
public void destroy() throws Exception {
log.info("destory connection");
if(this.connection!=null){
this.connection.close();
}
}
}
이렇게 해주고 위에서 getbean을 사용해서 사용했지만, 여기서는 ApplicationContext 보다 ApplicationContext클래스를 상속받고 있는 ConfigurableApplicationContext 를 사용해서 테스트를 진행해야 한다.
ConfigurableApplicationContext는 ApplicationContext, Lifecycle, Closeable 를 상속 받고 있다.
테스트를 위한 실행
ConfigurableApplicationContext context = new ClassPathXmlApplicationContext("dao.xml");
ConnectionFactory connectionFactory = context.getBean("connectionFactory",ConnectionFactory.class);
log.info("result : "+connectionFactory.getConnection());
context.close();
결과
00:58:37.149 [main] INFO kr.co.fastcampus.cli.Main - result : conn0: url=jdbc:h2:mem:test user=SA
00:58:37.151 [main] INFO k.c.fastcampus.cli.ConnectionFactory - destory connection
2.DisposableBean Bean (xml)
위의 initializing Bean을 xml 로 설정한것과 같다.destroy-method 속성을 추가 해주면 된다.
<bean id="connectionFactory" class="kr.co.fastcampus.cli.ConnectionFactory" init-method="init" destroy-method="destroy">
@Slf4j
public class ConnectionFactory {
private String driverClass;
private String url;
private String user;
private String password;
//bean을 만들지면서 Connection을 미리 생성 하기
@Getter
private Connection connection=null;
public ConnectionFactory( String driverClass,String url, String user, String password) {
this.driverClass = driverClass;
this.url = url;
this.user = user;
this.password = password;
}
//bean 메서드(xml)의 init의 메서드를 지정해주면 bean이 초기화될때 생성된다.
public void init() throws Exception {
this.connection = createConnection();
}
public Connection createConnection() throws SQLException {
try {
Class.forName("org.h2.Driver");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
String url = "jdbc:h2:mem:test;MODE=MySQL;";
return DriverManager.getConnection(this.url,this.user,this.password);
}
public void destroy() throws Exception {
log.info("destory connection");
if(this.connection!=null){
this.connection.close();
}
}
}
결과는 똑같이 나온다.
01:08:23.145 [main] INFO kr.co.fastcampus.cli.Main - result : conn0: url=jdbc:h2:mem:test user=SA
01:08:23.148 [main] INFO k.c.fastcampus.cli.ConnectionFactory - destory connection
##Default init, destroy
default-init-method , default-destroy-method 를 beans에 추가 해주면 기본적으로 bean에서 특정 메서드로 사용이 가능하다.
<beans default-init-method="init"
default-destroy-method="destroy"
xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans.xsd">
LifeCycle
Lifecycle 인터페이스
-
void start();
-
void stop();
-
boolean isRunning();
context가 실행 중인지 아닌지 lifeCycle의 상태를 조회 가능하다.
ConfigurableApplicationContext context = new ClassPathXmlApplicationContext("dao.xml");
Lifecycle lifecycle = context.getBean(Lifecycle.class);
log.info("lifeCycle is Running ? "+lifecycle.isRunning());
context.close();
log.info("lifeCycle is Running ? "+lifecycle.isRunning());
결과
01:37:25.064 [main] INFO kr.co.fastcampus.cli.Main - lifeCycle is Running ? true
01:37:25.069 [main] INFO k.c.fastcampus.cli.ConnectionFactory - destory connection
01:37:25.070 [main] INFO kr.co.fastcampus.cli.Main - lifeCycle is Running ? false
###ApplicationContextAware
특정 빈에서 application Context를 사용 하고 싶을때 사용
public interface ApplicationContextAware {
void setApplicationContext(ApplicationContext applicationContext) throws BeansException;
}
https://docs.spring.io/spring-framework/docs/current/spring-framework-reference/core.html#beans-factory-nature
