[Spring] 스프링 빈 설정파일 ( Spring Bean Configuration File )

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[Spring] 스프링 빈 설정파일 ( Spring Bean Configuration File ) - applicationContext.xml 예제

printf100 2020. 3. 18. 21:04

1. src 우클릭 > com.test01 패키지 생성

2. com.test01 우클릭 > New > Other... > Spring Bean Configuration File

생성 완료!

예제로 이해하기

1. 날짜 2020.12.25 출력하기 (java.util.Date 클래스 이용)

New > Class > BeanTest.java 생성하고 다음과 같이 작성

BeanTest.java

package com.test01;

import java.util.Date;

public class BeanTest {

	public BeanTest() {
		System.out.println("기본 생성자!");
	}

	public BeanTest(Date date) {
		System.out.println("파라미터 1개 생성자(Date date) : " + date);
	}
    
}

applicationContext.xml

<constructor-arg> : 생성자를 통해 주입 ( 여기서는 public BeanTest(Date date) )

<constructor-arg ref=""> : bean 객체를 주입 ( 여기서는 date라는 이름을 가진 bean )

<?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">

	<!-- 1. 2020.12.25 -->
	<bean id="date" class="java.util.Date">
		<constructor-arg name="year" value="120"></constructor-arg>
		<constructor-arg name="month" value="11"></constructor-arg>
		<constructor-arg name="date" value="25"></constructor-arg>
	</bean>

	<bean id="beanTest" class="com.test01.BeanTest">
		<!-- 1. public BeanTest(Date date) 호출 - 2020.12.25 -->
		<constructor-arg name="date" ref="date"></constructor-arg>
    	</bean>
        
 </beans>

New > Class > MTest.java 생성하고 다음과 같이 작성

MTest.java

beanTest라는 이름을 가진 bean 객체를 호출

package com.test01;

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

public class MTest {

	public static void main(String[] args) {

		ApplicationContext factory = new ClassPathXmlApplicationContext("com/test01/applicationContext.xml");

		BeanTest beans = (BeanTest) factory.getBean("beanTest");
	}
}

2. setter 이용하기 ( 클래스 )

New > Class > MyClass.java 생성하고 다음과 같이 작성

MyClass.java

package com.test01;

public class MyClass {

	public MyClass() {
		System.out.println("MyClass()");
	}
}

BeanTest.java에 MyClass 필드 작성, setter 작성

BeanTest.java

package com.test01;

import java.util.Date;

public class BeanTest {

	private MyClass myClass;

	public BeanTest() {
		System.out.println("기본 생성자!");
	}
    
    	public BeanTest(Date date) {
		System.out.println("파라미터 1개 생성자(Date date) : " + date);
		System.out.println();
	}

	public void setMyClass(MyClass myClass) {
		this.myClass = myClass;
		System.out.println("setMyClass(MyClass myClass) 호출");
	}
    
}

applicationContext.xml 에 myClass bean 객체 생성, property 추가

applicationContext.xml

<property> : setter를 호출 ( 여기서는 setMyClass(MyClass myClass) )

<!-- 2. -->
<bean id="myClass" class="com.test01.MyClass"></bean>

<bean id="beanTest" class="com.test01.BeanTest">
	<!-- 1. public BeanTest(Date date) 호출 - 2020.12.25 -->
	<constructor-arg name="date" ref="date"></constructor-arg>
        
	<!-- 2. setMyClass(MyClass myClass) 호출 -->
	<property name="myClass" ref="myClass"></property>
</bean>

MTest.java

package com.test01;

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

public class MTest {

	public static void main(String[] args) {

		ApplicationContext factory = new ClassPathXmlApplicationContext("com/test01/applicationContext.xml");

		MyClass my = (MyClass) factory.getBean("myClass");

		BeanTest beans = (BeanTest) factory.getBean("beanTest");
	}
}

applicationContext.xml에서 lazy-init 사용하기

lazy-init : bean 생성을 늦출 수 있습니다.

lazy-init="false" : 시작 시 생성합니다. ( default )

lazy-init="true" : 특정 bean에 대한 요청이 있을 시 생성합니다. ( 여기서는 myClass bean 객체를 호출했을 때 생성됨 )

<!-- 2. -->
<!-- lazy-init : 호출을 늦춤 -->
<bean id="myClass" class="com.test01.MyClass" lazy-init="true"></bean>

<bean id="beanTest" class="com.test01.BeanTest">
	<!-- 1. public BeanTest(Date date) 호출 - 2020.12.25 -->
	<constructor-arg name="date" ref="date"></constructor-arg>
        
	<!-- 2. setMyClass(MyClass myClass) 호출 -->
	<property name="myClass" ref="myClass"></property>
</bean>

3. setter 이용하기 ( 숫자 )

BeanTest.java

package com.test01;

public class BeanTest {

	public void setNumber(int i) {
		System.out.println();
		System.out.println("setNumber(int i) 호출 : " + i);
	}
    
}

applicationContext.xml

<bean id="beanTest" class="com.test01.BeanTest">
	<!-- 4. setNumber(int i) 호출 -->
	<property name="number">
		<value type="short">27</value>	<!-- 묵시적 형 변환 -->
	</property>
</bean>

setter의 파라미터로 들어가는 값의 타입을 short라고 지정해주어도 묵시적 형 변환이 일어나 27로 잘 나옵니다.

4. setter 이용하기 ( Array )

BeanTest.java

package com.test01;

public class BeanTest {

	public BeanTest() {
		System.out.println("기본 생성자!");
	}

	public void setArray(String[] arr) {
		System.out.println();
		System.out.println("setArray(String[] arr) 호출 : ");

		for (String str : arr) {
			System.out.println(str);
		}
	}

}

applicationContext.xml

<bean id="beanTest" class="com.test01.BeanTest">
	<!-- 5. setArray(String[] arr) 호출 -->
	<property name="array">
		<array>
			<value>홍길동</value>
			<value>이순신</value>
			<value>백승아</value>
		</array>
	</property>

</bean>

5. setter 이용하기 ( Collection - List , Set , Map )

BeanTest.java

package com.test01;

import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Set;

public class BeanTest {

	public BeanTest() {
		System.out.println("기본 생성자!");
	}

	public void setList(List<String> list) {
		System.out.println();
		System.out.println("setList(List<String> list) 호출");

		for (String str : list) {
			System.out.println(str);
		}
	}

	public void setMySet(Set<String> set) {
		System.out.println();
		System.out.println("setMySet(Set<String> set) 호출");

		for (String str : set) {
			System.out.println(str);
		}
	}

	public void setMap(Map<String, String> map) {
		System.out.println();
		System.out.println("setMap(Map<String, String> map) 호출");

		Collection<String> keys = map.keySet();
		Collection<String> values = map.values();

		for (String key : keys) {
			System.out.println(key + " : " + map.get(key));
		}
	}

}

applicationContext.xml

<bean id="beanTest" class="com.test01.BeanTest">

	<!-- 6. setList(List<String> list) 호출 -->
	<property name="list">
		<list>
			<value>봄</value>
			<value>여름</value>
			<value>가을</value>
			<value>겨울</value>
		</list>
	</property>

	<!-- 7. setMySet(Set<String> set) 호출 -->
	<property name="mySet">
		<!-- 중복을 허용하지 않음 -->
		<set>
			<value>1</value>
			<value>1</value>
			<value>2</value>
			<value>3</value>
			<value>3</value>
		</set>
	</property>

	<!-- 8. setMap(Map<String, String> map) 호출 - 1:봄, 2:여름, 3:가을, 4:겨울 -->
	<property name="map">
		<map>
			<entry key="1">
				<value>봄</value>
			</entry>
			<entry>
				<key><value>2</value></key>
				<value>여름</value>
			</entry>
			<entry key="3" value="가을"></entry>
			<entry key="4" value="겨울" />
		</map>
	</property>

</bean>

6. setter 이용하기

New > Class > Score.java 생성하고 다음과 같이 작성

package com.test01;

public class Score {

	private String name;
	private int kor;
	private int eng;
	private int math;

	public Score() {
	}

	public Score(String name, int kor, int eng, int math) {
		this.name = name;
		this.kor = kor;
		this.eng = eng;
		this.math = math;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public int getKor() {
		return kor;
	}

	public void setKor(int kor) {
		this.kor = kor;
	}

	public int getEng() {
		return eng;
	}

	public void setEng(int eng) {
		this.eng = eng;
	}

	public int getMath() {
		return math;
	}

	public void setMath(int math) {
		this.math = math;
	}

	@Override
	public String toString() {
		return "Score [name=" + name + ", kor=" + kor + ", eng=" + eng + ", math=" + math + "]";
	}

}

BeanTest.java

package com.test01;

import java.util.List;

public class BeanTest {

	public void setScore(List<Score> score) {
		System.out.println("setScore(List<Score> score) 호출");

		for (Score sc : score) {
			System.out.println(sc);
		}
	}

}

applicationContext.xml

<bean id="beanTest" class="com.test01.BeanTest">
    <!-- 9. setScore(List<Score> score) 호출 -->
	<property name="score">
		<list>
			<bean class="com.test01.Score">
				<property name="name" value="홍길동"></property>
				<property name="kor" value="90"></property>
				<property name="eng" value="88"></property>
				<property name="math" value="59"></property>
			</bean>

			<!-- 특정 bean을 가지고 옴 -->
			<ref bean="lee" />
		</list>
	</property>
</bean>

<!-- 9. -->
<bean id="lee" class="com.test01.Score">
	<constructor-arg value="이순신"></constructor-arg>
	<constructor-arg value="66"></constructor-arg>
	<constructor-arg value="99"></constructor-arg>
	<constructor-arg value="80"></constructor-arg>
</bean>

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