Spring | Spring DI 지시서 작성 | 객체 결합 | Namespaces

Spring DI 지시서 작성 - Spring Bean Configuraion

스프링 라이브러리 설정하기

maven pom.xml 만들기

스프링 라이브러리 포함시키기

maven index 설치하기 (시간이 오래 걸림)

설치하면 Dependencies에서 add 선택 후 검색해서 maven 라이브러리 추가가 가능하다.

mvnrepository.com/search?q=Springframework

Maven Repository: Springframework

Spring Web MVC Last Release on Feb 16, 2021

mvnrepository.com

injection setter방법과 생성자 방법에서 Spring DI를 이용한 객체 결합하기

xml 방식

Application Context 생성하기

Program.java

package spring.di;

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

import spring.di.entity.Exam;
import spring.di.entity.NewIecExam;
import spring.di.ui.ExamConsole;
import spring.di.ui.GridExamConsole;
import spring.di.ui.InlineExamConsole;

public class Program {

	public static void main(String[] args) {
		
		/* 스프링에게 지시하는 방법으로 코드를 변경
		 * Exam exam = new NewIecExam(); 
		 * ExamConsole console = new GridExamConsole();
		 * 
		 * console.setExam(exam);
		 */
		
		//지시서 읽어들이기
		ApplicationContext context = new ClassPathXmlApplicationContext("spring/di/setting.xml");
		
		//ExamConsole console = (ExamConsole) context.getBean("console"); //id로 꺼내기
		ExamConsole console = context.getBean(ExamConsole.class); //(가르키는 인터페이스 형식에 찹조하는 객체를 찾아준다.) 클래스명으로 가져오기
		console.print();
	}

}

ref 형식 DI

setting.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">
	<!-- Exam exam = new NewIecExam(); -->
	<bean id="exam" class="spring.di.entity.NewIecExam" />
	<!-- ExamConsole console = new GridExamConsole(); -->
	<bean id="console" class="spring.di.ui.GridExamConsole" >
		<!-- console.setExam(exam); -->
		<property name="exam" ref="exam" />
	</bean>	
</beans>

값 형식 DI

getter, setter 해준다.

NewIecExam.java

package spring.di.entity;

public class NewIecExam implements Exam {
	
	private int kor;
	private int eng;
	private int math;
	private int com;
	
	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;
	}

	public int getCom() {
		return com;
	}

	public void setCom(int com) {
		this.com = com;
	}

	@Override
	public int total() {
		// TODO Auto-generated method stub
		return kor+eng+math+com;
	}

	@Override
	public float avg() {
		// TODO Auto-generated method stub
		return total() / 4.0f;
	}

}

pom.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">
	<!-- Exam exam = new NewIecExam(); -->
	<bean id="exam" class="spring.di.entity.NewIecExam" >
		<property name="kor" >
			<value>10</value>
		</property>
		<property name="eng" value="10" />
		<property name="math" value="10" />
		<property name="com" value="10" />
	</bean>
	<!-- ExamConsole console = new GridExamConsole(); -->
	<bean id="console" class="spring.di.ui.GridExamConsole" >
		<!-- console.setExam(exam); -->
		<property name="exam" ref="exam" />
	</bean>	
</beans>

생성자 DI

생성자를 통해서 값을 설정하는 방법

Program.java

package spring.di;

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

import spring.di.entity.Exam;
import spring.di.entity.NewIecExam;
import spring.di.ui.ExamConsole;
import spring.di.ui.GridExamConsole;
import spring.di.ui.InlineExamConsole;

public class Program {

	public static void main(String[] args) {
		
		/* 스프링에게 지시하는 방법으로 코드를 변경
		 * Exam exam = new NewIecExam();
		 * Exam exam = new NewIecExam(10,10,10,10); 
		 * ExamConsole console = new GridExamConsole();
		 * 
		 * console.setExam(exam);
		 */
		
		//지시서 읽어들이기
		ApplicationContext context = new ClassPathXmlApplicationContext("spring/di/setting.xml");
		
		Exam exam = context.getBean(Exam.class);
		System.out.println(exam.toString());
		//ExamConsole console = (ExamConsole) context.getBean("console"); //id로 꺼내기
		ExamConsole console = context.getBean(ExamConsole.class); //(가르키는 인터페이스 형식에 찹조하는 객체를 찾아준다.) 클래스명으로 가져오기
		console.print();
	}

}

NewIecExam.java

package spring.di.entity;

public class NewIecExam implements Exam {
	
	private int kor;
	private int eng;
	private int math;
	private int com;
	
	//생성자
	public NewIecExam() {
		// TODO Auto-generated constructor stub
	}
	
	//생성자 오버로드
	public NewIecExam(int kor, int eng, int math, int com) {
		super();
		this.kor = kor;
		this.eng = eng;
		this.math = math;
		this.com = com;
	}

	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;
	}

	public int getCom() {
		return com;
	}

	public void setCom(int com) {
		this.com = com;
	}

	@Override
	public int total() {
		// TODO Auto-generated method stub
		return kor+eng+math+com;
	}

	@Override
	public float avg() {
		// TODO Auto-generated method stub
		return total() / 4.0f;
	}

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

}

pom.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">
	<!-- Exam exam = new NewIecExam(); -->
	<bean id="exam" class="spring.di.entity.NewIecExam" >
		<constructor-arg name="kor" value="10" />
		<constructor-arg name="math" value="10" />
		<constructor-arg name="com" value="10" />
		<constructor-arg name="eng" value="10" />
	</bean>
	<!-- ExamConsole console = new GridExamConsole(); -->
	<bean id="console" class="spring.di.ui.GridExamConsole" >
		<!-- console.setExam(exam); -->
		<property name="exam" ref="exam" />
	</bean>	
</beans>

설정 파일 처리기 - Namespaces 사용하기

추가적인 처리기의 도움을 받아서 사용함 - 처리기 불러오기

Namespaces p 체크

이름을 식별하기 위해서 확장된 이름을 사용한다.

pom.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"
	xmlns:p="http://www.springframework.org/schema/p"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
	<!-- Exam exam = new NewIecExam(); -->
	<bean id="exam" class="spring.di.entity.NewIecExam" p:kor="10"  p:eng="10" />
	<!-- 	
	<bean id="exam" class="spring.di.entity.NewIecExam" >
		<constructor-arg name="kor" value="10" />
		<constructor-arg name="math" value="10" />
		<constructor-arg name="com" value="10" />
		<constructor-arg name="eng" value="10" />
	</bean> 
	-->
	<!-- ExamConsole console = new GridExamConsole(); -->
	<bean id="console" class="spring.di.ui.GridExamConsole" >
		<!-- console.setExam(exam); -->
		<property name="exam" ref="exam" />
	</bean>	
</beans>