의존객체
- DI(Dependency injection)
- 다양한 의존 객체 주입 : constructor-arg(생성자), setter, List Type, Map Type
- 스프링 설정 파일 분리 : Singleton, Prototype
- 의존객체 자동 주입 : @Autowired, @Resource
- 의존객체 선택 : qualifier Tag, @Qualifier, @Inject

의존객체

DI(Dependency-Injection)

의존성 주입

Example)

장난감 배터리 주입 (in Java)

// 배터리 일체형 장난감
public class ElectronicCarToy {
    private Battery battery;

    public ElectronicCarToy() {
        // 생성자에서 주입
        battery = new NormalBattery(); 
    }
}

// 배터리 분리형 장난감
public class ElectronicRobotToy {
    private Battery battery;
    
    public ElectronicRobotToy() {
        // 배터리가 들어있지 않은 빈 장난감
    }
    
    public void setBattery(Battery battery) {
        // 필요 시 setBattery() method를 사용하여 배터리 주입
    	this.battery = battery;	
    }
}

// 배터리 분리형 장난감(구매 시 건전지 포함)
public class ElectronicRadioToy {
    private Battery battery;
    
    public ElectronicRadioToy(Battery battery) {
        // 배터리가 들어있는 장난감
    	this.battery = battery; 
    }
    
    public void setBattery(Battery battery) {
        // 필요 시 setBattery() method를 사용하여 배터리 주입
    	this.battery = battery; 
    }
}

DI ?

한 객체를 다른 객체가 생성될 때 주입

Java VS Spring (생성자에서 주입)

Java

/*
ems.member.assembler.StudentAssembler.java
*/
public class StudentAssembler {

	//..
	
	public StudentAssembler() {
		studentDao = new StudentDao();
        // registerService, modifyService 는 studentDao 객체의 의존(의존 주입)
		registerService = new StudentRegisterService(studentDao);
		modifyService = new StudentModifyService(studentDao);
		deleteService = new StudentDeleteService(studentDao);
		selectService = new StudentSelectService(studentDao);
		allSelectService = new StudentAllSelectService(studentDao);
	}

	// ...
}

// ems.member.service.StudentRegisterService.java
	private StudentDao studentDao;

	public StudentRegisterService(StudentDao studentDao) {
		this.studentDao = studentDao;
	}
// ems.member.service.StudentModifyService.java
	private StudentDao studentDao;
	
	public StudentModifyService(StudentDao studentDao) {
		this.studentDao = studentDao;
	}
// ems.member.service.StudentDeleteService.java
	private StudentDao studentDao;
	
	public StudentDeleteService(StudentDao studentDao) {
		this.studentDao = studentDao;
	}
// ems.member.service.StudentSelectService.java
	private StudentDao studentDao;
	
	public StudentSelectService(StudentDao studentDao) {
		this.studentDao = studentDao;
	}
// ems.member.service.StudentAllSelectService.java
	private StudentDao studentDao;
	
	public StudentAllSelectService(StudentDao studentDao) {
		this.studentDao = studentDao;
	}

    
/*
ems.member.main.MainClass.java
*/

StudentAssembler assembler = new StudentAssembler();

StudentRegisterService registerService = assembler.getRegisterService();
		
StudentModifyService modifyService = assembler.getModifyService();

StudentSelectService selectService = assembler.getSelectService();
				
StudentAllSelectService allSelectService = assembler.getAllSelectService();

Spring

<!-- 
src/main/resources/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">

    <!-- Dao 객체 생성 -->
	<bean id="studentDao" class="ems.member.dao.StudentDao" ></bean>
	
    <!-- constructor-arg tag를 이용한 StdentDao 객체 주입 -->
	<bean id="registerService" class="ems.member.service.StudentRegisterService">
		<constructor-arg ref="studentDao" ></constructor-arg>
	</bean>
	
	<bean id="modifyService" class="ems.member.service.StudentModifyService">
		<constructor-arg ref="studentDao" ></constructor-arg>
	</bean>
	
	<bean id="deleteService" class="ems.member.service.StudentDeleteService">
		<constructor-arg ref="studentDao" ></constructor-arg>
	</bean>
	
	<bean id="selectService" class="ems.member.service.StudentSelectService">
		<constructor-arg ref="studentDao" ></constructor-arg>
	</bean>
	
	<bean id="allSelectService" class="ems.member.service.StudentAllSelectService">
		<constructor-arg ref="studentDao" ></constructor-arg>
	</bean>
    
	<!-- ... -->
    
</beans>

/* 
ems.member.main.MainClassUseXML.java
*/

GenericXmlApplicationContext ctx = 
				new GenericXmlApplicationContext("classpath:applicationContext.xml");

StudentRegisterService registerService = 
    ctx.getBean("registerService", StudentRegisterService.class);

StudentModifyService modifyService  = ctx.getBean("modifyService", StudentModifyService.class);

StudentSelectService selectService = ctx.getBean("selectService", StudentSelectService.class);

StudentAllSelectService allSelectService = 
    ctx.getBean("allSelectService", StudentAllSelectService.class);

다양한-의존-객체-주입

생성자를 이용한 의존 객체 주입 (constructor-arg TAG)

Java

public StudentRegisterService(StudentDao studentDao) {
    this.studentDao = studentDao;
}
   
public StudentModifyService(StudentDao studentDao) {
    this.studentDao = studentDao;
}
   
public StudentDeleteService(StudentDao studentDao) {
    this.studentDao = studentDao;
}
   
public StudentSelectService(StudentDao studentDao) {
    this.studentDao = studentDao;
}
   
public StudentAllSelectService(StudentDao studentDao) {
    this.studentDao = studentDao;
}

Spring

<bean id="studentDao" class="ems.member.dao.StudentDao" ></bean>
   	
<bean id="registerService" class="ems.member.service.StudentRegisterService">
    <constructor-arg ref="studentDao" ></constructor-arg>
</bean>
   
<bean id="modifyService" class="ems.member.service.StudentModifyService">
    <constructor-arg ref="studentDao" ></constructor-arg>
</bean>
   
<bean id="deleteService" class="ems.member.service.StudentDeleteService">
    <constructor-arg ref="studentDao" ></constructor-arg>
</bean>
   
<bean id="selectService" class="ems.member.service.StudentSelectService">
    <constructor-arg ref="studentDao" ></constructor-arg>
</bean>
   
<bean id="allSelectService" class="ems.member.service.StudentAllSelectService">
    <constructor-arg ref="studentDao" ></constructor-arg>
</bean>

setter를 이용한 의존 객체 주입

Java

public void setJdbcUrl(String jdbcUrl) {
	this.jdbcUrl = jdbcUrl;
}
public void setUserId(String userId) {
	this.userId = userId;
}
public void setUserPw(String userPw) {
	this.userPw = userPw;
}
   

Spring

<bean id="dataBaseConnectionInfoDev" class="ems.member.DataBaseConnectionInfo">
	<property name="jdbcUrl" value="jdbc:oracle:thin:@localhost:1521:xe" />
	<property name="userId" value="scott" />
	<property name="userPw" value="tiger" />
</bean>

List타입 의존 객체 주입

Java

public void setDevelopers(List<String> developers) {
	this.developers = developers;
}

Spring

<property name="developers">
    <list>
        <value>Cheney.</value>
        <value>Eloy.</value>
        <value>Jasper.</value>
        <value>Dillon.</value>
        <value>Kian.</value>
    </list>
</property>
   

Map 타입 객체 주입

Java

public void setAdministrators(Map<String, String> administrators) {
	this.administrators = administrators;
}

Spring

<property name="administrators">
    <map>
        <entry>
            <key>
            	<value>Cheney</value>
            </key>
            	<value>cheney@springPjt.org</value>
        </entry>
        <entry>
            <key>
            	<value>Jasper</value>
            </key>
            	<value>jasper@springPjt.org</value>
        </entry>
    </map>
</property>

스프링-설정-파일-분리

기능이 추가되면서 xml 파일이 길어지는 것을 방지하기 위해 기능별로 xml 파일을 분리

1.여러 xml 파일을 배열 형태로 불러서 사용

applicationContext.xml (Original)

<?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="studentDao" class="ems.member.dao.StudentDao" ></bean>
  	
  	
	<bean id="registerService" class="ems.member.service.StudentRegisterService">
		<constructor-arg ref="studentDao" ></constructor-arg>
	</bean>
  	
	<bean id="modifyService" class="ems.member.service.StudentModifyService">
		<constructor-arg ref="studentDao" ></constructor-arg>
	</bean>
  	
	<bean id="deleteService" class="ems.member.service.StudentDeleteService">
		<constructor-arg ref="studentDao" ></constructor-arg>
	</bean>
  	
	<bean id="selectService" class="ems.member.service.StudentSelectService">
		<constructor-arg ref="studentDao" ></constructor-arg>
	</bean>
  	
	<bean id="allSelectService" class="ems.member.service.StudentAllSelectService">
		<constructor-arg ref="studentDao" ></constructor-arg>
	</bean>
  	
	<bean id="dataBaseConnectionInfoDev" class="ems.member.DataBaseConnectionInfo">
		<property name="jdbcUrl" value="jdbc:oracle:thin:@localhost:1521:xe" />
		<property name="userId" value="scott" />
		<property name="userPw" value="tiger" />
	</bean>
  	
	<bean id="dataBaseConnectionInfoReal" class="ems.member.DataBaseConnectionInfo">
		<property name="jdbcUrl" value="jdbc:oracle:thin:@192.168.0.1:1521:xe" />
		<property name="userId" value="masterid" />
		<property name="userPw" value="masterpw" />
	</bean>
  	
	<bean id="informationService" class="ems.member.service.EMSInformationService">
		<property name="info">
			<value>Education Management System program was developed in 2015.</value>
		</property>
		<property name="copyRight">
			<value>COPYRIGHT(C) 2015 EMS CO., LTD. ALL RIGHT RESERVED. CONTACT MASTER FOR MORE INFORMATION.</value>
		</property>
		<property name="ver">
			<value>The version is 1.0</value>
		</property>
		<property name="sYear">
			<value>2015</value>
		</property>
		<property name="sMonth">
			<value>1</value>
		</property>
		<property name="sDay">
			<value>1</value>
		</property>
		<property name="eYear" value="2015" />
		<property name="eMonth" value="2" />
		<property name="eDay" value="28" />
		<property name="developers">
			<list>
				<value>Cheney.</value>
				<value>Eloy.</value>
				<value>Jasper.</value>
				<value>Dillon.</value>
				<value>Kian.</value>
			</list>
		</property>
		<property name="administrators">
			<map>
				<entry>
					<key>
						<value>Cheney</value>
					</key>
					<value>cheney@springPjt.org</value>
				</entry>
				<entry>
					<key>
						<value>Jasper</value>
					</key>
					<value>jasper@springPjt.org</value>
				</entry>
			</map>
		</property>
		<property name="dbInfos">
			<map>
				<entry>
					<key>
						<value>dev</value>
					</key>
					<ref bean="dataBaseConnectionInfoDev"/>
				</entry>
				<entry>
					<key>
						<value>real</value>
					</key>
					<ref bean="dataBaseConnectionInfoReal"/>
				</entry>
			</map>
		</property>
	</bean>
  	
</beans>

appService.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="studentDao" class="ems.member.dao.StudentDao" ></bean>
  	
  	
	<bean id="registerService" class="ems.member.service.StudentRegisterService">
		<constructor-arg ref="studentDao" ></constructor-arg>
	</bean>
  	
	<bean id="modifyService" class="ems.member.service.StudentModifyService">
		<constructor-arg ref="studentDao" ></constructor-arg>
	</bean>
  	
	<bean id="deleteService" class="ems.member.service.StudentDeleteService">
		<constructor-arg ref="studentDao" ></constructor-arg>
	</bean>
  	
	<bean id="selectService" class="ems.member.service.StudentSelectService">
		<constructor-arg ref="studentDao" ></constructor-arg>
	</bean>
  	
	<bean id="allSelectService" class="ems.member.service.StudentAllSelectService">
		<constructor-arg ref="studentDao" ></constructor-arg>
	</bean>
  	
</beans>

appDatabase.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="dataBaseConnectionInfoDev" class="ems.member.DataBaseConnectionInfo">
		<property name="jdbcUrl" value="jdbc:oracle:thin:@localhost:1521:xe" />
		<property name="userId" value="scott" />
		<property name="userPw" value="tiger" />
	</bean>
  	
	<bean id="dataBaseConnectionInfoReal" class="ems.member.DataBaseConnectionInfo">
		<property name="jdbcUrl" value="jdbc:oracle:thin:@192.168.0.1:1521:xe" />
		<property name="userId" value="masterid" />
		<property name="userPw" value="masterpw" />
	</bean>
  	
</beans>

appInfo.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="informationService" class="ems.member.service.EMSInformationService">
		<property name="info">
			<value>Education Management System program was developed in 2015.</value>
		</property>
		<property name="copyRight">
			<value>COPYRIGHT(C) 2015 EMS CO., LTD. ALL RIGHT RESERVED. CONTACT MASTER FOR MORE INFORMATION.</value>
		</property>
		<property name="ver">
			<value>The version is 1.0</value>
		</property>
		<property name="sYear">
			<value>2015</value>
		</property>
		<property name="sMonth">
			<value>1</value>
		</property>
		<property name="sDay">
			<value>1</value>
		</property>
		<property name="eYear" value="2015" />
		<property name="eMonth" value="2" />
		<property name="eDay" value="28" />
		<property name="developers">
			<list>
				<value>Cheney.</value>
				<value>Eloy.</value>
				<value>Jasper.</value>
				<value>Dillon.</value>
				<value>Kian.</value>
			</list>
		</property>
		<property name="administrators">
			<map>
				<entry>
					<key>
						<value>Cheney</value>
					</key>
					<value>cheney@springPjt.org</value>
				</entry>
				<entry>
					<key>
						<value>Jasper</value>
					</key>
					<value>jasper@springPjt.org</value>
				</entry>
			</map>
		</property>
		<property name="dbInfos">
			<map>
				<entry>
					<key>
						<value>dev</value>
					</key>
					<ref bean="dataBaseConnectionInfoDev"/>
				</entry>
				<entry>
					<key>
						<value>real</value>
					</key>
					<ref bean="dataBaseConnectionInfoReal"/>
				</entry>
			</map>
		</property>
	</bean>
  	
</beans>

Main.java

String[] appCtxs =
	{"classpath:appCtx1.xml", "classpath:appCtx2.xml", "classpath:appCtx3.xml"};
GenericXmlApplicationContext ctx = new GenericXmlApplicationContext(appCtxs);

2.여러 xml 파일을 import 하여 사용

appCtximport.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">
  
	<import resource="classpath:appDatabase.xml"/>
	<import resource="classpath:appInfo.xml"/>
  
	<bean id="studentDao" class="ems.member.dao.StudentDao" ></bean>
  	
  	
	<bean id="registerService" class="ems.member.service.StudentRegisterService">
		<constructor-arg ref="studentDao" ></constructor-arg>
	</bean>
  	
	<bean id="modifyService" class="ems.member.service.StudentModifyService">
		<constructor-arg ref="studentDao" ></constructor-arg>
	</bean>
  	
	<bean id="deleteService" class="ems.member.service.StudentDeleteService">
		<constructor-arg ref="studentDao" ></constructor-arg>
	</bean>
  	
	<bean id="selectService" class="ems.member.service.StudentSelectService">
		<constructor-arg ref="studentDao" ></constructor-arg>
	</bean>
  	
	<bean id="allSelectService" class="ems.member.service.StudentAllSelectService">
		<constructor-arg ref="studentDao" ></constructor-arg>
	</bean>
  	
</beans>

Main.java

enericXmlApplicationContext ctx =  
    new GenericXmlApplicationContext("classpath:appCtxImport.xml");

빈(Bean)의 범위

싱글톤(Singleton) :
- 스프링 컨테이너에서 생성된 빈(Bean)객체의 경우 동일한 타입에 대해서는 기본적으 로 한 개만 생성이 되며, getBean() 메소드로 호출될 때 동일한 객체가 반환
- 객체를 여러 번 생성하더라고 동일한 객체를 공유
프로토타입(Prototype) :
- 싱글톤 범위와 반대의 개념도 있는데 이를 프로토타입(Prototype) 범위라고 한다. 프로토타입의 경우 개발자는 별도로 설정을 해줘야 하는데, 스프링 설정 파일에서 빈 (Bean)객체을 정의할 때 scope속성을 명시해 주면 된다.
- 객체를 호출할 때마다 다른 객체로 생성하고 싶은 경우
```
<bean id="injectionBean" class="scope.ex.InjectionBean" />
  	
<bean id="dependencyBean" class="scope.ex.DependencyBean" scope="prototype">
    <constructor-arg ref="injectionBean" />
    <property name="injectionBean" ref="injectionBean" />
</bean>
```

의존객체-자동-주입

의존객체 자동 주입 :
- 스프링 설정 파일에서 의존 객체를 주입할 때 또는 태그로 의존 대상 객체를 명시하지 않아도 스프링 컨테이너 가 자동으로 필요한 의존 대상 객체를 찾아서 의존 대상 객체가 필요한 객체에 주입해 주는 기능
- 구현 방법은 @Autowired와 @Resource 어노테이션을 이용해서 쉽게 구현
- 실무에서도 많이 사용(주로 @Autowired)

@Autowired

주입하려고 하는 객체의 타입이 일치하는 객체를 자동으로 주입

@Autowired가 적용되어 있는 구문에 필요한 객체의 데이터 타입을 가지고 있는 Bean 객체를 Ctx.xml 에서 찾고, 알맞는 데이터 타입을 넣어 주는 방식

appCtx.xml

<?xml version="1.0" encoding="UTF-8"?>
    
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:context="http://www.springframework.org/schema/context" <!-- +추가 -->
	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  <!-- +추가 -->
 		http://www.springframework.org/schema/context  <!-- +추가 -->
 		http://www.springframework.org/schema/context/spring-context.xsd" <!-- +추가 -->>
    
	<context:annotation-config /> <!-- +추가 --> 
    
	<bean id="wordDao" class="com.word.dao.WordDao" />
	<bean id="registerService" class="com.word.service.WordRegisterServiceUseAutowired" />
	<!-- constructor-arg ref="wordDao" /> -제거 -->
	<bean id="searchService" class="com.word.service.WordSearchServiceUseAutowired" />
	<!-- constructor-arg ref="wordDao" /> -제거 -->
    	
</beans>

java

// WordRegisterService.java
    
	@Autowired
	public WordRegisterService(WordDao wordDao) {
		this.wordDao = wordDao;
	}
    
// WordSearchService.java
    
    @Autowired
    public WordSearchService(WordDao wordDao) {
		this.wordDao = wordDao;
	}

property나 method에 @Autowired 사용 시 default 생성자 필요

	@Autowired
	private WordDao wordDao;
    	
	public WordRegisterService() {
	}
    
	@Autowired
	public void setWordDao(WordDao wordDao) {
		this.wordDao = wordDao;
	}

@Resource
- 주입하려고 하는 객체의 이름이 일치하는 객체를 자동으로 주입
- 생성자에서는 사용할 수 없고, property나 method에 사용 가능
- property나 method에 적용하기 위해서는 default 생성자 필요
- 객체가 일단 생성되어야 property나 method에 자동주입이 가능하므로
  - appCtx.xml 은 @Autowired 과 동일
  - Java
```
	@Resource
	private WordDao wordDao;
    	
	public WordRegisterService() {
	}
    
	@Resource
	public void setWordDao(WordDao wordDao) {
		this.wordDao = wordDao;
	}
```

의존객체-선택

다수의 빈(Bean)객체 중 의존 객체의 대상이 되는 객체를 선택하는 방법

동일한 객체가 2개 이상인 경우 스프링 컨테이너는 자동 주입 대상 객체를 판단하지 못해서 Exception을 발생

Problem

WordDao라는 class로부터 여러 객체가 만들어 질 경우 (.xml)

<bean id="wordDao1" class="com.word.dao.WordDao" />
<bean id="wordDao2" class="com.word.dao.WordDao" />
<bean id="wordDao3" class="com.word.dao.WordDao" />

property WordDao DataType의 wordDao를 @Autowired를 이용하여 자동주입 할 경우 (.java)
```
@Autowired
private WordDao wordDao;
```

어떤 Bean 객체를 주입해야할지 모르기 때문에 Exception 발생

No qualifying bean of type [com.word.dao.WordDao] is defined: expected single matching bean but found 3: wordDao1,wordDao2,wordDao3     
    
expected single matching bean but found 3: wordDao1,wordDao2,wordDao3

Solution

qualifier Tag 사용 (.xml)

<bean id="wordDao1" class="com.word.dao.WordDao" >
    <qualifier value="usedDao"/>
</bean>
<bean id="wordDao2" class="com.word.dao.WordDao" />
<bean id="wordDao3" class="com.word.dao.WordDao" />

Qualifier annotation 사용 (.java)

@Autowired
@Qualifier("usedDao")
private WordDao wordDao;

@Inject

@Autowired와 거의 비슷하게 @Inject 어노테이션을 이용해서 의존 객체를 자동으로 주입
@Autowired와 차이점 이라면 @Autowired의 경우 required 속성을 이용해서 의존 대상 객체가 없어도 익셉션을 피할 수 있지만, @Inject의 경우 required 속성을 지원하지 않음

@Autowired은 qualifier Tag를 사용했지만 @Inject는 Bean객체 ID만 명시

<bean id="wordDao1" class="com.word.dao.WordDao" />
<bean id="wordDao2" class="com.word.dao.WordDao" />
<bean id="wordDao3" class="com.word.dao.WordDao" />

@Inject
@Named(value = "wordDao1")
private WordDao wordDao;

Spring 의존객체

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