Spring DI(Dependency Injection), 세터 주입(Setter Injection), XML, 어노테이션기반, 생성자 주입(Constructor Injection) – XML 기반, 어노테이션기반, 메소드 주입(Method Injection)
2-5. Spring DI(Dependency Injection)
2-5-1. 세터 주입(Setter Injection) – XML 기반
n 세터주입은 클래스 사이의 의존관계를 연결시키기 위해 setter 메소드를 이용하는 방법이다.
[Emp.java]
package edu.ojc.setter1; interface Emp { public abstract void gotoOffice(); public abstract void getoffWork(); } |
[Programmer.java]
package edu.ojc.setter1; class Programmer implements Emp { public void gotoOffice() { System.out.println("프로그래머 출근 합니다."); } public void getoffWork() { System.out.println("프로그래머 퇴근 합니다."); } } |
[Designer.java]
package edu.ojc.setter1;
class Designer implements Emp { public void gotoOffice() { System.out.println("디자이너 출근 합니다."); } public void getoffWork() { System.out.println("디자이너 퇴근 합니다."); } } |
[Develop.java]
package edu.ojc.setter1;
public class Develope { Emp emp; public void setEmp(Emp emp) { this.emp = emp; } void coding() { emp.gotoOffice(); System.out.println("개발합니다..."); emp.getoffWork(); } } |
[Src/main/resources/ojc1.xml] – p 네임스페이스를 이용한 세터주입
<?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"> <bean id="programmer" class="edu.ojc.setter1.Programmer" /> <bean id="designer" class="edu.ojc.setter1.Designer" /> <bean id="develope" class="edu.ojc.setter1.Develope" p:emp-ref="programmer" /> <!-- //아래처럼 Property 태그를 이용해도 된다. <bean id="develope" class="edu.ojc.setter1.Develope"> <property name="emp“><ref bean="programmer"/></property> </bean> <bean id="develope" class="edu.ojc.setter1.Develope"> <property name="emp" ref="programmer"/> </bean> --> </beans> |
[TestMain.java]
package edu.ojc.setter1;
import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext;
public class TestMain { public static void main(String[] args) { ApplicationContext context = new ClassPathXmlApplicationContext("ojc1.xml");
Develope dev = (Develop)context.getBean("develope"); dev.coding(); } } |
2-5-2. 세터 주입(Setter Injection) – 어노테이션 기반
[Emp.java]
package edu.ojc.setter2; interface Emp { public abstract void gotoOffice(); public abstract void getoffWork(); } |
[Programmer.java]
package edu.ojc.setter2; import org.springframework.stereotype.Service; @Service class Programmer implements Emp { public void gotoOffice() { System.out.println("프로그래머 출근 합니다."); } public void getoffWork() { System.out.println("프로그래머 퇴근 합니다."); } } |
[Designer.java]
package edu.ojc.setter2; import org.springframework.stereotype.Service; @Service class Designer implements Emp { public void gotoOffice() { System.out.println("디자이너 출근 합니다."); } public void getoffWork() { System.out.println("디자이너 퇴근 합니다."); } } |
[Develop.java]
package edu.ojc.setter2;
import org.springframework.beans.factory.annotation.Autowired; import org.springframework.beans.factory.annotation.Qualifier; import org.springframework.stereotype.Service; @Service public class Develope { Emp emp; @Autowired @Qualifier("programmer") public void setEmp(Emp emp) { this.emp = emp; } void coding() { emp.gotoOffice(); System.out.println("개발합니다..."); emp.getoffWork(); } } |
[Src/main/resources/ojc2.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:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.2.xsd"> <context:component-scan base-package="edu.ojc.setter2"/> </beans> |
[TestMain.java]
package edu.ojc.setter2;
import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext;
public class TestMain { public static void main(String[] args) { ApplicationContext context = new ClassPathXmlApplicationContext("ojc1.xml");
Develope dev = (Develop)context.getBean("develope"); dev.coding(); } } |
2-5-3. 생성자 주입(Constructor Injection) – XML 기반
[Emp.java]
package edu.ojc.constructor1; interface Emp { public abstract void gotoOffice(); public abstract void getoffWork(); } |
[Programmer.java]
package edu.ojc.constructor1;
class Programmer implements Emp { public void gotoOffice() { System.out.println("프로그래머 출근 합니다."); } public void getoffWork() { System.out.println("프로그래머 퇴근 합니다."); } } |
[Designer.java]
package edu.ojc.constructor1;
class Designer implements Emp { public void gotoOffice() { System.out.println("디자이너 출근 합니다."); } public void getoffWork() { System.out.println("디자이너 퇴근 합니다."); } } |
[Develop.java]
package edu.ojc.constructor1;
public class Develope { Emp emp; public Develope(Emp emp) { this.emp = emp; }
void coding() { emp.gotoOffice(); System.out.println("개발합니다..."); emp.getoffWork(); } } |
[Src/main/resources/ojc3.xml] – C 네임스페이스를 이용한 세터주입
<?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:c="http://www.springframework.org/schema/c" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd"> <bean id="programmer" class="edu.ojc.constructor1.Programmer" /> <bean id="designer" class="edu.ojc.constructor1.Designer" /> <bean id="develope" class="edu.ojc.constructor1.Develope" c:emp-ref="programmer" /> <!--
<bean id="develope" class="edu.ojc.constructor1.Develope"> <constructor-arg ref="programmer"/> </bean> --> </beans> |
[TestMain.java]
package edu.ojc.constructor1;
import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext;
public class TestMain { public static void main(String[] args) { ApplicationContext context = new ClassPathXmlApplicationContext("ojc3.xml");
Develope dev = (Develope)context.getBean("develope"); dev.coding(); } } |
2-5-4. 생성자 주입(Constructor Injection) – 어노테이션 기반
[Emp.java]
package edu.ojc.constructor2; interface Emp { public abstract void gotoOffice(); public abstract void getoffWork(); } |
[Programmer.java]
package edu.ojc.constructor2; import org.springframework.stereotype.Service; @Service class Programmer implements Emp { public void gotoOffice() { System.out.println("프로그래머 출근 합니다."); } public void getoffWork() { System.out.println("프로그래머 퇴근 합니다."); } } |
[Designer.java]
package edu.ojc.constructor2; import org.springframework.stereotype.Service; @Service class Designer implements Emp { public void gotoOffice() { System.out.println("디자이너 출근 합니다."); } public void getoffWork() { System.out.println("디자이너 퇴근 합니다."); } } |
[Develop.java]
package edu.ojc.constructor2;
import org.springframework.beans.factory.annotation.Autowired; import org.springframework.beans.factory.annotation.Qualifier; import org.springframework.stereotype.Service;
@Service public class Develope { Emp emp; @Autowired public Develope(@Qualifier(value="programmer") Emp emp) { this.emp = emp; }
void coding() { emp.gotoOffice(); System.out.println("개발합니다..."); emp.getoffWork(); } } |
[Src/main/resources/ojc4.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:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.2.xsd"> <context:component-scan base-package="edu.ojc.constructor2"/> </beans> |
[TestMain.java]
package edu.ojc.constructor2;
import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext;
public class TestMain { public static void main(String[] args) { ApplicationContext context = new ClassPathXmlApplicationContext("ojc4.xml");
Develope dev = (Develop)context.getBean("develope"); dev.coding(); } } |
n 세터주입 또는 생성자 주입에서 멀티 아규멘트 처리방법
<bean id="myButton" class="java.awt.Button"> <property name="bounds" ref="rectangle"/> <property name="label" value="Click me..."/> </bean>
<bean id="rectangle" class="java.awt.Rectangle"> <constructor-arg value="0"/> <constructor-arg value="0"/> <constructor-arg value="100"/> <constructor-arg value="10"/> </bean>
<bean id="name" class="com.erjablow.Name" scope="prototype"p:givenName="Ming" p:middleName="the" p:surName="Merciless"/>
<bean id="someobject" class="SomeClass" /> <bean class="org.springframework.beans.factory.config.MethodInvokingFactoryBean"> <property name="targetObject"><ref local="someobject"/></property> <property name="targetMethod"><value>set</value></property> <property name="arguments"> <list> <value> "String1" </value> <value> "String2" </value> </list> </property> </bean> |
2-5-5. 메소드 주입(Method Injection)
n Method 정의 전체에 Bean을 주입하는 것으로 Method Replace와 Getter Injection으로 구별할 수 있다.
ü Method Replace(메소드 대체) : 기존 메소드를 런타임 중에 새로운 구현으로 대체
ü Getter Injection(게터 주입) : 기존 메소드를 런 타임중에 spring Context로 부터 특정한 빈을 반환하는 새로운 구현으로 대체. Method 주입의 특별한 경우로 Method가 특정 타입의 빈을 반환하도록 선언해 두고(보통 abstract) 런타임 중 실제 반환되는 빈은 Spring Context에서 오도록 하는 방법
2-5-5-1. Method Injection(Method Replace)
[Emp.java]
package ojc1;
public interface Emp { public String work(); } |
[Programmer.java]
package ojc1;
public class Programmer implements Emp { public String work() { return "Programmer Working..."; } } |
[Designer.java]
package ojc1;
import java.lang.reflect.Method;
import org.springframework.beans.factory.support.MethodReplacer; import org.springframework.stereotype.Service;
public class Designer implements MethodReplacer { public Object reimplement(Object target, Method method, Object[] args) throws Throwable { return "Designer Working..."; } } |
[MethodReplaceTest.java]
package ojc1;
import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext;
public class MethodReplaceTest { Emp programmer; public void setProgrammer(Programmer programmer) { this.programmer = programmer; }
public static void main(String[] args) { ApplicationContext context = new ClassPathXmlApplicationContext("lookup.xml"); MethodReplaceTest test = (MethodReplaceTest) context.getBean("methodReplaceTest"); //Programmer의 work()가 아닌 대체자인 Designer의 work()가 실행됨 System.out.println(test.programmer.work()); } } |
[/src/main/resources/lookup.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:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.2.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.2.xsd"> <bean id="programmer" class="ojc1.Programmer"> <replaced-method name="work" replacer="designer" /> </bean>
<bean id="designer" class="ojc1.Designer" />
<bean id="methodReplaceTest" class="ojc1.MethodReplaceTest"> <property name="programmer" ref="programmer"/> </bean> </beans> |
2-5-5-2. Method Injection(Getter Injection)
[Emp.java]
package ojc2; public abstract class Emp { public Emp() {} public void work() { getEmp().work(); //주입받은 객체의 getEmp() 메소드를 사용 } //getEmp를 주입, Emp가 주입된다. //Run-Time중에 xml 파일 정의로 부터 빈을 주입받는다. public abstract Emp getEmp() ; } |
[Programmer.java]
package ojc2;
public class Programmer extends Emp{ public Emp getEmp() { return this; }
public void work() { System.out.println("프로그래머가 개발을 합니다."); } } |
[Designer.java]
package ojc2;
public class Designer extends Emp{ public Emp getEmp() { return this; }
public void work() { System.out.println("디자이너가 디자인을 합니다."); } } |
[/src/main/resources/emp.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-4.2.xsd"> <!-- <bean id="myemp" class="ojc2.Designer" /> --> <bean id="myemp" class="ojc2.Programmer" /> <!-- 아래 lookup-method는 메소드를 런타임 중에 새로운 구현으로 대체 Getter주입은 Setter Injection의 역으로 생각. getEmp()를 호출할 때마다 다른 myemp가 반환 그러나 Getter Injectioin은 단 한번만 주입되는 메소드명이 반드시 getXXX로 시작할 필요는 없다. --> <bean id="emp" class="ojc2.Emp"> <!— 메소드 getEmp()에 myemp 라는 빈이 주입된다 à <lookup-method name="getEmp" bean="myemp" /> </bean> </beans> |
[EmpTest.java]
package ojc2;
import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext;
public class EmpTest { public static void main(String[] args) throws Exception{ ApplicationContext ctx = new ClassPathXmlApplicationContext("emp.xml");
Emp emp = (Emp) ctx.getBean("emp"); emp.work(); } } |
