국비학원_59일차(Spring-DI)

써니·2022년 10월 17일
Spring
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spring

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🌞Spring

💻Spring 폴더 기본 세팅

  1. C폴더 안에 spring 폴더를 만들고 Lec폴더를 만든다.
    java tool에 있는 sts.zip을 복사한 후 압축 풀기
    압축 풀 때 경고창이 뜨면 건너뛰기함

  2. Lec 폴더안에 다음과 같은 파일을 복붙한다.

  3. 압축 푼 폴더 안에 sts 오른쪽 마우스-보내기-바탕화면에 바로가기 만든 후 이름을 STS로 변경

  4. spring 폴더 안에 springSrc 폴더 생성

  5. spring workspace 변경

  6. 서버를 탐캣을 맞추기 위해 기존 서버를 delete함

  7. 탐캣 서버 세팅

  8. windows - web Browser - Chrome

  9. windows - preference - workspace / web-css, html, jsp utf-8로 모두 변경+apply

💡 Spring 프레임워크

  1. 대표적 오픈소스기반의 어플리케이션 프레임 워크 - 스프링의 대표적인 프레임워크
  • Spring MVC+ORM(DI 스프링의 기본)

💻IOC-DI 세팅

  1. file - new - Maven project - 첫번째 체크박스 선택

  2. Maven project Setting

  3. pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.oracle</groupId>
  <artifactId>och01_di01</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <description>DI</description>
  
  <dependencies>
  	<dependency>
  		<groupId>org.springframework</groupId>
  		<artifactId>spring-context</artifactId>
  		<version>4.1.1.RELEASE</version>
  	</dependency>
  </dependencies>
</project>
  • pom.xml에 dependencies을 적어주면 관련된 모듈이
    Maven Dependecies와 연결되어 자동으로 다운로드 받아 들어감
  1. java에 패키지 3개를 만듦(sam01, sam02, sam03)

🔻och01_di01

[sam01 - Message1]

  • MessageBeanEn.java
package sam01;

public class MessageBeanEn {
	void sayHello(String name) {
		System.out.println(name+" Hello");
	}
}
  • MessageBeanKo.java
package sam01;

public class MessageBeanKo {
	void sayHello(String name) {
		System.out.println(name+" 안녕");
	}
}
  • Ex01.java(실행파일)
package sam01;

public class Ex01 {

	public static void main(String[] args) {
		// MessageBeanEn mb = new MessageBeanEn();
		MessageBeanKo mb = new MessageBeanKo();
		mb.sayHello("spring");
	}

}

[sam02 - Message2/interface]

  • MessageBean.java-interface
package sam02;

public interface MessageBean {
	void sayHello(String name);
}
  • MessageBeanEn.java
package sam02;

public class MessageBeanEn implements MessageBean {

	public void sayHello(String name) {
		System.out.println(name+"! Hello");
	}
}
  • MessageBeanKo.java
package sam02;

public class MessageBeanKo implements MessageBean {

	public void sayHello(String name) {
		System.out.println(name+"! 안녕하세요");
	}
}
  • Ex02.java(실행파일)
package sam02;

public class Ex02 {

	public static void main(String[] args) {
		// MessageBean mb = new MessageBeanKo();
		MessageBean mb = new MessageBeanEn();
		mb.sayHello("spring");
	}
}

[sam03 - Message3]

  • MessageBean.java-interface
package sam03;

public interface MessageBean {
	void sayHello();
}
  • MessageBeanImpl.java
package sam03;

public class MessageBeanImpl implements MessageBean {
	private String name;
	private String greet;
	
	public MessageBeanImpl(String name, String greet) {
		this.name = name;
		this.greet = greet;
	}
	
	public void sayHello() {
		System.out.println(name+"님!! "+greet);
	}
}
  • Ex03.java(DI 호출 객체)
package sam03;

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

public class Ex03 {

	public static void main(String[] args) {
		// 기존 방식
		MessageBean cmb = new MessageBeanImpl("허유나", "전통적 안녕");
		cmb.sayHello();
		
		// DI 호출 객체
		ApplicationContext ac = new ClassPathXmlApplicationContext("bean03.xml");
		MessageBean mb = (MessageBean) ac.getBean("mb3");
		mb.sayHello();
	}
}
  • bean03.xml
의존성을 외부에서 주입하는 방식 DI(dependency Injection)
(src/main/resources) -> spring bean configuration file - 파일명 - bean checkbox
<?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="mb3" class="sam03.MessageBeanImpl">
		<constructor-arg><value>홍성대</value></constructor-arg>
		<constructor-arg value="DI 메리 크리스마스"></constructor-arg>
	</bean>
</beans>

[sam05 - Message5]

  • MessageBean.java-interface
package sam05;

public interface MessageBean {
	void sayHello();
}
  • MessageBeanImpl.java(Getter/Setter)
package sam05;

public class MessageBeanImpl implements MessageBean {
	private String name;
	private String greet;
	
	
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getGreet() {
		return greet;
	}
	public void setGreet(String greet) {
		this.greet = greet;
	}

	public void sayHello() {
		System.out.println(name+"님 "+greet+" !!");

	}

}
  • Ex05.java(DI 호출 객체)
package sam05;

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

public class Ex05 {

	public static void main(String[] args) {
		MessageBeanImpl mb5 = new MessageBeanImpl();
		mb5.setGreet("Good Bye");
		mb5.setName("한창훈");
        mb5.sayHello();
		
		ApplicationContext ac = new ClassPathXmlApplicationContext("bean05.xml");
		MessageBean mb = (MessageBean) ac.getBean("mb5");
		mb.sayHello();

	}
}
  • bean05.xml
    setter - properties 생성자 - constructor
<?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="mb5" class="sam05.MessageBeanImpl">
		<property name="name"><value>한창훈</value></property>
		<property name="greet" value="Good Bye"></property>
	</bean>

</beans>

[sam06 - vehicle/생성자와 setter 같이 세팅]

  • vehicle.java-interface
package sam06;

public interface vehicle {
	void ride();
}
  • VehicleImpl.java
    name은 생성자로 가져오고 나머지는 setter만 가져온다
package sam06;

public class VehicleImpl implements vehicle {
	private String name;
	private String rider;
	private int speed;
	
	public VehicleImpl(String name) {
		this.name = name;
	}
	public void setRider(String rider) {
		this.rider = rider;
	}
	public void setSpeed(int speed) {
		this.speed = speed;
	}
	public void ride() {
		System.out.println(name+" 님은(는) "+rider+"를 이용 "+speed+"km 속도로 탄다");

	}
}
  • Ex06.java(DI 호출 객체)
package sam06;

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

public class Ex06 {

	public static void main(String[] args) {
		ApplicationContext ac = new ClassPathXmlApplicationContext("bean06.xml");
		vehicle vh = (vehicle) ac.getBean("vh6");
		vh.ride();
	}
}
  • bean06.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="vh6" class="sam06.VehicleImpl">
		<constructor-arg value="한의정"></constructor-arg>
		<property name="rider" value="벤츠"></property>
		<property name="speed"><value>300</value></property>
	</bean>

</beans>

[sam07 - Message5]

  • MessageBean.java-interface
package sam07;

public interface MessageBean {
	void sayHello();
}
  • MessageBeanImpl.java
package sam07;

public class MessageBeanImpl implements MessageBean {
	private String name;
	private String greet;
	private Outputter outputter;
	
	public void setName(String name) {
		this.name = name;
	}
	public void setGreet(String greet) {
		this.greet = greet;
	}
	public void setOutputter(Outputter outputter) {
		this.outputter = outputter;
	}

	public void sayHello() {
		String msg = name+"님!! "+greet;
		System.out.println(msg);
		if(outputter!=null) outputter.output(msg);
	}
}
  • Outputter.java-interface
package sam07;

public interface Outputter {
	void output(String msg);
}
  • FileOutputter.java(순서가 가장 마지막으로 감)
package sam07;

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;

public class FileOutputter implements Outputter {
	private String fileName;
	
	public void setFileName(String fileName) {
		this.fileName = fileName;
	}
	
	//						최혜선님!! 클래식
	public void output(String msg) {
		try {
			System.out.println("fileName:"+fileName);
			FileWriter fw = new FileWriter(new File(fileName));
			fw.write(msg);
			fw.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
}
  • HelloApp.java(main)
package sam07;

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

public class HelloApp {

	public static void main(String[] args) {
		ApplicationContext ac = new ClassPathXmlApplicationContext("/sam07/bean07.xml");
		MessageBean mb = (MessageBean) ac.getBean("mb7");
		mb.sayHello();
	}
}
  • bean07.xml(sam07 패키지 안에 넣음)
    DI 방식으로 넘어갈 때 객체는 주소값을 넘어가야하기 때문에 reference방식으로 선언해줌 참조로 넣었기 때문에 helloApp에 없어도 xml 파일에 outputter이 알아서 호출됨 첫번째 bean의 outputter를 쓰기 위해서 다른 bean에 있는 property name도 outputter로 맞춰줌
<?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="outputter" class="sam07.FileOutputter">
		<property name="fileName" value="c:/log/msg1.txt"></property>
	</bean>
	<bean id="mb7" class="sam07.MessageBeanImpl">
		<property name="name" value="최혜선"></property>
		<property name="greet"><value>클래식</value></property>
		<property name="outputter"><ref bean="outputter"></ref></property>
	</bean>
</beans>


💡 IOC / DI

IOC(Inversion of Control)

역순으로 객체를 생성
기존의 프로그래밍에서 객체의 생성, 제어, 소멸 등의 객체의 라이프 사이클을 개발자가 관리하던 것을 컨테이터에게 그 제어권을 위임하는 프로그래밍 기법

DI(Dependecy Injection)

의존성 검색, 저장소에 저장되어 있는 빈(Bean)에 접근하기 위하여 개발자들이 컨테이너에서 제공하는 API를 이용하여 사용하고자 하는 빈(Bean)을 Lookup하는 것

부품을 조립해준다.

- Setter Inject과 Constructor Injection의 장점

🔻och03_di03

[DI01 - Calculator]

  • Calculator.java
package DI01;

public class Calculator {
	public void addition(int f, int s) {
		System.out.println("addition()");
		int result = f + s;
		System.out.println(f + "+" + s + "=" +result);
	}
	
	public void subtraction(int f, int s) {
		System.out.println("subtraction()");
		int result = f - s;
		System.out.println(f + "-" + s + "=" +result);
	}
	
	public void multiplication(int f, int s) {
		System.out.println("multiplication()");
		int result = f * s;
		System.out.println(f + "*" + s + "=" +result);
	}
	
	public void division(int f, int s) {
		System.out.println("division()");
		int result = f / s;
		System.out.println(f + "/" + s + "=" +result);
	}
}
  • MyCalculator.java
package DI01;

public class MyCalculator {
	Calculator calculator;
	private int firstNum;
	private int secondNum;
	
	public MyCalculator() {
		
	}
	public void add() {
		calculator.addition(firstNum, secondNum);
	}
	public void sub() {
		calculator.subtraction(firstNum, secondNum);
	}
	public void mul() {
		calculator.multiplication(firstNum, secondNum);
	}
	public void div() {
		calculator.division(firstNum, secondNum);
	}
	
	public void setCalculator(Calculator calculator) {
		this.calculator = calculator;
	}
	public void setFirstNum(int firstNum) {
		this.firstNum = firstNum;
	}
	public void setSecondNum(int secondNum) {
		this.secondNum = secondNum;
	}
}
  • MainClass01.java
    porm.xml에 관련 모듈 다운로드 클라스 명이 지정되어 casting을 쓰지 않는다
package DI01;

import org.springframework.context.support.AbstractApplicationContext;
import org.springframework.context.support.GenericXmlApplicationContext;

public class MainClass01 {

	public static void main(String[] args) {
		String configLocation = "classpath:applicationCTX01.xml";
		AbstractApplicationContext ctx = new GenericXmlApplicationContext(configLocation);
		MyCalculator myCalculator = ctx.getBean("myCalculator", MyCalculator.class);
		myCalculator.add();
		myCalculator.sub();
		myCalculator.mul();
		myCalculator.div();
		
		// 기존 방식
		System.out.println("===========myCalculator03============");
		MyCalculator myCalculator03 = new MyCalculator();
		// Calculator calculator = new Calculator();
		// myCalculator03.setCalculator(calculator);
		myCalculator03.setCalculator(new Calculator());
		myCalculator03.setFirstNum(20);
		myCalculator03.setSecondNum(2);
		myCalculator03.add();
		myCalculator03.sub();
		myCalculator03.mul();
		myCalculator03.div();
	}

}
  • applicationCTX01.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="calculator" class="DI01.Calculator"></bean>
	<bean id="myCalculator" class="DI01.MyCalculator">
		<property name="calculator"><ref bean="calculator"></ref></property>
		<property name="firstNum" value="20"></property>
		<property name="secondNum" value="2"></property>
	</bean>
</beans>

[DI02 - BMICalculator]

  • BMICalculator.java
package DI02;

public class BMICalculator {
	private double lowWeight;
	private double normal;
	private double overWeight;	// 과제충
	private double obesity;		// 비만
	
	public void bmicalculation(double weight, double height) {
		
		double h = height * 0.01;
		double result = weight / (h*h);
		
		System.out.println("BMI 지수 : "+(int)result);
		
		if(result > obesity) {
			System.out.println("비만 .");
		} else if(result > overWeight) {
			System.out.println("과체중 .");
		} else if(result > normal) {
			System.out.println("정상 .");
		} else {
			System.out.println("저체중 .");
		}
	}

	public void setLowWeight(double lowWeight) {
		this.lowWeight = lowWeight;
	}
	public void setNormal(double normal) {
		this.normal = normal;
	}
	public void setOverWeight(double overWeight) {
		this.overWeight = overWeight;
	}
	public void setObesity(double obesity) {
		this.obesity = obesity;
	}
}
  • MyInfo.java
package DI02;

import java.util.ArrayList;

public class MyInfo {
	private String name;
	private double height;
	private double weight;
	private ArrayList<String> hobbys;
	private BMICalculator bmiCalculator;
	
	public void bmiCalculator() {
		bmiCalculator.bmicalculation(weight, height);
	}
	
	public void getInfo() {
		System.out.println("이름 : "+name);
		System.out.println("키 : "+height);
		System.out.println("몸무게 : "+weight);
		System.out.println("취미 : "+hobbys);
		bmiCalculator();
	}

	public void setName(String name) {
		this.name = name;
	}
	public void setHeight(double height) {
		this.height = height;
	}
	public void setWeight(double weight) {
		this.weight = weight;
	}
	public void setHobbys(ArrayList<String> hobbys) {
		this.hobbys = hobbys;
	}
	public void setBmiCalculator(BMICalculator bmiCalculator) {
		this.bmiCalculator = bmiCalculator;
	}
}
  • MainClass02.java
package DI02;

import org.springframework.context.support.AbstractApplicationContext;
import org.springframework.context.support.GenericXmlApplicationContext;

public class MainClass02 {

	public static void main(String[] args) {
		String configLocation = "classpath:applicationCTX02.xml";
		AbstractApplicationContext ctx = new GenericXmlApplicationContext(configLocation);
		MyInfo myInfo = ctx.getBean("myInfo", MyInfo.class);
		myInfo.getInfo();
		ctx.close();
	}
}
  • applicationCTX02.xml
// list를 넣을 때
<property name="hobbys">
<list>
<value>바둑</value>
<value>낙시</value>
<value>대화</value>
</list>
<?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="bmiCalculator" class="DI02.BMICalculator">
		<property name="lowWeight" value="18.5"></property>
		<property name="normal" value="23"></property>
		<property name="overWeight" value="25"></property>
		<property name="obesity" value="30"></property>
	</bean>
	<bean id="myInfo" class="DI02.MyInfo">
		<property name="name" value="김춘추"></property>
		<property name="height" value="170"></property>
		<property name="weight" value="72"></property>
		<property name="hobbys">
			<list>
				<value>말타기</value>
				<value>활쏘기</value>
			</list>
		</property>
		<property name="bmiCalculator"><ref bean="bmiCalculator"></ref></property>
	</bean>
</beans>

💡 POJO 기반

스프링은 다른 프레임워크들과 달리 이 관계를 구성할 때 별도의 API 등을 사용하지 않는 POJO(Plain Old Java Object)의 구성만으로 가능하도록 제작되어 있습니다.

[DI03 - Student]

  • Student.java
package DI03;

public class Student {
	private String name;
	private int age;
	private String gradeNum;
	private String classNum;
	
	public Student(String name, int age, String gradeNum, String classNum) {
		this.name = name;
		this.age = age;
		this.gradeNum = gradeNum;
		this.classNum = classNum;
	}

	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	public String getGradeNum() {
		return gradeNum;
	}
	public void setGradeNum(String gradeNum) {
		this.gradeNum = gradeNum;
	}
	public String getClassNum() {
		return classNum;
	}
	public void setClassNum(String classNum) {
		this.classNum = classNum;
	}
}
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