update : 2주차 과제

build.gradle

@@ -24,10 +24,10 @@ repositories {
 }
 
 dependencies {
-    implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
+  //  implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
     implementation 'org.springframework.boot:spring-boot-starter-web'
     compileOnly 'org.projectlombok:lombok'
-    runtimeOnly 'com.mysql:mysql-connector-j'
+ //   runtimeOnly 'com.mysql:mysql-connector-j'
     annotationProcessor 'org.projectlombok:lombok'
     testImplementation 'org.springframework.boot:spring-boot-starter-test'
     testRuntimeOnly 'org.junit.platform:junit-platform-launcher'

src/main/java/com/example/week2/builder/App1.java

@@ -1,8 +1,16 @@
 package com.example.week2.builder;
 
+import com.example.week2.exception.CustomException;
+import com.example.week2.exception.ErrorCode;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 public class App1 {
 
+  private static final Logger log = LoggerFactory.getLogger(App1.class);
   public static void main(String[] args) {
+    log.error("error");
 
+    throw new CustomException(ErrorCode.INVALID_REQUEST);
   }
 }

src/main/java/com/example/week2/builder/Student.java

@@ -6,15 +6,27 @@
 import lombok.NoArgsConstructor;
 import lombok.Setter;
 import lombok.ToString;
+import lombok.extern.slf4j.Slf4j;
 
 @Getter
 @Setter
 @AllArgsConstructor
 @NoArgsConstructor
 @Builder
 @ToString
+@Slf4j
 public class Student {
   private String name;
   private int age;
   private String school;
-}
+
+  public static void main(String[] args) {
+    Student student = Student.builder()
+            .name("홍길동")
+            .age(20)
+            .school("세종대학교")
+            .build();
+
+    System.out.println(student);
+  }
+}

src/main/java/com/example/week2/exception/CustomException.java

@@ -11,4 +11,4 @@ public CustomException(ErrorCode errorCode) {
     super(errorCode.getMessage());
     this.errorCode = errorCode;
   }
-}
+}

src/main/java/com/example/week2/exception/ErrorCode.java

@@ -8,8 +8,8 @@
 @AllArgsConstructor
 public enum ErrorCode {
 
-  INVALID_REQUEST(HttpStatus.BAD_REQUEST, "잘못된 요청이 들어왔습니다"),;
-
+  INVALID_REQUEST(HttpStatus.BAD_REQUEST, "잘못된 요청이 들어왔습니다"),
+  SEJONG_UNI(HttpStatus.BAD_REQUEST, "세종대학교");
 
   private final HttpStatus status;
   private final String message;

src/main/java/com/example/week2/exception/ExceptionController.java

@@ -21,4 +21,9 @@ public void throwIllegalArgumentException() {
     throw new IllegalArgumentException();
   }
 
+  @GetMapping("/custom")
+  public void throwCustomException() {
+    throw new CustomException(ErrorCode.INVALID_REQUEST);
+  }
+
 }

src/main/java/com/example/week2/exception/GlobalExceptionHandler.java

@@ -1,13 +1,20 @@
 package com.example.week2.exception;
 
 import lombok.extern.slf4j.Slf4j;
+import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.ExceptionHandler;
 import org.springframework.web.bind.annotation.RestControllerAdvice;
 
+//body 반환
 @RestControllerAdvice
 @Slf4j
 public class GlobalExceptionHandler {
 
+  //RestControllerAdvice 선언하고
+  //ExceptionHandler 해당 에러 클랫스로 선언하고
+  //로드 에러 찍고
+  //메세지 반환
+
   @ExceptionHandler(NullPointerException.class)
   public String handleNullPointerException() {
     log.error("NullPointer Exception 처리 시작");
@@ -19,4 +26,24 @@ public String handleInternalError() {
     log.error("InternalError 처리 시작");
     return "InternalError 핸들링";
   }
+
+  @ExceptionHandler(CustomException.class)
+  public String handleCustomException() {
+    log.error("CustomError 처리 시작");
+    return "CustomException 핸들링";
+  }
+
+  //과제
+  @ExceptionHandler(CustomException.class)
+  public ResponseEntity<ErrorResponse> handleCustomException(CustomException e) {
+    log.error("CustomeException 발생 : {}", e.getMessage(), e);
+    ErrorCode errorCode = e.getErrorCode();
+
+    ErrorResponse response = ErrorResponse.builder()
+            .errorCode(errorCode)
+            .errorMessage(errorCode.getMessage())
+            .build();
+
+    return ResponseEntity.status(errorCode.getStatus()).body(response);
+  }
 }

src/main/java/com/example/week2/exception/GlobalExceptionHandler2.java

@@ -4,10 +4,13 @@
 import org.springframework.web.bind.annotation.ControllerAdvice;
 import org.springframework.web.bind.annotation.ExceptionHandler;
 
+//View를 반환
 @ControllerAdvice
 @Slf4j
 public class GlobalExceptionHandler2 {
 
+  //handler가 ILLegalAru~~ 에로를 자바준다. 잡고 싶은 에러.class로 선언
+  //@controller여서 view에서 찾고
   @ExceptionHandler(IllegalArgumentException.class)
   public String handleIllegalArgumentException() {
     log.error("IllegalArgumentException 발생");

src/main/java/com/example/week2/logger/LoggerExample1.java

@@ -13,5 +13,9 @@ public static void main(String[] args) {
     LOGGER.info("Info입니다");
     LOGGER.warn("Warn입니다");
     LOGGER.error("Error입니다");
+
+    //trace : 매우 상세한 디버깅 정보
+    //debug : 디버깅에 유용한 정보
+    //............................
   }
 }

src/main/java/com/example/week2/logger/LoggerExample2.java

@@ -4,7 +4,7 @@
 
 @Slf4j
 public class LoggerExample2 {
-
+  //어노테이션 사용해서 자동으로 log 생성
   public static void main(String[] args) {
     log.trace("Trace입니다");
     log.debug("Debug입니다");

src/main/java/com/example/week2/logger/LoggerExample3.java

@@ -13,8 +13,10 @@ public static void main(String[] args) {
         .school("세종대학교")
         .build();
 
-    log.info("학생 이름은" + student.getName() + "입니다");
+    log.info("학생 이름은" + student.getName() + "입니다"); //로그 레벨에 상관없이 항상 출력됨 + 계산이 처리된다.
 
     log.info("학생 이름은 {} 입니다.", student.getName());
+    //SLF4J 포매팅 방식
+    //INFO 레벨로 출력될 때만 호출되어 성능 최적화
   }
 }