[Feat] DTO 및 검증 로직 추가

urlshortener/src/main/java/com/prgrms/url_shortener/dto/ShortenUrlRequest.java

@@ -0,0 +1,10 @@
+package com.prgrms.url_shortener.dto;
+
+import com.prgrms.url_shortener.dto.valid.UrlValid;
+import jakarta.validation.constraints.Size;
+
+public record ShortenUrlRequest(
+    @UrlValid
+    @Size(max = 255, message = "URL은 255자 이내입니다.")
+    String originUrl
+){}

urlshortener/src/main/java/com/prgrms/url_shortener/dto/ShortenUrlResponse.java

@@ -0,0 +1,6 @@
+package com.prgrms.url_shortener.dto;
+
+public record ShortenUrlResponse(
+    String shortenUrl,
+    int requestCount
+){}

urlshortener/src/main/java/com/prgrms/url_shortener/dto/valid/UrlValid.java

@@ -0,0 +1,20 @@
+package com.prgrms.url_shortener.dto.valid;
+
+import jakarta.validation.Constraint;
+import jakarta.validation.Payload;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Target(ElementType.FIELD)
+@Retention(RetentionPolicy.RUNTIME)
+@Constraint(validatedBy = UrlValidation.class)
+public @interface UrlValid {
+
+    String message() default "URL 형식이 올바르지 않습니다.";
+
+    Class<?>[] groups() default {};
+
+    Class<? extends Payload>[] payload() default {};
+}

urlshortener/src/main/java/com/prgrms/url_shortener/dto/valid/UrlValidation.java

@@ -0,0 +1,31 @@
+package com.prgrms.url_shortener.dto.valid;
+
+import jakarta.validation.ConstraintValidator;
+import jakarta.validation.ConstraintValidatorContext;
+import java.net.URL;
+import java.net.URLConnection;
+
+public class UrlValidation implements ConstraintValidator<UrlValid, String> {
+    private static final String HTTPS_PROTOCOL = "https://";
+    private static final String HTTP_PROTOCOL = "http://";
+
+    @Override
+    public boolean isValid(String value, ConstraintValidatorContext context) {
+        try {
+            if (hasNotProtocol(value)) {
+                value = HTTPS_PROTOCOL + value;
+            }
+
+            URL url = new URL(value);
+            URLConnection conn = url.openConnection();
+            conn.connect();
+        } catch (Exception e) {
+            return false;
+        }
+        return true;
+    }
+
+    private boolean hasNotProtocol(String originUrl) {
+        return !(originUrl.startsWith(HTTPS_PROTOCOL) || originUrl.startsWith(HTTP_PROTOCOL));
+    }
+}