feat: search condition & paging with Querydsl (#5)

Querydsl을 활용하여 검색 조건에 맞게 검색 후 페이징 처리 - dto로 조회하여 최적화

src/main/java/com/api/TaveShot/domain/Post/dto/PostListResponse.java

@@ -0,0 +1,17 @@
+package com.api.TaveShot.domain.Post.dto;
+
+import java.util.List;
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Getter;
+
+@Getter
+@Builder
+@AllArgsConstructor
+public class PostListResponse {
+    private List<PostResponse> postResponses;
+    private Integer totalPage;
+    private Long totalElements;
+    private Boolean isFirst;
+    private Boolean isLast;
+}

src/main/java/com/api/TaveShot/domain/Post/dto/PostResponse.java

@@ -1,6 +1,8 @@
 package com.api.TaveShot.domain.Post.dto;
 
 import com.api.TaveShot.domain.Comment.dto.CommentDto;
+import com.api.TaveShot.domain.Comment.dto.CommentDto.Response;
+import com.querydsl.core.annotations.QueryProjection;
 import java.util.List;
 import lombok.AllArgsConstructor;
 import lombok.Builder;
@@ -18,4 +20,14 @@ public class PostResponse {
     private int view;
     private Long writerId;
     private List<CommentDto.Response> comments;
+
+    @QueryProjection
+    public PostResponse(Long postId, String title, String content, String writer, int view, Long writerId) {
+        this.postId = postId;
+        this.title = title;
+        this.content = content;
+        this.writer = writer;
+        this.view = view;
+        this.writerId = writerId;
+    }
 }

src/main/java/com/api/TaveShot/domain/Post/dto/PostSearchCondition.java

@@ -0,0 +1,14 @@
+package com.api.TaveShot.domain.Post.dto;
+
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Getter;
+
+@Getter
+@Builder
+@AllArgsConstructor
+public class PostSearchCondition {
+    private String writer;
+    private String content;
+    private String title;
+}

src/main/java/com/api/TaveShot/domain/Post/repository/PostRepositoryCustom.java

@@ -0,0 +1,11 @@
+package com.api.TaveShot.domain.Post.repository;
+
+import com.api.TaveShot.domain.Post.dto.PostResponse;
+import com.api.TaveShot.domain.Post.dto.PostSearchCondition;
+import java.util.List;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.Pageable;
+
+public interface PostRepositoryCustom {
+    List<PostResponse> searchPagePost(PostSearchCondition condition, Pageable pageable);
+}

src/main/java/com/api/TaveShot/domain/Post/repository/PostRepositoryImpl.java

@@ -0,0 +1,60 @@
+package com.api.TaveShot.domain.Post.repository;
+
+
+import static com.api.TaveShot.domain.Post.domain.QPost.post;
+
+import com.api.TaveShot.domain.Post.dto.PostResponse;
+import com.api.TaveShot.domain.Post.dto.PostSearchCondition;
+import com.api.TaveShot.domain.Post.dto.QPostResponse;
+import com.api.TaveShot.global.config.DataBaseConfig;
+import com.querydsl.core.types.dsl.BooleanExpression;
+import java.util.List;
+import lombok.RequiredArgsConstructor;
+import org.springframework.data.domain.Pageable;
+import org.springframework.util.StringUtils;
+
+@RequiredArgsConstructor
+public class PostRepositoryImpl implements PostRepositoryCustom {
+
+    private final DataBaseConfig dataBaseConfig;
+
+    @Override
+    public List<PostResponse> searchPagePost(PostSearchCondition condition, Pageable pageable) {
+
+        return dataBaseConfig.jpaQueryFactory()
+                .select(
+                        new QPostResponse(post.id, post.title, post.content,
+                                post.writer, post.viewCount, post.member.id))
+                .from(post)
+                .where(
+                        containTitle(condition.getTitle()),
+                        containContent(condition.getContent()),
+                        containWriter(condition.getWriter())
+                )
+                .limit(pageable.getPageSize())
+                .offset(pageable.getOffset())
+                .fetch();
+    }
+
+    private BooleanExpression containTitle(String title) {
+        if (StringUtils.hasText(title)) {
+            return post.title.contains(title);
+        }
+        return null;
+    }
+
+    private BooleanExpression containContent(String content) {
+        if (StringUtils.hasText(content)) {
+            return post.content.contains(content);
+        }
+        return null;
+    }
+
+    private BooleanExpression containWriter(String writer) {
+        if (StringUtils.hasText(writer)) {
+            return post.writer.contains(writer);
+        }
+        return null;
+    }
+
+}