public class PostSearchDto {

    private Long id;
    private String title;
    private String contents;

    private String author;

    public PostSearchDto(PostEntity entity) {
        this.id = entity.getId();
        this.title = entity.getTitle();
        this.contents = entity.getContents();
        this.author = entity.getAuthor();
    }
}

public interface PostRepository extends CrudRepository<PostEntity, Long> {
    @Query("SELECT p FROM PostEntity p WHERE p.title = :title ORDER BY p.id ASC")
    List<PostEntity> findByTitle(@Param("title") String title);

    @Query("SELECT p FROM PostEntity p WHERE p.contents LIKE %:contents% ORDER BY p.id ASC") 
    List<PostEntity> findByContentsContaining(@Param("contents") String contents);

    @Query("SELECT p FROM PostEntity p WHERE p.author = :author ORDER BY p.id ASC")
    List<PostEntity> findByAuthor(@Param("author") String author);
}

@Transactional
    @Override
    public List<PostSearchDto> getSearchList(String type, String keyword){
        if(type.equals("title")==true)
        {
            return postRepository.findByTitle(keyword).stream().map(PostSearchDto::new).collect(Collectors.toList());
        }
        else if(type.equals("contents")==true)
        {
            return postRepository.findByContentsContaining(keyword).stream().map(PostSearchDto::new).collect(Collectors.toList());
        }
        else // author
        {
          return  postRepository.findByAuthor(keyword).stream().map(PostSearchDto::new).collect(Collectors.toList());
        }
    }

@GetMapping("/showSearchList/{type}/{keyword}")
    public String getSearchList(@PathVariable String type,@PathVariable String keyword,@LoginUser SessionUser user,Model model) throws Exception{
       
        if (user != null) {
            model.addAttribute("userName", user.getName());
        }
        List<PostSearchDto> plist = postService.getSearchList(type, keyword);
        model.addAttribute("SearchList", plist);
        return "showSearchList";
    }