BlogController.java

@Controller
public class BlogController {

    private static final String BLOG_IMAGES = "blogImages";
    private static final String TOMCAT_HOME_PROPERTY = "catalina.home";
    private static final String TOMCAT_HOME_PATH = System.getProperty(TOMCAT_HOME_PROPERTY);
    private static final String BLOG_IMAGES_PATH = TOMCAT_HOME_PATH + File.separator + BLOG_IMAGES;

    private static final File BLOG_IMAGES_DIR = new File(BLOG_IMAGES_PATH);
    private static final String BLOG_IMAGES_DIR_ABSOLUTE_PATH = BLOG_IMAGES_DIR.getAbsolutePath() + File.separator;

    @Autowired
    private BlogPostService blogPostService;
    
    @Autowired
    BlogMapper blogMapper;

    @GetMapping("/add_blog_post")
    public String showBlogPostForm(Model model) throws Exception {

	BlogDto blogDto = new BlogDto();
	model.addAttribute("blogDto", blogDto);
	return "blog/add_blog_post";

    }

    @PostMapping("/add_blog_post")
    public String addBlogPost(@ModelAttribute @Valid BlogDto blogDto, BindingResult result, Model m) throws Exception {

	if (blogDto.getStatus() == BlogStatus.READY) {
	    m.addAttribute("globalError", "Unable to save");
	    m.addAttribute("blogDto", blogDto);
	    return "blog/add_blog_post";
	}

	if (result.hasErrors()) {

	    if (result.getGlobalError() != null) {
		m.addAttribute("globalError", result.getGlobalError().getDefaultMessage());
	    }

	    m.addAttribute("error", "Please check the form for errors");

	    m.addAttribute("blogDto", blogDto);
	    return "blog/add_blog_post";

	}

	MultipartFile file = blogDto.getImage();
	String imagePath = "";

	if (!file.isEmpty()) {

	    createBlogImagesDirIfNeeded();

	    imagePath = blogPostService.createImage(
		    (new SimpleDateFormat("yyyy.MM.dd.HH.mm.ss").format(new Date())) + file.getOriginalFilename(), file,
		    BLOG_IMAGES_DIR_ABSOLUTE_PATH);
	}

	BlogDto savedBlogDto = blogPostService.createBlogPost(blogDto, imagePath);

	if (blogDto.isPreview()) {
	    return "redirect:preview_blog?blogId=" + savedBlogDto.getId();
	} else if (blogDto.isSave()) {
	    m.addAttribute("message", "Draft was saved successfully");
	    m.addAttribute("blogDto", savedBlogDto);
	} else {
	    m.addAttribute("message", "Blog post is ready to be published after review.");
	    m.addAttribute("blogDto", savedBlogDto);
	}

	return "blog/add_blog_post";

    }

    @GetMapping("/image/{imageName}")
    public @ResponseBody byte[] getImage(@PathVariable("imageName") String imageName) throws IOException {
	createBlogImagesDirIfNeeded();

	File serverFile = new File(BLOG_IMAGES_DIR_ABSOLUTE_PATH + imageName);
	File file = ResourceUtils.getFile("classpath:static/image-not-found.png");

	try {
	    return Files.readAllBytes(serverFile.toPath());
	} catch (IOException e) {
	    return Files.readAllBytes(file.toPath());
	}

    }

    private void createBlogImagesDirIfNeeded() {
	if (!BLOG_IMAGES_DIR.exists()) {
	    BLOG_IMAGES_DIR.mkdirs();
	}
    }

    @GetMapping("/preview_blog")
    public String previewBlog(@RequestParam("blogId") Integer blogId, Model m) throws Exception {

	BlogDto blogDto = blogPostService.findByIdtoShow(blogId);
	m.addAttribute("blogDto", blogDto);

	return "blog/view_blog_post";
    }

    @GetMapping("/edit_blog")
    public String editBlog(@RequestParam("blogId") Integer blogId, Model m) throws Exception {

    BlogDto blogDto = blogPostService.findByIdtoShow(blogId);
	m.addAttribute("blogDto", blogDto);

	return "blog/add_blog_post";
    }

    @GetMapping("/blog_post_list")
    public String showPostList(Model model) {

	List<BlogDto> blogPostList = blogPostService.getAll();
	model.addAttribute("blogPostList", blogPostList);

	return "blog/blog_post_list";
    }

    @PostMapping("/change_blog_post_status")
    public String changeBlogStatus(@RequestParam("blogPostId") Integer blogPostId,
	    @RequestParam("approve") Boolean approve, @RequestParam("pubToDate") String date) throws ParseException {

	blogPostService.changeStatus(blogPostId, approve, date);

	return "redirect:blog_post_list";
    }

}