StringUtils.isBlank(null)      = true
StringUtils.isBlank("")        = true  
StringUtils.isBlank(" ")       = true  
StringUtils.isBlank("bob")     = false  
StringUtils.isBlank("  bob  ") = false

        

StringUtils.isBlank(null) = true
StringUtils.isBlank("") = true
StringUtils.isBlank(" ") = true
StringUtils.isBlank(" ") = true
StringUtils.isBlank("\t \n \f \r") = true //For tabs, newlines, the form feed character and StringUtils.isBlank (carriage return) all knowledge is blank
StringUtils.isBlank("\b") = false //"\b"As the word boundary.
StringUtils.isBlank("bob") = false
StringUtils.isBlank(" bob ") = false

        

String someWhiteSpace = "    \t  \n";
StringUtils.isEmpty(someWhiteSpace); // false
StringUtils.isBlank(someWhiteSpace); // true

        

public void testIsBlank() {
	assertTrue(StringUtils.isBlank(null));
	assertTrue(StringUtils.isBlank(""));
	assertTrue(StringUtils.isBlank(StringUtilsTest.WHITESPACE));
	assertFalse(StringUtils.isBlank("foo"));
	assertFalse(StringUtils.isBlank("  foo  "));
}

        

public class CheckEmptyString {
    public static void main(String[] args) {
        String var1 = null;
        String var2 = "";
        String var3 = "    ttt";
        String var4 = "Hello World";

        System.out.println("var1 is blank? = " + StringUtils.isBlank(var1));
        System.out.println("var2 is blank? = " + StringUtils.isBlank(var2));
        System.out.println("var3 is blank? = " + StringUtils.isBlank(var3));
        System.out.println("var4 is blank? = " + StringUtils.isBlank(var4));

        System.out.println("var1 is not blank? = " + StringUtils.isNotBlank(var1));
        System.out.println("var2 is not blank? = " + StringUtils.isNotBlank(var2));
        System.out.println("var3 is not blank? = " + StringUtils.isNotBlank(var3));
        System.out.println("var4 is not blank? = " + StringUtils.isNotBlank(var4));

        System.out.println("var1 is empty? = " + StringUtils.isEmpty(var1));
        System.out.println("var2 is empty? = " + StringUtils.isEmpty(var2));
        System.out.println("var3 is empty? = " + StringUtils.isEmpty(var3));
        System.out.println("var4 is empty? = " + StringUtils.isEmpty(var4));

        System.out.println("var1 is not empty? = " + StringUtils.isNotEmpty(var1));
        System.out.println("var2 is not empty? = " + StringUtils.isNotEmpty(var2));
        System.out.println("var3 is not empty? = " + StringUtils.isNotEmpty(var3));
        System.out.println("var4 is not empty? = " + StringUtils.isNotEmpty(var4));
    }
}

        

@GetMapping(value = "/{pagename}")
public String page(@PathVariable String pagename, HttpServletRequest request) {
    ContentVo contents = contentService.getContents(pagename);
    if (null == contents) {
        return this.render_404();
    }
    if (contents.getAllowComment()) {
        String cp = request.getParameter("cp");
        if (StringUtils.isBlank(cp)) {
            cp = "1";
        }
        PageInfo<CommentBo> commentsPaginator = commentService.getComments(contents.getCid(), Integer.parseInt(cp), 6);
        request.setAttribute("comments", commentsPaginator);
    }
    request.setAttribute("article", contents);
    updateArticleHit(contents.getCid(), contents.getHits());
    return this.render("page");
}

        

private String getRemoteIp(@NotNull final RequestContext context) {
    final HttpServletRequest request = WebUtils.getHttpServletRequest(context);
    String userAddress = request.getRemoteAddr();
    logger.debug("Remote Address = {}", userAddress);

    if (StringUtils.isNotBlank(this.alternativeRemoteHostAttribute)) {

        userAddress = request.getHeader(this.alternativeRemoteHostAttribute);
        logger.debug("Header Attribute [{}] = [{}]", this.alternativeRemoteHostAttribute, userAddress);

        if (StringUtils.isBlank(userAddress)) {
            userAddress = request.getRemoteAddr();
            logger.warn("No value could be retrieved from the header [{}]. Falling back to [{}].",
                    this.alternativeRemoteHostAttribute, userAddress);
        }
    }
    return userAddress;
}

        

public static Map<String, Map<String, Object>> getUpdateYamlScript(final ScriptClass scriptClass) {
    final Updater updater = scriptClass.getUpdater();

    Map<String, Object> properties = new LinkedHashMap<>();
    addNotEmptyProperty(JCR_PRIMARY_TYPE, HIPPOSYS_UPDATERINFO, properties);

    addNotEmptyProperty(HIPPOSYS_BATCHSIZE, updater.batchSize(), properties);
    addNotEmptyProperty(HIPPOSYS_DESCRIPTION, updater.description(), properties);
    addNotEmptyProperty(HIPPOSYS_DRYRUN, updater.dryRun(), properties);
    addNotEmptyProperty(HIPPOSYS_PARAMETERS, updater.parameters(), properties);
    if (StringUtils.isBlank(updater.xpath())) {
        addNotEmptyProperty(HIPPOSYS_PATH, updater.path(), properties);
    }
    addNotEmptyProperty(HIPPOSYS_QUERY, updater.xpath(), properties);
    addNotEmptyProperty(HIPPOSYS_SCRIPT, removeEmptyIndents(scriptClass.getContent()), properties);
    addNotEmptyProperty(HIPPOSYS_THROTTLE, updater.throttle(), properties);
    return Collections.singletonMap(getBootstrapPath(scriptClass), properties);
}

        

public int update(long id, ReviewStatus reviewStatus, String reviewer, long zkMtime) throws ShepherException {
    if (StringUtils.isBlank(reviewer) || reviewStatus == null) {
        throw ShepherException.createIllegalParameterException();
    }
    try {
        return snapshotMapper.update(id, reviewStatus.getValue(), reviewer, new Date(zkMtime));
    } catch (Exception e) {
        throw ShepherException.createDBUpdateErrorException();
    }
}

        

public void processCommentsForPageUpdate(final JSONObject page) throws Exception {
	final String pageId = page.getString(Keys.OBJECT_ID);

	final List<JSONObject> comments = commentDao.getComments(pageId, 1, Integer.MAX_VALUE);

	for (final JSONObject comment : comments) {
		final String commentId = comment.getString(Keys.OBJECT_ID);
		final String sharpURL = Comments.getCommentSharpURLForPage(page, commentId);

		comment.put(Comment.COMMENT_SHARP_URL, sharpURL);

		if (StringUtils.isBlank(comment.optString(Comment.COMMENT_ORIGINAL_COMMENT_ID))) {
			comment.put(Comment.COMMENT_ORIGINAL_COMMENT_ID, "");
		}
		if (StringUtils.isBlank(comment.optString(Comment.COMMENT_ORIGINAL_COMMENT_NAME))) {
			comment.put(Comment.COMMENT_ORIGINAL_COMMENT_NAME, "");
		}

		commentDao.update(commentId, comment);
	}
}