How to use

getBindStatus

method

in

org.springframework.web.servlet.tags.form.ErrorsTag

/**
 * Should rendering of this tag proceed at all?
 * <p>Only renders output when there are errors for the configured {@link #setPath path}.
 * @return {@code true} only when there are errors for the configured {@link #setPath path}
 */
@Override
protected boolean shouldRender() throws JspException {
  try {
    return getBindStatus().isError();
  }
  catch (IllegalStateException ex) {
    // Neither BindingResult nor target object available.
    return false;
  }
}

/**
 * Exposes any bind status error messages under {@link #MESSAGES_ATTRIBUTE this key}
 * in the {@link PageContext#PAGE_SCOPE}.
 * <p>Only called if {@link #shouldRender()} returns {@code true}.
 * @see #removeAttributes()
 */
@Override
protected void exposeAttributes() throws JspException {
  List<String> errorMessages = new ArrayList<>();
  errorMessages.addAll(Arrays.asList(getBindStatus().getErrorMessages()));
  this.oldMessages = this.pageContext.getAttribute(MESSAGES_ATTRIBUTE, PageContext.PAGE_SCOPE);
  this.pageContext.setAttribute(MESSAGES_ATTRIBUTE, errorMessages, PageContext.PAGE_SCOPE);
  this.errorMessagesWereExposed = true;
}

/**
 * Should rendering of this tag proceed at all?
 * <p>Only renders output when there are errors for the configured {@link #setPath path}.
 * @return {@code true} only when there are errors for the configured {@link #setPath path}
 */
@Override
protected boolean shouldRender() throws JspException {
  try {
    return getBindStatus().isError();
  }
  catch (IllegalStateException ex) {
    // Neither BindingResult nor target object available.
    return false;
  }
}

/**
 * Exposes any bind status error messages under {@link #MESSAGES_ATTRIBUTE this key}
 * in the {@link PageContext#PAGE_SCOPE}.
 * <p>Only called if {@link #shouldRender()} returns {@code true}.
 * @see #removeAttributes()
 */
@Override
protected void exposeAttributes() throws JspException {
  List<String> errorMessages = new ArrayList<>();
  errorMessages.addAll(Arrays.asList(getBindStatus().getErrorMessages()));
  this.oldMessages = this.pageContext.getAttribute(MESSAGES_ATTRIBUTE, PageContext.PAGE_SCOPE);
  this.pageContext.setAttribute(MESSAGES_ATTRIBUTE, errorMessages, PageContext.PAGE_SCOPE);
  this.errorMessagesWereExposed = true;
}

@Override
protected void renderDefaultContent(TagWriter tagWriter) throws JspException {
  tagWriter.startTag(getElement());
  writeDefaultAttributes(tagWriter);
  String delimiter = ObjectUtils.getDisplayString(evaluate("delimiter", getDelimiter()));
  String[] errorMessages = getBindStatus().getErrorMessages();
  for (int i = 0; i < errorMessages.length; i++) {
    String errorMessage = errorMessages[i];
    if (i > 0) {
      tagWriter.appendValue(delimiter);
    }
    tagWriter.appendValue(getDisplayString(errorMessage));
  }
  tagWriter.endTag();
}

@Override
protected void renderDefaultContent(TagWriter tagWriter) throws JspException {
  tagWriter.startTag(getElement());
  writeDefaultAttributes(tagWriter);
  String delimiter = ObjectUtils.getDisplayString(evaluate("delimiter", getDelimiter()));
  String[] errorMessages = getBindStatus().getErrorMessages();
  for (int i = 0; i < errorMessages.length; i++) {
    String errorMessage = errorMessages[i];
    if (i > 0) {
      tagWriter.appendValue(delimiter);
    }
    tagWriter.appendValue(getDisplayString(errorMessage));
  }
  tagWriter.endTag();
}