Learn Java for Web Development

tina meador (Tina Meador) 2019-07-26 16:01:33 UTC #1

CHAPTER 7: Rapid Web Development with Grails 343

43.
44.

45.<g:message code="book.isbn.label"
default="Isbn" />
46.
47.<g:fieldValue bean="${bookInstance}"
field="isbn"/>
48.
49.

50.</g:if>
51.
52.
53.
54.

55.
56.<g:message
code="default.button.edit.label" default="Edit" /></g:link>
57.
58.

59.</g:form>
60.

61.
62.

   Lines 55 to 56: The? after the bookInstance reference is a safe navigation

operator. When this expression is evaluated and if bookInstance is null, the

whole expression evaluates to null, and no exception is thrown.

   Line 57: The <g:actionSubmit> tag generates a submit button that maps to a

specific action, which lets you have multiple submit buttons in a single form.

JavaScript event handlers can be added using the same parameter names as in

HTML.

The Edit View

The edit view is illustrated in Listing 7-30.

Listing 7-30. edit.gsp

1.<%@ page import="bookstore.Book" %>
2.<!DOCTYPE html>
3.
4.
5.
6.
7.<g:message code="default.edit.label" args="[entityName]" />
8.

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