Best Practices in Java EE Web Development - Learn Java for Web Development - page 129

Table 3-8. <c:out> Attributes

Name Type Description

value Object

This is the expression to be evaluated.

escapeXml boolean This determines whether the characters <,>,&,',” in the

resulting string should be converted to their corresponding
character entity codes. The default value is true .

default Object This is the default value if the resulting value is null .

The value to be written to the JspWriter is specified as a value attribute. You can use expressions in
the value attribute.
 value : The expression to be evaluated is supplied via the value attribute,
and the result is converted into a string before being returned as part of the
response.
 default : You can optionally specify a default value that <c:out> sends to the
current JspWriter if the specified value is null or is not a valid expression. You
can specify the default value with the default attribute or in the body of the
<c:out> action.
 escapeXml : The escapeXml attribute specifies whether to convert certain
characters to the HTML character entity codes listed in Table 3-9 . By default, the
escapeXml attribute is set to true . If you specify false for the escapeXml attribute,
<c:out> will not convert these characters.

Table 3-9. Character Entity Codes

Character Character Entity Code

&lt; <

&gt;

>

&amp; &

&#039 '

&#034

"

Listing 3-35 illustrates replacing scripting elements with the <c:out> action.

Listing 3-35. Comparing <c:out> and Expression

<%= "hello" %> // Ouput "hello" using Expression
<c:out value = "hello"/> // Ouput "hello" using <c:out> action