MACROMEDIA ColdFusion MX, Develop Manual

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Handling exceptions 139
Handling exceptions
ColdFusion provides two statements for exception handling in CFScript:
try
and
catch
. These
statements are equivalent to the CFML
cftry
and
cfcatch
tags.
Note: This section does not explain exception-handling concepts. For a discussion of exception
handling in ColdFusion, see Chapter 14, “Handling Errors,” on page 285 .
Exception handling syntax and rules
Exception-handling code in CFScript has the following format:
try {
Code where exceptions will be caught
}
catch(
exceptionType exceptionVariable ) {
Code to handle exceptions of type exceptionType
that occur in the try block
}
...
catch(
exceptionTypeN exceptionVariableN ) {
Code to handle exceptions of type
exceptionTypeN that occur in the try block
}
Note: In CFScript,
catch
statements follow the
try
block; you do not put them inside the
try
block.
This structure differs from that of the
cftry
tag, which must include the
cfcatch
tags in its body.
When you have a
try
statement, you must have a
catch
statement. In the
catch
block, the
exceptionVariable variable contains the exception type. This variable is the equivalent of the
cfcatch
tag
cfcatch.Type
built-in variable.
Exception handling example
The following code shows exception handling in CFScript. It uses a
CreateObject
function to
create a Java object. The catch statement executes only if the
CreateObject
function generates an
exception. The displayed information includes the exception message; the except.Message variable
is the equivalent of calling the Java
getMessage
method on the returned Java exception object.
<cfscript>
try {
emp = CreateObject("Java", "Employees");
}
catch(Any excpt) {
WriteOutput("The application was unable to perform a required
operation.<br>
Please try again later.<br>If this problem persists, contact
Customer Service and include the following information:<br>
#excpt.Message#<br>");
}
</cfscript>