Chapter 9. Exception and Error Handling
Introduction
Any application can shine under normal conditions; how an application responds to unexpected conditions reveals much more about its robustness and production-readiness. As you saw in Chapter 8, the Struts Validator provides a means for handling unexpected user input. However, applications need to handle unexpected system behavior. This behavior typically manifests as exceptions. These exceptions may be business-related, may have meaning to the end user, or they may be system- and coding-related, or may have meaning to system administrators and developers. This chapter will show you some good solutions for handling both of these cases.
9.1. Simplifying Exception Processing in an Action
Problem
You want to reduce the number of
try . . .
catch
blocks within your Action
classes.
Solution
Remove the exception-handling
code from your Action
,
and define global and local exception handlers in your
struts-config.xml
file, as shown in Example 9-1.
... <global-exceptions> <exception key="error.unknown.user" type="com.oreilly.strutsckbk.ch09.UnknownUserException" path="/securityError.jsp"/> </global-exceptions> ... <action-mappings> <action path="/Login" type="com.oreilly.strutsckbk.ch09.LoginAction" scope="request" name="LoginForm" validate="true" input="/login.jsp"> <exception key="error.password.match" type="com.oreilly.strutsckbk.ch09.PasswordMatchException"> <forward name="success" ...
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