About Struts 1.1 Exception Handler Application Supplements

Typically, we have used Struts 1.0 for development, which is mainly manually handled.

These error messages are given to the user or developers, such as capturing exceptions by try / catch, then formbean.returnstring () or debug.println ("");

In Struts 1.1, new exception handling mechanisms are introduced, allowing us to customize the exception processing by profile (mainly struts-config.xml), just like definition formbean.

Below, let's take a look at how to use this new feature specifically.

First, custom abnormalities (defined in the struts-config.xml file)

There are two ways to customize anomalies, and it is divided into: "Global Excetions" and "Local Exception".

The "Global Abnormality" definition method is as follows:

Scope = "request"

Handler = "org.apache.struts.action.exceptionhandler"

Path = "error.jsp" />

The above code defines a global exception in struts-config.xml, and its role is to throw INVALITIUSERNAMEXCEPTION (meaning here is when the user has existed) anomaly, return to Error.jsp And carry the exception information of the self-specific comparisons struts.test.invaliDuserName, Struts.test.invaliDUserName can be found in the application's resource profile, such as:

Struts.test.invaliDuserName = Repeated registered users!

Local abnormality, the definition method is as follows:

TYPE = "struts.test.userlogonaction"

Name = "UserLogonform">

TYPE = "struts.test.invalidiusernameexception"

Handler = "org.apache.struts.action.exceptionhandler"

Path = "/ error.jsp" />

The definition of Struts-Config.xml in Struts 1.1 is as simple as it is.

Second, achieve our exception class (Test.invalidiUserNameException) In order to implement Struts.Test.invalidiUserNameException, we must write an exception inherited in Exception: InvaliTiUserNameException.

File name: invalidiusernameexception.java

Package struts.test;

Public Class InvaliUsernameException Extends Exception

{

Public invaliusernameException ()

{

Super ();

}

}

Third, an Action throwing anomalies

We assume that this exception will throw struts.test.invalidiUserNameException:

Public class userlogonaction extends baseAction {

Public ActionForward Execute (ActionMapping Mapping,

Actionform Form,

HTTPSERVLETREQUEST REQUEST,

HttpservletResponse response) throws exception {

Throw new struts.test.invalidiusernameException ();

}

}

Fourth, show our exception information

In order to display our friendly error prompt information, we can write an error.jsp file, the content is as follows:

Error.jsp

<% @ Taglib Uri = "/ Web-INF / STRUTS-Bean.tld" prefix = "bean"%>

<% @ Taglib URI = "/ Web-INF / STRUTS-LOGIC.TLD" prefix = "logic"%>

<% @ Taglib URI = "/ Web-INF / STRUTS-HTML.TLD" prefix = "html"%>