Part IV: Putting It All Together in Java

Encoder Quick Response Code in Java Part IV: Putting It All Together

The Home page serves an entry point for both registered and prospective users As such, this page provides a form for the user to log on as well as a mechanism for prospective users to create a user account Because of the logon function, the Home page requires the following addi tional components: A dynamic form for the logon fields Validation of the fields using the Validator plug-in A LoginAction class to process the logon A LoginBean to interact with the database to authorize the user The use of a common authorization mechanism so that after the user is authorized, each page request easily verifies the user s status

Let s sketch the content of the Home page to see what fields you need to include for user input Clearly, you need to have fields available for the user to enter an e-mail address and a password Furthermore, you need a button for the user to click to submit the information for logging on However, if the user has not yet registered for the MusicCollectioncom service, the user needs to fill out a registration form to get a user account Although a different page (the Join page) will gather this information, the Home page needs a button for the user to click to indicate the desire to join MusicCollectioncom Clicking the button should take the user to the Join page That is about all we need on the Login page However, for eye appeal, you probably want to add some marketing text as well as images to the body of the page Because this application uses the includes page composition technique, the main page (homejsp) defines the structure of the page and includes the header, footer, and body information from other files The header and footer are common to all pages and reside in the logojsp and footerjsp files, respectively The body of the page will go into a separate JSP page named homeContentjsp We follow this convention in creating all JSP pages Figure 14-4 shows how the Home page looks

The next step is to define the dynamic form associated with the Login page You define the dynamic loginForm in the struts-config file, as we explain in s 6 and 9 The loginForm has only two fields associated with it: the email and password fields The following code segment is the definition for loginForm:

<form-bean name= loginForm type= orgapachestrutsvalidatorDynaValidatorForm > <form-property name= email type= javalangString initial= /> <form-property name= password type= javalangString initial= /> </form-bean>

You need to perform declarative validation on the two fields in loginForm The email field is required and should look like an e-mail address The password field is also required In the validationxml file, you specify the validators for the loginForm as follows:

<arg0 key= erroremailrequired /> </field> <field property= password depends= required > <arg0 key= errorpasswordrequired /> </field> </form>

The basic idea behind LoginAction is to take the user s email and password values and give them to LoginBean for authorization If authorization is suc cessful, LoginAction saves the user information in the session and forwards control to the MusicList page If authorization fails, LoginAction creates an error message and returns control back to the Home page Because the user can also request to sign up for an account, you should add another button for joining This button is actually a Cancel button that, when clicked, submits the login form and puts an attribute (orgapachestruts actionCANCEL) with a value of true into the request LoginAction looks for this attribute-value pair If LoginAction finds this pair, it forwards control to the joinjsp page You could put a link on the Home page instead of a Cancel button However, using a link exposes the URL of the joinjsp page to the public Listing 14-1 shows the body of the execute method of LoginAction

Listing 14-1