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mysql> javac book/*.java in Java Display Code 3/9 in Java mysql> javac book/*.java




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mysql> javac book/*.java generate, create 39 barcode none on java projects VS.NET If you try to open the JSP n 3 of 9 barcode for Java ow, you should see the error message shown in Figure 6.1. This occurs because we haven"t yet set up the mappings that are used on the form:.

6 . Figure 6.1: Mapping Error The mappings must be placed in WEB-INF/struts-config.xml. Open this file, and add the lines highlighted in Listing 6.

2 at the appropriate places. Listing 6.2: struts-config.

xml. <!-- ==================== javabean Code 3/9 ================== Form Bean Definitions --> <form-beans> <form-bean name="bookForm" type="book.BookForm"/> </form-beans> <!-- ================================= Global Forward Definitions --> <global-forwards> <forward name="bookCreated" path="/BookView.jsp"/> </global-forwards> <!-- ================================= Action Mapping Definitions --> <action-mappings> <action path="/createBook" type="book.

BookAction" name="bookForm" scope="request" input="/book.jsp"> </action> </action-mappings>. All these settings seem a little complicated at first. Forms Figure 6.2 shows how all the relevant components interact. A Book bean has a form manager (BookForm) and an action class (BookAction).

The bean is then referenced by struts-config.xml. The ActionServlet works in the background we"ll look at ActionServlet a little later.

. Figure 6.2: Overview of a Struts Form The configuration comprises three parts:. <form-beans>: The name Code 39 Extended for Java attribute defines an alias for the class specified by the type attribute, which must be qualified by the appropriate package names. The alias must be unique. <global-forwards>: This defines an alias for the JSP page.

<action-mapping>: The value of the name attribute must match the alias defined by the <form-bean> element for the form class. The path attribute maps a specific request path to a corresponding Action Class. A JSP page is also given for error handling.

We are nearly in a position to execute the application. The next step is to create the Action class for the form. Create a new Java class in the Book subdirectory called BookAction.

java and add the code shown in Listing 6.3..

Listing 6.3: BookAction.java (first version).

package book; import javax.s jsp bar code 39 ervlet.http.

*; import org.apache.struts.

action.*; import tools.*;.

6 . public final class BookActio applet Code 39 n extends Action { java.util.logging.

Logger logger = LoggerInitiator.getLogger(); public BookAction() { logger.info("BookAction.

java"); } public ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest req, HttpServletResponse res) throws Exception { logger.info("Start execute(" + form + ") . .

." ); String title = req.getParameter("title"); Book book = new Book(); book.

setTitle( title ); req.setAttribute("BOOK", book); return mapping.findForward("bookCreated"); } }.

See that you don"t use javax .servlet.ServletRequest by mistake.

Its methods are available, so there will be no errors. You won"t see any warnings either, because syntactically it is correct. But it does not function exactly as we need.

. BookAction.java does not use Struts to its fulles t capacity. Still, the example illustrates the basic procedure very well and gets us close to the final version. In the later sections, we will improve it, coming back to compare both methods.

The next refinement includes debugging information.. There is one more class to c Code39 for Java reate before we can use the BookForm.java form shown in Listing 6.4.

Listing 6.4: BookForm.java.

package book; import javax.s ervlet.http.

HttpServletRequest; import org.apache.struts.

action.*; import tools.*; public class BookForm extends ActionForm { private Book book = new Book(); private java.

util.logging.Logger logger = LoggerInitiator.

getLogger(); public void setTitle(String title) { logger.info("setTitle("" + title+ "")");. Forms book.setTitle(title); } publ ic String getTitle() { logger.info("getTitle()"); return book.

getTitle(); } public void setBook(Book book) { this.book = book; } public Book getBook() { return this.book; } public void reset(ActionMapping mapping, HttpServletRequest request) { this.

book = new Book(); } public ActionErrors validate(ActionMapping mapping, HttpServletRequest request) { ActionErrors errors = new ActionErrors(); if ((book.getTitle() == null) . (book.getTitle().length() & javabean Code39 lt; 3)) { errors.

add("Title", new ActionError("error.book.title")); } return errors; } }.

The BookForm class extends A ctionForm. The ActionForm class contains various functions that Struts uses to set and read the input data (more details on this class are given in the Struts API documentation). The point of the class is to define tests that determine if the user"s input on the form is valid.

In this case, if the title was not supplied (getTitle() returns null) or was too short, an error message is added to the ActionErrors collection. The error message is in fact an error.book.

title key for the language file. Additionally, we define how the form will be initialized (see Exercise 1). We will go into the details of the get and set accessors a little later.

The text for error messages is still missing. Add the appropriate messages to the language files for the error.book.

title key..
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