Looking to study up for the new J2EE 1. This book will get you way up to speed on the technology you'll know it so well, in fact, that you can pass the brand new J2EE 1. If that's what you want. This book gets readers up to speed on the technology necessary to write servlets and JSPs, what makes the Container tick, how to use the new JSP Expression Language EL , how to write deployment descriptors, and even how to use some server-side design patterns. Opens with a chapter discussing the details of the SCWCD certification exam and process, then offers an overview of web applications as well as the servlet and JSP technologies, and, finally, covers each of the exam's thirteen objectives.
All Users. If that's what you want to do, that is. Maybe you don't care about the exam, but need to use servlets. We need another JSP element A comment EL: the answer to, well, everything.
But wait The param attribute to the rescue But wait! It gets even better Trying to display the property of the property Expression Language EL saves the day! How it runs Includes and imports can be messy Tag Files: like include, only better But how do you send it parameters?
SkipPageException: stops processing the page SkipPageException shows everything up to the point of the exception But what happens when the tag is invoked from an included page? We could just add more custom tag attributes But what if you DO need access to the body contents? A Tag can call its Parent Tag Find out just how deep the nesting goes Keep security out of the code!
Who implements security in a web app? RMI makes life easy What we want Time for a Transfer Object? Service Locator and Business Delegate both simplify model components Business tier patterns: quick review Our very first pattern revisited MVC Where we left off How does Front Controller fit in?
Index About the Authors Copyright Show and hide more. ISBN: You might also like book Designing Data-Intensive Applications by Martin Kleppmann Data is at the center of many challenges in system design today. Difficult issues need to … book Building Microservices, 2nd Edition by Sam Newman Distributed systems have become more fine-grained as organizations shift from code-heavy monolithic applications to smaller, self-contained … book Java Coding Problems by Anghel Leonard Develop your coding skills by exploring Java concepts and techniques such as Strings, Objects and Types, … video Clean Code by Robert C.
Get it now. Or what if you simply want to create a new request-scoped attribute? Set comes in two flavors: var and target. The var version is for setting attribute variables, the target version is for setting bean properties or Map values.
Each of the two flavors comes in two variations: with or without a body. This happens even if start looking at pag e, a scope, it will Duck, or a Broccoli.
Even attribute. Q: Why would I use the body version instead of the no-body version? It looks like they both do exactly the same thing. It might be a long and complex is page scope. If you put in a String look in the page scope space. A: We hear you. Once again, nobody asked US. That feels wrong. But remember, set does a remove only when you pass in a null value.
The answers are at the end of the chapter. The include directive use you do have different word for the attribu s ma kes sen se, wh en you think about it The imported chunk uses a reference to an image that is also on Server B. This is my horse. Welcome to our Web Services Support Group. How can you guarantee session tracking from a JSP He missed the point How can I get the session ID added to Ahhh It does URL rewriting automatically.
First we had to get the session either the existing one or a new one. The Container wants to use a cookie—it wants to include a unique cookie with the response, and then the client will send that cookie back with each subsequent request. Except one problem Then what? Query stringacpaes, for example, Uh-oh You can design a custom page to handle errors, then use the page directive to configure it. And what if I want a different error page depending on the error?
You can declare error pages in the DD for the entire web app, and you can even configure different error pages for different exception types, or HTTP error code types , , etc. That way you can show the client different error pages specific to the type of the problem that generated the error. Declaring a catch-all error page This applies to everything in your web app—not just JSPs. You can override it in individual JSPs by adding a page directive with an errorPage attribute.
The object is type java. Throwable, so in a script you can call methods, and with EL you can access the stackTrace and message properties. This time, you getabmly details. What if there are some errors I want to catch myself? The one that was actually thrown?
But with web app error handling, remember, only officially-designated error pages get the exception object. It puts the exception object into the page scope, under the name you declare as the value of var.
Inside the catch. If you bod y. The point is—learn catch or finally block. And on the exam, fooled. The JSTL is huge. Version 1. But nsformation e. The XML tra give it the delimiter. We have a whole chapter the next one devoted to developing your own custom tag handlers. But the last part of this chapter is about how to use custom tags. What happens, for example, if someone hands you a custom tag library they created for your company or project?
How do you know what the tags are and how to use them? You have to know how to figure out a tag even if the yo documentation is weak or nonexistent, and, eed to Everything you n one more thing—you have to know how to deploy a custom tag library. Main things you have to know: know is in there. You can use any prefix you want, but the name comes from the TLD. The syntax includes things like required and optional attributes, whether the tag can have a body and if so, what you can put there , the type of each attribute, and whether the attribute can be an expression vs.
The URI is what you put in your taglib directive. Besides the function we X M L s c hema that the This says that the tag must NOT have anything in the body. Java class that does the tag work package foo; import javax. JspException; import javax. IOException; things we need in stom tags. But with custom a custom tag. This must NOTt be a expression Or something that can be implicitly assigned to a Dog reference type.
The JSP developer cares most about the uri, the tag name, and the tag tag. Can the tag have a body? Does this attribute have to be a String literal, or can it be an expression?
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