Creating and Initializing a Servlet (original) (raw)
2. Using the Tutorial Examples
3. Getting Started with Web Applications
4. JavaServer Faces Technology
7. Using JavaServer Faces Technology in Web Pages
8. Using Converters, Listeners, and Validators
9. Developing with JavaServer Faces Technology
10. JavaServer Faces Technology: Advanced Concepts
11. Using Ajax with JavaServer Faces Technology
12. Composite Components: Advanced Topics and Example
13. Creating Custom UI Components and Other Custom Objects
14. Configuring JavaServer Faces Applications
Handling Servlet Lifecycle Events
Controlling Concurrent Access to Shared Resources
Getting Information from Requests
Filtering Requests and Responses
Programming Customized Requests and Responses
To Specify Filter Mappings Using NetBeans IDE
Including Other Resources in the Response
Transferring Control to Another Web Component
Associating Objects with a Session
To Set the Timeout Period Using NetBeans IDE
Notifying Methods to Shut Down
Creating Polite Long-Running Methods
Components of the mood Example Application
To Run the mood Example Using NetBeans IDE
To Run the mood Example Using Ant
Further Information about Java Servlet Technology
16. Uploading Files with Java Servlet Technology
17. Internationalizing and Localizing Web Applications
18. Introduction to Web Services
19. Building Web Services with JAX-WS
20. Building RESTful Web Services with JAX-RS
21. JAX-RS: Advanced Topics and Example
23. Getting Started with Enterprise Beans
24. Running the Enterprise Bean Examples
25. A Message-Driven Bean Example
26. Using the Embedded Enterprise Bean Container
27. Using Asynchronous Method Invocation in Session Beans
Part V Contexts and Dependency Injection for the Java EE Platform
28. Introduction to Contexts and Dependency Injection for the Java EE Platform
29. Running the Basic Contexts and Dependency Injection Examples
30. Contexts and Dependency Injection for the Java EE Platform: Advanced Topics
31. Running the Advanced Contexts and Dependency Injection Examples
32. Introduction to the Java Persistence API
33. Running the Persistence Examples
34. The Java Persistence Query Language
35. Using the Criteria API to Create Queries
36. Creating and Using String-Based Criteria Queries
37. Controlling Concurrent Access to Entity Data with Locking
38. Using a Second-Level Cache with Java Persistence API Applications
39. Introduction to Security in the Java EE Platform
40. Getting Started Securing Web Applications
41. Getting Started Securing Enterprise Applications
42. Java EE Security: Advanced Topics
Part VIII Java EE Supporting Technologies
43. Introduction to Java EE Supporting Technologies
45. Resources and Resource Adapters
46. The Resource Adapter Example
47. Java Message Service Concepts
48. Java Message Service Examples
49. Bean Validation: Advanced Topics
50. Using Java EE Interceptors
51. Duke's Bookstore Case Study Example
52. Duke's Tutoring Case Study Example
53. Duke's Forest Case Study Example
Use the @WebServlet annotation to define a servlet component in a web application. This annotation is specified on a class and contains metadata about the servlet being declared. The annotated servlet must specify at least one URL pattern. This is done by using the urlPatterns or value attribute on the annotation. All other attributes are optional, with default settings. Use the value attribute when the only attribute on the annotation is the URL pattern; otherwise use the urlPatternsattribute when other attributes are also used.
Classes annotated with @WebServlet must extend the javax.servlet.http.HttpServlet class. For example, the following code snippet defines a servlet with the URL pattern /report:
import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet;
@WebServlet("/report") public class MoodServlet extends HttpServlet { ...
The web container initializes a servlet after loading and instantiating the servlet class and before delivering requests from clients. To customize this process to allow the servlet to read persistent configuration data, initialize resources, and perform any other one-time activities, you can either override the init method of the Servlet interface or specify the initParams attribute of the @WebServlet annotation. The initParams attribute contains a @WebInitParamannotation. If it cannot complete its initialization process, a servlet throws an UnavailableException.
Use an initialization parameter to provide data needed by a particular servlet. By contrast, a context parameter provides data that is available to all components of a web application.
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