Table of Contents
How will you access a servlet context initialization parameter?
While the example is contrived, it shows how to use context initialization parameters to store immutable global data. As the data is bound to the application context, rather than to a particular servlet, we can access them from one or multiple servlets, using the getServletContext() and getInitParameter() methods.
What is context parameter in servlet?
Context parameters refers to the initialization parameters for all servlets of an application. attribute is used to define a context parameter. attribute has two main sub attributes and .
What is a context parameter in Java?
The “context-param” tag is define in “web. xml” file and it provides parameters to the entire web application. For example, store administrator’s email address in “context-param” parameter to send errors notification from our web application.
What do you mean by context initialization parameters?
Context Initialization parameters are the parameter name and value pairs that you can specify in the deployment descriptor file (the web. xml file). Here you can specify the parameters that will be accessible to all the servlets in the web application.
How are servlet parameters read?
Reading Form Data using Servlet getParameterValues() − Call this method if the parameter appears more than once and returns multiple values, for example checkbox. getParameterNames() − Call this method if you want a complete list of all parameters in the current request.
What is the difference between context init parameter and servlet init parameter?
Servlet init parameters are for a single servlet only. Nothing outside that servlet can access that. It is declared inside the tag of Deployment Descriptor, on the other hand context init parameter is for the entire web application. Any servlet or JSP in that web application can access context init parameter.
What is initialization parameters in servlets?
Initialization parameters are stored as key value pairs. They are included in web. xml file inside init-param tags. The key is specified using the param-name tags and value is specified using the param-value tags. Servlet initialization parameters are retrieved by using the ServletConfig object.
How will you read the servlet parameters explain with examples?
The ServletRequest interface includes methods that allow you to read the names and values of parameters that are included in a client request. We will develop a servlet that illustrates their use. The example contains two files. A web page is defined in PostParameters.
What is difference between attribute and parameter in servlet?
Important differences between attributes and parameters in JSP/servlets are: Parameters are read only, attributes are read/write objects. Parameters are String objects, attributes can be objects of any type.
How to configure a servlet with context parameters?
We can configure our servlet entirely with annotations, but as the context parameters are meant for all servlets we need to define them globally inside the web.xml servlet descriptor. A servlet context parameter is intend for global servlet parameters there is no way to include them with an annotation.
What is servletcontext in servlet?
The object of ServletContext provides an interface between the container and servlet. The ServletContext object can be used to get configuration information from the web.xml file.
When are the Servlet init parameters read by the container?
The servlet init parameters are read only ONCE – when the Container initializes the servlet. When the Container makes a servlet, it reads the DD and creates the name/value pairs for the ServletConfig.
How do HTTP Servlets work?
The API of HTTP servlets is aimed at handling HTTP requests through the typical request-processing-response cycle, implemented in client-server protocols. Furthermore, servlets can control the interaction between a client (typically a web browser) and the server using key-value pairs in the form of request/response parameters.