What is InputStream In Servlet?
What is InputStream In Servlet?
ServletInputStream class is a component of Java package javax. servlet, It is an abstract class that provides an input stream for reading binary data from a client request, including an efficient readLine method for reading data one line at a time. Syntax: public abstract class ServletInputStream extends InputStream.
What is the use of HttpServletRequestWrapper?
Class HttpServletRequestWrapper. Provides a convenient implementation of the HttpServletRequest interface that can be subclassed by developers wishing to adapt the request to a Servlet. This class implements the Wrapper or Decorator pattern. Methods default to calling through to the wrapped request object.
What is servlet output stream?
servlet, is an abstract class that provides an output stream to send binary data to the client. ServletOutputStream inherits OutputStream which is the superclass of all classes representing an output stream of bytes. Subclasses of ServletOutputStream class must implement the java. io. OutputStream.
How do I use Httpsession?
HttpSession object is used to store entire session with a specific client. We can store, retrieve and remove attribute from HttpSession object….Some Important Methods of Servlet HttpSession.
| Methods | Description |
|---|---|
| void invalidate() | destroy the session |
| boolean isNew() | returns true if the session is new else false |
How do I support both GET and POST protocol from the same servlet?
Q: What if I want to support both GET and POST from a single servlet? A: A: Developers who want to support both methods usually put logic in doGet(), then have the doPost() method delegate to the doGet() method if necessary.
What is HttpServletRequest and HttpServletResponse?
The HttpServletRequest object can be used to retrieve incoming HTTP request headers and form data. The HttpServletResponse object can be used to set the HTTP response headers (e.g., content-type) and the response message body.
What is the role of HttpServletRequest?
The HttpServletRequest provides methods for accessing parameters of a request. The type of the request determines where the parameters come from. In most implementations, a GET request takes the parameters from the query string, while a POST request takes the parameters from the posted arguments.
What is PrintWriter class in Java?
public class PrintWriter extends Writer. Prints formatted representations of objects to a text-output stream. This class implements all of the print methods found in PrintStream . It does not contain methods for writing raw bytes, for which a program should use unencoded byte streams.
Why do we need HttpSession?
public interface HttpSession Provides a way to identify a user across more than one page request or visit to a Web site and to store information about that user. The servlet container uses this interface to create a session between an HTTP client and an HTTP server.
What are the methods of HttpSession?
Methods in HttpSession Interface
| Method | Description |
|---|---|
| public String getId() | Returns the unique session id |
| public long getCreationTime() | It returns the time when this session was created, measured in milliseconds since midnight January 1, 1970 GMT. |
What is the difference between doGet () and doPost () in servlet?
doGet() shall be used when small amount of data and insensitive data like a query has to be sent as a request. doPost() shall be used when comparatively large amount of sensitive data has to be sent. Examples are sending data after filling up a form or sending login id and password.
Can we call doGet from doPost?
You can call doGet() from doPost() and vice-versa. No issues.
What is a HttpServletResponse?
HttpServletResponse is a predefined interface present in javax. servlet. http package. It can be said that it is a mirror image of request object. The response object is where the servlet can write information about the data it will send back.
What is a HttpServletRequest?
How is HttpServletRequest created?
In a typical Servlet container implementation if an HTTP request comes in, an HttpServletRequest is created right when the HTTP input data of the request is parsed by the Servlet container.
Is PrintWriter faster than system out?
PrintWriter class is the implementation of Writer class. By using PrintWriter than using System. out. println is preferred when we have to print a lot of items as PrintWriter is faster than the other to print data to the console.
What is Inputstream reader in java?
An InputStreamReader is a bridge from byte streams to character streams: It reads bytes and decodes them into characters using a specified charset . The charset that it uses may be specified by name or may be given explicitly, or the platform’s default charset may be accepted.
What is HttpSession and how it works?
Interface HttpSession. public interface HttpSession. Provides a way to identify a user across more than one page request or visit to a Web site and to store information about that user. The servlet container uses this interface to create a session between an HTTP client and an HTTP server.
How do I use HttpSession?
How can we get HttpSession object?
How to get the HttpSession object? The HttpServletRequest interface provides two methods to get the object of HttpSession: public HttpSession getSession():Returns the current session associated with this request, or if the request does not have a session, creates one.