Package javax.servlet

Class ServletInputStream


  • public abstract class ServletInputStream
extends java.io.InputStream
    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. With some protocols, such as HTTP POST and PUT, a ServletInputStream object can be used to read data sent from the client.

    A ServletInputStream object is normally retrieved via the ServletRequest.getInputStream() method.

    This is an abstract class that a servlet container implements. Subclasses of this class must implement the java.io.InputStream.read() method.

    See Also:
    ServletRequest

    • Constructor Summary

      Constructors 
      Modifier Constructor Description
      protected ServletInputStream​()
      Does nothing, because this is an abstract class.

    • Method Summary

      All Methods Instance Methods Abstract Methods Concrete Methods 
      Modifier and Type Method Description
      abstract boolean isFinished​()
      Returns true when all the data from the stream has been read else it returns false.
      abstract boolean isReady​()
      Returns true if data can be read without blocking else returns false.
      int readLine​(byte[] b, int off, int len)
      Reads the input stream, one line at a time.
      abstract void setReadListener​(ReadListener readListener)
      Instructs the ServletInputStream to invoke the provided ReadListener when it is possible to read

      • Methods inherited from class java.io.InputStream

        available, close, mark, markSupported, read, read, read, readAllBytes, readNBytes, reset, skip, transferTo

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Constructor Detail

      • ServletInputStream

        protected ServletInputStream​()
        Does nothing, because this is an abstract class.

    • Method Detail

      • readLine

        public int readLine​(byte[] b,
                    int off,
                    int len)
             throws java.io.IOException
        Reads the input stream, one line at a time. Starting at an offset, reads bytes into an array, until it reads a certain number of bytes or reaches a newline character, which it reads into the array as well.

        This method returns -1 if it reaches the end of the input stream before reading the maximum number of bytes.

        Parameters:
        b - an array of bytes into which data is read
        off - an integer specifying the character at which this method begins reading
        len - an integer specifying the maximum number of bytes to read
        Returns:
        an integer specifying the actual number of bytes read, or -1 if the end of the stream is reached
        Throws:
        java.io.IOException - if an input or output exception has occurred

      • isFinished

        public abstract boolean isFinished​()
        Returns true when all the data from the stream has been read else it returns false.
        Returns:
        true when all data for this particular request has been read, otherwise returns false.
        Since:
        Servlet 3.1

      • isReady

        public abstract boolean isReady​()
        Returns true if data can be read without blocking else returns false.
        Returns:
        true if data can be obtained without blocking, otherwise returns false.
        Since:
        Servlet 3.1

      • setReadListener

        public abstract void setReadListener​(ReadListener readListener)
        Instructs the ServletInputStream to invoke the provided ReadListener when it is possible to read
        Parameters:
        readListener - the ReadListener that should be notified when it's possible to read.
        Throws:
        java.lang.IllegalStateException - if one of the following conditions is true
        • the associated request is neither upgraded nor the async started
        • setReadListener is called more than once within the scope of the same request.
        java.lang.NullPointerException - if readListener is null
        Since:
        Servlet 3.1