Buffered output stream in java

An ObjectOutputStream writes primitive data types and graphs of Java objects to an OutputStream. The objects can be read (reconstituted) using an ObjectInputStream. Persistent storage of objects can be accomplished by using a file for the stream. If the stream is a network socket stream, the objects can be reconstituted on another host or in another process. Only objects that support the java.io.Serializable interface can be written to streams. The class of each serializable object is encoded including the class name and signature of the class, the values of the object's fields and arrays, and the closure of any other objects referenced from the initial objects. The method writeObject is used to write an object to the stream. Any object, including Strings and arrays, is written with writeObject. Multiple objects or primitives can be written to the stream. The objects must be read back from the corresponding ObjectInputstream with the same types and in the same order as they were written. Primitive data types can also be written to the stream using the appropriate methods from DataOutput. Strings can also be written using the writeUTF method. The default serialization mechanism for an object writes the class of the object, the class signature, and the values of all non-transient and non-static fields. References to other objects (except in transient or static fields) cause those objects to be written also. Multiple references to a single object are encoded using a reference...

• Login • Category • Academic Tutorials • Big Data & Analytics • Computer Programming • Computer Science • Databases • DevOps • Digital Marketing • Engineering Tutorials • Exams Syllabus • Famous Monuments • GATE Exams • Latest Technologies • Machine Learning • Mainframe Development • Management Tutorials • Mathematics Tutorials • Microsoft Technologies • Misc tutorials • Mobile Development • Java Technologies • Python Technologies • SAP Tutorials • Programming Scripts • Selected Reading • Software Quality • Soft Skills • Telecom Tutorials • UPSC IAS Exams • Web Development • Sports Tutorials • XML Technologies • Multi-Language • Interview Questions Introduction The Java.io.OutputStream class is the superclass of all classes representing an output stream of bytes. An output stream accepts output bytes and sends them to some sink.Applications that need to define a subclass of OutputStream must always provide at least a method that writes one byte of output. Class declaration Following is the declaration for Java.io.OutputStream class − public abstract class OutputStream extends Object implements Closeable, Flushable Class constructors Sr.No. Constructor & Description 1 OutputStream() Single Constructor. Class methods Sr.No. Method & Description 1 This method closes this output stream and releases any system resources associated with this stream. 2 This method flushes this output stream and forces any buffered output bytes to be written out. 3 This method writes b.length byt...

• BufferedOutputStream(OutputStream out) : Creates a new buffered output stream to write data to the specified underlying output stream. • BufferedOutputStream(OutputStream out, int size) : Creates a new buffered output stream to write data to the specified underlying output stream with the specified buffer size. Methods: • void flush() : Flushes this buffered output stream. Syntax :public void flush() throws IOException Overrides: flush in class FilterOutputStream Throws: IOException • void write(byte[] b, int off, int len) : Writes len bytes from the specified byte array starting at offset off to this buffered output stream. Syntax : Parameters: b - the data. off - the start offset in the data. len - the number of bytes to write. Throws: IOException • void write(int b) : Writes the specified byte to this buffered output stream. Syntax : Parameters: b - the byte to be written. Throws: IOException Program:

Most of the examples we've seen so far use unbuffered I/O. This means each read or write request is handled directly by the underlying OS. This can make a program much less efficient, since each such request often triggers disk access, network activity, or some other operation that is relatively expensive. To reduce this kind of overhead, the Java platform implements buffered I/O streams. Buffered input streams read data from a memory area known as a buffer; the native input API is called only when the buffer is empty. Similarly, buffered output streams write data to a buffer, and the native output API is called only when the buffer is full. A program can convert an unbuffered stream into a buffered stream using the wrapping idiom we've used several times now, where the unbuffered stream object is passed to the constructor for a buffered stream class. Here's how you might modify the constructor invocations in the CopyCharacters example to use buffered I/O: inputStream = new BufferedReader(new FileReader("xanadu.txt")); outputStream = new BufferedWriter(new FileWriter("characteroutput.txt")); There are four buffered stream classes used to wrap unbuffered streams: BufferedInputStream and BufferedOutputStream create buffered byte streams, while BufferedReader and BufferedWriter create buffered character streams. Flushing Buffered Streams It often makes sense to write out a buffer at critical points, without waiting for it to fill. This is known as flushing the buffer. Some bu...

The BufferedInputStream class of the java.io package is used with other input streams to read the data (in bytes) more efficiently. It extends the InputStream abstract class. Working of BufferedInputStream The BufferedInputStream maintains an internal buffer of 8192 bytes. During the read operation in BufferedInputStream, a chunk of bytes is read from the disk and stored in the internal buffer. And from the internal buffer bytes are read individually. Hence, the number of communication to the disk is reduced. This is why reading bytes is faster using the BufferedInputStream. Create a BufferedInputStream In order to create a BufferedInputStream, we must import the java.io.BufferedInputStream package first. Once we import the package here is how we can create the input stream. // Creates a FileInputStream FileInputStream file = new FileInputStream(String path); // Creates a BufferedInputStream BufferedInputStream buffer = new BufferInputStream(file); In the above example, we have created a BufferdInputStream named buffer with the FileInputStream named file. Here, the internal buffer has the default size of 8192 bytes. However, we can specify the size of the internal buffer as well. // Creates a BufferedInputStream with specified size internal buffer BufferedInputStream buffer = new BufferInputStream(file, int size); The buffer will help to read bytes from the files more quickly. Methods of BufferedInputStream The BufferedInputStream class provides implementations for differe...

public void postRequest(String urlStr, String jsonBodyStr) throws IOException • private void writeFile (File outFile, byte [] bytes) • public static void copyFile(InputStream from, File to) throws IOException • /** * Copy the contents of the given InputStream to the given OutputStream. * Leaves both streams open when done. * @param in the InputStream to copy from * @param out the OutputStream to copy to * @return the number of bytes copied * @throws IOException in case of I/O errors */ public static int copy(InputStream in, OutputStream out) throws IOException • /** * Flushes any pending data and closes output file. If writing to an * OutputStream, the stream is not closed. */ public boolean finish() • /** * Copy the contents of the given byte array to the given OutputStream. * Closes the stream when done. * @param in the byte array to copy from * @param out the OutputStream to copy to * @throws IOException in case of I/O errors */ public static void copy( byte [] in, OutputStream out) throws IOException • private File writeToFile( byte [] header, String data, Charset charset ) throws IOException • void writeInputStream(String filename, InputStream inputStream) throws IOException • /** * Copies information from the input stream to the output stream using * the specified buffer size * @throws java.io.IOException */ public static void copy(InputStream input, OutputStream output, int bufferSize) throws IOException •

Writes len bytes from the specified byte array starting at offset off to this buffered output stream. Ordinarily this method stores bytes from the given array into this stream's buffer, flushing the buffer to the underlying output stream as needed. If the requested length is at least as large as this stream's buffer, however, then this method will flush the buffer and write the bytes directly to the underlying output stream. Thus redundant BufferedOutputStreams will not copy data unnecessarily. Overrides: Parameters: b - the data. off - the start offset in the data. len - the number of bytes to write. Throws: See Also: • FilterOutputStream.write(int) • flush Flushes this buffered output stream. This forces any buffered output bytes to be written out to the underlying output stream. Specified by: Overrides: Throws: See Also: • FilterOutputStream.out For further API reference and developer documentation see the Java is a trademark or registered trademark of Oracle and/or its affiliates in the US and other countries. All rights reserved. Use is subject to Scripting on this page tracks web page traffic, but does not change the content in any way.

In our Java IO Stream classes tutorial we have already seen the Byte stream classes in Java and character stream classes in Java. But using these classes directly, without any buffering, results in very inefficient reading or writing of streams in turn making you program much less efficient, since each such request often triggers disk access, network activity, or some other operation that is relatively expensive. To make IO operations more efficient the Java platform implements buffered I/O streams. Buffered streams in Java Buffered input streams read data from a memory area known as a buffer; the native input API is called only when the buffer is empty. Similarly, buffered output streams write data to a buffer, and the native output API is called only when the buffer is full. Buffered stream wraps the unbuffered stream to convert it into a buffered stream. For that unbuffered stream object is passed to the constructor for a buffered stream class. For example wrapping FileReader and FileWriter to get BufferedReader and BufferedWriter. BufferedReader br = new BufferedReader(new FileReader("abc.txt")); BufferedWriter bw = new BufferedWriter(new FileWriter("write.txt")); Buffered streams classes in Java There are four buffered stream classes- BufferedInputStream and BufferedOutputStream are used to wrap unbuffered byte streams to create buffered byte streams. BufferedReader and BufferedWriter are used to wrap unbuffered character streams to create buffered character streams. ...

Writes len bytes from the specified byte array starting at offset off to this buffered output stream. Ordinarily this method stores bytes from the given array into this stream's buffer, flushing the buffer to the underlying output stream as needed. If the requested length is at least as large as this stream's buffer, however, then this method will flush the buffer and write the bytes directly to the underlying output stream. Thus redundant BufferedOutputStreams will not copy data unnecessarily. Overrides: Parameters: b - the data. off - the start offset in the data. len - the number of bytes to write. Throws: off is negative, len is negative, or len is greater than b.length - off See Also: • FilterOutputStream.write(int) • flush Flushes this buffered output stream. This forces any buffered output bytes to be written out to the underlying output stream. Specified by: Overrides: Throws: See Also: • FilterOutputStream.out For further API reference and developer documentation see the Java is a trademark or registered trademark of Oracle and/or its affiliates in the US and other countries. All rights reserved. Use is subject to DRAFT 22-ea+1-7 Scripting on this page tracks web page traffic, but does not change the content in any way.