Java: Java Programming For Beginners a simple Start To Java Programming (Written By a software Engineer)
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Java Programming For Beginners - A Simple Start to Java Programming ( PDFDrive )
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- File Handling
The finalize( ) Method:
It is conceivable to call a method that will be called just before an object’s last annihilation. This method is referred to as finalize(), and it can be utilized to guarantee that an item ends neatly. For instance, you may utilize finalize( ) to verify that an open record possessed by that object is shut. To add a finalizer to a class, you basically jus call finalize(). The Java runtime calls that technique at whatever point it is going to reuse an object of that class. Inside this function, you will point out those activities that must be performed before an object is removed. The syntax of using and implementing this function is: protected void finalize( ) { //Statements } The access modifier used for the method ensures that the method cannot be accessed by elements outside the particular class. This implies that you can’t know when or how the method executes. File Handling All the classes that you may require on a day to day I/O programming basis are contained in the package java.io. The streams present in this package broadly represent output and input locations. Moreover, the streams supported in Java include object, primitives and localized characters. A stream can simply be described as data, arranged in a sequence. While the inputStream can be used for inputting data from a source, the OutputStream can be sued for outputting data to a sink. The support for I/O provided by Java is flexible and extensive. This chapter sims to cover all the basic facets of File Handling in Java. Byte Streams Byte streams in Java are utilized to perform output and input of 8-bit bytes. In spite of the fact that there are numerous classes identified with byte streams yet most utilized classes are, Fileoutputstream and Fileinputstream. Here is an example of they can be used in real- life programming. import java.io.*; public class Filecopy { public static void main(string args[]) throws IOException { FileInputStream inputx = invalid; FileOutputStream outputx = invalid; try { inputx = new FileInputStream(“inputfile.txt”); outputx = new FileOutputStream(“outputfile.txt”); int charx; while ((charx = inputx.read()) != -1) { outputx.write(charx); } } finally { if (inputx != invalid) { inputx.close(); } if (outputx != invalid) { outputx.close(); } } } Presently we should have a record inputfile.txt with the accompanying content: This is for testing purpose only. As an important step, compile and execute the code shown above. The execution of the code shall result in the creation of outputfile.txt file. Download 0.82 Mb. Do'stlaringiz bilan baham: |
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