java utility class

provide byte stream reads in bytes (8 bits), so the FileReader class reads the file as a stream of characters, FileInputStream reads the file by byte stream; InputStreamReader can convert read as stream into character stream, which is the bridge between reader and stream.? Originally Java was not supporting the processing of text files, in order to compensate for this shortcoming introduced the reader and

Java String Class (Java.lang.String) is the most used class in Java, and is also the most special class, and many times we are both familiar and unfamiliar with it. A fundamental understanding of the Java.lang.String class and st

for (Student s:students) {if (s!=null) System.out.println (s.getname () + "," + S.getmathscore ()); } System.out.println ("According to the students ' grades "); C.sortbybuble (); Arrays.sort (students); C.sortbymerge (); for (Student s:students) {if (s!=null) System.out.println (s.getname () + "," +s.getmathscore () ); }}}class classset{Private String classname;//class n

Refer to this articleArticle: Http://docs.oracle.com/javase/tutorial/java/javaOO/nested.html Differences between Nested-class and inner-class: Nested classes are divided into two categories: static and non-static. Nested classes that are declaredStaticAre simply calledStatic Nested classes. Non-static Nested classes are calledInner classes. In the foll

parent class is private, and the subclass cannot have it, salute![Java]View PlainCopy Public class Helloa { public static void Main (string[] args) { new B (). print (); } } [Java]View PlainCopy classb extendsa{ private Strings= "B" NBSP;;NBSP;NBSP; publicvoidp

the name of the inner class is superfluous, soThe anonymous inner class is used.3, how to implement anonymous internal class? The implementation of an anonymous inner class is very simple, such as having an interface Interface a{public void Method (); At this point you can write a statement like the following to g

The difference between public class and classThere are two ways to define a class: public class class name Class name I can remove the public from the front of class, and if you declare

JAVA 46th-Other Object API (2) Date Class Calendar class (important), apidate Date class (important) During development, time is often displayed, so you must be familiar with the Date application. Conversion between date objects and millisecond values. Millisecond value-> Date object: 1.new Date (TimeMillis); 2. s

Directory Class Loader Dynamic loading Link Initialization Example Class LoaderBefore you understand the mechanics of java, you need to understand how the class is loaded in the JVM (the Java Virtual machine), which is important for understandin

Jad: decompilation tool download Jad: decompilation Tool Decompiling a class file into a Java File Install jad.exe in the F:/Java/Jad directory. Copy the file *. class to be decompiled to this directory and follow these steps, In the command line window, enter the Jad directory, Then run: Jad-s

') determines whether a character is a numberSystem.out.println (i);if (Character.isdigit (' a ')) {System.out.println ("This is a number");}else {System.out.println ("This is not a number");}Second, Isletter (' a ') determines whether the character is a letterif (Character.isletter (' a ')) {//This is a class name that calls a static method directly, the keyword is staticSystem.out.println ("This is a letter");}else {System.out.println ("This is not

Java class, abstract class, interface of the comprehensive small exercise Directory Use [TOC] to generate a table of contents: A comprehensive small practice catalog problem Description code block for Java class abstract class i

class method can be called by all pairs, and can be called with the class name . class method or object name. class Method . Instance methods can only be called with object names. It is important to note, however, that class methods cannot invoke instance variables, because

Class B extends A, then the type a is the parent class with static code blocks, common code blocks, static methods, static member variables, ordinary member variables, common methods.Subclasses are also like this, and then inherit the results about the printout of the program.Involves the initialization order of various members of the Java class.After testing, th

); System.out.println ("Tixing's" is: "+Tixing.down); }}Instance methods and class methods access to instance variables and class variablesAn instance method can manipulate instance variables of the current object, or it can manipulate class variables. An instance method is called by an instance object.Class methods cannot access instance variables, only

() +1;//plus 1 is to add the entire character sequence of the 0 subscript, It also serves as a set of 0 subscript positions. if (k>0) { for (inti =0;i Package test; Import Java.util.regex.Matcher; Import Java.util.regex.Pattern; Two important classes that use regular expressions in/** * Java: pattern and Matcher * @author fhd001/public class Patternandmatchertest {public static void Main (string[] a

{ Public Static voidMain (string[] args) {System.out.println (Getstringcount ("Ilikejava,andjavaisthebest,java", "Java")); } Public Static intGetstringcount (String str, string key) {intCount = 0; intindex = 0; while(index = Str.indexof (key))! =-1) {Count++; STR= Str.substring (index+key.length ()); } returncount; }}//Output: 3String strings cannot be changed, there are some inconveniencesSo i

In Java development, we sometimes define a parent class that only describes the method, but does not write out the implementation of the method in the parent class, which is called an abstract method. Naturally, classes that contain abstract methods are called abstract classes. Modified with the keyword abstract.For example I write a parent

Test code One:1 Public class Test {2 Public Static void Main (string[] args) {3 4 }5}6publicclass test1{7 8 }Test results:(public class Testtwo must be defined in its own class file)Conclusion: Therefore, a class file can have only one public class.Test code two:1 Public

Java class Inheritance summarizes conversion problems between a parent class type and a subclass typeThis article will describe the conversion problem between the parent class type and the subclass type through an instance, and this very special problem often leads to some potential dangers. For a whole night, you're d