Java
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Program flow control of Java
Sequential structure: the code is executed from top to bottom; Branch structure: if () { } else{ } if () { } else if (…… -
Object class of Java
Object is the parent class of all classes, also known as the base class. If you do not use the extends declaration in …… -
Java (I) basic knowledge
Common DOS commands: History of computer language: Javase: Java Standard Edition, which provides a complete Java core …… -
Ternary operator of Java
Logical operation? m : n; If the logical operation is true, M is returned; otherwise, n is returned example: Judge the…… -
Subclass object instantiation process of Java
Suppose there is a parent class: There is a subclass: Student stu = new student(); The process is as follows: -
Collection, a tool class of Java operation collection
Collections is a tool class that operates on collections such as set, list, and map. Collections provides a large numb…… -
Bit operator of Java
Integer to binary: integer toBInaryString(6) < <: move left, 3 < < 2 = 3 * 2 * 2 = 12 >>: shift righ…… -
Java of Java io. File related methods
java. io. Use of file. IO principle and stream classification. File stream: FileInputStream, fileoutputstream, FileRea…… -
Variable number formal parameters of Java
//Use array parameters to define methods public static void test (int a,String[] books); //A variable number of formal…… -
Object type conversion of Java
Conversion between basic data types: public class Person extends Object{} public class Student extends Person{} Cast J…… -
Priority of Java operators
The priority decreases from top to bottom, that is, the priority of the previous line is always greater than that of t…… -
Static keyword of Java
Design idea of class attribute and class method: Scope of use: in Java classes, static can be used to modify attribute…… -
Ternary operator of Java
Logical operation? m : n; If the logical operation is true, M is returned; otherwise, n is returned example: Judge the…… -
Java = = operator and equals operator
==Operator: Equals operator: Output: false false Output: true true Output: true true true false Note: A1 and B1 point …… -
How to automatically complete new objects in eclipse
For example, we are entering: Then press Ctrl + 1, Select the first item: -
Collection of Java (set, list, map)
The Java collection class is stored in the Java, UTI package and is a container for storing objects. Java collections …… -
Java interface
Sometimes you must derive a subclass from several classes and inherit all their properties and methods. However, Java …… -
Java (III) conversion between basic types
Automatic type conversion: types with small capacity are automatically converted into data types with large capacity. …… -
Java simple class object instantiation process
Suppose there is such a class: Person p = new Person(); The creation process of the whole object is as follows: -
Parameter passing of Java methods (value passing and reference passing)
Method is meaningful only when it is called by its class or object. If the method has parameters: Formal parameter: pa…… -
Examples of different data flow applications of Java
It is divided into byte stream (8bit) (InputStream and ouputstream) and character stream (16bit) (reader and writer) a…… -
Enumeration and annotation of Java
JDK1. 5. The newly added enum keyword is used to define enumeration classes. Differences between enumeration class and…… -
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Abstract class of Java
With the definition of new subclasses in the inheritance hierarchy, the class becomes more and more specific, while th…… -
Bit operator of Java
Integer to binary: integer toBInaryString(6) < <: move left, 3 < < 2 = 3 * 2 * 2 = 12 >>: shift righ…… -
Reflection mechanism of Java
It's hard to understand what this is, for example. Suppose we have a picture of animation now. Through this picture, w…… -
Java generics
What is generics? The generic type is jdk1 5 newly added to solve the security problem of data types. Its main princip…… -
Construction methods such as Java
Characteristics of the constructor: Function of constructor: create objects and initialize them; Syntax format: Modifi…… -
Dynamic agent design pattern of Java
Proxy: an operation class that specifically completes proxy requests. It is the parent class of all dynamic proxy clas…… -
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JDK1. 8 new feature (2): collectors collector class
I What are collectors? Java 8 API adds a new abstraction called stream. We can easily manipulate stream objects with t…… -
Java file upload and download
Two core packages should be introduced for file upload commons-fileupload-1.2. 1.jar commons-io-1.4. jar The following……