Java cơ bản

Introduction to
Java Programming
Y. Daniel Liang
Edited by Hoàng Văn Hậu – VTC Academy – THSoft co.,ltd
https://play.google.com/store/apps/developer?id=THSoft+Co.,Ltd
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Introduction
Course Objectives
Organization of the Book

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Course Objectives
Upon completing the course, you will understand
Create, compile, and run Java programs
Primitive data types
Java control flow
Methods
Arrays (for teaching Java in two semesters, this could be the end)
Object-oriented programming
Core Java classes (Swing, exception, internationalization, multithreading, multimedia, I/O, networking, Java Collections Framework)
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Course Objectives, cont.
You will be able to
Develop programs using Eclipse IDE
Write simple programs using primitive data types, control statements, methods, and arrays.
Create and use methods
Write interesting projects
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Session 01 Introduction to Java and Eclipse
What Is Java?
Getting Started With Java Programming
Create, Compile and Running a Java Application
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What Is Java?
Java language programming market
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History
James Gosling and Sun Microsystems
Oak
Java, May 20, 1995, Sun World
HotJava
The first Java-enabled Web browser
JDK Evolutions
J2SE, J2ME, and J2EE (not mentioned in the book, but could discuss here optionally)
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Characteristics of Java
Java is simple
Java is object-oriented
Java is distributed
Java is interpreted
Java is robust
Java is secure
Java is architecture-neutral
Java is portable
Java’s performance
Java is multithreaded
Java is dynamic
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Java IDE Tools
Forte by Sun MicroSystems
Borland JBuilder
Microsoft Visual J++
NetBean by Oracle
IBM Visual Age for Java
Eclipse by Sun MicroSystems
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Getting Started with Java Programming
A Simple Java Application
Compiling Programs
Executing Applications
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A Simple Application
Example 1.1
//This application program prints Welcome
//to Java!
package chapter1;

public class Welcome {
public static void main(String[] args) {
System.out.println("Welcome to Java!");
}
}
Run
Source
NOTE: To run the program, install slide files on hard disk.
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Creating and Compiling Programs
On command line
javac file.java
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Executing Applications
On command line
java classname
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Example
javac Welcome.java

java Welcome

output:...
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Compiling and Running a Program
Where are the files stored in the directory?
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Anatomy of a Java Program
Comments
Package
Keywords
Variables – Data type
Operators
Control flow
If else statement
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Comments
Eclipse shortcut key:
Ctrl + Shift + C
Ctrl + Shift + /
Ctrl + /
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Package
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Keywords (reserved words)
http://en.wikipedia.org/wiki/List_of_Java_keywords
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Blocks
A pair of braces in a program forms a block that groups components of a program.
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Data Types
byte 8 bits
short 16 bits
int 32 bits
long 64 bits
float 32 bits
double 64 bits
char 16 bits
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Constants
final datatype CONSTANTNAME = VALUE;

final double PI = 3.14159;
final int SIZE = 3;
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Operators
+, -, *, /, %, ++, --, +=, -=, *=, /=, ^, &, |
5/2 yields an integer 2.
5.0/2 yields a double value 2.5
5 % 2 yields 1 (the remainder of the division)
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Arithmetic Expressions
is translated to

(3+4*x)/5 – 10*(y-5)*(a+b+c)/x + 9*(4/x + (9+x)/y)
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Shortcut Assignment Operators
Operator Example Equivalent
+= i+=8 i = i+8
-= f-=8.0 f = f-8.0
*= i*=8 i = i*8
/= i/=8 i = i/8
%= i%=8 i = i%8
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Increment and
Decrement Operators
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Increment and
Decrement Operators, cont.
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Variables
// Compute the first area
radius = 1.0;
area = radius*radius*3.14159;
System.out.println("The area is “ + area + " for radius "+radius);

// Compute the second area
radius = 2.0;
area = radius*radius*3.14159;
System.out.println("The area is “ + area + " for radius "+radius);
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Declaring Variables
int x; // Declare x to be an
// integer variable;
double radius; // Declare radius to
// be a double variable;
char a; // Declare a to be a
// character variable;
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if ... Else
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Displaying Text in a Message Dialog Box
you can use the showMessageDialog method in the JOptionPane class. JOptionPane is one of the many predefined classes in the Java system, which can be reused rather than “reinventing the wheel.”
Run
Source
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Actions on Eclipse
Development environment
Copy folder: Java_setup_thsoft
Install JDK
JAVA_HOME=path_to_jre
Install Eclipse (copy folder only)
Create workspace
Create simple project
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Actions on Eclipse
Create, build, run welcome.java and welcomeBox.java
Rewrite demo
Calcule this expression with a = b = c = 2.5; x = y = z = 8.7

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Actions on Eclipse
Problem ax + b = 0
Problem ax^2 + bx + c = 0
Input data by user. (JOptionPane)
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Action on class
Teacher
[email protected]
0984380003
https://play.google.com/store/search?q=thsoft+co&c=apps
Captions
Members