Java Understanding Program Logic--first chapter knowledge of Java

1. Computer programs: a collection of ordered instructions written to allow a computer to perform certain operations or solve a problem.

2. JAVA Related technologies:

1), Install and run desktop programs on this computer

2), Internet-facing applications accessed through a browser

3), JAVA you can also make very good image effects.

3. steps to develop a Java program:

1), writing the source program

2), compiling the source program

3), Run

4. JAVA Basic framework of the program:

1), Write the program framework: public class Hello world{}

2), the framework for writing the main () method: Public static void Main (string[] args) {}

3), Write code: System.out. println ("Hello world!!!");

5. JAVA Types of annotations:

1), single-line Comment://(used to describe the function of a piece of code)

2), Multiline Comment:/* start */end

6. computers can develop two types of software: desktop applications, Internet Application

7. JAVA Structure Program:

1), the class name is exactly the same as the file name

2),main () method is the entry point for the Java program

3),main() Four elements of the method: public,static, void,string[] args,{ and} One by one, indispensable

8. to develop a Java program using Notepad:

1), Edit the source program to save with. Java as the suffix name

2),Java command to compile the. java file generation. Class

3),Java command to run the. class file

9. steps to develop a Java program using MyEclipse:

1), Create a Java project

2), manually creating a Java source program

3), compiling Java source Programs

4), Running Java programs

Ten , \ t space \ n Enter

One , JDK directory structure:

① , the bin directory has compilers, interpreters, and various tools, such as Server Tools, IDL, package tools, and Jdb.

② , the JRE directory is the root directory of the Java program's running environment, and underneath it is the bin subdirectory, which includes the platform's executable and DLL files using all the tools and libraries.

③ , the Lib subdirectory includes a code base for the Java runtime environment. The Lib directory is a library file.

④ , the demo directory has a variety of demonstration examples.

⑤ , the Include directory is the Win32 subdirectory

A , DOS command:

Cd\: Return to disk root directory

CD: return to the previous level

CD: go to that directory file

CLS: Clear Screen

exit: Exit

MD: New Catalog

dir: View all folders and files under the current folder

Toggle Drive Letter: Drive letter Name:

- , using the Doc window to run the Java file step:

1), enter the name of the disk where the file is located, and then enter

2), Enter the Javac file path (you can also drag the file you want to run into the DOS window), and then enter

3), Enter the Java file name, and then enter, you will output the contents of your code;

Java Understanding Program Logic--first chapter knowledge of Java