Java Basic Learning Note-java Overview and environment configuration

First Java Overview and environment configuration

First, basic knowledge:

1. Software development:

<1> What is software?

Software: A collection of computer data and instructions organized in a specific order.

Common software:

System software: such as Dos,windows, Linux and so on.

Application software: such as Minesweeper, Thunder, QQ and so on.

　　<2> What is development?

Authoring software

　　<3> Human-Computer Interaction

　　　　The advent of software enables better interaction between people and computers.

Interactive mode:

Graphical interface: This method is simple and intuitive, the user is easy to accept, easy to operate.

Command-line mode: You need to have a console, enter specific instructions, and let the computer do some work. More troublesome, the college recorded some orders.

DOS command line, common commands.

Dir: Lists the files and folders in the current directory

MD: Creating a Directory

RD: Deleting a directory

CD: Enter the specified directory

CD: Back to top level directory

Cd/: Go back to the root directory

Del: Delete Files

Exit: Exit DOS command line

Second, configure the Java environment

1. Download the JDK

　　　　JDK (Java De VELOPNEBT Kit Java Development Kit)

Official website: www.oracle.com See index.html

java.sun.com See index.html

　　2. Installing the JDK

　　　　Fool-mounted, next.

Recommendation: The installation path should not have Chinese or special symbols such as spaces.

When prompted to install the JRE, you can choose not to install.

3. Configure Environment variables

<1> typing javac in the DOS command line, an error message appears.

<2> Error Principle: The currently executing program in the current directory if it does not exist, the Windows system will find in the directory specified by an environment variable named path that is already in the system. If you have not found it, you will see the above error message.

<3> so go to the JDK installation path Bin directory and execute javac. See the Javac parameter tip information.

<4> It is cumbersome to go into the bin directory every time a Java tool is executed.

<5> in My Computer--Properties--advanced--environment variables

<6> edit java_home environment variable, variable value fill in the root directory of the JDK installation, for example:C:\Program files\java\jdk1.7.0_67

<7> Edit PATH environment variable, variable value is ;%java_home%\bin;

<8> edit Classpath, the variable value is .; %java_home%\lib\dt.jar;%java_home%\lib\tools.jar;

<9> Open the DOS command line and Javac in any directory.

<10> if the Javac parameter information appears, the configuration is successful.

<11> This configuration way, once and for all.

　　　　

Java Basic Learning Note-java Overview and environment configuration