JDK安装步骤

下载
JDK官网下载

https://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html

| Windows x64 | 211.58 MB | [jdk-8u202-windows-x64.exe](javascript: void(0)) |

安装
1.下载后安装
2.配置环境变量
3.java -version运行证明安装成功

JAVA_HOME
C:\Program Files\Java\jdk1.8.0_202\bin

CLASSPATH
.;%JAVA_HOME%\lib\dt.jar;%JAVA_HOME%\lib\tool.jar;

前三行
C:\Program Files\Java\jre\jre1.8.0_202\bin
%JAVA_HOME%\bin;
C:\Program Files\Java\jdk1.8.0_202\bin
最后一行
C:\Program Files\Java\jre\jre1.8.0_202\bin

敲代码

  public class Hello{
    public static void main (String args[])   {
         System.out.println("大家好");
         System.out.println("Nice to meet you");
         Student stu =new Student ( );
         stu.speak("We are students");
             }
        }
        class Student {
         public void speak (String s) {
               System.out.println(s);
                    }
               }
   

编译&运行过程

1.打开cmd运行代码
2.cd Desktop\JAVA
3.javac Hello.java
4.java Hello

最后成功运行的截图

image.png