正斜杠 反斜杠都可以

C:\Users\ehanmqi\Desktop\maven_action\helloword>java -jar target/helloword-1.0.0
.jar
Hello, world

C:\Users\ehanmqi\Desktop\maven_action\helloword>java -jar target\helloword-1.0.0
.jar
Hello, world

C:\Users\ehanmqi\Desktop\maven_action\helloword>



C:\Users\ehanmqi\Desktop\maven_action\helloword\target\classes>java com/frank/ma
ven_action/helloworld/helloworld
Hello, world

C:\Users\ehanmqi\Desktop\maven_action\helloword\target\classes>java com.frank.ma
ven_action.helloworld.helloworld
Hello, world

C:\Users\ehanmqi\Desktop\maven_action\helloword\target\classes>