java - 我不断收到错误消息 "Could not find or load main class gradebooktest.GradeBookTest"我不知道为什么

Question

我使用的是netbeans，我的代码如下

public class GradeBook
{
    private String courseName; // course name for this GradeBook
    private String courseInstructor; // instructor name for this GradeBook 

// constructor initializes courseName and courseInstructor with String Argument
    public GradeBook( String name, String insname ) // constructor name is class name
    {
        courseName = name; // initializes courseName
        courseInstructor = insname; // initializes courseInstructor 
    } // end constructor

    // method to set the course name
    public void setCourseName( String name )
    {
        courseName = name; // store the course name
    } // end method setCourse

    // method to retrieve the course name
    public String getCourseName()
    {
        return courseName;
    } // end method getCourseName

    // method to set the Instructor name 
    public void setInstructorName( String insname)
    { 
        courseInstructor = insname; // store the Instructor name 
    } // end method setInstructorName 

    // method to retrieve the Instructor name 
    public String getInstructorName()
    { 
        return courseInstructor; 
    } // end method getInstructorName 

    // display a welcome message to the GradeBook user
    public void displayMessage()
    {
        // this statement calls getCourseName to get the 
        // name of the course this GradeBook represents
        System.out.println( "\nWelcome to the grade book for: \n"+
        getCourseName()+"\nThis course is presented by: "+getInstructorName()); 
        System.out.println( "\nProgrammed by Jack Friedman");

    } // end method displayMessage
} // end

Answer 1

您应该在主方法中调用此类的构造函数。

创建一个新类 GradeBookTest，如下所示:

public class GradeBookTest {

  public static void main (String args[]) {
     GradeBook book = new GradeBook("Math", "T.I.");
    book.displayMessage(); //To see your results
   }

}

现在您可以启动此类来查看结果。