問題JFX TableView和HQL查詢

當我嘗試在JavaFX TableView中顯示數據庫中的數據時遇到了一個小問題。問題JFX TableView和HQL查詢

我有一個學生表

user_id | name | nick | password | surname | classroom_id 
---------|-----------|-----------|-----------|-----------|-------------- 
    2  | AAA  | studentA | test123 | AAA  |  1 
    3  | BBB  | studentB | test321 | BBB  |  1

該表連接到課堂表

classroom_id | classrooName | classroomYear 
--------------|--------------|------------- 
     1  | TestClass | 2016/2017

我使用這個查詢與他們所屬的教室讓所有的學生一起，沒有問題在這裏。當我嘗試打印出值時，一切都是正確的。

Select student from Student student Join Fetch student.classroom

現在，實際的問題是，classroomName和classroomYear不TableView中this顯示，像（Jméno - 姓名，Příjmení - 姓氏，尼克 - ，Třída - 教室名，Rok-課堂年）

單元格值工廠這2列

classroomNameColumn.setCellValueFactory(new PropertyValueFactory<>("classroomName")); 

classroomYearColumn.setCellValueFactory(new PropertyValueFactory<>("classroomYear"));

現在，我設法得到顯示所有數據的唯一方法是，以classroomName和classroomYear添加到裏面加他們爲2我的Java類額外的列數據庫。這種方式違背了我認爲的加入ID的目的，是否有更好的方式可以讓我的TableView中顯示「課堂」數據？

編輯：這裏是學生和課堂爲Java類

@Entity 
public class Student extends User{ 

    private Classroom classroom; 


    public Student() { 
    } 

    public Student(String name, String surname, String nick, String password, Classroom studentClassroom) { 
     super(name, surname, nick, password); 
     this.classroom = studentClassroom; 
    } 

    @ManyToOne 
    @JoinColumn(name = "classroom_id") 
    public Classroom getClassroom() { 
     return classroom; 
    } 

    public void setClassroom(Classroom classroom) { 
     this.classroom = classroom; 
    } 

} 


@Entity 
public class Classroom { 

    private SimpleStringProperty classroomName = new SimpleStringProperty(); 
    private SimpleStringProperty classroomYear = new SimpleStringProperty(); 

    private int classroom_id; 

    public Classroom() { 
    } 

    public Classroom(String name, String year) { 
     classroomName.set(name); 
     classroomYear.set(year); 
    } 


    @Column(nullable = false) 
    public String getClassroomName() { 
     return classroomName.get(); 
    } 

    public SimpleStringProperty nameProperty() { 
     return classroomName; 
    } 

    public void setClassroomName(String name) { 
     this.classroomName.set(name); 
    } 

    @Column(nullable = false) 
    public String getClassroomYear() { 
     return classroomYear.get(); 
    } 

    public SimpleStringProperty classroomYearProperty() { 
     return classroomYear; 
    } 

    public void setClassroomYear(String year) { 
     this.classroomYear.set(year); 
    } 


    @Id 
    @GenericGenerator(name="id" , strategy="increment") 
    @GeneratedValue(generator="id") 
    public int getClassroom_id() { 
     return classroom_id; 
    } 

    public void setClassroom_id(int classroom_id) { 
     this.classroom_id = classroom_id; 
    } 
}

來源

2016-12-31 Honza Štefánik

的PropertyValueFactory你用的是尋找所謂的classroomName在Student財產，這顯然不存在。您需要自行實施單元格價值工廠：

// assuming you declared 
TableColumn<Student, String> classroomNameColumn ; 

// ... 

classroomNameColumn.setCellValueFactory(cellData -> { 
    Student student = cellData.getValue(); 
    Classroom classroom = student.getClassroom(); 
    if (classroom == null) return new SimpleStringProperty(""); 
    return classroom.nameProperty(); 
});

以及類似的課堂年。

來源

2016-12-31 17:37:56

真棒，作品像一個魅力。我認爲這是因爲學生課沒有課堂年份和姓名，但我不知道如何寫。非常感謝你。 –

問題JFX TableView和HQL查詢

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