过滤器不能处理一对多关系的JPQL查询

Question

我创建了以下课程，即老师和学生。

JAVA代码：学生

@Entity
@Table(name="Student")

public class Student {

    @Id
    @Column(name = "cmp_id")
    private String cmpId;

    @OneToOne(cascade = CascadeType.REFRESH)
    @JoinColumn(name = "teacherid", referencedColumnName = "teacherid")
    private Teacher teacher;

    @OneToOne
    @JoinColumn(name = "typeid", referencedColumnName = "typeid")
    private Type type;
}

JAVA代码：老师

@Entity
@Table(name="Teacher")
public class Teacher {

    @Id
    @Column(name = "teacherid")
    private String teacherid;

    @Column(name = "teachername")
    private String teachername;

    @OneToMany(mappedBy = "Teacher", fetch = FetchType.EAGER, cascade = CascadeType.ALL)
    @OrderBy("cmpSequence ASC")
    private List<Student> std;
}

JAVA代码：类型

@Entity
@Table(name="Type")
public class Type{

    @Id
    @Column(name = "typeid")
    private Integer typeid;

    @Column(name = "uitype")
    private String uitype;    
}

老师是家长班，学生是小学班。我希望所有老师和他们的学生使用过滤器typeid是1，但它不起作用。

以下是我创建的JPQL查询：

SELECT teacher FROM Teacher teacher WHERE teacher.std.typeid = 1

它给了我以下错误：

java.lang.IllegalArgumentException：在EntityManager中创建查询时发生异常：异常描述：编译查询时出现问题。状态字段路径“teacher.std.typeid”无法解析为有效类型。

Answer 1

你的查询错了。 你有Teacher有std（ Student ），std有类型（ Type ）和类型有类型ID字段。 所以你的查询应如下所示：

SELECT teacher FROM Teacher teacher 
JOIN FETCH teacher.std AS s 
INNER JOIN s.type as t 
WHERE t.typeid = 1