Question

我有一个带有cooperator和student模型（以及其他模型）的spring boot应用程序。他们在合作者方面有@oneToMany关系，在学生方面有@ManyToOne

合作伙伴类：

@Entity
public class Cooperator{
    private Integer id;

    public void setId(Integer value) {
        this.id = value;
    }
    @Id
    public Integer getId() {
        return this.id;
    }
    private Set<Student> student;

    @OneToMany(mappedBy="cooperator", cascade={CascadeType.ALL})
    public Set<Student> getStudent() {
       return this.student;
    }

    public void setStudent(Set<Student> students) {
       this.student = students;
    }

    public void addStudent(Student student) {
        try {
            this.student.add(student);
        }
        catch(Exception e) {    
            this.student = new HashSet<Student>();
            this.student.add(student);
        }
    }
}

学生班：

@Entity
public class Student{
    private String studentID;

    public void setStudentID(String value) {
       this.studentID = value;
    }
    @Id
    public String getStudentID() {
        return this.studentID;
    }

    private Cooperator cooperator;

    @ManyToOne(optional=false)
    public Cooperator getCooperator() {
       return this.cooperator;
    }

    public void setCooperator(Cooperator cooperator) {
       this.cooperator = cooperator;
    }
}

我正在通过以下方式测试这种关系：

    @Test
    public void cooperatorStudent() {
        String studentID = "260632353";
        String firstname = "Saleh";
        String lastname = "Bakhit";
        Student student1 = service.createStudent(studentID, firstname, lastname, cooperator);
        assertEquals(cooperator, student1.getCooperator());

        studentID = "260632350";
        firstname = "testFirst";
        lastname = "testLast";
        Student student2 = service.createStudent(studentID, firstname, lastname, cooperator);
        assertEquals(cooperator, student2.getCooperator());

        Set<Student> cooperatorStudents = cooperator.getStudent();
        assertTrue(cooperatorStudents.contains(student1));
        assertTrue(cooperatorStudents.contains(student2));

    }

问题是即使cooperatorStudents实际上包含两个student对象，assertTrue语句也会失败。

非常感谢为什么提供帮助。

EDIT

我将student添加到cooperator中Set<Student> student的{{1}}中，这是它的代码：

createStudent

在创建第二个学生时，还添加@override哈希码和equals会产生stackoverflow

Answer 1

然后，您要比较对象，则必须覆盖“等于”和“哈希码”方法。默认情况下，每个类实例“对象”都是唯一的，尽管它们的字段相同。很好的解释：https://dzone.com/articles/working-with-hashcode-and-equals-in-java

Answer 2

据我所知，您没有在测试方法中将学生对象添加到合作者中。

在测试方法中调用addStudent()方法应该可以解决问题。

@Test
public void cooperatorStudent() {
    String studentID = "260632353";
    String firstname = "Saleh";
    String lastname = "Bakhit";
    Student student1 = service.createStudent(studentID, firstname, lastname, cooperator);
    assertEquals(cooperator, student1.getCooperator());

    studentID = "260632350";
    firstname = "testFirst";
    lastname = "testLast";
    Student student2 = service.createStudent(studentID, firstname, lastname, cooperator);
    assertEquals(cooperator, student2.getCooperator());

    cooperator.addStudent(student1);
    cooperator.addStudent(student2);

    Set<Student> cooperatorStudents = cooperator.getStudent();
    assertTrue(cooperatorStudents.contains(student1));
    assertTrue(cooperatorStudents.contains(student2));
}

春季启动应用程序oneToMany关系中的assertTrue异常

2 个答案: