我能夠通過Hibernate成功在表中創(chuàng)建和插入條目，但是由于某種原因，我的更新方法似乎無法正常工作。對于我的表，我選擇使用POJO文件中的Java批注來創(chuàng)建它。import javax.persistence.Column;import javax.persistence.Entity;import javax.persistence.Id;import javax.persistence.Table;/** * * @author */@Entity@Table(name="student") //name of DB table that will be created via Hibernatepublic class Student { @Id //Primary Key @Column(name = "id") //map to column private Integer id; @Column(name = "name") private String name; @Column(name = "marks") private Integer marks; public Student(Integer id, String name, Integer marks) { this.id = id; this.name = name; this.marks = marks; } public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public Integer getMarks(){ return marks; } public void setMarks(Integer marks) { this.marks = marks; } @Override public String toString() { return "Student: " + this.getId() + " | " + this.getName() + " | " + this.getMarks(); }}
2 回答
胡說叔叔
TA貢獻(xiàn)1804條經(jīng)驗(yàn) 獲得超8個贊
您沒有在此處發(fā)布錯誤，但是看起來您的Studentbean類沒有默認(rèn)的構(gòu)造函數(shù)，該構(gòu)造函數(shù)在執(zhí)行時被調(diào)用
Student studentToUpdate = (Student)newSession.get(Student.class, id);
您可以在將默認(rèn)構(gòu)造函數(shù)與自定義構(gòu)造函數(shù)一起添加到Student類之后嘗試。
GCT1015
TA貢獻(xiàn)1827條經(jīng)驗(yàn) 獲得超4個贊
我的刪除方法存在問題：
public static void deleteStudent() throws HibernateException {
Session newSession = factory.openSession();
newSession.beginTransaction();
newSession.createQuery("delete from student s where smarks < 35")
.executeUpdate(); //Used for updates and deletes
newSession.getTransaction().commit();
newSession.close();
}
如果仔細(xì)查看該查詢，則“從學(xué)生中刪除”應(yīng)該是用大寫字母s的“從學(xué)生中刪除”。粗心的錯誤。
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