我的User.java JPA代码
public class User implements java.io.Serializable {
private String mobile;
private String emailId;
private String userName;
private String password;
private Student student = new Student();
private Staff staff = new Staff();
public User() {
}
@Id
@GeneratedValue(strategy = IDENTITY)
@Column(name = "user_id", nullable = false)
public Long getUserId() {
return this.userId;
}
public void setUserId(Long userId) {
this.userId = userId;
}
@Column(name = "mobile", nullable = false)
public String getMobile() {
return this.mobile;
}
public void setMobile(String mobile) {
this.mobile = mobile;
}
@Column(name = "email_id", unique = true, nullable = false, length = 80)
public String getEmailId() {
return this.emailId;
}
public void setEmailId(String emailId) {
this.emailId = emailId;
}
@Column(name = "user_name", unique = true, nullable = false, length = 45)
public String getUserName() {
return this.userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
@Column(name = "password", nullable = false, length = 45)
public String getPassword() {
return this.password;
}
public void setPassword(String password) {
this.password = password;
}
@OneToOne(mappedBy = "studentUser", fetch = FetchType.LAZY)
public Student getStudent() {
return student;
}
public void setStudent(Student student) {
this.student = student;
}
@OneToOne(mappedBy = "staffUser", fetch = FetchType.LAZY)
public Staff getStaff() {
return staff;
}
public void setStaff(Staff staff) {
this.staff = staff;
}
}
我的Student.java JPA代码
public class Student implements java.io.Serializable {
private static final long serialVersionUID = 1L;
private Long id;
private User studentUser;
private String classRollNumber;
private Timestamp admissionDate;
public Student() {
}
public Student(User studentUser, String classRollNumber, Timestamp admissionDate) {
this.studentUser = studentUser;
this.classRollNumber = classRollNumber;
this.admissionDate = admissionDate;
}
@Id
@GeneratedValue(strategy = IDENTITY)
@Column(name = "id", nullable = false)
public Long getId() {
return this.id;
}
public void setId(Long id) {
this.id = id;
}
@OneToOne(cascade = CascadeType.ALL, fetch = FetchType.LAZY)
@JoinColumn(name = "user_id")
public User getStudentUser() {
return this.studentUser;
}
public void setStudentUser(User studentUser) {
this.studentUser = studentUser;
}
@Column(name = "class_roll_number", nullable = false, length = 55)
public String getClassRollNumber() {
return this.classRollNumber;
}
public void setClassRollNumber(String classRollNumber) {
this.classRollNumber = classRollNumber;
}
@Column(name = "admission_date", nullable = false, length = 19)
public Timestamp getAdmissionDate() {
return this.admissionDate;
}
public void setAdmissionDate(Timestamp admissionDate) {
this.admissionDate = admissionDate;
}
}
我的Staff.java JPA代码
public class Staff implements java.io.Serializable {
private static final long serialVersionUID = 1L;
private Long id;
private User staffUser;
private String staffNumber;
private Timestamp joiningDate;
public Staff() {
}
public Staff(User staffUser, String staffNumber, Timestamp joiningDate) {
this.staffUser = staffUser;
this.staffNumber = staffNumber;
this.joiningDate = joiningDate;
}
@Id
@GeneratedValue(strategy = IDENTITY)
@Column(name = "id", nullable = false)
public Long getId() {
return this.id;
}
public void setId(Long id) {
this.id = id;
}
@OneToOne(cascade = CascadeType.ALL, fetch = FetchType.LAZY)
@JoinColumn(name = "user_id")
public User getStaffUser() {
return staffUser;
}
public void setStaffUser(User staffUser) {
this.staffUser = staffUser;
}
@Column(name = "staff_number", nullable = false, length = 55)
public String getStaffNumber() {
return this.staffNumber;
}
public void setStaffNumber(String staffNumber) {
this.staffNumber = staffNumber;
}
@Column(name = "joining_date", nullable = false, length = 19)
public Timestamp getJoiningDate() {
return this.joiningDate;
}
public void setJoiningDate(Timestamp joiningDate) {
this.joiningDate = joiningDate;
}
}
我的持久性逻辑
public void createUser(){
User user = new User();
user.setEmailId("test");
user.setUserName("test");
user.setPassword("test");
user.setMobile("test");
saveEntity(user);
}
public void saveEntity(Object object){
getEntityManager().getTransaction().begin();
getEntityManager().persist(object);
getEntityManager().getTransaction().commit();
}
public static void main(String ar[]){
UserDaoImpl daoImpl = new UserDaoImpl();
daoImpl.createUser();
}
当我尝试坚持实体以下错误发生时，请建议可能的解决方案。 错误堆栈跟踪：
8 Apr, 2013 11:44:05 AM org.hibernate.annotations.common.Version <clinit>
INFO: HCANN000001: Hibernate Commons Annotations {4.0.1.Final}
8 Apr, 2013 11:44:05 AM org.hibernate.Version logVersion
INFO: HHH000412: Hibernate Core {4.1.7.Final}
8 Apr, 2013 11:44:05 AM org.hibernate.cfg.Environment <clinit>
INFO: HHH000206: hibernate.properties not found
8 Apr, 2013 11:44:05 AM org.hibernate.cfg.Environment buildBytecodeProvider
INFO: HHH000021: Bytecode provider name : javassist
8 Apr, 2013 11:44:05 AM org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
INFO: HHH000402: Using Hibernate built-in connection pool (not for production use!)
8 Apr, 2013 11:44:05 AM org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
INFO: HHH000115: Hibernate connection pool size: 20
8 Apr, 2013 11:44:05 AM org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
INFO: HHH000006: Autocommit mode: true
8 Apr, 2013 11:44:05 AM org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
INFO: HHH000401: using driver [com.mysql.jdbc.Driver] at URL [jdbc:mysql://localhost:3306/jpatest]
8 Apr, 2013 11:44:05 AM org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
INFO: HHH000046: Connection properties: {user=root, password=****, autocommit=true, release_mode=auto}
8 Apr, 2013 11:44:05 AM org.hibernate.dialect.Dialect <init>
INFO: HHH000400: Using dialect: org.hibernate.dialect.MySQLDialect
8 Apr, 2013 11:44:05 AM org.hibernate.engine.transaction.internal.TransactionFactoryInitiator initiateService
INFO: HHH000268: Transaction strategy: org.hibernate.engine.transaction.internal.jdbc.JdbcTransactionFactory
8 Apr, 2013 11:44:05 AM org.hibernate.hql.internal.ast.ASTQueryTranslatorFactory <init>
INFO: HHH000397: Using ASTQueryTranslatorFactory
Hibernate: insert into jpatest.tblmuser (email_id, manager_id, mobile, password, user_name) values (?, ?, ?, ?, ?)
Exception in thread "main" javax.persistence.RollbackException: Error while committing the transaction
at org.hibernate.ejb.TransactionImpl.commit(TransactionImpl.java:92)
at org.javalab.bl.dao.BaseDaoImpl.saveEntity(BaseDaoImpl.java:27)
at org.javalab.bl.dao.UserDaoImpl.createUser(UserDaoImpl.java:15)
at org.javalab.bl.dao.UserDaoImpl.main(UserDaoImpl.java:39)
Caused by: java.lang.IllegalStateException: org.hibernate.TransientPropertyValueException: object references an unsaved transient instance - save the transient instance before flushing: org.javalab.bl.entity.User.staff -> org.javalab.bl.entity.Staff
at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1374)
at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1300)
at org.hibernate.ejb.TransactionImpl.commit(TransactionImpl.java:80)
... 3 more
Caused by: org.hibernate.TransientPropertyValueException: object references an unsaved transient instance - save the transient instance before flushing: org.javalab.bl.entity.User.staff -> org.javalab.bl.entity.Staff
at org.hibernate.engine.spi.CascadingAction$8.noCascade(CascadingAction.java:380)
at org.hibernate.engine.internal.Cascade.cascade(Cascade.java:176)
at org.hibernate.event.internal.AbstractFlushingEventListener.cascadeOnFlush(AbstractFlushingEventListener.java:160)
at org.hibernate.event.internal.AbstractFlushingEventListener.prepareEntityFlushes(AbstractFlushingEventListener.java:151)
at org.hibernate.event.internal.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:88)
at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:51)
at org.hibernate.internal.SessionImpl.flush(SessionImpl.java:1210)
at org.hibernate.internal.SessionImpl.managedFlush(SessionImpl.java:399)
at org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.beforeTransactionCommit(JdbcTransaction.java:101)
at org.hibernate.engine.transaction.spi.AbstractTransactionImpl.commit(AbstractTransactionImpl.java:175)
at org.hibernate.ejb.TransactionImpl.commit(TransactionImpl.java:75)
... 3 more
提前致谢 vivek shah
答案 0 :(得分：2)
您的用户实体会在实例时自动创建关联人员。
private Staff staff = new Staff();
因此，当您保留用户时，此用户会引用未保存的工作人员实例，并且没有定义级联（级联在工作人员端）。
你有3种方法可以修复它：
private Staff staff = new Staff();实体中的默认实例User。
User实体中的员工OneToOne重新关联中添加级联。