Question

我是Spring的新手，还在学习Hibernate一对一的关系。我有这个问题，每当我更新一个特定的记录时，它会为子表创建一个新记录，并且我的所有者表中的外键也会更新。我期待的是两个连接表的记录只会更新。

以下是一些代码：

Employee.java

public class Employee implements Serializable {

private static final long serialVersionUID = -3465813074586302847L;

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private int empId;

@Column
private String name;

@Column
private String email;

@Column
private String address;

@Column
private String telephone;

@OneToOne(cascade = CascadeType.ALL)
@JoinColumn(name="empUserId")
private EmployeeUserAccount employeeUserAccount;

//getters and setters

EmployeeUserAccount.java

public class EmployeeUserAccount implements Serializable {

private static final long serialVersionUID = -3465813074586302847L;

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private int empUserId;

@Column
private String userName;

@Column
private String password;

@Column
private String userLevel;

@OneToOne(mappedBy="employeeUserAccount")
private Employee employee;

//getters and setters

EmployeeDAOImpl.java

public class EmployeeDAOImpl implements EmployeeDAO {

@Override
public Employee updateEmployee(Employee employee) {
    sessionFactory.getCurrentSession().update(employee);
    return employee;
}

EmployeeController.java

public class EmployeeController {

@RequestMapping(value = "/saveEmployee", method = RequestMethod.POST)
public ModelAndView saveEmployee(@ModelAttribute("command") Employee employee) {
    if (employee.getEmpId() == 0) {
        employeeService.addEmployee(employee);
    } else {
        employeeService.updateEmployee(employee);
    }
    return new ModelAndView("redirect:/");
}

EmployeeForm.jsp

<body>
<div align="center">
    <h1>New/Edit Employee</h1>
    <form:form action="saveEmployee" method="post" >
    <table>
        <form:hidden path="empId"/>
        <tr>
            <td>Name:</td>
            <td><form:input path="name" value="${employee.name}"/></td>
        </tr>
        <tr>
            <td>Email:</td>
            <td><form:input path="email" value="${employee.email}"/></td>
        </tr>
        <tr>
            <td>Address:</td>
            <td><form:input path="address" value="${employee.address}"/></td>
        </tr>
        <tr>
            <td>Telephone:</td>
            <td><form:input path="telephone" value="${employee.telephone}"/></td>
        </tr>
        <tr>
            <td>Username:</td>
            <td><form:input path="employeeUserAccount.userName" value="${employee.employeeUserAccount.userName}"/></td>
        </tr>
        <tr>
            <td>Password:</td>
            <td><form:input path="employeeUserAccount.password"  value="${employee.employeeUserAccount.password}"/></td>
        </tr>
        <tr>
            <td>Role:</td>
            <td>
                <form:select path="employeeUserAccount.userLevel">
                <c:forEach items="${role}" var="r">
                    <c:choose>
                        <c:when test="${r==employee.employeeUserAccount.userLevel}">
                            <option value="${r}" selected="true">${r}</option>
                        </c:when>
                        <c:otherwise>
                            <option value="${r}">${r}</option>
                        </c:otherwise>
                    </c:choose>
                </c:forEach>
                </form:select>
            </td>
        </tr>
        <tr>
            <td colspan="2" align="center"><input type="submit" value="Save"></td>
        </tr>
    </table>
    </form:form>
</div>

情境：

最初，tbl_employee中的列empUserId为1，它链接到tbl_employee_user_account的第一条记录。更新名称后（从name1到new-name1），tbl_employee_user_account创建id为2的新记录，tbl_employee中的empUserId变为2。

mysql> select * from tbl_employee;
 +-------+----------+--------+-----------+-----------+----------+
| empId | address  | email  | name      | telephone | empUserId |
+-------+----------+--------+-----------+-----------+-----------+
|     1 | address1 | email1 | new-name1 | tele1     |         2 |
+-------+----------+--------+-----------+-----------+-----------+

mysql> select * from tbl_employee_user_account;
+-----------+----------+-----------+-----------+----------+
| empUserId | employee | password  | userLevel | userName |
+-----------+----------+-----------+-----------+----------+
|         1 | NULL     | password1 | Admin     | user1    |
|         2 | NULL     | password1 | Admin     | user1    |
+-----------+----------+-----------+-----------+----------+

Answer 1

让自己置身于Hibernate之中。您被要求更新员工。此员工由ID标识，并且具有新名称，新地址等，还有新用户帐户，而不是旧用户帐户，已存在且由ID标识。新的没有任何ID。因此它不可能与旧帐户相同。因此，Hibernate只会做它被告知要做的事情：用新的帐户替换员工的帐户。

Spring Hibernate One-To-One关系在子表上创建新记录而不是更新

1 个答案: