我想使用Spring MVC 3,Hibernate和PostgresQL注册用户.
这是我想提交的表格：

<form:form name="registerForm" method="post"
        action="registerNewUser.html" commandName="user">

        <table>

            <tr>
                <td><spring:message code="label.userName" /></td>
                <td><form:input path="userName" /></td>
                <td><form:errors path="userName" cssClass="error" /></td>
            </tr>

            <tr>
                <td><spring:message code="label.password" /></td>
                <td><form:password path="password" /></td>
                <td><form:errors path="password" cssClass="error" /></td>
            </tr>


            <tr>
                <td><spring:message code="label.password" /></td>
                <td><form:password path="retypePassword" /></td>
                <td><form:errors path="retypePassword" cssClass="error" /></td>
            </tr>

            <tr>
                <td colspan="2"><input type="submit"
                    value="<spring:message code="register.label" />" /></td>
            </tr>
        </table>

    </form:form>

这是我要保存的POJO：

@Entity
@Table(name = "user_table")
public class User {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private Long id;

    @Column(name = "user_name", nullable = false, length = 50)
    private String userName;

    @Column(name = "password", nullable = false, length = 50)
    private String password;

    private String retypePassword;
        // getters setters

以下是财务主任的相关部分：

@RequestMapping(value = "/registerNewUser", method = RequestMethod.POST)
public String saveNewUser(@ModelAttribute User user, BindingResult result, Model model, HttpSession session) {

    UserValidator validator = new UserValidator();
    validator.validateUser(user, result, userService.existingUser(user));
    String ret = REGISTER_USER;
    if (!result.hasErrors()) {
        user.setPassword(PasswordEncripter.md5(user.getPassword()));
        userService.save(user);
        ret = goToPractice(user, model, session);
    }
    return ret;
}

因为我觉得将retypePassword的值存储在DB中是浪费的,所以我没有为它创建一个列.
当我提交表单时,这导致了以下异常：

org.postgresql.util.PSQLException: ERROR: column user0_.retypepassword does not exist

我可以通过在表中添加“retypePassword”列来轻松修复此异常,但我仍然认为这会浪费.有没有聪明的方法来修复问题而不在数据库中添加重复数据？

解决方法:

您可以使用@Transient在实体中标记retypePassword,这将指示hibernate不在表中创建列,但仍然可以使用此pojo与spring mvc绑定以进行验证.

@Entity
@Table(name = "user_table")
public class User {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private Long id;

    @Column(name = "user_name", nullable = false, length = 50)
    private String userName;

    @Column(name = "password", nullable = false, length = 50)
    private String password;

    @Transient
    private String retypePassword;
        // getters setters