java - 无法使用 Spring 和 Hibernate 保存表单数据

Question

我经历过这个:Unable to save form data to database in spring mvc但没有解决我的问题。现在，我创建了两个实体。一个(费用组)将用作另一个(费用)的下拉列表。但每当我尝试保存时，它都会生成此错误:

   Field error in object 'expense' on field 'expenseGroup': rejected value [3]; codes [typeMismatch.expense.expenseGroup,typeMismatch.expenseGroup,typeMismatch.com.pebnic.financemgr.entity.ExpenseGroup,typeMismatch]; arguments [org.springframework.context.support.DefaultMessageSourceResolvable: codes [expense.expenseGroup,expenseGroup]; arguments []; default message [expenseGroup]]; default message [Failed to convert property value of type 'java.lang.String' to required type 'com.pebnic.financemgr.entity.ExpenseGroup' for property 'expenseGroup'; nested exception is java.lang.IllegalStateException: Cannot convert value of type 'java.lang.String' to required type 'com.pebnic.financemgr.entity.ExpenseGroup' for property 'expenseGroup': no matching editors or conversion strategy found]].

查看实体 - ExpenseGroup:

@Entity
@Table(name="tab_expgroup")
public class ExpenseGroup {
    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    @Column(name="id")
    private int id;

    @Column(name="code")
    @NotNull(message="Expense Group Code is required")
    @Size(min=3,message="Expense Group Code must be minimum of 3 Characters")
    private String code;

    @Column(name="name")
    @NotNull(message="Expense Group Name is Required")
    private String name;

    @Column(name="flag")
    private String flag;

getter 和 setter

费用实体

@Entity
@Table(name="tab_expenses")
public class Expense {
    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    @Column(name="id")
    private int id;

    @Column(name="item")
    private String item;

    @Column(name="expense_date")
    private String expenseDate;

    @Column(name="amount")
    private double amount;

    @Column(name="narration")
    private String narration;

    //Foreign Key Mapping
    @OneToOne(cascade=CascadeType.ALL)
    @JoinColumn(name="expensegroup_id")
    private ExpenseGroup expenseGroup;
 Getters & setters


**Controller:**

@GetMapping("/showForm")

public String showFormAdd(Model theModel) {

Expense theExpense  = new Expense();

List<ExpenseGroup> theExpenseGroup  = expenseService.getExpenseGroupList();

theModel.addAttribute("expense", theExpense);

theModel.addAttribute("expenseGroups", theExpenseGroup);

return "expense-form";

}


@PostMapping("/saveExpense")

public String saveExpense(@ModelAttribute("expense")Expense theExpense) {

expenseService.saveExpense(theExpense);

return "redirect:/expense/list";

}

DAO实现:

@Override

public void saveExpense(Expense theExpense) {

Session currentSession = sessionFactory.getCurrentSession();

currentSession.saveOrUpdate(theExpense);

}

查看表格:

form:select path="expenseGroup" class="form-control">

<form:option value="">Select the Category</form:option>

<c:forEach  items="${expenseGroups}" var="grp">

<form:option value="${grp.id}">${grp.name}</form:option>

</c:forEach>

</form:select>

这是上面表单的输出:

<select id="expenseGroup" name="expenseGroup" class="form-control">
<option value="">Select the Category</option>

<option value="1">Beverages</option>

<option value="3">Cooking</option>

<option value="6">Self Development</option>

<option value="2">Grains</option>

<option value="5">Personal Allowance</option>

<option value="15">Self Training</option>

<option value="4">Utility</option>

</select>

问题:每当我尝试保存时，无论我选择什么选项，它都会抛出拒绝值的错误。我如何解决这个问题，以便保存/保存数据，知道我正在使用 Hibernate 查询保存数据调用 saveorUpdate 函数的语言。我是 Spring 和 hibernate 的新手。

Answer 1

在费用模型中使用一对一(mappedBy)，并在费用组模型中使用与连接列名称相同的名称。