Question

我有一个带有一些绑定到表单的简单属性的对象。问题是：这个对象还有一个对象Map，我想绑定到同一个表单。

对象是＆＃34;事件＆＃34;，＆＃34;捐赠＆＃34;和＃34; Donor＆＃34;，定义如下：

// each event has a map of donations. the map key is the id of the donor
@Entity
public class Event {
    @Column
    private name;

    // the key for this collection is the id of the donor
    @OneToMany(mappedBy="event")
    @MapKey(name="donor")
    private Map<Integer,Donation> donations;
}

// each donation is for one event, has properties 'amount' and 'donor'
@Entity
public class Donation {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name="ID", nullable = false)
    private Integer id;

    @ManyToOne
    @JoinColumn(name="EVENT_ID")
    private Event event;

    @Column
    private Double amount;

    @ManyToOne
    @JoinColumn(name="DONOR_ID")
    private Donor donor;
}

// the donors are set elsewhere in the application
@Entity
public class Donor {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name="ID", nullable = false)
    private Integer id;

    @Column
    private String name;
}

我的JSP中的相关代码是：

<form:form name="form" method="post" commandName="event">
    Name: <form:input path="name"/><br/>
    Donations:<br/>
    <c:forEach var="donation" items="${event.donations}">
        ${donation.value.donor.name}: <input name="donations[${donation.key}]" value="${donation.value.amount}" /><br/>
    </c:forEach>
</form:form>

最后，表单提交以下控制器方法：

@RequestMapping(value="/{id}", method=RequestMethod.POST)
    public String saveEvent(@Valid @ModelAttribute Event event, BindingResult result, Model model) {
    // save event here
}

表单显示正确，但保存时出现以下错误：

Failed to convert property value of type java.lang.String to required type java.lang.Integer for property null; nested exception is java.lang.NumberFormatException: For input string: "myclasses.Donor@7cabee72"

从错误消息中我假设需要一个属性编辑器。我已经为简单的情况创建了属性编辑器，但在这里我很难过。

当集合是主对象的属性并且集合中的每个项目都有两个属性（金额和捐赠者）时，绑定对象集合的正确方法是什么？

在Spring中绑定并验证Map属性

0 个答案: