Java 8 可选项和 JSP

Question

有人知道如何在 JSP 上使用 Optional 对象吗？

我有一个类:

@Entity
@Table(name = "projects")
public class Project {

@Expose
@ManyToOne
@JoinColumn(name = "customer_id")
private Customer endCustomer;
....

public Optional<Customer> getEndCustomer() {
    return Optional.ofNullable(endCustomer);
}

public void setEndCustomer(Customer endCustomer) {
    this.endCustomer = endCustomer;
}
....
}

我有 jsp:

<td>
   <form:select class="form-control" id="endCustomer" path="endCustomer.id" tabindex="4">
       <form:options items="${endCustomers}" itemValue="id" itemLabel="name"/>
   </form:select>
</td>

由于显而易见的原因，这部分不起作用:path="endCustomer.id"

有解决办法吗？ 谢谢!

Answer 1

尝试这样的事情

<td>
   <form:select class="form-control" id="endCustomer" path="${endCustomer.get().id}" tabindex="4">
       <form:options items="${endCustomers}" itemValue="id" itemLabel="name"/>
   </form:select>
</td>

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