小编twi*_*ezo的帖子

我有 Spring Web 应用程序（JPA/Hibernate + MySQL）。我有两个 DAO 类。

客户DAO

@Entity
@Table(name = "customers")
public class Customer {

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

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

  @Column(name = "surname", length = 50)
  private String surname;

  @OneToMany(mappedBy = "customer")
  private Set<Order> orders = new HashSet<>();
}

订单DAO

@Entity
@Table(name = "orders")
public class Order {

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

  @Column(name = "date")
  private Date date; …

我有在 eclipse 中创建的工作 spring boot maven 项目。然后我将其导入 Intellij Ultimate，一切正常，单击运行并：

之后我有错误：

2017-02-15 12:46:58.459 ERROR 6020 --- [  restartedMain] o.s.boot.SpringApplication               : Application startup failed

java.lang.IllegalStateException: Could not evaluate condition on org.springframework.boot.devtools.autoconfigure.DevToolsDataSourceAutoConfiguration due to javax/servlet/Filter not found. Make sure your own configuration does not rely on that class. This can also happen if you are @ComponentScanning a springframework package (e.g. if you put a @ComponentScan in the default package by mistake)

....

2017-02-15 12:46:58.478 ERROR 6020 --- [  restartedMain] o.s.b.f.s.DefaultListableBeanFactory     : Destroy method …

我有一个结构对象，该对象具有一个来自外部库的字段，该字段定义为： pub struct SomeId(pub i64);

使用println!打印对象将显示此信息，例如：SomeId(123)

我创建了自己的结构：

#[derive(Debug)]
pub struct Something {
    pub id: i64,
}

而我试图把价值从外部结构SomeId到外地id在我的结构Something：

let test = Something { id: ?? };

或者从struct中提取值SomeId：

let test: i64 = ??;