如何在 Spring Data JPA 中过滤 @OneToMany 映射字段？答案

【问题标题】：How to filter a @OneToMany mapped field in spring data JPA?如何在 Spring Data JPA 中过滤 @OneToMany 映射字段？
【发布时间】：2022-01-24 13:47:25
【问题描述】：

我正在尝试使用 Spring Boot REST api 构建费用跟踪器应用程序。以下是我创建的实体类。

用户模型

@Entity
public class User{
    
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private long id;
    
    @NotBlank(message = "username is required !")
    @Column(unique = true)
    @Size(min = 10,max = 10,message = "username must be exactly 10 characters in length !")
    private String username;
    
    @Email(message = "Must be a valid Email !")
    @NotBlank(message = "Email is required !")
    @Size(min = 5, max = 256, message = "Email must be between 5 and 256 characters in length !")
    private String email;
    
    @NotBlank(message = "Password is required !")
    @Size(min = 8 , message = "Password must be greater than 8 characters in length !")
    private String password;
    
    @NotBlank(message = "FirstName is required !")
    @Size(min = 3 , max = 100 , message = "FirstName must be between 3 and 100 characters in length !")
    private String firstName;
    
    @NotBlank(message = "LastName is required !")
    @Size(min = 3 , max = 100 , message = "LastName must be between 3 and 100 characters in length !")
    private String lastName;
    
    @OneToOne(cascade = CascadeType.ALL)
    private Balance balance;
    
    @OrderBy("createdAt DESC")
    @OneToMany(fetch = FetchType.LAZY , cascade = CascadeType.ALL)
    private List<Expense> expensesList;
    
    @Temporal(TemporalType.TIMESTAMP)
    private Date createdAt;
   ......
}

费用模型

@Entity
@Table(name = "expense_tracker_expenses")
public class Expense {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private long id;
    
    @ManyToOne(fetch = FetchType.LAZY)
    private User user;
    
    @NotBlank(message = "Title is required !")
    @Size(min = 3 , max = 60 , message = "Title must be between 3 and 8 characters !")
    private String title;
    
    @Size(max = 256, message = "Note must be less than 256 characters !")
    private String note;
    
    @DecimalMin(value = "0.0",message = "Amount cannot be less than 0.0 !")
    private double amount;
    
    @NotBlank(message = "Category is required !")
    @Pattern(regexp = "Clothing|Entertainment|Food|Fuel|Health|Salary|Misc", message = "Invalid category !")
    private String category;
    
    @Temporal(TemporalType.TIMESTAMP)
    private Date createdAt;
 ...
}

我创建了一个方法

public List<Expense> findByCreatedAtBetween(Date startCreatedAt,Date endCreatedAt);

获取日期之间的费用列表，但返回日期之间所有用户的费用。

如何获取某个用户在开始日期和结束日期之间的费用列表？

【问题讨论】：

this resource 会回答你的问题吗？
spring docs 还包含一个关于“查询创建”的部分。按照他们的约定，我猜下面的查询应该可以工作：findByUserAndCreatedAtBetween(User user, Date startCreatedAt, Date endCreatedAt)
非常感谢，我会试试这个。

标签： java spring hibernate spring-data-jpa

【解决方案1】：

有两种方法

使用 JPA 使用 AND 谓词进行查询。

public List<Expense> findByUserAndCreatedAtBetween(User user,
                                                   Date startCreatedAt,
                                                   Date endCreatedAt);

获取用户的所有费用后在 Java 中进行过滤。

user.getExpensesList().stream().filter(item -> 
    item.getCreatedAt().after(startDate) && 
    item.getCreatedAt().before(endDate)
).collect(Collectors.toList());

【讨论】：