java - 面临无法延迟初始化集合并且无法初始化代理 - 无 session

Question

当我从 Angular 发送 post 请求时，然后在 Spring Boot requestfilter 程序中验证 jwt token 时显示错误。

面临的问题org.hibernate.LazyInitializationException:

failed to lazily initialize a collection of role: in.yis.mains.model.OpsUsersLogin.roles, could not initialize proxy - no Session

import java.util.Date;
import java.util.LinkedHashSet;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.OneToMany;
import javax.persistence.JoinTable;
import javax.persistence.Table;
import javax.persistence.JoinColumn;
import javax.persistence.UniqueConstraint;

import com.fasterxml.jackson.annotation.JsonFormat;

import lombok.Data;

@Data
@Entity
@Table(
        name="ops_users_login",
        uniqueConstraints={@UniqueConstraint(columnNames={"username"})}
    )
public class OpsUsersLogin {

    @Id
    @GeneratedValue( strategy = GenerationType.AUTO )
    private long id;

    private String name;

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

    private String password;

    private String oldPassword;

    private String status_flag;

    private int wrong_attampts;

    @JsonFormat(pattern="yyyy-MM-dd")
    private Date created_date;

    @JsonFormat(pattern="yyyy-MM-dd")
    private Date expiry_date;


    private long rights;

    private String address;

    private String designation;

    private long empId;

    @JsonFormat(pattern="yyyy-MM-dd")
    private Date created_by;

    @JsonFormat(pattern="yyyy-MM-dd")
    private Date updated_by;

    @ManyToMany
    @JoinTable( 
        name = "opsUsersLogin_roles", 
        joinColumns=@JoinColumn(name = "user_id", referencedColumnName = "id"), 
        inverseJoinColumns=@JoinColumn(name = "role_id", referencedColumnName = "id")) 
    private Collection<Role> roles;

}

Answer 1

This describes what you need basically

org.hibernate.LazyInitializationException意味着，在您的情况下，相关实体或实体集合 roles ，尚未初始化，因为相关实体的默认获取策略为 LAZY .

要解决此问题，您必须初始化 roles获取 ops_user_login 后的集合实体，或者如果您已经使用一个查询来获取实体，则可以通过查询来获取它们。初始化roles可以用Hibernate.initialize(entity.getRoles())来完成，如果这不起作用您也可以调用 entity.getRoles().size()作为解决方法。

如果您使用查询来选择您的ops_user_login你可以做类似的事情:

Query query = session.createQuery(
    "from ops_user_login o " +
    "join fetch o.roles"
); 

或

TypedQuery<OpsUsersLogin> query = entityManager.createQuery("Select o from ops_user_login o join fetch o.roles", OpsUsersLogin.class);