java - JPA 外键约束违规无法插入 Null

标签 java hibernate jpa

我有一个具有一对多映射的简单用户和角色实体。一个用户具有多个角色。尝试保存用户实体时出现错误。我在调用 persist 之前设置角色对象用户。

下面是实体的快照。

用户:

package com.petpe.ejbadmin.entity;

import java.io.Serializable;
import java.util.Date;
import java.util.Set;

import javax.annotation.Generated;
import javax.persistence.Basic;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.NamedQueries;
import javax.persistence.NamedQuery;
import javax.persistence.OneToMany;
import javax.persistence.Table;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlTransient;


@Entity
@Table(name = "users")
@XmlRootElement
@NamedQueries({
    @NamedQuery(name = "User.findAll", query = "SELECT u FROM User u"),
    @NamedQuery(name = "User.findByUsernameandPassword", query = "SELECT u FROM User u WHERE u.username = :username AND u.password = :password"),
    @NamedQuery(name = "User.findByUserfirstname", query = "SELECT u FROM User u WHERE u.userfirstname = :userfirstname"),
    @NamedQuery(name = "User.findByUserlastname", query = "SELECT u FROM User u WHERE u.userlastname = :userlastname"),
    @NamedQuery(name = "User.findByPhonenumber", query = "SELECT u FROM User u WHERE u.phonenumber = :phonenumber"),
    @NamedQuery(name = "User.findByEmail", query = "SELECT u FROM User u WHERE u.email = :email"),
    @NamedQuery(name = "User.findByErpid", query = "SELECT u FROM User u WHERE u.erpid = :erpid"),
    @NamedQuery(name = "User.findByBuyerid", query = "SELECT u FROM User u WHERE u.buyerid = :buyerid"),
    @NamedQuery(name = "User.findByCreatedDate", query = "SELECT u FROM User u WHERE u.createdDate = :createdDate"),
    @NamedQuery(name=  "User.findByfirstletter",query="SELECT u FROM User u join fetch u.RoleSet ur WHERE LOWER(u.userfirstname) LIKE :firstname"),
    @NamedQuery(name=  "User.findallusers",query="From User u join fetch u.RoleSet ur")})
public class User implements Serializable {
    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    @Basic(optional = true)
    @Column(name = "USER_ID")
    private Integer userId;
    @Size(max = 120)
    @Column(name = "USERNAME")
    private String username;
    @Size(max = 60)
    @Column(name = "USERFIRSTNAME")
    private String userfirstname;
    @Size(max = 60)
    @Column(name = "USERLASTNAME")
    private String userlastname;
    @Size(max = 50)
    @Column(name = "PASSWORD")
    private String password;
    @Size(max = 20)
    @Column(name = "PHONENUMBER")
    private String phonenumber;
    // @Pattern(regexp="[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*@(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?", message="Invalid email")//if the field contains email address consider using this annotation to enforce field validation
    @Size(max = 50)
    @Column(name = "EMAIL")
    private String email;
    @Size(max = 250)
    @Column(name = "ERPID")
    private String erpid;
    @Size(max = 250)
    @Column(name = "BUYERID")
    private String buyerid;
    @Basic(optional = false)
    @NotNull
    @Column(name = "CREATED_DATE")
    @Temporal(TemporalType.DATE)
    private Date createdDate;
    @OneToMany(cascade = CascadeType.ALL, mappedBy = "user", fetch = FetchType.LAZY)
    private Set<Role> RoleSet;

    public User() {
    }

    public User(Integer userId) {
        this.userId = userId;
    }

    public User(Integer userId, Date createdDate) {
        this.userId = userId;
        this.createdDate = createdDate;
    }

    public Integer getUserId() {
        return userId;
    }

    public void setUserId(Integer userId) {
        this.userId = userId;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getUserfirstname() {
        return userfirstname;
    }

    public void setUserfirstname(String userfirstname) {
        this.userfirstname = userfirstname;
    }

    public String getUserlastname() {
        return userlastname;
    }

    public void setUserlastname(String userlastname) {
        this.userlastname = userlastname;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getPhonenumber() {
        return phonenumber;
    }

    public void setPhonenumber(String phonenumber) {
        this.phonenumber = phonenumber;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getErpid() {
        return erpid;
    }

    public void setErpid(String erpid) {
        this.erpid = erpid;
    }

    public String getBuyerid() {
        return buyerid;
    }

    public void setBuyerid(String buyerid) {
        this.buyerid = buyerid;
    }

    public Date getCreatedDate() {
        return createdDate;
    }

    public void setCreatedDate(Date createdDate) {
        this.createdDate = createdDate;
    }

    @XmlTransient
    public Set<Role> getRoleSet() {
        return RoleSet;
    }

    public void setRoleSet(Set<Role> RoleSet) {
        this.RoleSet = RoleSet;
    }

    @Override
    public int hashCode() {
        int hash = 0;
        hash += (userId != null ? userId.hashCode() : 0);
        return hash;
    }

    @Override
    public boolean equals(Object object) {
        // TODO: Warning - this method won't work in the case the id fields are not set
        if (!(object instanceof User)) {
            return false;
        }
        User other = (User) object;
        if ((this.userId == null && other.userId != null) || (this.userId != null && !this.userId.equals(other.userId))) {
            return false;
        }
        return true;
    }

    @Override
    public String toString() {
        return "[ userId=" + userId + " ]";
    }

}

作用:

/* * 要更改此许可 header ，请在项目属性中选择许可 header 。 * 要更改此模板文件，请选择工具 |模板 * 并在编辑器中打开模板。 */

package com.petpe.ejbadmin.entity;

import java.io.Serializable;

import javax.persistence.Basic;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.NamedQueries;
import javax.persistence.NamedQuery;
import javax.persistence.Table;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;
import javax.xml.bind.annotation.XmlRootElement;


@Entity
@Table(name = "user_roles")
@XmlRootElement
public class Role implements Serializable {
    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    @Basic(optional = false)
    @Column(name = "ROLEID")
    private Integer roleid;
    @Basic(optional = false)
    @NotNull
    @Size(min = 1, max = 30)
    @Column(name = "ROLENAME")
    private String rolename;
    @JoinColumn(name = "USER_ID", referencedColumnName = "USER_ID")
    @ManyToOne( fetch = FetchType.LAZY)
    private User user;

    public Role() {
    }

    public Role(String rolename) {
        this.rolename = rolename;
    }

    public Role(Integer roleid, String rolename) {
        this.roleid = roleid;
        this.rolename = rolename;
    }

    public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;
    }

    public Integer getRoleid() {
        return roleid;
    }

    public void setRoleid(Integer roleid) {
        this.roleid = roleid;
    }

    public String getRolename() {
        return rolename;
    }

    public void setRolename(String rolename) {
        this.rolename = rolename;
    }



    @Override
    public int hashCode() {
        int hash = 0;
        hash += (roleid != null ? roleid.hashCode() : 0);
        return hash;
    }

    @Override
    public boolean equals(Object object) {
        // TODO: Warning - this method won't work in the case the id fields are not set
        if (!(object instanceof Role)) {
            return false;
        }
        Role other = (Role) object;
        if ((this.roleid == null && other.roleid != null) || (this.roleid != null && !this.roleid.equals(other.roleid))) {
            return false;
        }
        return true;
    }

    @Override
    public String toString() {
        return "[ roleid=" + roleid + " ]";
    }

}

错误:

1.Cannot insert the value NULL into column 'USER_ID', table 'pedb.pedb.user_roles'; column does not allow nulls. INSERT fails.
2.could not insert: [com.petpe.ejbadmin.entity.Role]
3.org.hibernate.exception.ConstraintViolationException: could not insert: [com.petpe.ejbadmin.entity.Role]
4.javax.persistence.PersistenceException: org.hibernate.exception.ConstraintViolationException: could not insert: [com.petpe.ejbadmin.entity.Role]

设置和持久化代码:

public boolean AddorModifyUser(UserAdminDTO udato) {

        User usr=this.populateUserobj(udato);
        pet_em.persist(usr);

        return true;
    }

public User populateUserobj(UserAdminDTO udto)
    {
        User usr=new User();

        usr.setBuyerid(udto.getbuyerid());
        usr.setCreatedDate(new Date());
        usr.setEmail(udto.getEmail());
        usr.setErpid(udto.geterpid());
        usr.setPassword(udto.getPassword());
        usr.setPhonenumber(udto.getPhoneNumber());
        usr.setUserfirstname(udto.getFirstName());
        usr.setUserlastname(udto.getLastName());
        usr.setUsername(udto.getUserName());
        for(Role r: udto.getRole())
        {
            Set<Role> RoleSet=new HashSet<>();
            RoleSet.add(r);     
            usr.setRoleSet(RoleSet);
        }
        return usr;
    }

表格布局:

enter image description here

最佳答案

所以您在角色表中的 USER_ID 上有一个 NOT NULL 约束。持久化时(即使存在级联关系)，外键(或实体关系)不会自动设置。

很可能在创建 Role 时，您没有设置 User，因此在持久化时，提供者不知道 USER_ID 是什么是，因此尝试在数据库中将其设置为 null，这违反了数据库模式。

您需要做的就是为每个角色设置用户

Set<Role> RoleSet=new HashSet<>();
for(Role r: udto.getRole())
{
    r.setUser(usr);   // <------
    RoleSet.add(r);     
}
usr.setRoleSet(RoleSet);

还要注意 Set 是在循环外创建的

然后...但是...等待...

你还没有走出困境。以上将解决错误，但您还有另一个问题。它很微妙，肯定会导致难以发现错误。

您已经生成了 Role id。

@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
private Integer roleid;

所以你在创建角色的时候不要设置

Set<Role> roles = new HashSet<>();
Role userRole = new Role("USER");
userRole.setUser(user);
roles.add(userRole);
Role coolRole = new Role("COOL_GUY");
coolRole.setUser(user);
roles.add(coolRole);
user.setRoleSet(roles);

看起来不是问题，但错误在 hashCode

@Override
public int hashCode() {
    int hash = 0;
    hash += (roleid != null ? roleid.hashCode() : 0);
    return hash;
}

hashCode 只包含roleId。但是您没有设置 roleId 因为它应该被生成。因此，当您将角色添加到 Set 时，它们都具有相同的 hashCode，因此您最终只会将一个 Role 添加到 Set，因为 Set 中的对象不能具有相同的 hashCode。

要解决此问题，您只需更改 hashCode 以同时包含 rolename。

在测试时，我只是让 Netbeans 生成 hashCode 和 equals。这是结果。

@Override
public int hashCode() {
    int hash = 7;
    hash = 31 * hash + Objects.hashCode(this.roleid);
    hash = 31 * hash + Objects.hashCode(this.rolename);
    return hash;
}

@Override
public boolean equals(Object obj) {
    if (obj == null) {
        return false;
    }
    if (getClass() != obj.getClass()) {
        return false;
    }
    final Role other = (Role) obj;
    if (!Objects.equals(this.roleid, other.roleid)) {
        return false;
    }
    if (!Objects.equals(this.rolename, other.rolename)) {
        return false;
    }
    return true;
}

这应该可以修复错误。

关于java - JPA 外键约束违规无法插入 Null，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/32915640/

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