Java not null属性引用Hibernate中的null或瞬时值错误

我正在构建一个Hibernate应用程序，在MySql数据库中存储国家、州和城市信息。但我在线程“main”org.hibernate.PropertyValueException中不断遇到

异常：notnull属性引用空值或瞬时值

，即使我在相关实体中有空检查

这里是

Country.java

package com.models;

import java.util.ArrayList;
import java.util.List;

import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToMany;
import javax.persistence.OneToOne;
import javax.persistence.Table;

import com.sun.istack.NotNull;

@Entity
@Table(name = "COUNTRY")
public class Country {

    public Country() {
        super();
        // TODO Auto-generated constructor stub
    }

    public Country(String country, String countryCode) {
        super();
        this.country = country;
        this.countryCode = countryCode;

    }

    private String country;
    @Id
    @NotNull
    private String countryCode;

    @OneToMany(mappedBy = "state", cascade = CascadeType.ALL,fetch = FetchType.LAZY)
    private List<State> state = new ArrayList<State>();



    public List<State> getState() {
        return state;
    }

    public void setState(List<State> state) {
        this.state = state;
    }

    public String getCountry() {
        return country;
    }
    public void setCountry(String country) {
        this.country = country;
    }
    public String getCountryCode() {
        return countryCode;
    }
    public void setCountryCode(String countryCode) {
        this.countryCode = countryCode;
    }


}

package com.models;

import java.util.ArrayList;
import java.util.List;
import java.util.Set;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.OneToMany;
import javax.persistence.OneToOne;
import javax.persistence.Table;

@Entity
@Table(name = "STATE")
public class State {


    public State() {
        super();

    }
    public State(String state, String statecode) {
        super();

        this.state = state;
        this.statecode = statecode;


    }


    private String state;
    @Id
    private String statecode;


    @OneToMany
    List<City> city = new ArrayList<City>();

    @ManyToOne  
    @JoinColumn(name="countryCode", nullable=false)
    private Country country;


    public Country getCountry() {
        return country;
    }
    public void setCountry(Country country) {
        this.country = country;
    }
    public List<City> getCity() {
        return city;
    }
    public void setCity(List<City> city) {
        this.city = city;
    }

    public String getState() {
        return state;
    }
    public void setState(String state) {
        this.state = state;
    }
    public String getStatecode() {
        return statecode;
    }
    public void setStatecode(String statecode) {
        this.statecode = statecode;
    }




}

package com.models;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;

@Entity
@Table(name="CITY")
public class City {


    public City() {
        super();
        // TODO Auto-generated constructor stub
    }
    public City(String city, boolean isStateCapital, boolean isCountryCapital, 
            String statecode, String countrycode) {
        super();

        this.city = city;
        this.isStateCapital = isStateCapital;
        this.isCountryCapital = isCountryCapital;
        this.statecode = statecode;
        this.countrycode = countrycode;
    }
    @Id 
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int cityid;
    private String city;
    private boolean isStateCapital;
    private boolean isCountryCapital;
    private String statecode;
    private String countrycode;


    public String getStatecode() {
        return statecode;
    }
    public void setStatecode(String statecode) {
        this.statecode = statecode;
    }
    public String getCity() {
        return city;
    }
    public void setCity(String city) {
        this.city = city;
    }
    public boolean isStateCapital() {
        return isStateCapital;
    }
    public void setStateCapital(boolean isStateCapital) {
        this.isStateCapital = isStateCapital;
    }
    public boolean isCountryCapital() {
        return isCountryCapital;
    }
    public void setCountryCapital(boolean isCountryCapital) {
        this.isCountryCapital = isCountryCapital;
    }

    public String getCountrycode() {
        return countrycode;
    }
    public void setCountrycode(String countrycode) {
        this.countrycode = countrycode;
    }



}

这里是

City.java

package com.models;

import java.util.ArrayList;
import java.util.List;

import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToMany;
import javax.persistence.OneToOne;
import javax.persistence.Table;

import com.sun.istack.NotNull;

@Entity
@Table(name = "COUNTRY")
public class Country {

    public Country() {
        super();
        // TODO Auto-generated constructor stub
    }

    public Country(String country, String countryCode) {
        super();
        this.country = country;
        this.countryCode = countryCode;

    }

    private String country;
    @Id
    @NotNull
    private String countryCode;

    @OneToMany(mappedBy = "state", cascade = CascadeType.ALL,fetch = FetchType.LAZY)
    private List<State> state = new ArrayList<State>();



    public List<State> getState() {
        return state;
    }

    public void setState(List<State> state) {
        this.state = state;
    }

    public String getCountry() {
        return country;
    }
    public void setCountry(String country) {
        this.country = country;
    }
    public String getCountryCode() {
        return countryCode;
    }
    public void setCountryCode(String countryCode) {
        this.countryCode = countryCode;
    }


}

package com.models;

import java.util.ArrayList;
import java.util.List;
import java.util.Set;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.OneToMany;
import javax.persistence.OneToOne;
import javax.persistence.Table;

@Entity
@Table(name = "STATE")
public class State {


    public State() {
        super();

    }
    public State(String state, String statecode) {
        super();

        this.state = state;
        this.statecode = statecode;


    }


    private String state;
    @Id
    private String statecode;


    @OneToMany
    List<City> city = new ArrayList<City>();

    @ManyToOne  
    @JoinColumn(name="countryCode", nullable=false)
    private Country country;


    public Country getCountry() {
        return country;
    }
    public void setCountry(Country country) {
        this.country = country;
    }
    public List<City> getCity() {
        return city;
    }
    public void setCity(List<City> city) {
        this.city = city;
    }

    public String getState() {
        return state;
    }
    public void setState(String state) {
        this.state = state;
    }
    public String getStatecode() {
        return statecode;
    }
    public void setStatecode(String statecode) {
        this.statecode = statecode;
    }




}

package com.models;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;

@Entity
@Table(name="CITY")
public class City {


    public City() {
        super();
        // TODO Auto-generated constructor stub
    }
    public City(String city, boolean isStateCapital, boolean isCountryCapital, 
            String statecode, String countrycode) {
        super();

        this.city = city;
        this.isStateCapital = isStateCapital;
        this.isCountryCapital = isCountryCapital;
        this.statecode = statecode;
        this.countrycode = countrycode;
    }
    @Id 
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int cityid;
    private String city;
    private boolean isStateCapital;
    private boolean isCountryCapital;
    private String statecode;
    private String countrycode;


    public String getStatecode() {
        return statecode;
    }
    public void setStatecode(String statecode) {
        this.statecode = statecode;
    }
    public String getCity() {
        return city;
    }
    public void setCity(String city) {
        this.city = city;
    }
    public boolean isStateCapital() {
        return isStateCapital;
    }
    public void setStateCapital(boolean isStateCapital) {
        this.isStateCapital = isStateCapital;
    }
    public boolean isCountryCapital() {
        return isCountryCapital;
    }
    public void setCountryCapital(boolean isCountryCapital) {
        this.isCountryCapital = isCountryCapital;
    }

    public String getCountrycode() {
        return countrycode;
    }
    public void setCountrycode(String countrycode) {
        this.countrycode = countrycode;
    }



}

下面是

Application.java

class

package com.application;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.boot.MetadataSources;
import org.hibernate.boot.registry.StandardServiceRegistry;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.cfg.Configuration;

import com.models.City;
import com.models.Country;
import com.models.State;

public class Application {

    public static void main(String[] args) {

        SessionFactory sessionFactory = getSessionFactory();
        Session session = sessionFactory.openSession();
        Transaction t = session.beginTransaction();

        Country country = new Country("India","IN");
        State state= new State("Delhi","DL");
        City city = new City("New Delhi",true,true,"DL","IN");

        country.getState().add(state);
        state.getCity().add(city);

        session.save(country);
        session.save(state);
        session.save(city);

        t.commit();
        session.close();
        sessionFactory.close();
    }

    private static SessionFactory getSessionFactory() {
        Configuration configuartion = new Configuration().configure();
        configuartion.addAnnotatedClass(Country.class);
        configuartion.addAnnotatedClass(State.class);
        configuartion.addAnnotatedClass(City.class);
//      StandardServiceRegistryBuilder registry = new StandardServiceRegistryBuilder();
//      registry.applySettings(configuartion.getProperties());
//      StandardServiceRegistry serviceRegistry = registry.build();
//      SessionFactory sessionFactory = new MetadataSources(serviceRegistry).buildMetadata().buildSessionFactory();
        SessionFactory sessionFactory = configuartion.buildSessionFactory();
        return sessionFactory;
    }

}

hibernate.cfg.xml

文件

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory>
        <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="hibernate.connection.password">pwdrd</property>
        <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/countryinfo</property>
        <property name="hibernate.connection.username">root</property>
        <property name="hibernate.dialect">org.hibernate.dialect.MySQL55Dialect</property>
        <property name="show_sql">true</property>
        <property name="hbm2ddl.auto">update</property>
    </session-factory>
</hibernate-configuration>

---

虽然我在国家和州实体上有可为空的检查，但我有级联和获取类型惰性属性集，但它仍然没有解析。我们将非常感谢您在这方面的帮助。谢谢Sid

修改

Application.java

。保存顺序是错误的

public class Application {

    public static void main(String[] args) {

        SessionFactory sessionFactory = getSessionFactory();
        Session session = sessionFactory.openSession();
        Transaction t = session.beginTransaction();

        Country country = new Country("India","IN");
        State state= new State("Delhi","DL");
        City city = new City("New Delhi",true,true,"DL","IN");
        // first save city
        session.save(city); 
        // then add city to state
        state.getCity().add(city);
        state.setCountry(country);
        // save state
        session.save(state);
        // add state to country
        country.getState().add(state);
        // save country
        session.save(country);
        t.commit();
        session.close();
        sessionFactory.close();
    }
}

---

您可以做以下更改并重试吗

在

国家/地区

实体中存在映射问题，

mappedBy

字段设置为

状态

，这将创建一个额外的外键。请更新如下

@OneToMany(mappedBy = "country", cascade = CascadeType.ALL,fetch = FetchType.LAZY)
private List<State> state = new ArrayList<State>();

现在在

应用程序.java中进行以下更改

package com.models;

import java.util.ArrayList;
import java.util.List;

import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToMany;
import javax.persistence.OneToOne;
import javax.persistence.Table;

import com.sun.istack.NotNull;

@Entity
@Table(name = "COUNTRY")
public class Country {

    public Country() {
        super();
        // TODO Auto-generated constructor stub
    }

    public Country(String country, String countryCode) {
        super();
        this.country = country;
        this.countryCode = countryCode;

    }

    private String country;
    @Id
    @NotNull
    private String countryCode;

    @OneToMany(mappedBy = "state", cascade = CascadeType.ALL,fetch = FetchType.LAZY)
    private List<State> state = new ArrayList<State>();



    public List<State> getState() {
        return state;
    }

    public void setState(List<State> state) {
        this.state = state;
    }

    public String getCountry() {
        return country;
    }
    public void setCountry(String country) {
        this.country = country;
    }
    public String getCountryCode() {
        return countryCode;
    }
    public void setCountryCode(String countryCode) {
        this.countryCode = countryCode;
    }


}

package com.models;

import java.util.ArrayList;
import java.util.List;
import java.util.Set;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.OneToMany;
import javax.persistence.OneToOne;
import javax.persistence.Table;

@Entity
@Table(name = "STATE")
public class State {


    public State() {
        super();

    }
    public State(String state, String statecode) {
        super();

        this.state = state;
        this.statecode = statecode;


    }


    private String state;
    @Id
    private String statecode;


    @OneToMany
    List<City> city = new ArrayList<City>();

    @ManyToOne  
    @JoinColumn(name="countryCode", nullable=false)
    private Country country;


    public Country getCountry() {
        return country;
    }
    public void setCountry(Country country) {
        this.country = country;
    }
    public List<City> getCity() {
        return city;
    }
    public void setCity(List<City> city) {
        this.city = city;
    }

    public String getState() {
        return state;
    }
    public void setState(String state) {
        this.state = state;
    }
    public String getStatecode() {
        return statecode;
    }
    public void setStatecode(String statecode) {
        this.statecode = statecode;
    }




}

package com.models;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;

@Entity
@Table(name="CITY")
public class City {


    public City() {
        super();
        // TODO Auto-generated constructor stub
    }
    public City(String city, boolean isStateCapital, boolean isCountryCapital, 
            String statecode, String countrycode) {
        super();

        this.city = city;
        this.isStateCapital = isStateCapital;
        this.isCountryCapital = isCountryCapital;
        this.statecode = statecode;
        this.countrycode = countrycode;
    }
    @Id 
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int cityid;
    private String city;
    private boolean isStateCapital;
    private boolean isCountryCapital;
    private String statecode;
    private String countrycode;


    public String getStatecode() {
        return statecode;
    }
    public void setStatecode(String statecode) {
        this.statecode = statecode;
    }
    public String getCity() {
        return city;
    }
    public void setCity(String city) {
        this.city = city;
    }
    public boolean isStateCapital() {
        return isStateCapital;
    }
    public void setStateCapital(boolean isStateCapital) {
        this.isStateCapital = isStateCapital;
    }
    public boolean isCountryCapital() {
        return isCountryCapital;
    }
    public void setCountryCapital(boolean isCountryCapital) {
        this.isCountryCapital = isCountryCapital;
    }

    public String getCountrycode() {
        return countrycode;
    }
    public void setCountrycode(String countrycode) {
        this.countrycode = countrycode;
    }



}

Country-Country=新国家（“印度”、“印度”）；
州=新州（“德里”、“DL”）；
城市=新市（“新德里”，真，真，“DL”，“IN”）；
会议.拯救（城市）；
state.getCity（）.add（城市）；
country.addState（state）；
会议.拯救（国家）；
t、 提交（）；
session.close（）；
sessionFactory.close（）；
谢谢，我试过了，但现在遇到了这个错误<代码>Hibernate：在线程“main”org.Hibernate.PropertyValueException中插入CITY（CITY，countrycode，isCountryCapital，isStateCapital，statecode）值（？，，，？，？，？）异常：not null属性引用空值或临时值：com.models.State.country位于org.Hibernate.engine.internal.Nullability.checkNullability（Nullability.java:111）位于org.hibernate.engine.internal.Nullability.checkNullability（Nullability.java:55）

@Sid111Math just put state.setCountry（country）；在此state.getCity（）之后添加（city）；我已经更新了我的答案，现在明白了，

原因是：java.sql.SQLIntegrityConstraintViolationException:com.mysql.cj.jdbc.exceptions.SQLError.createSQLException（SQLError.java:117）在com.mysql.cj.jdbc.exceptions.SQLError.createSQLException（SQLError.java:97）上的列“countryCode”不能为空com.mysql.cj.jd.jdbc.exceptions.sqlexceptions映射.translateException（sqlexceptions映射.java:122）com.mysql.cj.jdbc.ClientPreparedStatement.executeInternal（ClientPreparedStatement.java:953）com.mysql.cj.jdbc.ClientPreparedStatement.executeUpdateInternal（ClientPreparedStatement.java:1092）

@SID1111Math您在应用程序类的某个地方将countrycode设置为null。请检查。此外，请正确编写您的实体。注意：您在countrycode中保留了countrycode上的

@NotNull

。因此，这就是为什么您会出现此错误。我已从

Country

中删除了

@NotNull

，如下所示现在。

@Id private String countryCode；

在

状态下

类中，我已经删除了

nullable=false

，它看起来像是

@manytone@JoinColumn（name=“countryCode”）private Country Country；

但我仍然得到了

列“countryCode”不能为null的错误。