Question

我正在尝试用hibernate实现ManyToMany单向关系。问题是当我尝试向数据库添加一些值时，我收到以下错误：

运行时发生异常。 null：InvocationTargetException：无法执行ApplicationRunner：传递给persist的分离实体：dnd35cg.model.DnDClass;嵌套异常是org.hibernate.PersistentObjectException：传递给persist的分离实体：dnd35cg.model.DnDClass

这些是我的课程：

Hero.java

@Entity
@Table(name = "HEROES")
public class Hero {

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

private Short strength;
private Short dexterity;
private Short constitution;
private Short intelligence;
private Short wisdom;
private Short charisma;
private String name;

@ManyToOne
private Race race;

@ManyToMany(cascade = CascadeType.ALL)
@JoinTable(name = "HERO_CLASSES",
            joinColumns = { @JoinColumn(name = "HERO_ID") },
            inverseJoinColumns = { @JoinColumn(name = "DNDCLASS_ID") })
private Set<DnDClass> dnDClasses = new HashSet<>();

public Hero() {
}

public Hero(Short strength, Short dexterity, Short constitution, Short intelligence, Short wisdom, Short charisma, String name, Race race, Set<DnDClass> dnDClasses) {
    this.strength = strength;
    this.dexterity = dexterity;
    this.constitution = constitution;
    this.intelligence = intelligence;
    this.wisdom = wisdom;
    this.charisma = charisma;
    this.name = name;
    this.race = race;
    this.dnDClasses = dnDClasses;
}

public Long getId() {
    return id;
}

public Short getStrength() {
    return strength;
}

public Short getDexterity() {
    return dexterity;
}

public Short getConstitution() {
    return constitution;
}

public Short getIntelligence() {
    return intelligence;
}

public Short getWisdom() {
    return wisdom;
}

public Short getCharisma() {
    return charisma;
}

public String getName() {
    return name;
}

public Race getRace() {
    return race;
}

public Set<DnDClass> getDnDClasses() {
    return dnDClasses;
}

@Override
public String toString() {
    return "Hero{" +
            "id=" + id +
            ", strength=" + strength +
            ", dexterity=" + dexterity +
            ", constitution=" + constitution +
            ", intelligence=" + intelligence +
            ", wisdom=" + wisdom +
            ", charisma=" + charisma +
            ", name='" + name + '\'' +
            ", race=" + race +
            ", dnDClasses=" + dnDClasses +
            '}';
}

public static HeroBuilder builder(){
    return new HeroBuilder();
}

public static class HeroBuilder {
    private Short strength;
    private Short dexterity;
    private Short constitution;
    private Short intelligence;
    private Short wisdom;
    private Short charisma;
    private String name;
    private Race race;
    private Set<DnDClass> dndClasses;

    public HeroBuilder setStrength(Short strength) {
        this.strength = strength;
        return this;
    }

    public HeroBuilder setDexterity(Short dexterity) {
        this.dexterity = dexterity;
        return this;
    }

    public HeroBuilder setConstitution(Short constitution) {
        this.constitution = constitution;
        return this;
    }

    public HeroBuilder setIntelligence(Short intelligence) {
        this.intelligence = intelligence;
        return this;
    }

    public HeroBuilder setWisdom(Short wisdom) {
        this.wisdom = wisdom;
        return this;
    }

    public HeroBuilder setCharisma(Short charisma) {
        this.charisma = charisma;
        return this;
    }

    public HeroBuilder setName(String name) {
        this.name = name;
        return this;
    }

    public HeroBuilder setRace(Race race) {
        this.race = race;
        return this;
    }

    public HeroBuilder setDnDClasses(Set<DnDClass> dndClasses) {
        this.dndClasses = dndClasses;
        return this;
    }

    public Hero build() {
        return new Hero(strength, dexterity, constitution, intelligence, wisdom, charisma, name, race, dndClasses);
    }
}
}

DnDClass.java

@Entity
@Table(name = "DNDCLASSES")
public class DnDClass {

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

private String name;
private Byte hitDie;

public DnDClass() {
}

public DnDClass(String name, Byte hitDie) {
    this.name = name;
    this.hitDie = hitDie;
}

public Long getId() {
    return id;
}

public void setId(Long id) {
    this.id = id;
}

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public Byte getHitDie() {
    return hitDie;
}

public void setHitDie(Byte hitDie) {
    this.hitDie = hitDie;
}

@Override
public String toString() {
    return "DnDClass{" +
            "id=" + id +
            ", name='" + name + '\'' +
            ", hitDie=" + hitDie +
            '}';
}
}

Dnd35cgApplication.java

@SpringBootApplication
public class Dnd35cgApplication implements ApplicationRunner{

public static final Logger LOGGER = LoggerFactory.getLogger(Dnd35cgApplication.class);
public static void main(String[] args) {
    SpringApplication.run(Dnd35cgApplication.class, args);
}

@Autowired
HeroRepository heroRepository;

@Autowired
RaceRepository raceRepository;

@Autowired
DnDClassRepository dnDClassRepository;

@Override
public void run(ApplicationArguments applicationArguments) throws Exception {
    List<Race> races = new ArrayList<>();
    races.add(new Race("Human", "Medium", 30));
    races.add(new Race("Dwarf", "Medium", 20));
    races.add(new Race("Elf", "Medium", 30));
    races.add(new Race("Half-Elf", "Medium", 30));
    races.add(new Race("Half-Orc", "Medium", 30));
    races.add(new Race("Gnome", "Small", 20));
    races.add(new Race("Halfling", "Small", 20));

    for(Race r : races)
        raceRepository.save(r);

    List<DnDClass> classes = new ArrayList<>();
    classes.add(new DnDClass("Barbarian", (byte)12));
    classes.add(new DnDClass("Bard", (byte)6));
    classes.add(new DnDClass("Cleric", (byte)8));
    classes.add(new DnDClass("Druid", (byte)8));
    classes.add(new DnDClass("Fighter", (byte)10));
    classes.add(new DnDClass("Monk", (byte)8));
    classes.add(new DnDClass("Paladin", (byte)10));
    classes.add(new DnDClass("Ranger", (byte)10));
    classes.add(new DnDClass("Rogue", (byte)6));
    classes.add(new DnDClass("Sorcerer", (byte)4));
    classes.add(new DnDClass("Wizard", (byte)4));

    for(DnDClass c : classes)
        dnDClassRepository.save(c);

    List<Hero> initialHeroes = new ArrayList<>();

    Random rand = new Random();

    Set<DnDClass> dnDClassesSet = new HashSet<>();
    dnDClassesSet.add(dnDClassRepository.findById(1L));

    for (int i=0; i<=10; i++) {
        initialHeroes.add(new Hero().builder().setName("Hero " + i)
                .setStrength((short) (rand.nextInt(16) + 3))
                .setDexterity((short) (rand.nextInt(16) + 3))
                .setConstitution((short) (rand.nextInt(16) + 3))
                .setIntelligence((short) (rand.nextInt(16) + 3))
                .setWisdom((short) (rand.nextInt(16) + 3))
                .setCharisma((short) (rand.nextInt(16) + 3))
                .setRace(raceRepository.findById(rand.nextInt(7) + 1L))
                .setDnDClasses(dnDClassesSet)
                .build());
    }

    for (Hero h : initialHeroes) {
        heroRepository.save(h);
    }

}
}

问题是当我在run方法中构建新英雄时使用.setDnDClasses(dnDClassesSet)。

我怀疑这可能是因为我正在使用构建器模式并且没有合适的setter。我稍后会重构，因为Hero类有太多的字段，但目前我希望它能像那样运行。

我想提前感谢您的帮助。

Answer 1

错误已修复。

CascadeType.ALL导致了这个问题。我不知道为什么，但是当我删除它时它起作用了。

欢迎解释。

非常感谢。

Hibernate分离实体传递持久化

1 个答案: