Question

我已经创建了如下的实体类：

@Entity
@Table(name = "state_flows")
public class StateFlowEntity {

private int id;
private StateMachineEntity stateMachine;
private StateEntity currentState;
private StateEntity nextState;

@ManyToOne
@JoinColumn(name = "current_state", referencedColumnName = "id",
    insertable = false, updatable = false)
public StateEntity getCurrentState() {
return currentState;
}

@ManyToOne
@JoinColumn(name = "next_state", referencedColumnName = "id",
    insertable = false, updatable = false)
public StateEntity getNextState() {
return nextState;
}

@ManyToOne
@JoinColumn(name = "machine_id", referencedColumnName = "id",
    insertable = false, updatable = false)
public StateMachineEntity getStateMachine() {
return stateMachine;
}

//setters and getters

=============================================== ====================

@Entity
@Table(name = "states")
public class StateEntity {

public enum NodeType {
EVENT
};

private int id;
private String name;
private NodeType nodeType;
private String nodeId;
private int ratio;
private int missingRatio;
private String nodeDetail;
private Set<StateFlowEntity> nextStateFlows = new HashSet<StateFlowEntity>();
private Set<StateFlowEntity> currentStateFlows = new HashSet<StateFlowEntity>();

@OneToMany(cascade = CascadeType.ALL, mappedBy = "nextState",
    targetEntity = StateEntity.class)
public Set<StateFlowEntity> getNextStateFlows() {
return nextStateFlows;
}

@OneToMany(cascade = CascadeType.ALL, mappedBy = "currentState",
    targetEntity = StateEntity.class)
public Set<StateFlowEntity> getCurrentStateFlows() {
return currentStateFlows;
}

@Column(name = "node_type", nullable = false,
    columnDefinition = "ENUM('EVENT') default 'EVENT'")
@Enumerated(EnumType.STRING)
private NodeType getNodeType() {
return nodeType;
}

//setter and getters

=============================================== =======================================

@Entity
@Table(name = "state_machines")
public class StateMachineEntity {

private int id;
private String name;
private String description;
private int initialState;
private int combinational;
private Set<StateFlowEntity> machineId = new HashSet<StateFlowEntity>();
private Set<InstanceEntity> instances = new HashSet<InstanceEntity>();

@OneToMany(cascade = CascadeType.ALL, mappedBy = "stateMachine")
public Set<StateFlowEntity> getMachineId() {
return machineId;
}

@OneToMany(cascade = CascadeType.ALL, mappedBy = "stateMachine")
public Set<InstanceEntity> getInstances() {
return instances;
}

//setters and getters

=============================================== ==============

但它给我以下错误：

初始化数据库连接时出错。 org.hibernate.AnnotationException：mappedBy引用一个未知的目标实体属性：com.test.entity.StateEntity.currentStateFlows中的com.test.orm.entity.StateEntity.currentState

我是新来的hibernate，我做错了吗？

Answer 1

与@Naros一样，targetEntity应为“StateFlowEntity.class”或根本不需要指定。

@OneToMany(cascade = CascadeType.ALL, mappedBy = "currentState",
    targetEntity = StateEntity.class)

由于您在代码中明确提到“targetEntity = StateEntity.class”，因此它正在“StateEntity”类中查找“currentState”字段。这就是错误信息的含义。

我可以在进行这些更改后使用Spring Boot加载这些实体。

@OneToMany(cascade = CascadeType.ALL, mappedBy = "nextState",
        targetEntity = StateFlowEntity.class)
private Set<StateFlowEntity> nextStateFlows = new HashSet<StateFlowEntity>();

@OneToMany(cascade = CascadeType.ALL, mappedBy = "currentState" )
private Set<StateFlowEntity> currentStateFlows = new HashSet<StateFlowEntity>();

在hibernate中如何将一个表中的两个外键映射到另一个表中的一个主键

1 个答案: