java – 如何使用enum与jpa作为持久化实体的数据成员？

请使用jum作为持久化实体的数据成员的最佳实践和“如何”使用enum.
什么是最佳做法？
我想从枚举中坚持“C”,“O”. (代码).如果这不是正确的方法,请建议.

Enum defination是 –

public enum Status{
CLOSED ("C")
OPEN ("O")
private final int value;
private Status(final int pValue){
this.value = pValue;
}

public int value(){
 return this.value;
}

解决方法:

预期解决方案
枚举定义：

public enum Status {
    CLOSED(1), NEW(2), RUNNING(3), OPEN(4), ADDED(5), SUCEESS(-1), DONE(0);
        private int code;
        private Status(int code) {
        this.code = code;
    }
        public int getCode() {
        return code;
    }
        public void setCode(int code) {
        this.code = code;
    }
        public static Status valueOf(int i){
        for (Status s : values()){
            if (s.code == i){
                return s;
            }
        }
        throw new IllegalArgumentException("No matching constant for " + i);
    }

}

实体定义：

@Entity
@NamedQuery(name="Process.findAll", query="select p from Process p ")
public class Process {

    @Id
    private long id;
    private String name;

    @Transient
    private transient Status status; //actual enum; not stored in db
        @Column(name="STATUS")  
    private int statusCode; // enum code gets stored in db

    @PrePersist
    void populateDBFields(){
        statusCode = status.getCode();
    }

    @PostLoad
    void populateTransientFields(){
        status = Status.valueOf(statusCode);
    }
    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 Status getStatus() {
        return status;
    }
        public void setStatus(Status status) {
        this.status = status;
    }
}

标签：java,enums,openjpa
来源： https://codeday.me/bug/20190715/1472916.html