Spring Boot 设置联合主键

1.创建一个实体类

@Entity
@Table(name = "cmaq")

public class Cmaq implements Serializable {

    @Id
    @Column(nullable = false,name = "pred_date")
    private Date prediction_date;

    @Id
    @Column(nullable = false,name = "st_date")
    private Date start_date;

    @Id
    @Column(nullable = false,name = "id")
    private int city_id;

    @Column(nullable = false,name = "avg")
    private int avg;


    public Cmaq(){

    }

    public Cmaq(Date st_date, Date pred_date, int id) {
        this.st_date = st_date;
        this.pred_date = pred_date;
        this.id = id;
    }

    public Date getPred_date() { return pred_date; }

    public void setPred_date(Date pred_date) { this.pred_date = pred_date; }

    public Date getSt_date() { return st_date; }

    public void setSt_date(Date st_date) { this.st_date = st_date; }

    public int getId() { return id; }

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

    public int getAvg() { return avg; }

    public void setAvg(int avg) { this.avg = avg; }


}

2.创建主键实现类

public class Key implements Serializable  {//主键实现类

    @Column(nullable = false,name = "st_date")
    private Date prediction_date;

    @Column(nullable = false,name = "pred_date")
    private Date start_date;

    @Column(nullable = false,name = "id")
    private int id;

    public Key(){

    }
    public Key(Date pred_date, Date st_date, int id){
        this.pred_date = pred_date;
        this.st_date = st_date;
        this.id = id;

    }

    public Date getStt_date() {
        return st_date;
    }

    public void setSt_date(Date st_date) {
        this.st_date = st_date;
    }

    public Date getPred_date() {
        return pred_date;
    }

    public void setPred_date(Date pred_date) {
        this.pred_date = pred_date;
    }

    public int getId() { return id; }

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


}

3.在实体类里改动一点点

@Entity
@Table(name = "cmaq")
@IdClass(Key.class)  //增加了这个
public class Cmaq implements Serializable {

    @Id
    @Column(nullable = false,name = "pred_date")
    private Date prediction_date;

    @Id
    @Column(nullable = false,name = "st_date")
    private Date start_date;

    @Id
    @Column(nullable = false,name = "id")
    private int city_id;

    @Column(nullable = false,name = "avg")
    private int avg;


    public Cmaq(){

    }

    public Cmaq(Date st_date, Date pred_date, int id) {
        this.st_date = st_date;
        this.pred_date = pred_date;
        this.id = id;
    }

    public Date getPred_date() { return pred_date; }

    public void setPred_date(Date pred_date) { this.pred_date = pred_date; }

    public Date getSt_date() { return st_date; }

    public void setSt_date(Date st_date) { this.st_date = st_date; }

    public int getId() { return id; }

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

    public int getAvg() { return avg; }

    public void setAvg(int avg) { this.avg = avg; }


}