如何在 Spring Boot JPA 中加入两个表，我的代码出错了

Posted 2023-04-12

【中文标题】如何在 Spring Boot JPA 中加入两个表，我的代码出错了

【英文标题】：how to join two table in spring boot JPA , iam getting error with my code

【发布时间】：2018-12-13 04:06:13

【问题描述】：

您好，我想从 oracle 加入我的表，如何加入这个表？我正在使用 jpa 在 spring boot 上加入我的表。这是我的代码：

package com.emerio.rnd.bali.oraclemongoservice.entity;

import java.io.Serializable;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.OneToOne;
import javax.persistence.Table;
import com.emerio.rnd.bali.oraclemongoservice.entity.TblmFormManagement;


@Table(name = "TBLM_FORM")
@Entity
public class TblmForm

    // @Column(name = "PKID")
    @Id
    private Long pkid;
    // @Column(name = "FORMCODE")
    private String formcode;

    @OneToOne(cascade=CascadeType.ALL, mappedBy="TblmFormManagement")
    private TblmFormManagement tblmFormManagement;



    public TblmFormManagement getTblmFormManagement()
        return tblmFormManagement;
    

    public void setMapping(TblmFormManagement tblmFormManagement)
        this.tblmFormManagement=tblmFormManagement;
    


    // @Column(name = "REPORTITEM")
    // private String reportitem;
    // @Column(name = "REPORTFIELD")
    // private String reportfield;

    public TblmForm() 
    

    public Long getPkid() 
        return this.pkid;
    

    public void setPkid(Long pkid) 
        this.pkid = pkid;
    

    public String getFormcode() 
        return this.formcode;
    

    public void setFormcode(String formcode) 
        this.formcode = formcode;
    

    // public String getReportitem() 
    //     return this.reportitem;
    // 

    // public void setReportitem(String reportitem) 
    //     this.reportitem = reportitem;
    // 

    // public String getReportfield() 
    //     return this.reportfield;
    // 

    // public void setReportfield(String reportfield) 
    //     this.reportfield = reportfield;
    // 
    // @OneToOne(mappedBy = "tblmForm")
    // public Mapping getMapping() 
    //     return mapping;
    // 

    // public void setBook(Mapping mapping) 
    //     this.mapping = mapping;
    // 

我的第二个实体：

package com.emerio.rnd.bali.oraclemongoservice.entity;

import java.io.Serializable;

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

@Table(name = "TBLM_FORMMANAGEMENT")
@Entity
public class TblmFormManagement


    // @OneToOne(mappedBy = "mapping")
    @Id
    private Long pkid;
    private String formcode;
    private String reportitem;
    private String reportfield;

    @OneToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "pkid", nullable=true)
    private TblmForm tblmForm;


    public TblmForm getTblmForm() 
        return tblmForm;
    

    public void setTblmForm(TblmForm tblmForm) 
        this.tblmForm = tblmForm;
    


    public TblmFormManagement() 
    



    public Long getPkid() 
        return this.pkid;
    

    public void setPkid(Long pkid) 
        this.pkid = pkid;
    

    public String getFormcode() 
        return this.formcode;
    

    public void setFormcode(String formcode) 
        this.formcode = formcode;
    

    public String getReportitem() 
        return this.reportitem;
    

    public void setReportitem(String reportitem) 
        this.reportitem = reportitem;
    

    public String getReportfield() 
        return this.reportfield;
    

    public void setReportfield(String reportfield) 
        this.reportfield = reportfield;
    

    // @OneToOne(cascade = CascadeType.ALL)
    // @JoinColumn(name = "pkid")

我收到错误：

在上下文初始化期间遇到异常 - 取消刷新尝试：org.springframework.beans.factory.BeanCreationException：在类路径资源 [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaConfiguration 中定义名称为“entityManagerFactory”的 bean 创建时出错.class]: init 方法调用失败；嵌套异常是 org.hibernate.AnnotationException: Unknown mappedBy in: com.emerio.rnd.bali.oraclemongoservice.entity.TblmForm.tblmFormManagement，引用属性未知：com.emerio.rnd.bali.oraclemongoservice.entity.TblmFormManagement.Mapping

有什么办法可以解决我的问题吗？谢谢

【问题讨论】：

只需将您的 mappedBy 设置为 tblmForm，就像所有在线 JPA 文档会告诉您的那样。

【参考方案1】：

@OneToOne 映射错误，以下代码适用于 H2 测试数据库：

@Table(name = "TBLM_FORM")
@Entity
public class TblmForm

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private Long pkid;

    // TAKE NOTE that form points to a property in the second entity TblmFormManagement
    @OneToOne(fetch = FetchType.EAGER,
            cascade =  CascadeType.ALL,
            mappedBy = "form")
    private TblmFormManagement tblmFormManagement;

因此第二个实体将是这样的：

public class TblmFormManagement 

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private Long pkid;

    private String formcode;

    private String reportitem;

    private String reportfield;

    @OneToOne(fetch = FetchType.EAGER)
    @JoinColumn(name = "form_id", nullable=true)
    private TblmForm form;

注意事项：

TblmForm.tblmFormManagement 中的 mappedBy 指向 TblmFormManagement 中的 Java 属性 TblmFormManagement.form 中@JoinColumn 的名称指向 TblmFormManagement 中定义的表的数据库列

希望以上几点对你有用。

【讨论】：

在我的数据库中，我没有 form_id 列，form_id 取自哪里？

以上只是一个例子，请确保您有一个用于加入目的的数据库列。

【参考方案2】：

试试这个。

package com.emerio.rnd.bali.oraclemongoservice.entity;

    import java.io.Serializable;

    import javax.persistence.CascadeType;
    import javax.persistence.Column;
    import javax.persistence.Entity;
    import javax.persistence.Id;
    import javax.persistence.OneToOne;
    import javax.persistence.Table;
    import com.emerio.rnd.bali.oraclemongoservice.entity.TblmFormManagement;


    @Table(name = "TBLM_FORM")
    @Entity
    public class TblmForm


        @Id
        private Long pkid;

        @Column(name = "FORMCODE")
        private String formcode;

        @OneToOne(cascade=CascadeType.ALL, mappedBy="tblmForm")
        private TblmFormManagement tblmFormManagement;



        public TblmFormManagement getTblmFormManagement()
            return tblmFormManagement;
        

        public void setMapping(TblmFormManagement tblmFormManagement)
            this.tblmFormManagement=tblmFormManagement;
        

       public Long getPkid() 
            return this.pkid;
        

        public void setPkid(Long pkid) 
            this.pkid = pkid;
        

        public String getFormcode() 
            return this.formcode;
        

        public void setFormcode(String formcode) 
            this.formcode = formcode;
        

.

package com.emerio.rnd.bali.oraclemongoservice.entity;

import java.io.Serializable;

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

@Table(name = "TBLM_FORMMANAGEMENT")
@Entity
public class TblmFormManagement



    @Id
    private Long pkid;
    private String formcode;
    private String reportitem;
    private String reportfield;

    @OneToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "pkid", nullable=true)
    private TblmForm tblmForm;


    public TblmForm getTblmForm() 
        return tblmForm;
    

    public void setTblmForm(TblmForm tblmForm) 
        this.tblmForm = tblmForm;
    


    public TblmFormManagement() 
    



    public Long getPkid() 
        return this.pkid;
    

    public void setPkid(Long pkid) 
        this.pkid = pkid;
    

    public String getFormcode() 
        return this.formcode;
    

    public void setFormcode(String formcode) 
        this.formcode = formcode;
    

    public String getReportitem() 
        return this.reportitem;
    

    public void setReportitem(String reportitem) 
        this.reportitem = reportitem;
    

    public String getReportfield() 
        return this.reportfield;
    

    public void setReportfield(String reportfield) 
        this.reportfield = reportfield;
    

    // @OneToOne(cascade = CascadeType.ALL)
    // @JoinColumn(name = "pkid")