java hibernate使用注解来定义联合主键

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java hibernate使用注解来定义联合主键

下面使用hibernate的API中说明的三种方式来定义主键，主要使用Annotation来定义hibernate中的联合主键

下面取至hibernate的API文档：

定义组合主键的几种语法：

1、将组件类注解为@Embeddable，并将组件的属性注解为@Id
2、将组件的属性注解为@EmbeddedId
3、将类注解为@IdClass，并将该实体中所有属于主键的属性都注解为@Id

下面就分别使用这三种方式来定义联合主键。

建表的SQL语句：

CREATE TABLE `syslogs` ( 
 `id` varchar(50) NOT NULL, 
 `yhid` varchar(50) NOT NULL, 
 `modelname` varchar(100) DEFAULT NULL, 
 `content` varchar(500) DEFAULT NULL, 
 `inserttime` varchar(20) DEFAULT NULL, 
 `remark` varchar(50) DEFAULT NULL, 
 PRIMARY KEY (`id`,`yhid`) 
) ENGINE=InnoDB DEFAULT CHARSET=utf-8;

一、将组件类注解为@Embeddable

/** 
 * SysLogsDtoId代表主键类 
 */ 
package com.hibernate.dto; 
 
import javax.persistence.Embeddable; 
/** 
 * 1、主键类必须要实现java.io.Serializable接口 
 * 2、主键类必须要重写equals和hashCode方法 
 * @author ibm 
 */ 
@Embeddable 
public class SysLogsDtoId implements java.io.Serializable { 
 
  private static final long serialVersionUID = 1L; 
  private String id; 
  private String yhid; 
 
  public SysLogsDtoId() { 
  } 
 
  public SysLogsDtoId(String id, String yhid) { 
    this.id = id; 
    this.yhid = yhid; 
  } 
 
  public String getId() { 
    return this.id; 
  } 
 
  public void setId(String id) { 
    this.id = id; 
  } 
 
  public String getYhid() { 
    return this.yhid; 
  } 
 
  public void setYhid(String yhid) { 
    this.yhid = yhid; 
  } 
 
  public boolean equals(Object other) { 
    if ((this == other)) 
      return true; 
    if ((other == null)) 
      return false; 
    if (!(other instanceof SysLogsDtoId)) 
      return false; 
    SysLogsDtoId castOther = (SysLogsDtoId) other; 
 
    return ((this.getId() == castOther.getId()) || (this.getId() != null && castOther.getId() != null && this.getId().equals(castOther.getId()))) 
        && ((this.getYhid() == castOther.getYhid()) || (this.getYhid() != null && castOther.getYhid() != null && this.getYhid().equals( 
            castOther.getYhid()))); 
  } 
 
  public int hashCode() { 
    int result = 17; 
 
    result = 37 * result + (getId() == null ? 0 : this.getId().hashCode()); 
    result = 37 * result + (getYhid() == null ? 0 : this.getYhid().hashCode()); 
    return result; 
  } 
 
}

/** 
 * SysLogsDto为表对象映射类，其中主键为主键类SysLogsDtoId 
 */ 
package com.hibernate.dto; 
 
import javax.persistence.Column; 
import javax.persistence.Entity; 
import javax.persistence.Id; 
import javax.persistence.Table; 
 
@Entity 
@Table(name = "syslogs") 
public class SysLogsDto implements java.io.Serializable { 
  private static final long serialVersionUID = 1L; 
  private SysLogsDtoId id; 
  private String modelname; 
  private String content; 
  private String inserttime; 
  private String remark; 
 
  public SysLogsDto() { 
  } 
 
  public SysLogsDto(SysLogsDtoId id) { 
    this.id = id; 
  } 
 
  public SysLogsDto(SysLogsDtoId id, String modelname, String content, String inserttime, String remark) { 
    this.id = id; 
    this.modelname = modelname; 
    this.content = content; 
    this.inserttime = inserttime; 
    this.remark = remark; 
  } 
 
  @Id 
  public SysLogsDtoId getId() { 
    return this.id; 
  } 
 
  public void setId(SysLogsDtoId id) { 
    this.id = id; 
  } 
 
  @Column(name = "modelname", length = 100) 
  public String getModelname() { 
    return this.modelname; 
  } 
 
  public void setModelname(String modelname) { 
    this.modelname = modelname; 
  } 
 
  @Column(name = "content", length = 500) 
  public String getContent() { 
    return this.content; 
  } 
 
  public void setContent(String content) { 
    this.content = content; 
  } 
 
  @Column(name = "inserttime", length = 20) 
  public String getInserttime() { 
    return this.inserttime; 
  } 
 
  public void setInserttime(String inserttime) { 
    this.inserttime = inserttime; 
  } 
 
  @Column(name = "remark", length = 50) 
  public String getRemark() { 
    return this.remark; 
  } 
 
  public void setRemark(String remark) { 
    this.remark = remark; 
  } 
 
}

二、将组件的属性注解为@EmbeddedId

这种情况最简单，主键类只用定义主键字段，不需要写任何注解。然后在对象类中在主键类的get方法上加上@EmbeddedId注解。

/** 
 * SysLogsDtoId代表主键类 
 */ 
package com.hibernate.dto; 
 
public class SysLogsDtoId implements java.io.Serializable { 
 
  private static final long serialVersionUID = 1L; 
  private String id; 
  private String yhid; 
 
  public SysLogsDtoId() { 
  } 
 
  public SysLogsDtoId(String id, String yhid) { 
    this.id = id; 
    this.yhid = yhid; 
  } 
 
  public String getId() { 
    return this.id; 
  } 
 
  public void setId(String id) { 
    this.id = id; 
  } 
 
  public String getYhid() { 
    return this.yhid; 
  } 
 
  public void setYhid(String yhid) { 
    this.yhid = yhid; 
  } 
 
  public boolean equals(Object other) { 
    if ((this == other)) 
      return true; 
    if ((other == null)) 
      return false; 
    if (!(other instanceof SysLogsDtoId)) 
      return false; 
    SysLogsDtoId castOther = (SysLogsDtoId) other; 
 
    return ((this.getId() == castOther.getId()) || (this.getId() != null && castOther.getId() != null && this.getId().equals(castOther.getId()))) 
        && ((this.getYhid() == castOther.getYhid()) || (this.getYhid() != null && castOther.getYhid() != null && this.getYhid().equals( 
            castOther.getYhid()))); 
  } 
 
  public int hashCode() { 
    int result = 17; 
 
    result = 37 * result + (getId() == null ? 0 : this.getId().hashCode()); 
    result = 37 * result + (getYhid() == null ? 0 : this.getYhid().hashCode()); 
    return result; 
  } 
 
}



/** 
 * SysLogsDto为表对象映射类，其中主键为主键类SysLogsDtoId 
 */ 
package com.hibernate.dto; 
 
import javax.persistence.Column; 
import javax.persistence.EmbeddedId; 
import javax.persistence.Entity; 
import javax.persistence.Table; 
 
@Entity 
@Table(name = "syslogs") 
public class SysLogsDto implements java.io.Serializable { 
  private static final long serialVersionUID = 1L; 
  private SysLogsDtoId id; 
  private String modelname; 
  private String content; 
  private String inserttime; 
  private String remark; 
 
  public SysLogsDto() { 
  } 
 
  public SysLogsDto(SysLogsDtoId id) { 
    this.id = id; 
  } 
 
  public SysLogsDto(SysLogsDtoId id, String modelname, String content, String inserttime, String remark) { 
    this.id = id; 
    this.modelname = modelname; 
    this.content = content; 
    this.inserttime = inserttime; 
    this.remark = remark; 
  } 
 
  @EmbeddedId 
  public SysLogsDtoId getId() { 
    return this.id; 
  } 
 
  public void setId(SysLogsDtoId id) { 
    this.id = id; 
  } 
 
  @Column(name = "modelname", length = 100) 
  public String getModelname() { 
    return this.modelname; 
  } 
 
  public void setModelname(String modelname) { 
    this.modelname = modelname; 
  } 
 
  @Column(name = "content", length = 500) 
  public String getContent() { 
    return this.content; 
  } 
 
  public void setContent(String content) { 
    this.content = content; 
  } 
 
  @Column(name = "inserttime", length = 20) 
  public String getInserttime() { 
    return this.inserttime; 
  } 
 
  public void setInserttime(String inserttime) { 
    this.inserttime = inserttime; 
  } 
 
  @Column(name = "remark", length = 50) 
  public String getRemark() { 
    return this.remark; 
  } 
 
  public void setRemark(String remark) { 
    this.remark = remark; 
  } 
 
}

三、将类注解为@IdClass，并将该实体中所有属于主键的属性都注解为@Id

/** 
 * SysLogsDtoId代表主键类 
 */ 
package com.hibernate.dto; 
 
public class SysLogsDtoId implements java.io.Serializable { 
 
  private static final long serialVersionUID = 1L; 
  private String id; 
  private String yhid; 
 
  public SysLogsDtoId() { 
  } 
 
  public SysLogsDtoId(String id, String yhid) { 
    this.id = id; 
    this.yhid = yhid; 
  } 
 
  public String getId() { 
    return this.id; 
  } 
 
  public void setId(String id) { 
    this.id = id; 
  } 
 
  public String getYhid() { 
    return this.yhid; 
  } 
 
  public void setYhid(String yhid) { 
    this.yhid = yhid; 
  } 
 
  public boolean equals(Object other) { 
    if ((this == other)) 
      return true; 
    if ((other == null)) 
      return false; 
    if (!(other instanceof SysLogsDtoId)) 
      return false; 
    SysLogsDtoId castOther = (SysLogsDtoId) other; 
 
    return ((this.getId() == castOther.getId()) || (this.getId() != null && castOther.getId() != null && this.getId().equals(castOther.getId()))) 
        && ((this.getYhid() == castOther.getYhid()) || (this.getYhid() != null && castOther.getYhid() != null && this.getYhid().equals( 
            castOther.getYhid()))); 
  } 
 
  public int hashCode() { 
    int result = 17; 
 
    result = 37 * result + (getId() == null ? 0 : this.getId().hashCode()); 
    result = 37 * result + (getYhid() == null ? 0 : this.getYhid().hashCode()); 
    return result; 
  } 
 
}

/** 
 * SysLogsDto为表对象映射类，其中主键为主键类SysLogsDtoId 
 */ 
package com.hibernate.dto; 
 
import javax.persistence.Column; 
import javax.persistence.Entity; 
import javax.persistence.Id; 
import javax.persistence.IdClass; 
import javax.persistence.Table; 
 
@Entity 
@Table(name = "syslogs") 
@IdClass(value=SysLogsDtoId.class) 
public class SysLogsDto implements java.io.Serializable { 
  private static final long serialVersionUID = 1L; 
  private String id; 
  private String yhid; 
  private String modelname; 
  private String content; 
  private String inserttime; 
  private String remark; 
 
  public SysLogsDto() { 
  } 
 
  @Id 
  public String getId() { 
    return id; 
  } 
 
 
  public void setId(String id) { 
    this.id = id; 
  } 
 
  @Id 
  public String getYhid() { 
    return yhid; 
  } 
 
 
  public void setYhid(String yhid) { 
    this.yhid = yhid; 
  } 
 
 
  @Column(name = "modelname", length = 100) 
  public String getModelname() { 
    return this.modelname; 
  } 
 
  public void setModelname(String modelname) { 
    this.modelname = modelname; 
  } 
 
  @Column(name = "content", length = 500) 
  public String getContent() { 
    return this.content; 
  } 
 
  public void setContent(String content) { 
    this.content = content; 
  } 
 
  @Column(name = "inserttime", length = 20) 
  public String getInserttime() { 
    return this.inserttime; 
  } 
 
  public void setInserttime(String inserttime) { 
    this.inserttime = inserttime; 
  } 
 
  @Column(name = "remark", length = 50) 
  public String getRemark() { 
    return this.remark; 
  } 
 
  public void setRemark(String remark) { 
    this.remark = remark; 
  } 
 
}

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