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;
    }

}