关于使用hibernate注解总结

package com.zwk;

import javax.persistence.*;

@Entity
@Table(name = "student", schema = "mytest")
public class StudentEntity {
    private int sid;
    private String sname;
    private String sex;
    private GradeEntity grade;
    public  StudentEntity(){

    }
    //gid是外键  与grade表的主键关联，表示可以多个学生属于一个班级
    @ManyToOne              //指定多对一关系映射
    @JoinColumn(name="gid")   //指定对应的列
    public GradeEntity getGrade() {
        return grade;
    }

    public void setGrade(GradeEntity grade) {
        this.grade = grade;
    }

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "sid")
    public int getSid() {
        return sid;
    }

    public void setSid(int sid) {
        this.sid = sid;
    }

    @Basic
    @Column(name = "sname")
    public String getSname() {
        return sname;
    }

    public void setSname(String sname) {
        this.sname = sname;
    }

    @Basic
    @Column(name = "sex")
    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        StudentEntity that = (StudentEntity) o;

        if (sid != that.sid) return false;
        if (sname != null ? !sname.equals(that.sname) : that.sname != null) return false;
        if (sex != null ? !sex.equals(that.sex) : that.sex != null) return false;

        return true;
    }

    @Override
    public int hashCode() {
        int result = sid;
        result = 31 * result + (sname != null ? sname.hashCode() : 0);
        result = 31 * result + (sex != null ? sex.hashCode() : 0);
        return result;
    }
}

package com.zwk;

import org.hibernate.annotations.Cascade;

import javax.persistence.*;
import java.util.HashSet;
import java.util.Set;
@Entity
@Table(name = "grade", schema = "mytest")
public class GradeEntity {
    private int gid;
    private String gname;
    private String gdesc;
    private Set<StudentEntity> students=new HashSet<StudentEntity>();
    public GradeEntity(){

    }
    @OneToMany//指定一对多关系
    @Cascade(value = {org.hibernate.annotations.CascadeType.SAVE_UPDATE})//设置级联关系
    @JoinColumn(name="gid")
    public Set<StudentEntity> getStudents() {
        return students;
    }

    public void setStudents(Set<StudentEntity> students) {
        this.students = students;
    }

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "gid")

    public int getGid() {
        return gid;
    }

    public void setGid(int gid) {
        this.gid = gid;
    }

    @Basic
    @Column(name = "gname")
    public String getGname() {
        return gname;
    }

    public void setGname(String gname) {
        this.gname = gname;
    }

    @Basic
    @Column(name = "gdesc")
    public String getGdesc() {
        return gdesc;
    }

    public void setGdesc(String gdesc) {
        this.gdesc = gdesc;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        GradeEntity that = (GradeEntity) o;

        if (gid != that.gid) return false;
        if (gname != null ? !gname.equals(that.gname) : that.gname != null) return false;
        if (gdesc != null ? !gdesc.equals(that.gdesc) : that.gdesc != null) return false;

        return true;
    }

    @Override
    public int hashCode() {
        int result = gid;
        result = 31 * result + (gname != null ? gname.hashCode() : 0);
        result = 31 * result + (gdesc != null ? gdesc.hashCode() : 0);
        return result;
    }
}