hibernate映射简单实例

1创建数据库：

 1 --班级表
 2 create table grade
 3 (
 4        gid       number           primary key,  --班级ID
 5        gname     varchar2(50),                  --班级名称
 6        gdesc     varchar2(50)                   --班级介绍
 7 );
 8 --学生表
 9 create table student
10 (
11        sid       number           primary key,  --主键ID学生ID
12        sname     varchar2(20),            --学生姓名
13        sex       varchar2(20),            --学生性别
14        gid       number           references grade(gid) ---外键班级ID
15 );
16 
17 --学生证表
18 create table paper
19 (
20        pid   number primary key,
21        pdesc varchar2(100)  ,
22        sid   number references student(sid) not null
23        
24 );

二、创建配置文件和持久化类：

学生类

package entity;

/*
 * 学生类
 */
public class Student implements java.io.Serializable {

    // Fields

    private static final long serialVersionUID = 1L;
    private int sid;
    private String sname;
    private String sex;
    //增加班级属性
    private Grade grade;
    //学生证类
    private Paper paper;

    // Constructors

    /** default constructor */
    public Student() {
    }

    /** minimal constructor */
    public Student(int sid) {
        this.sid = sid;
    }

    /** full constructor */
    public Student(int sid, String sname, String sex ) {
    
        this.sid = sid;

        this.sname = sname;
        this.sex = sex;
    }

    // Property accessors

    public int getSid() {
        return this.sid;
    }

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

    

    public String getSname() {
        return this.sname;
    }

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

    public String getSex() {
        return this.sex;
    }

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

    public Grade getGrade() {
        return grade;
    }

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

    public Paper getPaper() {
        return paper;
    }

    public void setPaper(Paper paper) {
        this.paper = paper;
    }
    

}
View Code

学生证类

 1 package entity;
 2 
 3 /*
 4  * 学生证类
 5  */
 6 
 7 public class Paper implements java.io.Serializable {
 8 
 9     // Fields
10 
11     private static final long serialVersionUID = 1L;
12     private int pid;
13     private Student student;
14     private String pdesc;
15 
16     // Constructors
17 
18     /** default constructor */
19     public Paper() {
20     }
21 
22     /** minimal constructor */
23     public Paper(int pid) {
24         this.pid = pid;
25     }
26 
27     /** full constructor */
28     public Paper(int pid, Student student, String pdesc) {
29         this.pid = pid;
30         this.student = student;
31         this.pdesc = pdesc;
32     }
33 
34     // Property accessors
35 
36     public int getPid() {
37         return this.pid;
38     }
39 
40     public void setPid(int pid) {
41         this.pid = pid;
42     }
43 
44     public Student getStudent() {
45         return this.student;
46     }
47 
48     public void setStudent(Student student) {
49         this.student = student;
50     }
51 
52     public String getPdesc() {
53         return this.pdesc;
54     }
55 
56     public void setPdesc(String pdesc) {
57         this.pdesc = pdesc;
58     }
59 
60 }
View Code

hibernate.cfg.xml配置文件

 1 <?xml version='1.0' encoding='UTF-8'?>
 2 <!DOCTYPE hibernate-configuration PUBLIC
 3           "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
 4           "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
 5 
 6 <hibernate-configuration>
 7 
 8     <session-factory>
 9         <property name="dialect">
10             org.hibernate.dialect.Oracle9Dialect
11         </property>
12         <property name="connection.url">
13             jdbc:oracle:thin:@localhost:1521:orcl
14         </property>
15         <property name="connection.username">root</property>
16         <property name="connection.password">root</property>
17         <property name="connection.driver_class">
18             oracle.jdbc.OracleDriver
19         </property>
20         <property name="show_sql">true</property>
21         <property name="format_sql">true</property>
22 
23         <mapping resource="entity/Grade.hbm.xml" />
24         <mapping resource="entity/Student.hbm.xml" />
25         <mapping resource="entity/Paper.hbm.xml" />
26 
27     </session-factory>
28 
29 </hibernate-configuration>

Student类配置文件

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
 3 "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
 4 
 5 <hibernate-mapping>
 6     <class name="entity.Student" table="STUDENT" schema="ROOT">
 7         <id name="sid" type="java.lang.Integer">
 8             <column name="SID" precision="22" scale="0" />
 9             <generator class="assigned" />
10         </id>
11         <property name="sname" type="java.lang.String">
12             <column name="SNAME" length="20" />
13         </property>
14         <property name="sex" type="java.lang.String">
15             <column name="SEX" length="20" />
16         </property>
17         <!--配置grade属性  -->
18         <many-to-one name="grade" class="entity.Grade" cascade="save-update">
19         <!--指定学生表中的外键  -->
20         <column name="GID" />
21         </many-to-one>
22         <!-- 添加学生证的配置 -->
23         <one-to-one name="paper" class="entity.Paper" cascade="all" lazy="false"/>
24     </class>
25 </hibernate-mapping>

Paper类配置文件

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
 3 "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
 4 
 5 <hibernate-mapping>
 6     <class name="entity.Student" table="STUDENT" schema="ROOT">
 7         <id name="sid" type="java.lang.Integer">
 8             <column name="SID" precision="22" scale="0" />
 9             <generator class="assigned" />
10         </id>
11         <property name="sname" type="java.lang.String">
12             <column name="SNAME" length="20" />
13         </property>
14         <property name="sex" type="java.lang.String">
15             <column name="SEX" length="20" />
16         </property>
17  
18         <!-- 添加学生证的配置 -->
19         <one-to-one name="paper" class="entity.Paper" cascade="all" lazy="false" property-ref="student"/>
20     </class>
21 </hibernate-mapping>

测试类

 1 package Test;
 2 
 3 import org.hibernate.Session;
 4 import org.hibernate.Transaction;
 5 import org.hibernate.cfg.Configuration;
 6 
 7 import entity.Paper;
 8 import entity.Student;
 9 
10 public class Demo6 {
11 
12     public static void main(String[] args) {
13         findByStu();
14     }
15 
16     public static void save() {
17         
18         Student stu1 = new Student();
19         stu1.setSid(20151109);
20         stu1.setSname("王霸");
21         stu1.setSex("女");
22     
23         Paper paper=new Paper();
24         paper.setPid(9001);
25         paper.setPdesc("王霸的学生证");
26         paper.setStudent(stu1);
27         
28         
29         stu1.setPaper(paper);
30         
31         // 建立session
32                 Session session = new Configuration().configure().buildSessionFactory()
33                         .openSession();
34                 // 开始事务
35                 Transaction transaction = session.beginTransaction();
36             
37             
38                 // 保存学生证
39                 session.save(stu1);
40                 // 提交事务
41                 transaction.commit();
42                 // 关闭session
43                 session.close();
44 
45     }
46 
47     public static void find() {
48         // 建立session
49         Session session = new Configuration().configure().buildSessionFactory()
50                 .openSession();
51         Paper paper=(Paper) session.get(Paper.class, 9001);
52         System.out.println(paper.getPid()+paper.getPdesc());
53         Student stu1=paper.getStudent();
54         System.out.println(stu1.getSid()+"	"+stu1.getSname());
55     }
56     public static void findByStu() {
57         // 建立session
58         Session session = new Configuration().configure().buildSessionFactory()
59                 .openSession();
60         Student stu=(Student) session.get(Student.class, 20151109);
61         System.out.println(stu.getSname());
62         Paper paper=stu.getPaper();
63         System.out.println(paper.getPid()+"	"+paper.getPdesc());
64     }
65 
66 }
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原文地址：https://www.cnblogs.com/smellpawn/p/10805392.html