创建持久化和映射文件并配置单向一对多关系
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2022-07-12 18:09:32
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一 Grade
package com.imooc.entity;
import java.io.Serializable;
import java.util.HashSet;
import java.util.Set;
public class Grade implements Serializable {
private int gid;
private String gname;
private String gdesc;
private Set<Student> students =new HashSet<Student>();
public int getGid() {
return gid;
}
public void setGid(int gid) {
this.gid = gid;
}
public String getGname() {
return gname;
}
public void setGname(String gname) {
this.gname = gname;
}
public String getGdesc() {
return gdesc;
}
public void setGdesc(String gdesc) {
this.gdesc = gdesc;
}
public Grade() {
super();
}
public Set<Student> getStudents() {
return students;
}
public void setStudents(Set<Student> students) {
this.students = students;
}
public Grade(int gid, String gname, String gdesc) {
super();
this.gid = gid;
this.gname = gname;
this.gdesc = gdesc;
}
public Grade(String gname, String gdesc) {
super();
this.gname = gname;
this.gdesc = gdesc;
}
}
二 Student
package com.imooc.entity;
import java.io.Serializable;
public class Student implements Serializable {
private int sid;
private String sname;
private String sex;
public int getSid() {
return sid;
}
public void setSid(int sid) {
this.sid = sid;
}
public String getSname() {
return sname;
}
public void setSname(String sname) {
this.sname = sname;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public Student() {
super();
}
public Student(String sname, String sex) {
super();
this.sname = sname;
this.sex = sex;
}
}
三 Grade.hbm.xml
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
<hibernate-mapping>
<class name="com.imooc.entity.Grade" table="grade">
<id name="gid" column="gid" type="java.lang.Integer">
<generator class="increment"></generator>
</id>
<property name="gname" type="java.lang.String">
<column name="gname" length="20" not-null="true"></column>
</property>
<property name="gdesc">
<column name="gdesc"></column>
</property>
<!-- 配置一对多关联关系 -->
<set name="students" table="student">
<key column="gid"></key>
<one-to-many class="com.imooc.entity.Student"/>
</set>
</class>
</hibernate-mapping>
四 Student.hbm.xml
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
<hibernate-mapping>
<class name="com.imooc.entity.Student" table="student">
<id name="sid" column="sid" type="java.lang.Integer">
<generator class="increment"></generator>
</id>
<property name="sname" type="java.lang.String">
<column name="sname" length="20" not-null="true"></column>
</property>
<property name="sex">
<column name="sex"></column>
</property>
</class>
</hibernate-mapping>
五 hibernate.cfg.xml
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
<hibernate-configuration>
<session-factory>
<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.connection.password">root</property>
<property name="hibernate.connection.url">
<![CDATA[
jdbc:mysql://localhost:3306/imooc?useUnicode=true&characterEncoding=utf8
]]>
</property>
<property name="show_sql">true</property>
<property name="hbm2ddl.auto">update</property>
<!-- 指定映射文件的路径 -->
<mapping resource="com/imooc/entity/Grade.hbm.xml"/>
<mapping resource="com/imooc/entity/Student.hbm.xml"/>
</session-factory>
</hibernate-configuration>
六 set元素的常用属性
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