直接上步驟:
1.修改pom.xml,添加hibernate相關包
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.htt.hibernate</groupId>
<artifactId>Hibernate_Test</artifactId>
<version>1.0-SNAPSHOT</version>
<dependencies>
<!-- https://mvnrepository.com/artifact/org.hibernate/hibernate-core -->
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>5.3.6.Final</version>
</dependency>
<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.12</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.0</version>
</dependency>
</dependencies>
</project>
2.在resources裏面添加hibernate.cfg.xml,用於連接數據庫
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<!-- Database connection settings -->
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="connection.url">jdbc:mysql://localhost:3306/javaweb?serverTimezone=UTC</property>
<property name="connection.username">...</property>
<property name="connection.password">...</property>
<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property>
<!-- SQL dialect -->
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<!-- Enable Hibernate's automatic session context management -->
<property name="current_session_context_class">thread</property>
<!-- Echo all executed SQL to stdout -->
<property name="show_sql">true</property>
<!--指定映射文件路徑-->
<!--<mapping class="UserMod" />-->
<mapping resource="Grade.hbm.xml"/>
<mapping resource="Student.hbm.xml"/>
</session-factory>
</hibernate-configuration>
3.一對多(班級和和學生)(一對一可看成特殊的一對多)
3.1 創建班級和學生的對應持久化類(//在一方定義一個多方的集合),對於構造函數,根據測試類中的需求進行構造,不過無參構造函數和包含全部參數的構造函數最好都寫上
//Grade.java
package com.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;
//一對多時,在一方定義一個多方的集合
private Set<Student> students = new HashSet<Student>();
public Set<Student> getStudents() {
return students;
}
public void setStudents(Set<Student> students) {
this.students = students;
}
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() {
}
public Grade(int gid, String gname, String gdesc,Set<Student> students) {
this.gid = gid;
this.gname = gname;
this.gdesc = gdesc;
this.students = students;
}
public Grade(String gname, String gdesc) {
this.gname = gname;
this.gdesc = gdesc;
}
}
//Student.java
package com.entity;
import java.io.Serializable;
public class Student implements Serializable{
private int sid;
private String sname;
private String sex;
//多對一時,在多方定義一個一方的引用
private Grade grade;
public Grade getGrade() {
return grade;
}
public void setGrade(Grade grade) {
this.grade = grade;
}
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() {
}
public Student(String sname, String sex) {
this.sname = sname;
this.sex = sex;
}
}
3.2.創建Hibrnate對應的映射類
//HibernateUtils.java
package com.util;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
public class HibernateUtils {
// 1.創建工廠對象;
private static SessionFactory sessionFactory;
// 2.初始化工廠對象;
static {
sessionFactory = new Configuration().configure().buildSessionFactory();
}
//4.獲取sessionFactory
public static SessionFactory getSessionFactory(){
return sessionFactory;
}
// 3.獲得Session;
public static Session getSession() {
return sessionFactory.openSession();
}
//4.關閉session
public static void closeSession(Session session){
if (session!= null){
session.close();
}
}
}
3.3 3.創建持久化類對應的映射文件
//Grade.hbm.xml
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="com.entity.Grade" table="grade">
<id name="gid" column="gid" type="java.lang.Integer">
<!--設置主鍵爲自增模式-->
<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>
<!--配置單向的一對多關聯關係 , inverse爲false表示由一方進行關聯關係的維護,設置爲true表示由多方進行關聯關係的維護-->
<!--cascade代表級聯,設置爲all代表對於所有操作都可以進行級聯操作。例,在班級表中添加一個班級後,該班級對應的所有學生也會添加到相應的數據庫中-->
<set name="students" table="student" inverse="false" cascade="all">
<key column="gid"></key>
<one-to-many class="com.entity.Student"/>
</set>
</class>
</hibernate-mapping>
//Student.hbm.xml
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="com.entity.Student" table="student">
<id name="sid" column="sid" type="java.lang.Integer">
<!--設置主鍵爲自增模式-->
<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>
<many-to-one name="grade" class="com.entity.Grade" column="gid"></many-to-one>
</class>
</hibernate-mapping>
3.4 創建測試類測試
//test.java
package com.entity;
import com.util.HibernateUtils;
import org.hibernate.Session;
import org.hibernate.Transaction;
import java.util.Set;
/*單向一對多關係(班級--->學生)
* 建立關聯關係後,可以方便的從一個對象導航到另一個對象
* 當建立了雙向一對多關係後,既可以方便的由學生查找到對應的班級信息,也可以方便的由班級查找到其所包含的學生信息
* */
public class test {
public static void main(String[] args){
// add();
// findStudentsByGrade();
update();
}
//將學生添加到班級
public static void add(){
Grade g = new Grade("Java一班","Java軟件開發一班");
Student stu1 = new Student("張三","男");
Student stu2 = new Student("王蘭","女");
//如果希望在學生表中添加對應的班級編號,需要在班級中添加學生,建立關聯關係
g.getStudents().add(stu1);
g.getStudents().add(stu2);
Session session = HibernateUtils.getSession();
Transaction tx = session.beginTransaction();
session.save(g);
session.save(stu1);
session.save(stu2);
tx.commit();
HibernateUtils.closeSession(session);
}
//查詢班級中包含的學生
public static void findStudentsByGrade(){
Session session = HibernateUtils.getSession();
Grade grade = (Grade)session.get(Grade.class,1);
System.out.println(grade.getGname()+","+grade.getGdesc());
Set<Student> students = grade.getStudents();
for (Student stu:students){
System.out.println(stu.getSname()+","+stu.getSex());
}
}
//修改學生信息
public static void update(){
Grade g = new Grade("Java二班","Java軟件開發二班");//新建一個班級
Session session = HibernateUtils.getSession();
Transaction tx = session.beginTransaction();
Student stu = (Student) session.get(Student.class,1);//獲取id爲1的學生信息,將他保存起來
g.getStudents().add(stu);//在新建的班級中加入該學生
session.save(g);
tx.commit();
HibernateUtils.closeSession(session);
}
//刪除學生信息
public static void delete(){
Session session = HibernateUtils.getSession();
Transaction tx = session.beginTransaction();
Student stu = (Student)session.get(Student.class,2);
session.delete(stu);
tx.commit();
HibernateUtils.closeSession(session);
}
}
4.多對多 與一對多類似,後面看情況再寫吧。。