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Hibernate注解配置
1.注解方式：
注解的方式与xml很很多类似：
首先是需要在pom文件中加入4个jar包：
1 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 2 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> 3 <modelVersion>4.0.0</modelVersion> 4 <groupId>cn.yunhe</groupId> 5 <artifactId>hibernate3</artifactId> 6 <packaging>war</packaging> 7 <version>1.0-SNAPSHOT</version> 8 <name>hibernate3 Maven Webapp</name> 9 <url>http://maven.apache.org</url> 10 <dependencies> 11 <dependency> 12 <groupId>junit</groupId> 13 <artifactId>junit</artifactId> 14 <version>4.12</version> 15 <scope>test</scope> 16 </dependency> 17 18 <dependency> 19 <groupId>javax.servlet</groupId> 20 <artifactId>javax.servlet-api</artifactId> 21 <version>3.1.0</version> 22 <scope>provided</scope> 23 </dependency> 24 25 <dependency> 26 <groupId>mysql</groupId> 27 <artifactId>mysql-connector-java</artifactId> 28 <version>5.1.6</version> 29 </dependency> 30 31 <dependency> 32 <groupId>org.apache.struts</groupId> 33 <artifactId>struts2-core</artifactId> 34 <version>2.3.31</version> 35 </dependency> 36 37 <dependency> 38 <groupId>javax.servlet</groupId> 39 <artifactId>jstl</artifactId> 40 <version>1.2</version> 41 </dependency> 42 43 <dependency> 44 <groupId>org.apache.struts</groupId> 45 <artifactId>struts2-dojo-plugin</artifactId> 46 <version>2.3.16</version> 47 </dependency> 48 49 50 <!--以下四个包，缺一不可--> 51 <dependency> 52 <groupId>org.hibernate</groupId> 53 <artifactId>hibernate-core</artifactId> 54 <version>3.5.0-Final</version> 55 </dependency> 56 57 <dependency> 58 <groupId>org.hibernate</groupId> 59 <artifactId>hibernate-annotations</artifactId> 60 <version>3.5.0-Final</version> 61 </dependency> 62 63 <dependency> 64 <groupId>org.slf4j</groupId> 65 <artifactId>slf4j-log4j12</artifactId> 66 <version>1.5.8</version> 67 </dependency> 68 69 <dependency> 70 <groupId>org.javassist</groupId> 71 <artifactId>javassist</artifactId> 72 <version>3.13.0-GA</version> 73 </dependency> 74 </dependencies> 75 <build> 76 <finalName>hibernate3</finalName> 77 <plugins> 78 <plugin> 79 <groupId>org.eclipse.jetty</groupId> 80 <artifactId>jetty-maven-plugin</artifactId> 81 <version>9.3.14.v20161028</version> 82 </plugin> 83 </plugins> 84 </build> 85 </project>
下面是不同的地方：
（1）：hibernate.hbm.xml 文件中把引用：xxx.hbm.xml改为引用实体类：
即把：<mapping resource="com/wsw/hibernate/model/Person.hbm.xml"/>
改为：<mapping class="com.wsw.hibernate.model.Teacher" />
（2）：获取SessionFactory方式发生了变化：
即：由SessionFactory sf = new Configuration().configure().buildSessionFactory()
改为：SessionFactory sf = new AnnotationConfiguration().configure().buildSessionFactory()
（3）：注解方式不需要在xxx.hbm.xml把实体类与表进行映射。而采用在实体类中进行注解。
注意：
（1）：如果实体类属性名与表字段名不一致的时候，要么都注解在属性前，要么都注解在get方法前。不能部分注解在属性前，部分注解在方法前。
（2）：如果实体类属性名与表字段名一致的时候，可以部分注解在属性前，部分注解在方法前。
（3）：如果在实体类中某些属性不注解：（属性和get都不写注解），默认为表字段名与实体类属性名一致。
（4）：如果实体类的某个成员属性不需要存入数据库中，使用@Transient 进行注解就可以了。即类似于：(xxx.hbm.Xml配置中的某些字段不写(就是不需要对这个成员属性进行映射))
（5）：表名称可以在实体类前进行注解。
（6）：所有这些注解在：javax.persistence包下。而不是在hibernate包中。
2.单向一对多、单向多对一、双向多对一
1.实体类配置
1 package cn.yunhe.entity; 2 3 import javax.persistence.*; 4 import java.io.Serializable; 5 6 7 @Entity 8 @Table(name = "jd") 9 public class Jd {//街道 10 private int jdid; 11 private String jdname; 12 private Qx qx;//区县 13 14 @Id 15 @GeneratedValue 16 @Column(name = "jdid") 17 public int getJdid() { 18 return jdid; 19 } 20 21 public void setJdid(int jdid) { 22 this.jdid = jdid; 23 } 24 25 @Column(name = "jdname") 26 public String getJdname() { 27 return jdname; 28 } 29 30 public void setJdname(String jdname) { 31 this.jdname = jdname; 32 } 33 34 @ManyToOne(cascade = CascadeType.ALL,fetch = FetchType.LAZY) 35 @JoinColumn(name = "qxid") 36 public Qx getQx() { 37 return qx; 38 } 39 40 public void setQx(Qx qx) { 41 this.qx = qx; 42 } 43 }
1 package cn.yunhe.entity; 2 3 import javax.persistence.*; 4 import java.util.HashSet; 5 import java.util.Set; 6 7 @Entity 8 @Table(name = "qx")//实体类映射表 9 public class Qx {//区县 10 private int qxid; 11 private String qxname; 12 private Set<Jd> jds=new HashSet<Jd>(); 13 14 @Id 15 @GeneratedValue 16 @Column(name = "qxid") 17 public int getQxid() { 18 return qxid; 19 } 20 21 public void setQxid(int qxid) { 22 this.qxid = qxid; 23 } 24 25 @Column(name = "qxname") 26 public String getQxname() { 27 return qxname; 28 } 29 30 public void setQxname(String qxname) { 31 this.qxname = qxname; 32 } 33 34 //@OneToMany(cascade = CascadeType.ALL,fetch = FetchType.LAZY ,mappedBy = "qx")//mappedBy里面写的是对象 35 //@JoinColumn(name ="qxid" ) 双向操作Qx一对多声明可以不需要@JoinColumn，但@OneToMany(...mappedBy="category") 36 public Set<Jd> getJds() { 37 return jds; 38 } 39 40 public void setJds(Set<Jd> jds) { 41 this.jds = jds; 42 } 43 }
1 <?xml version="1.0" encoding="UTF-8"?> 2 <!DOCTYPE hibernate-configuration 3 PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" 4 "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd"> 5 <hibernate-configuration> 6 <session-factory> 7 <property name="hibernate.hbm2ddl.auto" >update</property><!--自动生成数据库表--> 8 <property name="dialect">org.hibernate.dialect.MySQLDialect</property><!--数据库方言--> 9 <property name="connection.driver_class">com.mysql.jdbc.Driver</property> 10 <property name="connection.url">jdbc:mysql://localhost:3306/hibernate</property> 11 <property name="connection.username">root</property> 12 <property name="connection.password">1234</property> 13 <property name="show_sql">true</property><!--显示sql--> 14 15 <mapping class="cn.yunhe.entity.Qx"/> 16 <mapping class="cn.yunhe.entity.Jd"/> 17 </session-factory> 18 </hibernate-configuration>
2. 测试类
1 import cn.yunhe.entity.Jd; 2 import cn.yunhe.entity.Qx; 3 import org.hibernate.Session; 4 import org.hibernate.SessionFactory; 5 import org.hibernate.Transaction; 6 import org.hibernate.cfg.AnnotationConfiguration; 7 import org.hibernate.cfg.Configuration; 8 import org.junit.After; 9 import org.junit.Before; 10 import org.junit.Test; 11 12 import java.util.List; 13 import java.util.Set; 14 15 /** 16 * Created by Administrator on 2017/7/6. 17 */ 18 public class Demo { 19 Session session=null; 20 Transaction tr=null; 21 22 @Before 23 public void setUp(){ 24 Configuration config=new AnnotationConfiguration().configure(); 25 SessionFactory factory= config.buildSessionFactory(); 26 session=factory.openSession(); 27 tr=session.beginTransaction(); 28 } 29 @Test 30 public void testQuery(){ 31 List<Qx> list = session.createQuery("from Qx").list(); 32 for (Qx qx : list) { 33 System.out.println(qx.getQxname()); 34 } 35 } 36 37 @Test 38 //单向一对多（使用时注意只能在实体类一的一方建多的一方对象，不能两边都创建） 39 public void testOneToMany(){ 40 Qx qx= (Qx) session.get(Qx.class,1); 41 System.out.println(qx.getQxname()+"下的街道有："); 42 Set<Jd> set=qx.getJds(); 43 for(Jd jd:set){ 44 System.out.println(jd.getJdname()); 45 } 46 } 47 @Test 48 //单向多对一 /双向多对一（使用时注意只能在实体类多的一方建一的一方对象，不能两边都创建） 49 public void testManyToOne(){ 50 Jd jd= (Jd) session.get(Jd.class,1); 51 System.out.println(jd.getJdname()+"属于"); 52 System.out.println(jd.getQx().getQxname()); 53 } 54 55 56 @After 57 public void tearDowm(){ 58 session.close(); 59 } 60 }
3.双向多对多
1.实体类
1 package cn.yunhe.entity; 2 3 import javax.persistence.*; 4 import java.util.HashSet; 5 import java.util.Set; 6 7 @Entity 8 @Table(name = "student") 9 public class Student {//学生表 10 private int id; 11 private String name; 12 public Set<Teacher> teachers =new HashSet<Teacher>();//互相建对方的set集合 13 14 @Id 15 @GeneratedValue 16 @Column(name = "id") 17 public int getId() { 18 return id; 19 } 20 21 public void setId(int id) { 22 this.id = id; 23 } 24 25 @Column(name = "name") 26 public String getName() { 27 return name; 28 } 29 30 public void setName(String name) { 31 this.name = name; 32 } 33 34 @ManyToMany(cascade = CascadeType.ALL,fetch = FetchType.LAZY) 35 //配置中间表，并将外键对照起来 36 @JoinTable(name = "student_teacher", 37 joinColumns = @JoinColumn(name = "studentid"), 38 inverseJoinColumns = @JoinColumn(name ="teacherid")) 39 public Set<Teacher> getTeachers() { 40 return teachers; 41 } 42 43 public void setTeachers(Set<Teacher> teachers) { 44 this.teachers = teachers; 45 } 46 }
1 package cn.yunhe.entity; 2 3 import javax.persistence.*; 4 import java.util.HashSet; 5 import java.util.Set; 6 7 8 @Entity 9 @Table(name = "teacher") 10 public class Teacher {//教师 11 private int id; 12 private String name; 13 public Set<Student> students =new HashSet<Student>();//互相建对方的集合 14 15 @Id 16 @GeneratedValue 17 @Column(name = "id") 18 public int getId() { 19 return id; 20 } 21 22 public void setId(int id) { 23 this.id = id; 24 } 25 26 @Column(name = "name") 27 public String getName() { 28 return name; 29 } 30 31 public void setName(String name) { 32 this.name = name; 33 } 34 35 @ManyToMany(cascade = CascadeType.ALL, 36 fetch = FetchType.LAZY,mappedBy = "teachers") 37 public Set<Student> getStudents() { 38 return students; 39 } 40 41 public void setStudents(Set<Student> students) { 42 this.students = students; 43 } 44 }
2.测试类
1 import cn.yunhe.entity.Jd; 2 import cn.yunhe.entity.Qx; 3 import cn.yunhe.entity.Student; 4 import cn.yunhe.entity.Teacher; 5 import org.hibernate.Session; 6 import org.hibernate.SessionFactory; 7 import org.hibernate.Transaction; 8 import org.hibernate.cfg.AnnotationConfiguration; 9 import org.hibernate.cfg.Configuration; 10 import org.junit.After; 11 import org.junit.Before; 12 import org.junit.Test; 13 14 import java.util.List; 15 import java.util.Set; 16 17 /** 18 * Created by Administrator on 2017/7/6. 19 */ 20 public class Demo { 21 Session session=null; 22 Transaction tr=null; 23 24 @Before 25 public void setUp(){ 26 Configuration config=new AnnotationConfiguration().configure(); 27 SessionFactory factory= config.buildSessionFactory(); 28 session=factory.openSession(); 29 tr=session.beginTransaction(); 30 } 31 32 33 @Test 34 //双向多对多(要有中间表，实体类互相建对方的对象的Set集合) 35 public void testManyToMany(){ 36 //根据学生查老师 37 Student student= (Student) session.get(Student.class,5); 38 System.out.println("学生："+student.getName()+"的老师有："); 39 Set<Teacher> teachers=student.getTeachers(); 40 for (Teacher t:teachers){ 41 System.out.println(t.getName()); 42 } 43 44 //根据老师查学生 45 Teacher teacher= (Teacher) session.get(Teacher.class,4); 46 System.out.println("老师："+teacher.getName()+"的学生有："); 47 Set<Student> students=teacher.getStudents(); 48 for (Student s:students){ 49 System.out.println(s.getName()); 50 } 51 } 52 53 @After 54 public void tearDowm(){ 55 session.close(); 56 } 57 }
3.主配置文件
1 <?xml version="1.0" encoding="UTF-8"?> 2 <!DOCTYPE hibernate-configuration 3 PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" 4 "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd"> 5 <hibernate-configuration> 6 <session-factory> 7 <property name="hibernate.hbm2ddl.auto" >update</property><!--自动生成数据库表--> 8 <property name="dialect">org.hibernate.dialect.MySQLDialect</property><!--数据库方言--> 9 <property name="connection.driver_class">com.mysql.jdbc.Driver</property> 10 <property name="connection.url">jdbc:mysql://localhost:3306/hibernate</property> 11 <property name="connection.username">root</property> 12 <property name="connection.password">1234</property> 13 <property name="show_sql">true</property><!--显示sql--> 14 15 <mapping class="cn.yunhe.entity.Student"/> 16 <mapping class="cn.yunhe.entity.Teacher"/> 17 18 </session-factory> 19 </hibernate-configuration>
Hibernate注解配置
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