maven项目 hibernate一对多注解例子
pom.xml
<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>cn.orm</groupId> <artifactId>db</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>db</name> <url>http://maven.apache.org</url> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> </properties> <dependencies> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>3.8.1</version> <scope>test</scope> </dependency> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-core</artifactId> <version>4.3.6.Final</version> </dependency> <dependency> <groupId>postgresql</groupId> <artifactId>postgresql</artifactId> <version>9.1-901-1.jdbc4</version> </dependency> <dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>1.2.17</version> </dependency> </dependencies> </project>
hibernate.cfg.xml
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.connection.url">jdbc:postgresql://127.0.0.1/db_cloud</property>
<property name="hibernate.connection.driver_class">org.postgresql.Driver</property>
<property name="hibernate.connection.username">postgres</property>
<property name="hibernate.connection.password">admin</property>
<property name="hibernate.dialect">org.hibernate.dialect.PostgreSQLDialect</property>
<property name="hibernate.show_sql">true</property>
<property name="hibernate.hbm2ddl.auto">update</property>
<property name="hibernate.current_session_context_class">thread</property>
<mapping class="cn.orm.vo.User"/>
<mapping class="cn.orm.vo.Topic"/>
</session-factory>
</hibernate-configuration>
package cn.orm.vo;
import java.util.ArrayList;
import java.util.List;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToMany;
import javax.persistence.Table;
@Entity
@Table(name="t_user2")
public class User
{
@Id
@GeneratedValue
@Column(name = "uid")
private Integer id;
@Column
private String username;
@Column
private String nickname;
@Column
private String stype;
@OneToMany(cascade=CascadeType.ALL)
@JoinColumn(name="uid") //对应儿子类的哪个字段
private List<Topic> topics = new ArrayList<Topic>();
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getNickname() {
return nickname;
}
public void setNickname(String nickname) {
this.nickname = nickname;
}
public String getStype() {
return stype;
}
public void setStype(String stype) {
this.stype = stype;
}
public List<Topic> getTopics() {
return topics;
}
public void setTopics(List<Topic> topics) {
this.topics = topics;
}
public String toString()
{
return "[id="+id+",username="+username+",nickname="+nickname+"]";
}
}
package cn.orm.vo;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;
@Entity
@Table(name="t_topic2")
public class Topic
{
@Id
@GeneratedValue
@Column(name = "tid")
private Integer id;
@ManyToOne(cascade = CascadeType.ALL, optional = false)
@JoinColumn(name="uid")//外键为uid，与User中的id关联
private User user;
@Column
private String title;
@Column
private String content;
@Column(name = "t_status")
private String status;
@Column(name = "t_type")
private String type;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getContent() {
return content;
}
public void setContent(String content) {
this.content = content;
}
public String getStatus() {
return status;
}
public void setStatus(String status) {
this.status = status;
}
public String getType() {
return type;
}
public void setType(String type) {
this.type = type;
}
public String toString()
{
return "[user.uid="+user.getId()+",title="+title+"]";
}
}
package cn.orm.db;
import java.util.List;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.AnnotationConfiguration;
import cn.orm.vo.Topic;
import cn.orm.vo.User;
/**
* Hello world!
*
*/
public class App
{
static SessionFactory sf;
static {
sf = new AnnotationConfiguration().configure().buildSessionFactory();
}
public static void init() throws Exception
{
Session session = sf.openSession();
Transaction ts=session.beginTransaction();
//ts.begin();
// User u1 = new User();
// u1.setUsername("tomcat");
// u1.setNickname("web服务器");
// u1.setStype("0");
User u1 = (User)session.load(User.class, 22);
Topic t = new Topic();
t.setContent("xx");
t.setTitle("Apache Tomcat v7.0.1正式发布");
t.setStatus("0");
t.setType("0");
t.setUser(u1);
//session.save(u1);
session.save(t);
ts.commit();
session.close();
sf.close();
}
public static void query() throws Exception
{
Session session = sf.openSession();
User u1 = (User)session.load(User.class, 22);
List<Topic> list = u1.getTopics();
for(Topic topic : list)
{
System.out.println(topic + "\t" + topic.getUser());
}
sf.close();
}
public static void main(String[] args) throws Exception {
query();
}
}