maven项目 hibernate一对多注解例子

电玩女神 2022-08-10 13:46 109阅读 0赞

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();
    	}
    }