利用Hibernate注解生成表
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Hibernate4注释
@Entity(name = "tbl_user") 将一个类声明为一个实体bean(即一个持久化POJO类)
@Id注解则声明了该实体bean的标识属性，必填属性
@GenericGeneratorhibernate在JPA的基础上进行了扩展，可以用一下方式引入hibernate独有的主键生成策略。
@Column name解决属性名和字段名不对应 length限制字符串长度 unique , nullable , precision 数据长度, scale 无小数
hibernate.cfg.xml
<?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"> <!-- Generated by MyEclipse Hibernate Tools. --> <hibernate-configuration> <session-factory> <property name="myeclipse.connection.profile">mysql</property> <property name="connection.url"> jdbc:mysql://localhost:3306/forums </property> <property name="connection.username">root</property> <property name="connection.password">root</property> <property name="connection.driver_class"> com.mysql.jdbc.Driver </property> <property name="hibernate.current_session_context_class">thread</property> <property name="dialect"> org.hibernate.dialect.MySQLDialect </property> <property name="show_sql">true</property> <property name="hibernate.current_session_context_class">thread</property> <property name="hibernate.hbm2ddl.auto">update</property> <!-- 连接池 配置 c3p0--> <property name="hibernate.connection.provider_class">org.hibernate.c3p0.internal.C3P0ConnectionProvider</property> <!-- 在连接池中可用数据连接的最大数目 --> <property name="hibernate.c3p0.max_size">20</property> <!-- 在连接池中可用数据连接的最小数目 --> <property name="hibernate.c3p0.min_size">5</property> <!-- 设定数据库连接的过期时间，以秒为单位，如果连接池中的某个数据库连接处于空闲状态的时间超过了timeout时间，就会从连接池中清除--> <property name="hibernate.c3p0.timeout">120</property> <!-- 每3000秒查询所有连接池的空闲连接以秒为单位 --> <property name="hibernate.c3p0.idle_test_period">3000</property> <!--当连接池里面的连接用完的时候，C3P0一下获取的新的连接数 <property name="hibernate.c3p0.acquire_increment">2</property> 每次都验证连接是否可用 <property name="hibernate.c3p0.validate">true</property> --> <!-- 映射文件引入 --> <mapping class="csdn.forum.model.TblUser" /> <mapping class="csdn.forum.model.TblTopic" /> <mapping class="csdn.forum.model.TblBoard" /> <mapping class="csdn.forum.model.TblReply" /> </session-factory> </hibernate-configuration>
package csdn.forum.util; import org.hibernate.Session; import org.hibernate.SessionFactory; import org.hibernate.boot.registry.StandardServiceRegistryBuilder; import org.hibernate.cfg.Configuration; import org.hibernate.service.ServiceRegistry; public class HibernateSessionFactory { static Configuration cfg; static SessionFactory sessionFactory; static ServiceRegistry serviceRegistry; static { cfg = new Configuration().configure();// 默认找文件hibernate.hbm.xml // 创建服务注册对象 serviceRegistry = new StandardServiceRegistryBuilder().applySettings( cfg.getProperties()).build(); // 创建Factory工厂 sessionFactory = cfg.buildSessionFactory(serviceRegistry); } // 获取session对象 public static Session getSession() { // 打开session return sessionFactory.getCurrentSession(); } } fetch在Hibernate里用时默认值：FetchType.LAZY，它要求程序运行时延迟加载所有的集合和实体。
fetch设置为FetchType.EAGER，它提示程序在首次访问数据时应马上加载所有的集合和实体mappedBy默认值：如果关系是单向的，则该关联提供程序确定拥有该关系的字段。如果关系是双向的，则将关联相反（非拥有）方上的mappedBy元素设置为拥有此关系的字段或属性的名称
@BatchSize(size=10) 对查询抓取的优化方案，通过指定一个主键或外键列表，Hibernate使用单条SELECT语句获取一批对象实例或集合。
package csdn.forum.model; import java.util.ArrayList; import java.util.List; import javax.persistence.CascadeType; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.FetchType; import javax.persistence.GeneratedValue; import javax.persistence.Id; import javax.persistence.JoinColumn; import javax.persistence.ManyToOne; import javax.persistence.OneToMany; import org.hibernate.annotations.GenericGenerator; @Entity(name = "tbl_board") public class TblBoard { private String id; private String name; private TblBoard parentBoard; private List<TblBoard> board = new ArrayList<TblBoard>(); private List<TblTopic> topics=new ArrayList<TblTopic>(); // @id必填 @GenericGenerator(name = "generator", strategy = "uuid.hex") // hibernate独有的16进制算法 @Id @GeneratedValue(generator = "generator") @Column(name = "id", unique = true, nullable = false, length = 32) public String getId() { return id; } public void setId(String id) { this.id = id; } @Column(name ="name") public String getName() { return name; } public void setName(String name) { this.name = name; } @ManyToOne(cascade = {CascadeType.ALL}) @JoinColumn(name = "parent_id") public TblBoard getParentBoard() { return parentBoard; } public void setParentBoard(TblBoard parentBoard) { this.parentBoard = parentBoard; } @OneToMany(cascade = {CascadeType.ALL},fetch = FetchType.LAZY,mappedBy = "parentBoard")//在1这方加入@OneToMany(cascade = {CascadeType.ALL},mappedBy = "user") ，只调用session.sa//ve(user); //在多这方加入@ManyToOne(cascade = {CascadeType.ALL}) @JoinColumn(name = "user_id")，只调用s//ession.save(topic); public List<TblBoard> getBoard() { return board; } public void setBoard(List<TblBoard> board) { this.board = board; } @OneToMany(cascade = {CascadeType.ALL},fetch = FetchType.LAZY,mappedBy = "board") public List<TblTopic> getTopics() { return topics; } public void setTopics(List<TblTopic> topics) { this.topics = topics; } } 
TblReply.Java
package csdn.forum.model; import java.util.Date; 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.Temporal; import javax.persistence.TemporalType; import org.hibernate.annotations.GenericGenerator; @Entity(name = "tbl_reply") public class TblReply{ private String id; private String title; private String content; private Date publishTime; private Date modifyTime; private TblUser user; private TblTopic tblTopic; @GenericGenerator(name = "generator", strategy = "uuid.hex") @Id @GeneratedValue(generator = "generator") @Column(name = "id", unique = true, nullable = false, length = 32) public String getId() { return id; } public void setId(String id) { this.id = id; } @Column(name = "title", length = 32) public String getTitle() { return title; } public void setTitle(String title) { this.title = title; } @Column(name = "content", length = 2000) public String getContent() { return content; } public void setContent(String content) { this.content = content; } @Temporal(TemporalType.DATE) @Column(name = "publishTime") public Date getPublishTime() { return publishTime; } public void setPublishTime(Date publishTime) { this.publishTime = publishTime; } @Temporal(TemporalType.DATE) @Column(name = "modifyTime") public Date getModifyTime() { return modifyTime; } public void setModifyTime(Date modifyTime) { this.modifyTime = modifyTime; } @ManyToOne(cascade = {CascadeType.ALL}) @JoinColumn(name = "user_id") public TblUser getUser() { return user; } public void setUser(TblUser user) { this.user = user; } @ManyToOne(cascade = {CascadeType.ALL}) @JoinColumn(name = "topic_id") public TblTopic getTblTopic() { return tblTopic; } public void setTblTopic(TblTopic tblTopic) { this.tblTopic = tblTopic; } } 
TblTopic.java
package csdn.forum.model; import java.util.ArrayList; import java.util.Date; import java.util.List; import javax.persistence.CascadeType; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.FetchType; import javax.persistence.GeneratedValue; import javax.persistence.Id; import javax.persistence.JoinColumn; import javax.persistence.ManyToOne; import javax.persistence.OneToMany; import javax.persistence.Temporal; import javax.persistence.TemporalType; import org.hibernate.annotations.BatchSize; import org.hibernate.annotations.GenericGenerator; @Entity(name = "tbl_topic") public class TblTopic { private String id; private String title; private String content; private Date pubishTime; private Date modifyTime; private TblUser user; private TblBoard board; private List<TblReply> replys=new ArrayList<TblReply>(); @GenericGenerator(name = "generator", strategy = "uuid.hex") @Id @GeneratedValue(generator = "generator") @Column(name = "id", unique = true, nullable = false, length = 32) public String getId() { return id; } public void setId(String id) { this.id = id; } @Column(name = "title", length = 32) public String getTitle() { return title; } public void setTitle(String title) { this.title = title; } @Column(name = "content", length = 2000) public String getContent() { return content; } public void setContent(String content) { this.content = content; } @Temporal(TemporalType.DATE) @Column(name = "publishTime") public Date getPubishTime() { return pubishTime; } public void setPubishTime(Date pubishTime) { this.pubishTime = pubishTime; } @Temporal(TemporalType.DATE) @Column(name = "modifyTime") public Date getModifyTime() { return modifyTime; } public void setModifyTime(Date modifyTime) { this.modifyTime = modifyTime; } // 多这方映射user_id @ManyToOne(cascade = {CascadeType.ALL}) @JoinColumn(name = "user_id") public TblUser getUser() { return user; } public void setUser(TblUser user) { this.user = user; } @OneToMany(cascade = {CascadeType.ALL},fetch = FetchType.LAZY,mappedBy = "tblTopic") public List<TblReply> getReplys() { return replys; } public void setReplys(List<TblReply> replys) { this.replys = replys; } @ManyToOne(cascade = {CascadeType.ALL}) @JoinColumn(name = "board_id") public TblBoard getBoard() { return board; } public void setBoard(TblBoard board) { this.board = board; } } 
TblUser.java
package csdn.forum.model; import java.util.ArrayList; import java.util.Date; import java.util.List; import javax.persistence.CascadeType; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.FetchType; import javax.persistence.GeneratedValue; import javax.persistence.Id; import javax.persistence.OneToMany; import javax.persistence.Temporal; import javax.persistence.TemporalType; import org.hibernate.annotations.GenericGenerator; @Entity(name="tbl_user") public class TblUser { /** * */ private static final long serialVersionUID = 1L; private String id; private String uname; private String upass; private String head; private Date regTime; private boolean gender; private List<TblTopic> topic=new ArrayList<TblTopic>(); private List<TblReply> replies=new ArrayList<TblReply>(); //@id必填 @GenericGenerator(name = "generator", strategy = "uuid.hex")//hibernate独有的16进制算法 @Id @GeneratedValue(generator = "generator") @Column(name = "id", unique = true, nullable = false, length = 32) public String getId() { return id; } public void setId(String id) { this.id = id; } @Column (name="uname",length=20) public String getUname() { return uname; } public void setUname(String uname) { this.uname = uname; } @Column (name="upass",length=20) public String getUpass() { return upass; } public void setUpass(String upass) { this.upass = upass; } @Column (name="head") public String getHead() { return head; } public void setHead(String head) { this.head = head; } @Temporal(TemporalType.DATE) @Column(name = "regTime") public Date getRegTime() { return regTime; } public void setRegTime(Date regTime) { this.regTime = regTime; } @Column(name="gender",length=20) public boolean isGender() { return gender; } public void setGender(boolean gender) { this.gender = gender; } //现在是一的一方直接通过它映射user,user是多的这一方的属性 // @OneToMany(mappedBy="user") @OneToMany(cascade = {CascadeType.ALL},fetch = FetchType.LAZY,mappedBy = "user") public List<TblTopic> getTopic() { return topic; } public void setTopic(List<TblTopic> topic) { this.topic = topic; } @OneToMany(cascade={CascadeType.ALL},fetch=FetchType.LAZY,mappedBy="user") public List<TblReply> getReplies() { return replies; } public void setReplies(List<TblReply> replies) { this.replies = replies; } } 
测试类TestUser.java
package csdn.forum.test; import java.util.Date; import java.util.List; import org.hibernate.Query; import org.hibernate.Session; import org.junit.Test; import csdn.forum.model.TblBoard; import csdn.forum.model.TblReply; import csdn.forum.model.TblTopic; import csdn.forum.model.TblUser; import csdn.forum.util.HibernateSessionFactory; public class TestUser { @Test public void save() { Session session = HibernateSessionFactory.getSession(); session.getTransaction().begin(); /* * //1.保存java板块包含jsp,ajax,struts2,hiberante子版块 TblBoard java =new * TblBoard(); java.setName("java"); * * TblBoard jsp =new TblBoard(); jsp.setName("jsp"); TblBoard struts2 * =new TblBoard(); struts2.setName("struts2"); TblBoard hiberante =new * TblBoard(); hiberante.setName("hiberante"); //相互持有 * java.getBoard().add(jsp); java.getBoard().add(struts2); * java.getBoard().add(hiberante); jsp.setParentBoard(java); * struts2.setParentBoard(java); hiberante.setParentBoard(java); * * * session.save(java); session.getTransaction().commit(); */ // 2.利用csdn用户身份，在struts2板块下发表帖子 /* * TblUser user=new TblUser(); user.setUname("csdn"); TblBoard * struts2=(TblBoard * )session.get(TblBoard.class,"2c96c05e44da48600144da4861f60002"); * TblTopic topic=new TblTopic(); topic.setTitle("struts TblBoard"); * topic.setUser(user); topic.setBoard(struts2); topic.setPubishTime(new * Date()); user.getTopic().add(topic); session.save(topic); * session.getTransaction().commit(); */ /* * //3.利用admin用户身份，给帖子回帖 TblUser user=new TblUser(); * user.setUname("admin"); TblTopic topic1=(TblTopic) * session.get(TblTopic.class,"2c96c05e44da44660144da4469390000"); * TblReply reply=new TblReply(); reply.setTitle("reply title"); * reply.setUser(user); user.getReplies().add(reply); * reply.setTblTopic(topic1); topic1.getReplys().add(reply); * session.getTransaction().commit(); */ // 4.利用admin用户身份，修改回帖内容 /* * Query query=session.createQuery( * "from csdn.forum.model.TblReply r where r.user.uname='admin'"); * TblReply reply=(TblReply) query.list().get(0); * reply.setTitle("update"); session.save(reply); * session.getTransaction().commit(); */ // 5.利用admin用户身份，查看回帖//根据帖子查看回帖，查看下面的所有回帖 /* * Query query=session.createQuery( * "from csdn.forum.model.TblReply t where t.user.uname='admin'"); * List<TblReply> lisst=query.list(); * * for(TblReply tabl:lisst){ System.out.println("1111111111111"); * System.out.println(tabl.getContent()); } * session.getTransaction().commit(); */ // 6.利用csdn用户身份,删除回帖，条件限制为有回帖存在不允许删除 /* * Query query1=session.createQuery( * "from csdn.forum.model.TblTopic t where t.user.uname='csdn'"); * TblTopic topic1=(TblTopic) query1.list().get(0); * if(topic1.getReplys().size()==0){ session.delete(topic1); }else{ * System.out.println("提示不能删除"); } * * session.getTransaction().commit(); */ // 7.统计struts2板块下的发帖数 // Query // query2=session.createQuery("select count(*) from csdn.forum.model.TblTopic t where t.board.name='struts2'"); /* * Query query2 = session.createQuery( * " from csdn.forum.model.TblTopic t where t.board.name='struts2'"); * * System.out.println(query2.list().size()+"---"); // * System.out.println(query2.list().get(0)); // * System.out.println(query2.list().get(1)); // * System.out.println(query2.list().get(2)); * session.getTransaction().commit(); */ // 8.查询struts2板块下所有帖子按时间倒序排列 /* * Query query=session.createQuery( * "from csdn.forum.model.TblTopic t where t.board.name='struts2' order by t.pubishTime desc" * ); //System.out.println(query); for(int * i=0;i<query.list().size();i++){ TblTopic topic=(TblTopic) * query.list().get(i); System.out.println(topic.getTitle()); } */ // 9.查询帖子下所有回帖，按时间倒序排列 /* * Query query=session.createQuery( * "from csdn.forum.model.TblReply t where t.tblTopic.title='struts TblBoard' order by t.publishTime desc" * ); //System.out.println(query); for(int * i=0;i<query.list().size();i++){ TblReply topic=(TblReply) * query.list().get(i); System.out.println(topic.getTitle()); } */ /* * * 查询父亲java板块 * TblBoard board = (TblBoard) session.get(TblBoard.class, "2c96c05e44da48600144da4861dd0000"); System.out.println(board); session.getTransaction().commit();*/ // 10.查出最后发表帖子标题 Query query = session .createQuery("from csdn.forum.model.TblTopic t order by t.pubishTime asc"); // System.out.println(query); TblTopic topic=(TblTopic) query.list().get(query.list().size()-1); System.out.println(topic.getTitle()); } } 
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