QBC以及QBE例子

总共涉及到三个实体类：

 

(1)Category.java

package edu.smc.hibernate;import javax.persistence.Entity;import javax.persistence.GeneratedValue;import javax.persistence.Id;@Entitypublic class Category {private int id;private String name;@Id@GeneratedValuepublic int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}}

(2)Topic.java

package edu.smc.hibernate;import javax.persistence.Entity;import javax.persistence.GeneratedValue;import javax.persistence.Id;import javax.persistence.ManyToOne;@Entitypublic class Topic {private int id;private String title;private Category category;@Id@GeneratedValuepublic int getId() {return id;}public String getTitle() {return title;}public void setTitle(String title) {this.title = title;}public Category getCategory() {return category;}public void setCategory(Category category) {this.category = category;}public void setId(int id) {this.id = id;}    @ManyToOnepublic Category getCatetory() {return category;}public void setCatetory(Category catetory) {this.category = category;}}

(3)Msg.java

package edu.smc.hibernate;import javax.persistence.Entity;import javax.persistence.GeneratedValue;import javax.persistence.Id;import javax.persistence.ManyToOne;@Entitypublic class Msg {private int id;private String cont;public String getCont() {return cont;}public void setCont(String cont) {this.cont = cont;}private Topic topic;@Id@GeneratedValuepublic int getId() {return id;}public void setId(int id) {this.id = id;}@ManyToOnepublic Topic getTopic() {return topic;}public void setTopic(Topic topic) {this.topic = topic;}} 

Session session = sf.openSession();session.beginTransaction();//criterion 标准/准则/约束Criteria c = session.createCriteria(Topic.class) //from Topic  .add(Restrictions.gt("id", 2)) //greater than = id > 2 .add(Restrictions.lt("id", 8)) //little than = id < 8 .add(Restrictions.like("title", "t_")) .createCriteria("category") .add(Restrictions.between("id", 3, 5)) //category.id >= 3 and category.id <=5 ;//DetachedCritereafor(Object o : c.list()) {Topic t = (Topic)o;System.out.println(t.getId() + "-" + t.getTitle());}session.getTransaction().commit();session.close();

Session session = sf.openSession();session.beginTransaction();Topic tExample = new Topic();tExample.setTitle("T_");Example e = Example.create(tExample).ignoreCase().enableLike();Criteria c = session.createCriteria(Topic.class) .add(Restrictions.gt("id", 2)) .add(Restrictions.lt("id", 8)) .add(e) ; for(Object o : c.list()) {Topic t = (Topic)o;System.out.println(t.getId() + "-" + t.getTitle());}session.getTransaction().commit();session.close();