hibernate 3

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第17课 hibernate树形结构(重点)

树形结构：也就是目录结构，有父目录、子目录、文件等信息，而在程序中树形结构只是称为节点。

一棵树有一个根节点，而根节点也有一个或多个子节点，而一个子节点有且仅有一个父节点(当前除根节点外)，而且也存在一个或多个子节点。

也就是说树形结构，重点就是节点，也就是我们需要关心的节点对象。

节点：一个节点有一个ID、一个名称、它所属的父节点(根节点无父节点或为null)，有一个或多的子节点等其它信息。

Hibernate将节点抽取出成实体类，节点相对于父节点是“多对一”映射关系，节点相对于子节点是“一对多”映射关系。

一、节点实体类：

/** * 节点*/

public class Node {

private int id; //标识符

private String name; //节点名称

private int level; //层次，为了输出设计

private boolean leaf; //是否为叶子节点，这是为了效率设计，可有可无

//父节点：因为多个节点属于一个父节点，因此用hibernate映射关系说是“多对一”

private Node parent;

//子节点：因为一个节点有多个子节点，因此用hibernate映射关系说是“一对多”

private Set children;

public int getId() {return id;}

public void setId(int id) {this.id = id;}

public String getName() {return name;}

public void setName(Stringname) { this.name = name;}

public int getLevel() { return level;}

public void setLevel(int level) {this.level = level;}

public boolean isLeaf() {return leaf;}

public void setLeaf(boolean leaf) {this.leaf = leaf;}

public Node getParent() {return parent;}

public void setParent(Nodeparent) {this.parent = parent;}

public SetgetChildren() {return children;}

public void setChildren(Setchildren) {this.children = children;}}

二、 xml方式：映射文件：

</id>

<!— 一对多：加入一个外键，参照当前表t_node主键，而属性parent类型为Node，也就是当前类，则会在同一个表中加入这个字段，参照这个表的主键-->

<many-to-one name="parent" column="pid"/>

<one-to-many class="com.wjt276.hibernate.Node"/>

</set>

</class>

三、 annotation注解

因为树型节点所有的数据，在数据库中只是存储在一个表中，而对于实体类来说，节点对子节点来说是一对多的关系，而对于父节点来说是多对一的关系。因此可以在一个实体类中注解。如下

@Entity

public class Node {

private int id; // 标识符

private String name; // 节点名称

private int level; // 层次，为了输出设计

private boolean leaf; // 是否为叶子节点，这是为了效率设计，可有可无

// 父节点：因为多个节点属于一个父节点，因此用hibernate映射关系说是“多对一”

private Node parent;

// 子节点：因为一个节点有多个子节点，因此用hibernate映射关系说是“一对多”

private Set<Node> children = newHashSet<Node>();

@Id

@GeneratedValue

public int getId() {return id;}

@OneToMany(mappedBy="parent")

public Set<Node>getChildren() {return children;}

@ManyToOne

@JoinColumn(name="pid")

public Node getParent() {return parent;}

四、测试代码：

public class NodeTest extends TestCase {

//测试节点的存在

public void testSave1(){

NodeManage.getInstanse().createNode("F:\\hibernate\\hibernate_training_tree");

}

//测试节点的加载

public void testPrintById(){

NodeManage.getInstanse().printNodeById(1);

}}

五、相应的类代码：

public classNodeManage {

private static NodeManage nodeManage= newNodeManage();

private NodeManage(){}//因为要使用单例，所以将其构造方法私有化

//向外提供一个接口

public static NodeManage getInstanse(){

return nodeManage;

}

/**

* 创建树

*@param filePath 需要创建树目录的根目录

public void createNode(String dir) {

Session session = null;

try {

session =HibernateUtils.getSession();

session.beginTransaction();

File root = new File(dir);

//因为第一个节点无父节点，因为是null

this.saveNode(root, session, null,0);

session.getTransaction().commit();

} catch (HibernateException e) {

e.printStackTrace();

session.getTransaction().rollback();

} finally {

HibernateUtils.closeSession(session);

}}

/**

* 保存节点对象至数据库

*@param file 节点所对应的文件

*@param session session

*@param parent 父节点

*@param level 级别

public void saveNode(File file, Sessionsession, Node parent, int level) {

if (file == null ||!file.exists()){return;}

//如果是文件则返回true,则表示是叶子节点，否则为目录，非叶子节点

boolean isLeaf = file.isFile();

Node node = new Node();

node.setName(file.getName());

node.setLeaf(isLeaf);

node.setLevel(level);

node.setParent(parent);

session.save(node);

//进行循环迭代子目录

File[] subFiles = file.listFiles();

if (subFiles != null &&subFiles.length > 0){

for (int i = 0; i <subFiles.length ; i++){

this.saveNode(subFiles[i],session, node, level + 1);

}}}

/**

* 输出树结构

*@param id

public void printNodeById(int id) {

Session session = null;

try {

session =HibernateUtils.getSession();

session.beginTransaction();

Node node =(Node)session.get(Node.class, 1);

printNode(node);

session.getTransaction().commit();

} catch (HibernateException e) {

e.printStackTrace();

session.getTransaction().rollback();

} finally {

HibernateUtils.closeSession(session);

}

private void printNode(Node node) {

if (node == null){ return; }

int level = node.getLevel();

if (level > 0){

for (int i = 0; i < level; i++){

System.out.print(" |");

}

System.out.print("--");

}

System.out.println(node.getName() +(node.isLeaf() ? "" : "[" + node.getChildren().size() +"]"));

Set children = node.getChildren();

for (Iterator iter = children.iterator();iter.hasNext(); ){

Node child = (Node)iter.next();

printNode(child);

}}}

第18课作业-学生、课程、分数的映射关系

一、设计

1、实体类(表)

2、导航(编程方便)

a) 通过学生取出学生所先的课程

b) 但是通过课程取出学该课程的学生不好。学的学生太多

c) 确定编程的方式

3、可以利用联合主键映射可以，

a) 学生生成一个表

b) 课程生成一个表

c) 再生成一个表，主键是联合主键(学生ID、课程ID) + 学生共生成一个表

4、也可以利用一对多，多对多都可以(推荐)

a) 学生生成一个表

b) 课程生成一个表

c) 分数生成一个表，并且有两个外键，分别指向学生、课程表

二、代码：

* 课程

@Entity

public class Course {

private int id;

private String name;

@Id

@GeneratedValue

public int getId() {return id;}

public void setId(int id) { this.id = id;}

public String getName() {return name;}

public void setName(Stringname) {this.name = name;}}

* 分数

@Entity

@Table(name = "score")

public class Score {

private int id;

private int score;

private Student student;

private Course course;

@Id

@GeneratedValue

public int getId() {return id;}

@ManyToOne

@JoinColumn(name = "student_id")

public StudentgetStudent() {return student;}

@ManyToOne

@JoinColumn(name = "score_id")

public Course getCourse(){ return course;}

public int getScore() { return score;}

public void setScore(int score) {this.score = score;}

public void setStudent(Studentstudent) {this.student = student;}

public void setCourse(Coursecourse) {this.course = course;}

public void setId(int id) { this.id = id;}}

* 学生通过课程可以导航到分数

@Entity

public class Student {

private int id;

private String name;

private Set<Course> courses = newHashSet<Course>();

@Id

@GeneratedValue

public int getId() {return id;}

@ManyToMany

@JoinTable(name = "score", //此表就是Score实体类在数据库生成的表叫score

joinColumns= @JoinColumn(name = "student_id"),

inverseJoinColumns= @JoinColumn(name = "course_id")

)

public Set<Course>getCourses() {return courses;}

public voidsetCourses(Set<Course> courses) {this.courses = courses;}

public void setId(int id) { this.id = id;}

public String getName() {return name;}

public void setName(Stringname) {this.name = name;}}

三、注意

在Student实体类中的使用的第三方表使用了两个字段，而hibernate会使这两个字段生成联合主键，这并不是我们需要的结果，因为我们需要手动到数据库中修改。这样才可以存储数据，否则数据存储不进去。这可能是hibernate的一个小bu

————————————————————————————————————————————————————

树状结构（重点）

面向对象的模型：这么去做映射----> 再去做增删改查

package com.demo.hibernate;import java.util.HashSet;import java.util.Set;import javax.persistence.CascadeType;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;@Entitypublic class Org {private int id;private String name;private Set<Org> chirden = new HashSet<Org>();private Org parent;@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;}//@OneToMany(cascade=CascadeType.ALL,mappedBy="parent",fetch=FetchType.EAGER)  //设置对手Org @ManyToOne 的那个字段 即 parent  @OneToMany(cascade=CascadeType.ALL,mappedBy="parent")  //设置对手Org @ManyToOne 的那个字段 即 parentpublic Set<Org> getChirden() {return chirden;}public void setChirden(Set<Org> chirden) {this.chirden = chirden;}@ManyToOne@JoinColumn(name="parent_id")public Org getParent() {return parent;}public void setParent(Org parent) {this.parent = parent;}}

@Testpublic void testSaveOrg() {Org o = new Org();o.setName("总公司");Org o1 = new Org();o1.setName("分公司1");Org o2 = new Org();o2.setName("分公司2");Org o11 = new Org();o11.setName("分公司1下部门1");Org o12 = new Org();o12.setName("分公司1下部门2");o.getChirden().add(o1);o.getChirden().add(o2);o1.getChirden().add(o11);o1.getChirden().add(o12);o11.setParent(o1);o12.setParent(o1);o1.setParent(o);o2.setParent(o);Session session = sf.getCurrentSession();session.beginTransaction();/*session.save(o);  第一种存储session.save(o1);session.save(o2);session.save(o11);session.save(o12);*///第二种存储 @OneToMany(cascade=CascadeType.ALL,mappedBy="parent") 用级联session.save(o);session.getTransaction().commit();}@Testpublic void testLoad() {testSaveOrg();Session session = sf.getCurrentSession();session.beginTransaction();Org o = (Org)session.load(Org.class, 1);//fetch=FetchType.EAGER  读取的时候可以 但是打印还是要写递归,如果这个树非常大就不合适用EAGER了，树大用ajax，远程异步的访问print(o,0); //0 是从根节点开始读取session.getTransaction().commit();}// 树的递归private void print(Org o,int level) {String preStr = "";for(int i=0; i<level; i++) {preStr += "====";}System.out.println(preStr + o.getName());for(Org child : o.getChirden()) {print(child,level+1);}}

作业-学生、课程、分数的映射关系

一、设计

1、实体类(表)

2、导航(编程方便)

a) 通过学生取出学生所先的课程

b) 但是通过课程取出学该课程的学生不好。学的学生太多

c) 确定编程的方式

3、可以利用联合主键映射可以，

a) 学生生成一个表

b) 课程生成一个表

c) 再生成一个表，主键是联合主键(学生ID、课程ID) + 学生共生成一个表

4、也可以利用一对多，多对多都可以(推荐)

a) 学生生成一个表

b) 课程生成一个表

c) 分数生成一个表，并且有两个外键，分别指向学生、课程表

————————————————————————————————————————————————————————————————

create table score (        id int primary key auto_increment,        score int,        course_id int references course(id),        student_id int references student(id)    )

package com.demo.hibernate;import java.util.HashSet;import java.util.Set;import javax.persistence.Entity;import javax.persistence.GeneratedValue;import javax.persistence.Id;import javax.persistence.JoinColumn;import javax.persistence.JoinTable;import javax.persistence.ManyToMany;@Entitypublic class Student {private int id;private String name;private Set<Course> courses = new HashSet<Course>();@ManyToMany@JoinTable(name = "score",            joinColumns = @JoinColumn(name="student_id"),        inverseJoinColumns = @JoinColumn(name="course_id")    )/* 生成表语句有问题 * 手动插入 * create table score (        id int primary key auto_increment,        score int,        course_id int references course(id),        student_id int references student(id)    ) *  * */public Set<Course> getCourses() {return courses;}public void setCourses(Set<Course> courses) {this.courses = courses;}@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;}}

package com.demo.hibernate;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="score")public class Score {private int id;private int score;private Student student;private Course course;@Id@GeneratedValuepublic int getId() {return id;}public void setId(int id) {this.id = id;}public int getScore() {return score;}public void setScore(int score) {this.score = score;}@ManyToOne@JoinColumn(name="student_id")public Student getStudent() {return student;}public void setStudent(Student student) {this.student = student;}@ManyToOne@JoinColumn(name="course_id")public Course getCourse() {return course;}public void setCourse(Course course) {this.course = course;}}

package com.demo.hibernate;import javax.persistence.Entity;import javax.persistence.GeneratedValue;import javax.persistence.Id;@Entitypublic class Course {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;}}

@Testpublic void testSave() {Student s = new Student();s.setName("lishi");Course c = new Course();c.setName("java");Score score = new Score();score.setScore(100);score.setStudent(s);score.setCourse(c);Session session = sf.getCurrentSession();session.beginTransaction();session.save(s);session.save(c);session.save(score);session.getTransaction().commit();}@Testpublic void testLoad() {testSave();Session session = sf.getCurrentSession();session.beginTransaction();Student s = (Student)session.load(Student.class, 1);for(Course c : s.getCourses()) {System.out.println(c.getName());}session.getTransaction().commit();}

第19课 Hibernate查询(Query Language)

HQL VS EJBQL

一、 Hibernate可以使用的查询语言

1、 NativeSQL：本地语言(数据库自己的SQL语句)

2、 HQL ：Hibernate自带的查询语句，可以使用HQL语言，转换成具体的方言

3、 EJBQL：JPQL 1.0，可以认为是HQL的一个子节(重点)

4、 QBC：Query By Cretira

5、 QBE：Query By Example

注意：上面的功能是从1至5的比较，1的功能最大，5的功能最小

二、实例一

1、版块

/** 版块*/

@Entity

public class Category {

private int id;

private String name;

@Id

@GeneratedValue

public int getId() {return id;}

public void setId(int id) {this.id = id;}

public String getName() {return name;}

public void setName(Stringname) {this.name = name;}}

2、主题

/**主题*/

@Entity

public class Topic {

private int id;

private String title;

private Category category;

//private Category category2;

private Date createDate;

public DategetCreateDate() {return createDate;}

public void setCreateDate(DatecreateDate) {this.createDate = createDate;}

@ManyToOne(fetch=FetchType.LAZY)

public CategorygetCategory() { return category;}

public voidsetCategory(Category category) {this.category = category; }

@Id

@GeneratedValue

public int getId() {return id;}

public void setId(int id) {this.id = id;}

public String getTitle(){return title;}

public void setTitle(Stringtitle) {this.title = title;}}

3、主题回复

/**主题回复*/

@Entity

public class Msg {

private int id;

private String cont;

private Topic topic;

@ManyToOne

public Topic getTopic() {return topic;}

public void setTopic(Topictopic) {this.topic = topic;}

@Id

@GeneratedValue

public int getId() {return id;}

public void setId(int id) {this.id = id;}

public String getCont() {return cont;}

public void setCont(Stringcont) {this.cont = cont;}}

4、临时类

/**临时类 */

public class MsgInfo { //VO DTO Value Object username p1 p2UserInfo->User->DB

private int id;

private String cont;

private String topicName;

private String categoryName;

public MsgInfo(int id, String cont,String topicName, String categoryName) {

super();

this.id = id;

this.cont = cont;

this.topicName = topicName;

this.categoryName =categoryName;

}

public StringgetTopicName() {return topicName;}

public voidsetTopicName(String topicName) {this.topicName = topicName;}

public StringgetCategoryName() {return categoryName;}

public voidsetCategoryName(String categoryName) {

this.categoryName =categoryName;

}

public int getId() {return id;}

public void setId(int id) {this.id = id;}

public String getCont() {return cont;}

public void setCont(Stringcont) {this.cont = cont;}}

三、实体一测试代码：

//初始化数据

@Test

public void testSave() {

Sessionsession = sf.openSession();

session.beginTransaction();

for(int i=0; i<10; i++){

Categoryc = new Category();

c.setName("c" + i);

session.save(c);

}

for(int i=0; i<10; i++){

Categoryc = new Category();

c.setId(1);

Topic t= new Topic();

t.setCategory(c);

t.setTitle("t" + i);

t.setCreateDate(new Date());

session.save(t);

}

for(int i=0; i<10; i++){

Topic t= new Topic();

t.setId(1);

Msg m = new Msg();

m.setCont("m" + i);

m.setTopic(t);

session.save(m);

}

session.getTransaction().commit();

session.close();

}

/** QL:from + 实体类名称 */

Query q = session.createQuery("from Category");

List<Category>categories = (List<Category>)q.list();

for(Category c : categories) {

System.out.println(c.getName());

}

/* 可以为实体类起个别名，然后使用它 */

Query q =session.createQuery("from Category c wherec.name > 'c5'");

List<Category>categories = (List<Category>)q.list();

for(Category c : categories) {

System.out.println(c.getName());

}

//排序

Query q =session.createQuery("from Category c orderby c.name desc");

List<Category>categories = (List<Category>)q.list();

for(Category c : categories) {

System.out.println(c.getName());

}

* 为加载上来的对象属性起别名，还可以使用

Query q =session.createQuery("select distinct c fromCategory c order by c.name desc");

List<Category>categories = (List<Category>)q.list();

for(Category c : categories) {

System.out.println(c.getName());

}

/*Query q = session.createQuery("from Category c where c.id > :minand c.id < :max");

//q.setParameter("min",2);

//q.setParameter("max",8);

q.setInteger("min",2);

q.setInteger("max",8);*/

* 可以使用冒号(：),作为占位符，来接受参数使用。如下(链式编程)

Query q =session.createQuery("from Category c wherec.id > :min and c.id < :max")

.setInteger("min", 2)

.setInteger("max", 8);

List<Category>categories = (List<Category>)q.list();

for(Category c : categories) {

System.out.println(c.getId()+ "-" + c.getName());

}

Query q =session.createQuery("from Category c wherec.id > ? and c.id < ?");

q.setParameter(0, 2)

.setParameter(1, 8);

// q.setParameter(1, 8);

List<Category>categories = (List<Category>)q.list();

for(Category c : categories) {

System.out.println(c.getId()+ "-" + c.getName());

}

//分页

Query q =session.createQuery("from Category c orderby c.name desc");

q.setMaxResults(4);//每页显示的最大记录数

q.setFirstResult(2);//从第几条开始显示，从0开始

List<Category>categories = (List<Category>)q.list();

for(Category c : categories) {

System.out.println(c.getId()+ "-" + c.getName());

}

Query q =session.createQuery("select c.id, c.name from Category c order by c.namedesc");

List<Object[]>categories = (List<Object[]>)q.list();

for(Object[] o : categories) {

System.out.println(o[0] + "-" + o[1]);

}

//设定fetch type 为lazy后将不会有第二条sql语句

Query q =session.createQuery("from Topic t where t.category.id= 1");

List<Topic>topics = (List<Topic>)q.list();

for(Topic t : topics) {

System.out.println(t.getTitle());

//System.out.println(t.getCategory().getName());

}

//设定fetch type 为lazy后将不会有第二条sql语句

Query q =session.createQuery("from Topic t wheret.category.id = 1");

List<Topic>topics = (List<Topic>)q.list();

for(Topic t : topics) {

System.out.println(t.getTitle());

}

Query q =session.createQuery("from Msg m wherem.topic.category.id = 1");

for(Object o : q.list()) {

Msg m = (Msg)o;

System.out.println(m.getCont());

}

//了解即可

//VO Value Object

//DTO data transfer object

Query q =session.createQuery("select newcom.bjsxt.hibernate.MsgInfo(m.id, m.cont, m.topic.title, m.topic.category.name)from Msg");

for(Object o : q.list()) {

MsgInfo m = (MsgInfo)o;

System.out.println(m.getCont());

}

//动手测试left right join

//为什么不能直接写Category名，而必须写t.category

//因为有可能存在多个成员变量（同一个类），需要指明用哪一个成员变量的连接条件来做连接

Query q =session.createQuery("select t.title, c.namefrom Topic t join t.category c "); //join Category c

for(Object o : q.list()) {

Object[] m = (Object[])o;

System.out.println(m[0] + "-" + m[1]);

}

//学习使用uniqueResult

Query q =session.createQuery("from Msg m where m =:MsgToSearch "); //不重要

Msgm = new Msg();

m.setId(1);

q.setParameter("MsgToSearch", m);

Msg mResult =(Msg)q.uniqueResult();

System.out.println(mResult.getCont());

Query q =session.createQuery("select count(*) fromMsg m");

long count = (Long)q.uniqueResult();

System.out.println(count);

Query q = session.createQuery("select max(m.id), min(m.id), avg(m.id), sum(m.id)from Msg m");

Object[] o =(Object[])q.uniqueResult();

System.out.println(o[0] + "-" + o[1] + "-" + o[2] + "-" + o[3]);

Query q = session.createQuery("from Msg m where m.id between 3 and 5");

for(Object o : q.list()) {

Msg m = (Msg)o;

System.out.println(m.getId()+ "-" + m.getCont());

}

Query q =session.createQuery("from Msg m where m.idin (3,4, 5)");

for(Object o : q.list()) {

Msg m = (Msg)o;

System.out.println(m.getId()+ "-" + m.getCont());

}

//is null 与 is notnull

Query q =session.createQuery("from Msg m where m.contis not null");

for(Object o : q.list()) {

Msg m = (Msg)o;

System.out.println(m.getId()+ "-" + m.getCont());

}

四、实例二

注意：实体二，实体类，只是在实体一的基础上修改了Topic类，添加了多对一的关联关系

@Entity

@NamedQueries({

@NamedQuery(name="topic.selectCertainTopic", query="from Topic t where t.id = :id")

})

/*@NamedNativeQueries(

{

@NamedNativeQuery(name="topic.select2_5Topic",query="select * from topic limit 2, 5")

})*/

public class Topic {

private int id;

private String title;

private Category category;

private Date createDate;

private List<Msg> msgs = newArrayList<Msg>();

@OneToMany(mappedBy="topic")

public List<Msg> getMsgs() {return msgs;}

public void setMsgs(List<Msg> msgs) {this.msgs = msgs;}

public Date getCreateDate() {return createDate;}

public void setCreateDate(Date createDate) {this.createDate = createDate; }

@ManyToOne(fetch=FetchType.LAZY)

public Category getCategory() { return category;}

public void setCategory(Category category) {this.category = category;}

@Id

@GeneratedValue

public int getId() {return id;}

public void setId(int id) {this.id = id;}

public String getTitle() { return title;}

public void setTitle(String title) {this.title = title;}}

五、实例二测试代码

注意：测试数据是实例一的测试数据

//is empty and is not empty

Query q =session.createQuery("from Topic t wheret.msgs is empty");

for(Object o : q.list()) {

Topic t = (Topic)o;

System.out.println(t.getId()+ "-" + t.getTitle());

}

Query q =session.createQuery("from Topic t wheret.title like '%5'");

for(Object o : q.list()) {

Topic t = (Topic)o;

System.out.println(t.getId()+ "-" + t.getTitle());

}

Query q =session.createQuery("from Topic t wheret.title like '_5'");

for(Object o : q.list()) {

Topic t = (Topic)o;

System.out.println(t.getId()+ "-" + t.getTitle());

}

//不重要

Query q =session.createQuery("selectlower(t.title)," +

"upper(t.title)," +

"trim(t.title)," +

"concat(t.title,'***')," +

"length(t.title)" +

" from Topict ");

for(Object o : q.list()) {

Object[] arr =(Object[])o;

System.out.println(arr[0] + "-" + arr[1] + "-" + arr[2] + "-" + arr[3] + "-" + arr[4] + "-");

}

Query q =session.createQuery("select abs(t.id)," +

"sqrt(t.id)," +

"mod(t.id,2)" +

" from Topict ");

for(Object o : q.list()) {

Object[] arr = (Object[])o;

System.out.println(arr[0] + "-" + arr[1] + "-" + arr[2] );

}

Query q = session.createQuery("selectcurrent_date, current_time, current_timestamp, t.id from Topic t");

for(Object o : q.list()) {

Object[] arr =(Object[])o;

System.out.println(arr[0] + " | " + arr[1] + " | " + arr[2] + " | " + arr[3]);

}

Query q =session.createQuery("from Topic t wheret.createDate < :date");

q.setParameter("date", new Date());

for(Object o : q.list()) {

Topic t = (Topic)o;

System.out.println(t.getTitle());

}

Query q =session.createQuery("select t.title,count(*) from Topic t group by t.title") ;

for(Object o : q.list()) {

Object[] arr =(Object[])o;

System.out.println(arr[0] + "|" + arr[1]);

}

Query q = session.createQuery("selectt.title, count(*) from Topic t group by t.title having count(*) >= 1") ;

for(Object o : q.list()) {

Object[] arr =(Object[])o;

System.out.println(arr[0] + "|" + arr[1]);

}

Query q =session.createQuery("from Topic t where t.id< (select avg(t.id) from Topic t)") ;

for(Object o : q.list()) {

Topic t = (Topic)o;

System.out.println(t.getTitle());

}

Query q =session.createQuery("from Topic t where t.id< ALL (select t.id from Topic t where mod(t.id, 2)= 0) ") ;

for(Object o : q.list()) {

Topic t = (Topic)o;

System.out.println(t.getTitle());

}

//用in 可以实现exists的功能

//但是exists执行效率高

// t.id not in (1)

Query q =session.createQuery("from Topic t where notexists (select m.id from Msg m where m.topic.id=t.id)") ;

// Query q =session.createQuery("from Topic t where exists (select m.id from Msg mwhere m.topic.id=t.id)") ;

for(Object o : q.list()) {

Topic t = (Topic)o;

System.out.println(t.getTitle());

}

//update and delete

//规范并没有说明是不是要更新persistent object，所以如果要使用，建议在单独的trasaction中执行

Query q =session.createQuery("update Topic t sett.title = upper(t.title)") ;

q.executeUpdate();

q = session.createQuery("from Topic");

for(Object o : q.list()) {

Topic t = (Topic)o;

System.out.println(t.getTitle());

}

session.createQuery("update Topic t set t.title = lower(t.title)")

.executeUpdate();

//不重要

Query q =session.getNamedQuery("topic.selectCertainTopic");

q.setParameter("id", 5);

Topic t =(Topic)q.uniqueResult();

System.out.println(t.getTitle());

//Native（了解）

SQLQuery q =session.createSQLQuery("select *from category limit 2,4").addEntity(Category.class);

List<Category>categories = (List<Category>)q.list();

for(Category c : categories) {

System.out.println(c.getName());

}

public void testHQL_35() {

//尚未实现JPA命名的NativeSQL

}

——————————————————————————————————————————————————————————————————

以BBS为例子

package com.demo.hibernate;import javax.persistence.Entity;import javax.persistence.GeneratedValue;import javax.persistence.Id;// 模板@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;}}

package com.demo.hibernate;import java.util.ArrayList;import java.util.Date;import java.util.List;import javax.persistence.Entity;import javax.persistence.FetchType;import javax.persistence.GeneratedValue;import javax.persistence.Id;import javax.persistence.ManyToOne;import javax.persistence.NamedQueries;import javax.persistence.NamedQuery;import javax.persistence.OneToMany;/* * HQL语句支持使用英文问号（？）作为参数占位符，这与JDBC的参数占位符一致；也使用命名参数占位符号， * 方法在参数名前加英文冒号（：），例如:start_date等 * */@Entity// 取了名字的查询@NamedQueries(        {            @NamedQuery(name="topic.selectCertainTopic", query="from Topic t where t.id = :id")        }        )        /*@NamedNativeQueries(        {            @NamedNativeQuery(name="topic.select2_5Topic", query="select * from topic limit 2, 5")        }        )        */// 主题public class Topic {    private int id;    private String title;    private Category category;    private Date createDate;    private List<Msg> msgs = new ArrayList<Msg>();    @OneToMany(mappedBy="topic")    public List<Msg> getMsgs() {        return msgs;    }    public void setMsgs(List<Msg> msgs) {        this.msgs = msgs;    }    @Id    @GeneratedValue    public int getId() {        return id;    }    public void setId(int id) {        this.id = id;    }    public String getTitle() {        return title;    }    public void setTitle(String title) {        this.title = title;    }        @ManyToOne(fetch=FetchType.LAZY)    public Category getCategory() {        return category;    }    public void setCategory(Category category) {        this.category = category;    }    public Date getCreateDate() {        return createDate;    }    public void setCreateDate(Date createDate) {        this.createDate = createDate;    }   }

package com.demo.hibernate;import javax.persistence.Entity;import javax.persistence.GeneratedValue;import javax.persistence.Id;import javax.persistence.ManyToOne;// 回复跟帖信息数@Entitypublic class Msg {private int id;private String count;private Topic topic;@Id@GeneratedValuepublic int getId() {return id;}public void setId(int id) {this.id = id;}public String getCount() {return count;}public void setCount(String count) {this.count = count;}@ManyToOnepublic Topic getTopic() {return topic;}public void setTopic(Topic topic) {this.topic = topic;}}

package com.demo.hibernate;import javax.persistence.Entity;// 回复信息统计public class MsgInfo {private int id;private String count;private String topicName;private String categoryName;public MsgInfo(int id, String count, String topicName, String categoryName) {super();this.id = id;this.count = count;this.topicName = topicName;this.categoryName = categoryName;}public int getId() {return id;}public void setId(int id) {this.id = id;}public String getCount() {return count;}public void setCount(String count) {this.count = count;}public String getTopicName() {return topicName;}public void setTopicName(String topicName) {this.topicName = topicName;}public String getCategoryName() {return categoryName;}public void setCategoryName(String categoryName) {this.categoryName = categoryName;}}

package com.demo.hibernate;import java.util.Date;import java.util.List;import java.util.Map;import java.util.Set;import javax.persistence.CascadeType;import javax.persistence.FetchType;import javax.persistence.OneToMany;import org.hibernate.Query;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.cfg.AnnotationConfiguration;import org.hibernate.tool.hbm2ddl.SchemaExport;import org.junit.AfterClass;import org.junit.BeforeClass;import org.junit.Test;public class HibernateTreeTest {private static SessionFactory sf = null;@BeforeClasspublic static void beforClass() {  //new SchemaExport(new AnnotationConfiguration().configure()).create(false, true); //自动创建SQL语句try {sf = new AnnotationConfiguration().configure().buildSessionFactory();} catch (Exception e) {e.printStackTrace();}}@AfterClasspublic static void afterClass() {sf.close();}@Testpublic void testSchemaExport() {  //生成建表语句//new SchemaExport(new AnnotationConfiguration().configure()).create(false, true); //自动创建SQL语句}@Testpublic void testSave() {Session session = sf.openSession();session.beginTransaction();// 存入10个板块for(int i=0; i<10; i++) {Category c = new Category();c.setName("c"+i);session.save(c);}//在c1板块下面，又有10个主题for(int i=0; i<10; i++) {Category c = new Category();c.setId(1);Topic t = new Topic();t.setCategory(c);t.setTitle("t" + i);t.setCreateDate(new Date());session.save(t);}// 在t1 在这个主题下面有又10个回复信息for(int i=0; i<10; i++) {Topic t = new Topic();t.setId(1);Msg m = new Msg();m.setCount("m" + i);m.setTopic(t);session.save(m);}session.getTransaction().commit();session.close();}@Testpublic void testHQL_01() {Session session = sf.getCurrentSession();session.beginTransaction();Query q =  session.createQuery("from Category");List<Category> categories = (List<Category>)q.list();for(Category c : categories) {System.out.println(c.getName());}session.getTransaction().commit();}@Testpublic void testHQL_02() {Session session = sf.getCurrentSession();session.beginTransaction();Query q =  session.createQuery("from Category c where c.name > 'c5'");List<Category> categories = (List<Category>)q.list();for(Category c : categories) {System.out.println(c.getName());}session.getTransaction().commit();}@Testpublic void testHQL_03() {Session session = sf.getCurrentSession();session.beginTransaction();Query q =  session.createQuery("from Category c order by c.name desc");List<Category> categories = (List<Category>)q.list();for(Category c : categories) {System.out.println(c.getName());}session.getTransaction().commit();}@Testpublic void testHQL_04() {Session session = sf.getCurrentSession();session.beginTransaction();Query q =  session.createQuery("select distinct c from Category c order by c.name desc");/*SQL SELECT DISTINCT 语句在表中，可能会包含重复值。这并不成问题，不过，有时您也许希望仅仅列出不同（distinct）的值。关键词 DISTINCT 用于返回唯一不同的值。*/List<Category> categories = (List<Category>)q.list();for(Category c : categories) {System.out.println(c.getName());}session.getTransaction().commit();}@Testpublic void testHQL_05() {Session session = sf.openSession();session.beginTransaction();/*Query q = session.createQuery("from Category c where c.id > :min and c.id < :max");//q.setParameter("min", 2);//q.setParameter("max", 8);q.setInteger("min", 2);q.setInteger("max", 8);*/Query q = session.createQuery("from Category c where c.id > :min and c.id < :max").setInteger("min", 2).setInteger("max", 8);  //下标值大于2开始取值到第8个idList<Category> categories = (List<Category>)q.list();for(Category c : categories) {System.out.println(c.getId() + "-" + c.getName());}session.getTransaction().commit();session.close();}//分页@Testpublic void testHQL_07() {Session session = sf.openSession();session.beginTransaction();Query q = session.createQuery("from Category c order by c.name desc");  //降序q.setMaxResults(4);// 设置检索的行数q.setFirstResult(2);  //设置开始检索位置List<Category> categories = (List<Category>)q.list();for(Category c : categories) {System.out.println(c.getId() + "-" + c.getName());}session.getTransaction().commit();session.close();}@Testpublic void testHQL_08() {Session session = sf.openSession();session.beginTransaction();Query q = session.createQuery("select c.id,  c.name from Category c order by c.name desc");List<Object[]> categories = (List<Object[]>)q.list();for(Object[] o : categories) {System.out.println(o[0] + "-" + o[1]);}session.getTransaction().commit();session.close();}//设定fetch type 为lazy后将不会有第二条sql语句@Testpublic void testHQL_09() {Session session = sf.openSession();session.beginTransaction();Query q = session.createQuery("from Topic t where t.category.id = 1");List<Topic> topics = (List<Topic>)q.list();for(Topic t : topics) {//System.out.println(t.getTitle());System.out.println(t.getCategory().getName());}session.getTransaction().commit();session.close();}//设定fetch type 为lazy后将不会有第二条sql语句@Testpublic void testHQL_10() {Session session = sf.openSession();session.beginTransaction();Query q = session.createQuery("from Topic t where t.category.id = 1");List<Topic> topics = (List<Topic>)q.list();for(Topic t : topics) {System.out.println(t.getTitle());}session.getTransaction().commit();session.close();}@Testpublic void testHQL_11() {Session session = sf.openSession();session.beginTransaction();Query q = session.createQuery("from Msg m where m.topic.category.id = 1");for(Object o : q.list()) {Msg m = (Msg)o;System.out.println(m.getCount());}session.getTransaction().commit();session.close();}//了解即可//VO Value Object//DTO data transfer object@Testpublic void testHQL_12() {Session session = sf.openSession();session.beginTransaction();Query q = session.createQuery("select new com.demo.hibernate.MsgInfo(m.id, m.count, m.topic.title, m.topic.category.name) from Msg m");//前提必须是在MsgInfo里面有一个构造方法for(Object o : q.list()) {MsgInfo m = (MsgInfo)o;System.out.println(m.getId()+"--"+m.getCount()+"--"+m.getTopicName()+"--"+m.getCategoryName());}session.getTransaction().commit();session.close();}//动手测试left right join//为什么不能直接写Category名，而必须写t.category//因为有可能存在多个成员变量（同一个类），需要指明用哪一个成员变量的连接条件来做连接@Testpublic void testHQL_13() {Session session = sf.openSession();session.beginTransaction();Query q = session.createQuery("select t.title, c.name from Topic t join t.category c "); //join Category cfor(Object o : q.list()) {Object[] m = (Object[])o;System.out.println(m[0] + "-" + m[1]);}session.getTransaction().commit();session.close();}//学习使用uniqueResult@Testpublic void testHQL_14() {Session session = sf.openSession();session.beginTransaction();Query q = session.createQuery("from Msg m where m = :MsgToSearch "); //不重要Msg m = new Msg();m.setId(1);q.setParameter("MsgToSearch", m);Msg mResult = (Msg)q.uniqueResult();System.out.println(mResult.getCount());session.getTransaction().commit();session.close();}@Testpublic void testHQL_15() {Session session = sf.openSession();session.beginTransaction();Query q = session.createQuery("select count(*) from Msg m");long count = (Long)q.uniqueResult();System.out.println(count);session.getTransaction().commit();session.close();}@Testpublic void testHQL_16() {Session session = sf.openSession();session.beginTransaction();Query q = session.createQuery("select max(m.id), min(m.id), avg(m.id), sum(m.id) from Msg m");Object[] o = (Object[])q.uniqueResult();System.out.println(o[0] + "-" + o[1] + "-" + o[2] + "-" + o[3]);  //数组分别代表查询的第几个数session.getTransaction().commit();session.close();}@Testpublic void testHQL_17() {Session session = sf.openSession();session.beginTransaction();Query q = session.createQuery("from Msg m where m.id between 3 and 5");for(Object o : q.list()) {Msg m = (Msg)o;System.out.println(m.getId() + "-" + m.getCount());}session.getTransaction().commit();session.close();}@Testpublic void testHQL_18() {Session session = sf.openSession();session.beginTransaction();Query q = session.createQuery("from Msg m where m.id in (3,4, 5)");for(Object o : q.list()) {Msg m = (Msg)o;System.out.println(m.getId() + "-" + m.getCount());}session.getTransaction().commit();session.close();}//is null 与 is not null@Testpublic void testHQL_19() {Session session = sf.openSession();session.beginTransaction();Query q = session.createQuery("from Msg m where m.count is not null");for(Object o : q.list()) {Msg m = (Msg)o;System.out.println(m.getId() + "-" + m.getCount());}session.getTransaction().commit();session.close();}public static void main(String[] args) {beforClass();}}

package com.demo.hibernate;import java.util.ArrayList;import java.util.Date;import java.util.List;import javax.persistence.Entity;import javax.persistence.FetchType;import javax.persistence.GeneratedValue;import javax.persistence.Id;import javax.persistence.ManyToOne;import javax.persistence.NamedQueries;import javax.persistence.NamedQuery;import javax.persistence.OneToMany;/* * HQL语句支持使用英文问号（？）作为参数占位符，这与JDBC的参数占位符一致；也使用命名参数占位符号， * 方法在参数名前加英文冒号（：），例如:start_date等 * */@Entity// 取了名字的查询@NamedQueries({@NamedQuery(name="topic.selectCertainTopic", query="from Topic t where t.id = :id")})/*@NamedNativeQueries({@NamedNativeQuery(name="topic.select2_5Topic", query="select * from topic limit 2, 5")})*/// 主题public class Topic {private int id;private String title;private Category category;private Date createDate;private List<Msg> msgs = new ArrayList<Msg>();@OneToMany(mappedBy="topic")public List<Msg> getMsgs() {return msgs;}public void setMsgs(List<Msg> msgs) {this.msgs = msgs;}@Id@GeneratedValuepublic int getId() {return id;}public void setId(int id) {this.id = id;}public String getTitle() {return title;}public void setTitle(String title) {this.title = title;}@ManyToOne(fetch=FetchType.LAZY)public Category getCategory() {return category;}public void setCategory(Category category) {this.category = category;}public Date getCreateDate() {return createDate;}public void setCreateDate(Date createDate) {this.createDate = createDate;}}

QBC

package com.demo.hibernate;import java.util.Date;import org.hibernate.Criteria;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.cfg.AnnotationConfiguration;import org.hibernate.criterion.Restrictions;import org.junit.AfterClass;import org.junit.BeforeClass;import org.junit.Test;public class HibernateTreeTest {private static SessionFactory sf = null;@BeforeClasspublic static void beforClass() {  //new SchemaExport(new AnnotationConfiguration().configure()).create(false, true); //自动创建SQL语句try {sf = new AnnotationConfiguration().configure().buildSessionFactory();} catch (Exception e) {e.printStackTrace();}}@AfterClasspublic static void afterClass() {sf.close();}@Testpublic void testSchemaExport() {  //生成建表语句//new SchemaExport(new AnnotationConfiguration().configure()).create(false, true); //自动创建SQL语句}@Testpublic void testSave() {Session session = sf.openSession();session.beginTransaction();// 存入10个板块for(int i=0; i<10; i++) {Category c = new Category();c.setName("c"+i);session.save(c);}//在c1板块下面，又有10个主题for(int i=0; i<10; i++) {Category c = new Category();c.setId(1);Topic t = new Topic();t.setCategory(c);t.setTitle("t" + i);t.setCreateDate(new Date());session.save(t);}// 在t1 在这个主题下面有又10个回复信息for(int i=0; i<10; i++) {Topic t = new Topic();t.setId(1);Msg m = new Msg();m.setCount("m" + i);m.setTopic(t);session.save(m);}session.getTransaction().commit();session.close();}//is empty and is not empty@Testpublic void testQBC() {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 ;//DetachedCriterea 自己创建 完了之后绑定到session上面for(Object o : c.list()) {Topic t = (Topic)o;System.out.println(t.getId() + "-" + t.getTitle());}session.getTransaction().commit();session.close();}public static void main(String[] args) {beforClass();}}

QBE

package com.demo.hibernate;import java.util.Date;import org.hibernate.Criteria;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.cfg.AnnotationConfiguration;import org.hibernate.criterion.Example;import org.hibernate.criterion.Restrictions;import org.junit.AfterClass;import org.junit.BeforeClass;import org.junit.Test;public class HibernateTreeTest {private static SessionFactory sf = null;@BeforeClasspublic static void beforClass() {  //new SchemaExport(new AnnotationConfiguration().configure()).create(false, true); //自动创建SQL语句try {sf = new AnnotationConfiguration().configure().buildSessionFactory();} catch (Exception e) {e.printStackTrace();}}@AfterClasspublic static void afterClass() {sf.close();}@Testpublic void testSchemaExport() {  //生成建表语句//new SchemaExport(new AnnotationConfiguration().configure()).create(false, true); //自动创建SQL语句}@Testpublic void testSave() {Session session = sf.openSession();session.beginTransaction();// 存入10个板块for(int i=0; i<10; i++) {Category c = new Category();c.setName("c"+i);session.save(c);}//在c1板块下面，又有10个主题for(int i=0; i<10; i++) {Category c = new Category();c.setId(1);Topic t = new Topic();t.setCategory(c);t.setTitle("t" + i);t.setCreateDate(new Date());session.save(t);}// 在t1 在这个主题下面有又10个回复信息for(int i=0; i<10; i++) {Topic t = new Topic();t.setId(1);Msg m = new Msg();m.setCount("m" + i);m.setTopic(t);session.save(m);}session.getTransaction().commit();session.close();}//is empty and is not empty//query by criteria query by example@Testpublic void testQBE() {Session session = sf.openSession();session.beginTransaction();Topic tExample = new Topic();tExample.setTitle("T_");Example e = Example.create(tExample).ignoreCase().enableLike();  //ignoreCase 忽略大小写 使用likeCriteria 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();}public static void main(String[] args) {beforClass();}}

hibernate 3

第17课 hibernate树形结构(重点)

一、 节点实体类：

二、 xml方式：映射文件：

三、 annotation注解

四、 测试代码：

五、 相应的类代码：

第18课 作业-学生、课程、分数的映射关系

一、 设计

二、 代码：

三、 注意

作业-学生、课程、分数的映射关系

一、 设计

第19课 Hibernate查询(Query Language)

一、 Hibernate可以使用的查询语言

二、 实例一

三、 实体一测试代码：

四、 实例二

五、 实例二测试代码

一、节点实体类：

四、测试代码：

五、相应的类代码：

第18课作业-学生、课程、分数的映射关系

一、设计

二、代码：

三、注意

一、设计

二、实例一

三、实体一测试代码：

四、实例二

五、实例二测试代码