java：Hibernate框架3（使用Myeclipse逆向工程生成实体和配置信息，hql语句各种查询（使用hibernate执行原生SQL语句，占位符和命名参数，封装Vo查询多个属性，聚合函数，链接查询，命名查询），Criteria）

1.使用Myeclipse逆向工程生成实体和配置信息：

　　步骤1:配置MyEclipse Database Explorer：

　　步骤2:为项目添加hibernate的依赖：

　　此处打开后，点击next进入下个页面：

　　此处选择，主键自增，然后点击Finish：

2.hql语句各种查询：

　　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">udisk</property>
    <property name="connection.url">
        jdbc:mysql://localhost:3306/udisk
    </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="dialect">
        org.hibernate.dialect.MySQLDialect
    </property>
    <mapping resource="cn/zzsxt/entity/Fileinfo.hbm.xml" />
    <mapping resource="cn/zzsxt/entity/Userinfo.hbm.xml" />

</session-factory>

</hibernate-configuration>

　　Fileinfo:

package cn.zzsxt.entity;

import java.sql.Timestamp;


/**
 * Fileinfo entity. @author MyEclipse Persistence Tools
 */

public class Fileinfo  implements java.io.Serializable {


    // Fields    

     private Integer fileId;
     private Userinfo userinfo;
     private String fileName;
     private Timestamp uploadTime;
     private Long fileSize;
     private String fileCode;
     private String filePath;


    // Constructors

    /** default constructor */
    public Fileinfo() {
    }

    
    /** full constructor */
    public Fileinfo(Userinfo userinfo, String fileName, Timestamp uploadTime, Long fileSize, String fileCode, String filePath) {
        this.userinfo = userinfo;
        this.fileName = fileName;
        this.uploadTime = uploadTime;
        this.fileSize = fileSize;
        this.fileCode = fileCode;
        this.filePath = filePath;
    }

   
    // Property accessors

    public Integer getFileId() {
        return this.fileId;
    }
    
    public void setFileId(Integer fileId) {
        this.fileId = fileId;
    }

    public Userinfo getUserinfo() {
        return this.userinfo;
    }
    
    public void setUserinfo(Userinfo userinfo) {
        this.userinfo = userinfo;
    }

    public String getFileName() {
        return this.fileName;
    }
    
    public void setFileName(String fileName) {
        this.fileName = fileName;
    }

    public Timestamp getUploadTime() {
        return this.uploadTime;
    }
    
    public void setUploadTime(Timestamp uploadTime) {
        this.uploadTime = uploadTime;
    }

    public Long getFileSize() {
        return this.fileSize;
    }
    
    public void setFileSize(Long fileSize) {
        this.fileSize = fileSize;
    }

    public String getFileCode() {
        return this.fileCode;
    }
    
    public void setFileCode(String fileCode) {
        this.fileCode = fileCode;
    }

    public String getFilePath() {
        return this.filePath;
    }
    
    public void setFilePath(String filePath) {
        this.filePath = filePath;
    }


    @Override
    public String toString() {
        return "Fileinfo [fileId=" + fileId + ", fileName=" + fileName + ", uploadTime=" + uploadTime + ", fileSize="
                + fileSize + ", fileCode=" + fileCode + ", filePath=" + filePath + "]";
    }
   








}

　　Fileinfo.hbm.xml:

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<!-- 
    Mapping file autogenerated by MyEclipse Persistence Tools
-->
<hibernate-mapping>
    <class name="cn.zzsxt.entity.Fileinfo" table="fileinfo" catalog="udisk">
        <id name="fileId" type="java.lang.Integer">
            <column name="fileId" />
            <generator class="native" />
        </id>
        <many-to-one name="userinfo" class="cn.zzsxt.entity.Userinfo" fetch="select" lazy="false">
            <column name="userId" />
        </many-to-one>
        <property name="fileName" type="java.lang.String">
            <column name="fileName" length="100" />
        </property>
        <property name="uploadTime" type="java.sql.Timestamp">
            <column name="uploadTime" length="19" />
        </property>
        <property name="fileSize" type="java.lang.Long">
            <column name="fileSize" />
        </property>
        <property name="fileCode" type="java.lang.String">
            <column name="fileCode" />
        </property>
        <property name="filePath" type="java.lang.String">
            <column name="filePath" />
        </property>
    </class>
</hibernate-mapping>

　　Userinfo:

package cn.zzsxt.entity;

import java.util.HashSet;
import java.util.Set;

/**
 * Userinfo entity. @author MyEclipse Persistence Tools
 */

public class Userinfo implements java.io.Serializable {

    // Fields

    private Integer userId;
    private String userName;
    private String userPass;
    private Integer userType;
    private Set fileinfos = new HashSet(0);

    // Constructors

    /** default constructor */
    public Userinfo() {
    }

    /** full constructor */
    public Userinfo(String userName, String userPass, Integer userType, Set fileinfos) {
        this.userName = userName;
        this.userPass = userPass;
        this.userType = userType;
        this.fileinfos = fileinfos;
    }

    // Property accessors

    public Integer getUserId() {
        return this.userId;
    }

    public void setUserId(Integer userId) {
        this.userId = userId;
    }

    public String getUserName() {
        return this.userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String getUserPass() {
        return this.userPass;
    }

    public void setUserPass(String userPass) {
        this.userPass = userPass;
    }

    public Integer getUserType() {
        return this.userType;
    }

    public void setUserType(Integer userType) {
        this.userType = userType;
    }

    public Set getFileinfos() {
        return this.fileinfos;
    }

    public void setFileinfos(Set fileinfos) {
        this.fileinfos = fileinfos;
    }

}

　　Userinfo.hbm.xml:

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<!-- 
    Mapping file autogenerated by MyEclipse Persistence Tools
-->
<hibernate-mapping>
    <class name="cn.zzsxt.entity.Userinfo" table="userinfo" catalog="udisk">
        <id name="userId" type="java.lang.Integer">
            <column name="userId" />
            <generator class="native" />
        </id>
        <property name="userName" type="java.lang.String">
            <column name="userName" length="50" />
        </property>
        <property name="userPass" type="java.lang.String">
            <column name="userPass" length="50" />
        </property>
        <property name="userType" type="java.lang.Integer">
            <column name="userType" />
        </property>
        <set name="fileinfos" inverse="true">
            <key>
                <column name="userId" />
            </key>
            <one-to-many class="cn.zzsxt.entity.Fileinfo" />
        </set>
    </class>
    <query name="getAllUsers">
        <!-- hql语句 -->
        <![CDATA[
        from Userinfo
        ]]>
    </query>
</hibernate-mapping>

　　FileinfoVo:

package cn.zzsxt.vo;

public class FileinfoVo {
    private int fileId;
    private String fileName;
    private long fileSize;
    
    public FileinfoVo(int fileId, String fileName, long fileSize) {
        super();
        this.fileId = fileId;
        this.fileName = fileName;
        this.fileSize = fileSize;
    }
    
    public FileinfoVo() {
        super();
        // TODO Auto-generated constructor stub
    }

    public int getFileId() {
        return fileId;
    }
    public void setFileId(int fileId) {
        this.fileId = fileId;
    }
    public String getFileName() {
        return fileName;
    }
    public void setFileName(String fileName) {
        this.fileName = fileName;
    }
    public long getFileSize() {
        return fileSize;
    }
    public void setFileSize(long fileSize) {
        this.fileSize = fileSize;
    }
    
}

　　A.使用hibernate执行原生SQL语句(不推荐):

package cn.zzsxt.demo;

import java.util.List;

import org.hibernate.SQLQuery;
import org.hibernate.Session;

import cn.zzsxt.entity.Userinfo;
import cn.zzsxt.util.HibernateSessionFactory;

/**
 * 使用hibernate执行原生SQL语句(不推荐)
 * 使用SQLQuery执行sql语句
 * 使用Query执行HQL语句
 * 
 * @author Think
 *
 */
public class TestNativeSQL {
    public static void main(String[] args) {
        String sql="select * from userinfo";
        Session session = HibernateSessionFactory.getSession();
        SQLQuery sqlQuery = session.createSQLQuery(sql);
        sqlQuery.addEntity(Userinfo.class);//将查询出的记录封装成Userinfo类型的对象
        List<Userinfo> list = sqlQuery.list();
        for (Userinfo userinfo : list) {
            System.out.println(userinfo.getUserId()+"---"+userinfo.getUserName());
        }
        HibernateSessionFactory.closeSession();
    }

}

　　B.hql基本语句：

package cn.zzsxt.demo;

import java.util.List;

import org.hibernate.Query;
import org.hibernate.Session;

import cn.zzsxt.entity.Userinfo;
import cn.zzsxt.util.HibernateSessionFactory;

public class TestQuery1 {
    public static void main(String[] args) {
        //String sql="select * from userinfo ";
        //String hql="select u from Userinfo u";
//        String hql="from Userinfo";
//        String sql="select * from userinfo where userType=1";
//        String hql="from Userinfo where userType=1";
//        String sql="select * from userinfo where userId between 1 and 5";
//        String hql="from Userinfo where userId between 1 and 5";
//        String sql="select * from userinfo where userId in(3,4)";
//        String hql="from Userinfo where userId in(3,4)";
//        String sql="select * from userinfo where userName like '%zhang%'";
        String hql="from Userinfo where userName like '%zhang%'";
        Session session = HibernateSessionFactory.getSession();
        //创建Query对象，类似与PreparedStatement对象
        Query query = session.createQuery(hql);
        List<Userinfo> list = query.list();
        for (Userinfo userinfo : list) {
            System.out.println(userinfo.getUserId()+"--"+userinfo.getUserName()+"---"+userinfo.getUserType());
        }
        HibernateSessionFactory.closeSession();
    }
}

　　C.占位符和命名参数：

package cn.zzsxt.demo;

import java.util.List;

import org.hibernate.Query;
import org.hibernate.Session;

import cn.zzsxt.entity.Userinfo;
import cn.zzsxt.util.HibernateSessionFactory;
/**
 * 占位符(?):使用setXxx方法为占位符绑定值，占位符的下标从0开始。
 * 命名参数:使用自定义名称来代替占位符(?)，优点:可以解决占位符过多而导致的绑定时出现的错乱现象。
 * 定义命名参数:使用冒号(:)开头+自定义的参数的名称
 * from Userinfo where userName=:userName and userPass=:userPass
 * 
 * @author Think
 *
 */
public class TestQuery2 {
    public static void main(String[] args) {
    
        Session session = HibernateSessionFactory.getSession();
//        String sql="select * from userinfo where userName=? and userPass=?";
//        String hql="from Userinfo where userName=? and userPass=?";
//        //创建Query对象，类似与PreparedStatement对象
//        Query query = session.createQuery(hql);
//        //为占位符?绑定参数的值 query.setXxx(占位符的下标,绑定的值); 与PreparedStatement占位符的下标不同(PreparedStatement占位符的下标从1开始，Query占位符的下标从0开始)
//        query.setString(0, "zhangsan");
//        query.setString(1, "81dc9bdb52d04dc20036dbd8313ed055");
        String hql="from Userinfo where userName=:userName and userPass=:userPass";
        Query query = session.createQuery(hql);
        //为命名参数绑定值,去掉冒号
        query.setString("userName", "zhangsan");
        query.setString("userPass", "81dc9bdb52d04dc20036dbd8313ed055");
        //命名参数
        List<Userinfo> list = query.list();
        for (Userinfo userinfo : list) {
            System.out.println(userinfo.getUserId()+"--"+userinfo.getUserName()+"---"+userinfo.getUserType());
        }
        HibernateSessionFactory.closeSession();
    }
}

　　D：查询实体类中多个属性，需要封装Vo：

package cn.zzsxt.demo;

import java.util.List;

import org.hibernate.Query;
import org.hibernate.Session;

import cn.zzsxt.util.HibernateSessionFactory;
import cn.zzsxt.vo.FileinfoVo;
/**
 * Object[] objs = new Object[3];
    objs[0]=2;
    objs[1]="ajax原理.png";
    objs[2]=85356;
    list.add(objs);
    
    Object[] objs2 = new Object[3];
    objs2[0]=3;
    objs2[1]="MD5加密.txt";
    objs2[2]=85356;
    list.add(objs2);
 * 查询部分列数据:默认将每一行数据封装成Object[]进行返回
 *  
 * @author Think
 *
 */
public class TestQuery3 {
    /**
     * 查询部分列，返回将每行记录封装成Object[]
     */
    public static void test1(){
        Session session = HibernateSessionFactory.getSession();
//        String sql="select fileId,fileName,fileSize from fileinfo";
        String hql="select fileId,fileName,fileSize from Fileinfo";
        Query query = session.createQuery(hql);
        //错误:java.lang.ClassCastException
//        List<Fileinfo> list = query.list();
//        for (Fileinfo fileinfo : list) {
//            System.out.println(fileinfo.getFileId()+"---"+fileinfo.getFileName()+"---"+fileinfo.getFileSize());
//        }
        //查询部分列其返回值为list，list中包含是一个Object[]
        List<Object[]> list = query.list();
        for (Object[] objects : list) {
            System.out.println(objects[0]+"---"+objects[1]+"---"+objects[2]);
        }
        HibernateSessionFactory.closeSession();
    }
    
    /**
     * 将查询出的结果封装成VO(推荐)
     */
    public  static void test2(){
        Session session = HibernateSessionFactory.getSession();
        String hql="select new cn.zzsxt.vo.FileinfoVo(fileId,fileName,fileSize) from Fileinfo";
        Query query = session.createQuery(hql);
        List<FileinfoVo> list = query.list();
        for (FileinfoVo fileinfoVo : list) {
            System.out.println(fileinfoVo.getFileId()+"--"+fileinfoVo.getFileName()+"--"+fileinfoVo.getFileSize());
        }
    }
    
    public static void main(String[] args) {
        test2();
        
    }
}

　　E.聚合函数：

package cn.zzsxt.demo;

import java.util.List;

import org.hibernate.Query;
import org.hibernate.Session;

import cn.zzsxt.entity.Userinfo;
import cn.zzsxt.util.HibernateSessionFactory;
/*
 *  聚合函数(统计函数):
 *  max():最大值
 *  min():最小值
 *  avg():平均值
 *  sum():求和
 *  count():计数
 * 排序：order by 属性 asc|desc
     * asc:升序(默认)
     * desc：降序
 * 分组:group by
 * 分页:
 *  setFirstResult()
 *  setMaxResult()
 */
public class TestQuery4 {
    /**
     * 聚合函数
     * uniqueResult():执行查询结果唯一的方法
     */
    public static void test1(){
        Session session = HibernateSessionFactory.getSession();
//        String sql="select count(*) from userinfo";
//        String hql="select count(u) from Userinfo u";
        String hql="select max(u.userId) from Userinfo u";
        Query query = session.createQuery(hql);
//        List list = query.list();
//        System.out.println(list.get(0));
        //当结果唯一时可以使用uniqueResult()方法
        Object obj = query.uniqueResult();
        System.out.println(obj);
        HibernateSessionFactory.closeSession();
    }
    /**
     * 排序：order by 属性 asc|desc
     * asc:升序(默认)
     * desc：降序
     */
    public static void test2(){
        Session session = HibernateSessionFactory.getSession();
        String hql="from Userinfo order by userId desc";
        Query query = session.createQuery(hql);
        List<Userinfo> list = query.list();
        for (Userinfo userinfo : list) {
            System.out.println(userinfo.getUserId()+"--"+userinfo.getUserName());
        }
        HibernateSessionFactory.closeSession();
    }
    /**
     * 分组: group by 属性
     * 需求:查询用户类型的用户数量和用户类型
     */
    public static void test3(){
        Session session = HibernateSessionFactory.getSession();
        String hql="select count(u),u.userType from Userinfo u group by u.userType";
        Query query = session.createQuery(hql);
        List<Object[]> list=  query.list();
        for (Object[] objects : list) {
            System.out.println(objects[0]+"---"+objects[1]);
        }
        HibernateSessionFactory.closeSession();
    }
    
    /**
     * 分页:
     * setFirstResult(int beginRow):设置起始位置=(当前页-1)*分页单位
     * setMaxResult(int pageSize):设置分页单位
     */
    public static void test4(){
        Session session = HibernateSessionFactory.getSession();
        String hql="from Userinfo ";
        Query query = session.createQuery(hql);
        //设置起始位置=(当前页-1)*分页单位;
        query.setFirstResult(2);
        //设置分页单位
        query.setMaxResults(2);
        List<Userinfo> list = query.list();
        for (Userinfo userinfo : list) {
            System.out.println(userinfo.getUserId()+"---"+userinfo.getUserName());
        }
        HibernateSessionFactory.closeSession();
    }
    
    public static void main(String[] args) {
        test4();
    }
}

　　F.链接查询，左右连接查询：

package cn.zzsxt.demo;

import java.util.List;

import org.hibernate.Query;
import org.hibernate.Session;

import cn.zzsxt.entity.Fileinfo;
import cn.zzsxt.util.HibernateSessionFactory;
/*
 *链接查询:
 *1.等值链接查询:where子语句
 *2.链接查询:inner join(内连接)/left join(左连接) /right join(右连接)
 *子查询:将一个查询语句的结果作为另外一个查询语句的条件。所有用链接查询能实现的功能都可以使用子查询实现，但反之则不一定成立。
 *
 */
public class TestQuery5 {
    /**
     * 等值链接查询:where子语句
     */
    public static void test1(){
        Session session = HibernateSessionFactory.getSession();
//        String sql="SELECT f.* FROM userinfo u,fileinfo f WHERE u.userId=f.userId AND u.userName='zhangsan'";
        String hql="select f from Userinfo u,Fileinfo f where u.userId=f.userinfo.userId and u.userName='zhangsan'";
        Query query = session.createQuery(hql);
        List<Fileinfo> list = query.list();
        for (Fileinfo fileinfo : list) {
            System.out.println(fileinfo.getFileId()+"---"+fileinfo.getFileName());
        }
        HibernateSessionFactory.closeSession();
    }
    /**
     * 使用内连接查询:inner join
     */
    public static void test2(){
        Session session = HibernateSessionFactory.getSession();
//        String sql="SELECT f.* FROM userinfo u INNER JOIN fileinfo f ON(u.userId=f.userId) WHERE u.userName='zhangsan'";
        String hql="select f from Userinfo u inner join Fileinfo f on(u.userId=f.userinfo.userId) where u.userName='zhangsan'";
        Query query = session.createQuery(hql);
        List<Fileinfo> list = query.list();
        for (Fileinfo fileinfo : list) {
            System.out.println(fileinfo.getFileId()+"---"+fileinfo.getFileName());
        }
        HibernateSessionFactory.closeSession();
    }
    /**
     * 左连接: left join
     * 右连接: right join
     */
    public static void test3(){
        Session session = HibernateSessionFactory.getSession();
//        String sql="SELECT u.userName,f.* FROM userinfo u LEFT JOIN fileinfo f ON(u.userId=f.userId) ";
//        String hql="SELECT u.userName,f FROM Userinfo u LEFT JOIN Fileinfo f ON(u.userId=f.userinfo.userId) ";
//        String sql="SELECT u.userName,f.* FROM userinfo u RIGHT JOIN fileinfo f ON(u.userId=f.userId) ";
        String hql="SELECT u.userName,f FROM Userinfo u RIGHT JOIN Fileinfo f ON(u.userId=f.userinfo.userId) ";
        Query query = session.createQuery(hql);
        List<Object[]> list = query.list();
        for (Object[] objects : list) {
            
            System.out.println(objects[0]+"---"+objects[1]);
        }
        
        HibernateSessionFactory.closeSession();
    }
    /**
     * 子查询:
     * 查询用户名为zhangsan的所上传的文件信息
     */
    public static void test4(){
        Session session = HibernateSessionFactory.getSession();
//        String sql="SELECT * FROM fileinfo WHERE userId=(SELECT userId FROM userinfo WHERE username='zhangsan')";
        String hql="SELECT f FROM Fileinfo f WHERE f.userinfo.userId=(SELECT userId FROM Userinfo WHERE userName='zhangsan')";
        Query query = session.createQuery(hql);
        List<Fileinfo> list = query.list();
        for (Fileinfo fileinfo : list) {
            System.out.println(fileinfo.getFileId()+"---"+fileinfo.getFileName());
        }
        HibernateSessionFactory.closeSession();
    }
    public static void main(String[] args) {
        test4();
    }
}

　　G：命名查询：

package cn.zzsxt.demo;

import java.util.List;

import org.hibernate.Query;
import org.hibernate.Session;

import cn.zzsxt.entity.Userinfo;
import cn.zzsxt.util.HibernateSessionFactory;
/*
 *命名查询:将hql查询语句配置到映射文件中，通过名称获取配置信息
 */
public class TestQuery6 {
    public static void test1(){
        Session session = HibernateSessionFactory.getSession();
        Query query = session.getNamedQuery("getAllUsers");
        List<Userinfo> list = query.list();
        for (Userinfo userinfo : list) {
            System.out.println(userinfo.getUserId()+"---"+userinfo.getUserName());
        }
        HibernateSessionFactory.closeSession();
    }
    
    public static void main(String[] args) {
        test1();
    }
}

 　　

　　H.Criteria:

package cn.zzsxt.demo2;

import java.util.ArrayList;
import java.util.List;

import org.hibernate.Criteria;
import org.hibernate.Session;
import org.hibernate.criterion.MatchMode;
import org.hibernate.criterion.Order;
import org.hibernate.criterion.Projection;
import org.hibernate.criterion.Projections;
import org.hibernate.criterion.Restrictions;

import cn.zzsxt.entity.Userinfo;
import cn.zzsxt.util.HibernateSessionFactory;

/**
 * Criteria是Hibernate提供的一组纯面向对象的查询API. 
 * 其功能类似Query, 但完全以面向对象的形式管理查询逻辑. 更符合ORM的设计思想.
 * @author Think
 *
 */
public class TestCriteria {
    /**
     * 查询所有
     */
    public static void test(){
        Session session = HibernateSessionFactory.getSession();
        Criteria c = session.createCriteria(Userinfo.class);
        List<Userinfo> list = c.list();
        for (Userinfo userinfo : list) {
            System.out.println(userinfo.getUserId()+"---"+userinfo.getUserName());
        }
        HibernateSessionFactory.closeSession();
    }
    
    public static void test2(){
        Session session = HibernateSessionFactory.getSession();
        Criteria c = session.createCriteria(Userinfo.class);
        //添加约束条件
//        c.add(Restrictions.between("userId", 1, 5));//userId>=1 and userId<=5
//        c.add(Restrictions.eq("userType", 1));//userType=1
//        List<Integer> ids = new ArrayList<Integer>();
//        ids.add(3);
//        ids.add(4);
//        c.add(Restrictions.in("userId",ids ));
//        c.add(Restrictions.like("userName", "%zhang%"));
        /*
         * MatchMode.START==>zhang%
         * MatchMode.END==>%zhang
         * MatchMode.ANYWHERE==>%zhang%
         * 
         */
//        c.add(Restrictions.like("userName", "zhang", MatchMode.ANYWHERE));
//        c.add(Restrictions.le("userId", 5));//le==>less equals小于等于
//        c.add(Restrictions.ge("userId", 2));//ge==>great equals大于等于
//        c.add(Restrictions.gt("userId", 2));//gt==>great than大于
//        c.add(Restrictions.lt("userId", 5));//lt==>less than小于
        //排序
//        c.addOrder(Order.asc("userId"));//按照userId进行升序排列
        c.addOrder(Order.desc("userId"));//按照userId进行升序排列
        List<Userinfo> list = c.list();
        for (Userinfo userinfo : list) {
            System.out.println(userinfo.getUserId()+"---"+userinfo.getUserName());
        }
        HibernateSessionFactory.closeSession();
    }
    
    /**
     * 分页:
     * setFirstResult()
     * setMaxResult()
     */
    public static void test3(){
        Session session = HibernateSessionFactory.getSession();
        Criteria c = session.createCriteria(Userinfo.class);
        c.setFirstResult(2);
        c.setMaxResults(2);
        List<Userinfo> list = c.list();
        for (Userinfo userinfo : list) {
            System.out.println(userinfo.getUserId()+"---"+userinfo.getUserName());
        }
        HibernateSessionFactory.closeSession();
    }
    
    /**
     * 聚合函数:使用投影
     */
    public static void test4(){
        Session session = HibernateSessionFactory.getSession();
        Criteria c = session.createCriteria(Userinfo.class);
        c.setProjection(Projections.count("userId"));//设置聚合函数的投影
//        List list = c.list();
//        System.out.println(list.get(0));
        Object obj = c.uniqueResult();
        System.out.println(obj);
        HibernateSessionFactory.closeSession();
    }
    
    /**
     * 分组
     */
    public static void test5(){
        Session session = HibernateSessionFactory.getSession();
        Criteria c = session.createCriteria(Userinfo.class);
        c.setProjection(Projections.groupProperty("userType"));//设置分组的投影
        List <Integer> list = c.list();
        for (Integer i : list) {
            System.out.println(i);
        }
        HibernateSessionFactory.closeSession();
    }
    public static void main(String[] args) {
        test5();
    }
}