[Hibernate]

使用Hibernate的Criteria做查询。

参考文档：

http://docs.jboss.org/hibernate/orm/3.5/reference/zh-CN/html/querycriteria.html

---

Java Beans:

package com.my.bean;

import java.util.Date;
import java.util.Set;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.persistence.Table;

@Entity
@Table(name="user")
public class User {
    @Id @GeneratedValue @Column(name="user_id", nullable=false)
    private long userID;
    
    @Column(name="user_name", length=100, nullable=false)
    private String userName;
    
    @Column(name="create_time", nullable=false)
    private Date createTime;
    
    @OneToMany(mappedBy="user", cascade=CascadeType.ALL)
    private Set<UserCard> cards;

    public long getUserID() {
        return userID;
    }

    public void setUserID(long userID) {
        this.userID = userID;
    }

    public String getUserName() {
        return userName;
    }

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

    public Date getCreateTime() {
        return createTime;
    }

    public void setCreateTime(Date createTime) {
        this.createTime = createTime;
    }

    public Set<UserCard> getCards() {
        return cards;
    }

    public void setCards(Set<UserCard> cards) {
        this.cards = cards;
    }
}

package com.my.bean;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;

@Entity
@Table(name="user_card")
public class UserCard {
    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    @Column(name="card_id")
    private long cardID;
    
    @Column(name="card_name")
    private String cardName;
    
    @ManyToOne(cascade=CascadeType.ALL)
    @JoinColumn(name="user_id")
    private User user;
    
    public long getCardID() {
        return cardID;
    }
    public void setCardID(long cardID) {
        this.cardID = cardID;
    }
    public String getCardName() {
        return cardName;
    }
    public void setCardName(String cardName) {
        this.cardName = cardName;
    }
    public User getUser() {
        return user;
    }
    public void setUser(User user) {
        this.user = user;
    }
}

Java DTO beans:

package com.my.bean.dto;

public class GroupByTemp {
    private long sumUser;
    private long count;
    private long userID;
    
    public long getSumUser() {
        return sumUser;
    }
    public void setSumUser(long sumUser) {
        this.sumUser = sumUser;
    }
    public long getCount() {
        return count;
    }
    public void setCount(long count) {
        this.count = count;
    }
    public long getUserID() {
        return userID;
    }
    public void setUserID(long userID) {
        this.userID = userID;
    }
}

package com.my.bean.dto;

public class UserCardTemp {
    private long userID;
    private String userName;
    private String cardName;

    public String getUserName() {
        return userName;
    }

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

    public void setCardName(String cardName) {
        this.cardName = cardName;
    }

    public UserCardTemp() {
    }

    public long getUserID() {
        return userID;
    }

    public void setUserID(long userID) {
        this.userID = userID;
    }
    
}

测试例子：

package com.my.init;

import java.util.List;

import org.hibernate.Criteria;
import org.hibernate.Session;
import org.hibernate.Transaction;
import org.hibernate.criterion.DetachedCriteria;
import org.hibernate.criterion.Order;
import org.hibernate.criterion.ProjectionList;
import org.hibernate.criterion.Projections;
import org.hibernate.criterion.Property;
import org.hibernate.criterion.Restrictions;
import org.hibernate.sql.JoinType;
import org.hibernate.transform.Transformers;

import com.my.bean.User;
import com.my.bean.UserCard;
import com.my.bean.dto.GroupByTemp;
import com.my.bean.dto.UserCardTemp;
import com.my.dao.util.HibernateUtil;

public class Test {

    @SuppressWarnings("unchecked")
    public static void main(String[] args) {
        Session session = HibernateUtil.getSessionFactory().openSession();
        Transaction tx = session.beginTransaction();

        try {
            // ----------------------------------------------------
            // Set limit and get user info
            // ----------------------------------------------------
            Criteria crit = session.createCriteria(User.class);
            List<User> users = crit.setFirstResult(1).setMaxResults(1).list();
            for (User user : users) {
                System.out.println("User name:" + user.getUserName());
            }

            // ----------------------------------------------------
            // Order by
            // ----------------------------------------------------
            crit = session.createCriteria(User.class);
            crit.addOrder(Order.desc("userName"));
            crit.addOrder(Order.asc("userID"));
            users = crit.list();
            for (User user : users) {
                System.out.println("User name:" + user.getUserName());
            }

            // ----------------------------------------------------
            // Where: like and equal
            // ----------------------------------------------------
            crit = session.createCriteria(User.class);
            crit.add(Restrictions.like("userName", "%b%")).add(
                    Restrictions.eq("userID", (long) 1));
            users = crit.list();
            for (User user : users) {
                System.out.println("User name:" + user.getUserName());
            }

            // ----------------------------------------------------
            // Where: more than or less than
            // ----------------------------------------------------
            crit = session.createCriteria(User.class);
            crit.add(Restrictions.or(Restrictions.gt("userID", (long) 1)).add(
                    Restrictions.lt("userID", (long) 2)));
            users = crit.list();
            for (User user : users) {
                System.out.println("User name:" + user.getUserName());
            }

            // ----------------------------------------------------
            // Where: in
            // ----------------------------------------------------
            crit = session.createCriteria(User.class);
            crit.add(Restrictions.in("userName",
                    new String[] { "Robin", "Amy" }));
            users = crit.list();
            for (User user : users) {
                System.out.println("User name:" + user.getUserName());
            }

            // ----------------------------------------------------
            // Property
            // ----------------------------------------------------
            crit = session.createCriteria(User.class);
            crit.add(Property.forName("userName").like("%b%"))
                    .add(Property.forName("userID").between((long) 1, (long) 2))
                    .addOrder(Property.forName("userID").desc());
            users = crit.list();
            for (User user : users) {
                System.out.println("User name:" + user.getUserName());
            }

            // ----------------------------------------------------
            // Left join
            // ----------------------------------------------------
            crit = session.createCriteria(User.class);
            crit.add(Restrictions.eq("userName", "Robin")).setFetchMode(
                    "cards", org.hibernate.FetchMode.JOIN);
            users = crit.list();
            for (User user : users) {
                System.out.println("User name:" + user.getUserName());
            }

            // ----------------------------------------------------
            // Left join 2
            // ----------------------------------------------------
            crit = session.createCriteria(User.class);
            crit.createAlias("cards", "C", JoinType.LEFT_OUTER_JOIN);
            crit.add(Restrictions.eq("userName", "Robin"));
            users = crit.list();
            for (User user : users) {
                System.out.println("User name:" + user.getUserName());
            }

            // ----------------------------------------------------
            // Inner join
            // ----------------------------------------------------
            crit = session.createCriteria(User.class);
            crit.add(Restrictions.eq("userName", "Robin"));
            crit.createCriteria("cards").add(
                    Restrictions.eq("cardID", (long) 1));
            users = crit.list();
            for (User user : users) {
                System.out.println("User name:" + user.getUserName());
            }

            // ----------------------------------------------------
            // Inner join 2
            // ----------------------------------------------------
            crit = session.createCriteria(User.class);
            crit.add(Restrictions.eq("userName", "Robin"));
            crit.createAlias("cards", "C", JoinType.INNER_JOIN);
            users = crit.list();
            for (User user : users) {
                System.out.println("User name:" + user.getUserName());
            }

            // ----------------------------------------------------
            // Count
            // ----------------------------------------------------
            crit = session.createCriteria(User.class);
            crit.setProjection(Projections.rowCount()).add(
                    Restrictions.eq("userName", "Robin"));
            System.out.println("Row count:" + crit.uniqueResult().toString());

            // ----------------------------------------------------
            // Max
            // ----------------------------------------------------
            crit = session.createCriteria(User.class);
            crit.setProjection(Projections.max("userID"));
            System.out.println("Max ID:" + crit.uniqueResult().toString());

            // ----------------------------------------------------
            // Min
            // ----------------------------------------------------
            crit = session.createCriteria(User.class);
            crit.setProjection(Projections.min("userID"));
            System.out.println("Max ID:" + crit.uniqueResult().toString());

            // ----------------------------------------------------
            // ProjectionList and left join
            // ----------------------------------------------------
            crit = session.createCriteria(User.class);
            crit.createAlias("cards", "C", JoinType.LEFT_OUTER_JOIN);
            ProjectionList proList = Projections.projectionList();
            proList.add(Projections.property("userID"), "userID");
            proList.add(Projections.property("userName"), "userName");
            proList.add(Projections.property("C.cardName"), "cardName");
            crit.setProjection(proList);
            crit.setResultTransformer(Transformers
                    .aliasToBean(UserCardTemp.class));
            List<UserCardTemp> temps = crit.list();
            for (UserCardTemp uc : temps) {
                System.out.println("User ID:" + uc.getUserID() + "	User name:"
                        + uc.getUserName() + "	Card name:" + uc.getCardName());
            }

            // ----------------------------------------------------
            // ProjectionList Group by
            // ----------------------------------------------------
            crit = session.createCriteria(User.class);
            crit.createAlias("cards", "C", JoinType.LEFT_OUTER_JOIN);
            proList = Projections.projectionList();
            proList.add(Projections.sum("userID"), "sumUser");
            proList.add(Projections.count("userID"), "count");
            proList.add(Projections.groupProperty("userID"), "userID");
            crit.setProjection(proList);
            crit.setResultTransformer(Transformers
                    .aliasToBean(GroupByTemp.class));
            List<GroupByTemp> gt = crit.list();
            for (GroupByTemp g : gt) {
                System.out.println("Sum:" + g.getSumUser() + "	User ID:"
                        + g.getUserID() + "	Count:" + g.getCount());
            }

            // ----------------------------------------------------
            // Sub search
            // ----------------------------------------------------
            crit = session.createCriteria(User.class);
            DetachedCriteria sub = DetachedCriteria.forClass(UserCard.class);
            sub.setProjection(Property.forName("cardID"));
            sub.add(Restrictions.eq("cardID", (long) 1));
            crit.add(Property.forName("cards").in(sub));
            users = crit.list();
            for (User item : users) {
                System.out.println("User ID:" + item.getUserID());
            }

            tx.commit();
        } catch (Exception e) {
            tx.rollback();
            e.printStackTrace();
        }

        session.close();
    }
}