使用Hibernate的Criteria做查询。

参考文档：

 

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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
     
       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
      
        getCards() {        return cards;    }    public void setCards(Set
       
         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
     
       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
      
        temps = crit.list();            for (UserCardTemp uc : temps) {                System.out.println("User ID:" + uc.getUserID() + "\tUser name:"                        + uc.getUserName() + "\tCard 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
       
         gt = crit.list();            for (GroupByTemp g : gt) {                System.out.println("Sum:" + g.getSumUser() + "\tUser ID:"                        + g.getUserID() + "\tCount:" + 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();    }}