Hibernate實戰——命名SQL查詢

一配置檔案

<?xml version="1.0" encoding="GBK"?>
<!-- 指定Hibernate配置檔案的DTD資訊 -->
<!DOCTYPE hibernate-configuration PUBLIC
     "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
     "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<!-- hibernate-configuration是配置檔案的根元素 -->
<hibernate-configuration>
     <session-factory>
           <!-- 指定連接配接資料庫所用的驅動 -->
           <property  name="connection.driver_class">com.mysql.jdbc.Driver</property>
           <!-- 指定連接配接資料庫的url，其中hibernate是本應用連接配接的資料庫名 -->
           <property  name="connection.url">jdbc:mysql://localhost/hibernate</property>
           <!-- 指定連接配接資料庫的使用者名 -->
           <property name="connection.username">root</property>
           <!-- 指定連接配接資料庫的密碼 -->
           <property name="connection.password">32147</property>
           <!-- 指定連接配接池裡最大連接配接數 -->
           <property  name="hibernate.c3p0.max_size">20</property>
           <!-- 指定連接配接池裡最小連接配接數 -->
           <property name="hibernate.c3p0.min_size">1</property>
           <!-- 指定連接配接池裡連接配接的逾時時長 -->
           <property  name="hibernate.c3p0.timeout">5000</property>
           <!-- 指定連接配接池裡最大緩存多少個Statement對象 -->
           <property  name="hibernate.c3p0.max_statements">100</property>
           <property  name="hibernate.c3p0.idle_test_period">3000</property>
           <property  name="hibernate.c3p0.acquire_increment">2</property>
           <property  name="hibernate.c3p0.validate">true</property>
           <!-- 指定資料庫方言 -->
           <property  name="dialect">org.hibernate.dialect.MySQL5InnoDBDialect</property>
           <!-- 根據需要自動建立資料庫 -->
           <property name="hbm2ddl.auto">update</property>
           <!-- 顯示Hibernate持久化操作所生成的SQL -->
           <property name="show_sql">true</property>
           <!-- 将SQL腳本進行格式化後再輸出 -->
           <property name="hibernate.format_sql">true</property>
           <!-- 羅列所有持久化類的類名 -->
           <mapping class="org.crazyit.app.domain.Enrolment"/>
           <mapping class="org.crazyit.app.domain.Student"/>
           <mapping class="org.crazyit.app.domain.Course"/>
     </session-factory>
</hibernate-configuration>

二 PO

Student

package org.crazyit.app.domain;

import java.util.*;
import javax.persistence.*;

@Entity
@Table(name="student_inf")
public class Student
{
    // 代表學生學号的成員變量，将作為辨別屬性
    @Id @Column(name="student_id")
    private Integer studentNumber;
    // 代表學生姓名的成員變量
    private String name;
    // 該學生的所有選課記錄對應的關聯實體
    @OneToMany(targetEntity=Enrolment.class
        , mappedBy="student" , cascade=CascadeType.REMOVE)
    private Set<Enrolment> enrolments
        = new HashSet<>();

    // 無參數的構造器
    public Student()
    {
    }
    // 初始化全部成員變量的構造器
    public Student(Integer studentNumber , String name)
    {
        this.studentNumber = studentNumber;
        this.name = name;
    }

    // studentNumber的setter和getter方法
    public void setStudentNumber(Integer studentNumber)
    {
        this.studentNumber = studentNumber;
    }
    public Integer getStudentNumber()
    {
        return this.studentNumber;
    }

    // name的setter和getter方法
    public void setName(String name)
    {
        this.name = name;
    }
    public String getName()
    {
        return this.name;
    }

    // enrolments的setter和getter方法
    public void setEnrolments(Set<Enrolment> enrolments)
    {
        this.enrolments = enrolments;
    }
    public Set<Enrolment> getEnrolments()
    {
        return this.enrolments;
    }
}

Enrolment

package org.crazyit.app.domain;
import javax.persistence.*;

@Entity
@Table(name = "enrolment_inf")
public class Enrolment
{
     // 定義辨別屬性
     @Id
     @Column(name = "enrolment_id")
     @GeneratedValue(strategy = GenerationType.IDENTITY)
     private Integer enrolmentId;
     // 定義選課記錄所屬的學年
     private int year;
     // 定義選課記錄所屬的學期
     private int semester;
     // 定義選課記錄關聯的學生實體
     @ManyToOne(targetEntity = Student.class)
     @JoinColumn(name = "student_id")
     private Student student;
     // 定義選課記錄關聯的課程實體
     @ManyToOne(targetEntity = Course.class)
     @JoinColumn(name = "course_code")
     private Course course;
     // enrolmentId的setter和getter方法
     public void setEnrolmentId(Integer enrolmentId) {
           this.enrolmentId = enrolmentId;
     }
     public Integer getEnrolmentId() {
           return this.enrolmentId;
     }
     // year的setter和getter方法
     public void setYear(int year) {
           this.year = year;
     }
     public int getYear() {
           return this.year;
     }
     // semester的setter和getter方法
     public void setSemester(int semester) {
           this.semester = semester;
     }
     public int getSemester() {
           return this.semester;
     }
     // student的setter和getter方法
     public void setStudent(Student student) {
           this.student = student;
     }
     public Student getStudent() {
           return this.student;
     }
     // course的setter和getter方法
     public void setCourse(Course course) {
           this.course = course;
     }
     public Course getCourse() {
           return this.course;
     }
}

Course

package org.crazyit.app.domain;
import javax.persistence.*;

@Entity
@Table(name="course_inf")
public class Course
{
     // 代表課程編号的成員變量，将作為辨別屬性
     @Id @Column(name="course_code")
     private String courseCode;
     // 代表課程名成員變量
     private String name;
     // 無參數的構造器
     public Course()
     {
     }
     // 初始化全部成員變量的構造器
     public Course(String courseCode , String name)
     {
           this.courseCode = courseCode;
           this.name = name;
     }
     // courseCode的setter和getter方法
     public void setCourseCode(String courseCode)
     {
           this.courseCode = courseCode;
     }
     public String getCourseCode()
     {
           return this.courseCode;
     }
     // name的setter和getter方法
     public void setName(String name)
     {
           this.name = name;
     }
     public String getName()
     {
           return this.name;
     }
}

三 VO

package org.crazyit.app.vo;

public class StudentCourse
{
     private String stuName;
     private String courseName;
     // stuName的setter和getter方法
     public void setStuName(String stuName)
     {
           this.stuName = stuName;
     }
     public String getStuName()
     {
           return this.stuName;
     }
     // courseName的setter和getter方法
     public void setCourseName(String courseName)
     {
           this.courseName = courseName;
     }
     public String getCourseName()
     {
           return this.courseName;
     }
}

四測試

1 工具類

package lee;

import org.hibernate.*;
import org.hibernate.cfg.*;
import org.hibernate.service.*;
import org.hibernate.boot.registry.*;

public class HibernateUtil
{
    public static final SessionFactory sessionFactory;

    static
    {
        try
        {
            // 使用預設的hibernate.cfg.xml配置檔案建立Configuration執行個體
            Configuration cfg = new Configuration()
                .configure();
            // 以Configuration執行個體來建立SessionFactory執行個體
            ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder()
                .applySettings(cfg.getProperties()).build();
            sessionFactory = cfg.buildSessionFactory(serviceRegistry);
        }
        catch (Throwable ex)
        {
            System.err.println("Initial SessionFactory creation failed." + ex);
            throw new ExceptionInInitializerError(ex);
        }
    }

    // ThreadLocal可以隔離多個線程的資料共享，是以不再需要對線程同步
    public static final ThreadLocal<Session> session
        = new ThreadLocal<Session>();

    public static Session currentSession()
        throws HibernateException
    {
        Session s = session.get();
        // 如果該線程還沒有Session,則建立一個新的Session
        if (s == null)
        {
            s = sessionFactory.openSession();
            // 将獲得的Session變量存儲在ThreadLocal變量session裡
            session.set(s);
        }
        return s;
    }

    public static void closeSession()
        throws HibernateException
    {
        Session s = session.get();
        if (s != null)
            s.close();
        session.set(null);
    }
}

2 測試類

package lee;

import org.hibernate.*;
import org.hibernate.transform.*;

import java.util.*;

import org.crazyit.app.domain.*;


public class NamedSQLTest {
    public static void main(String[] args) {
        NamedSQLTest test = new NamedSQLTest();
        System.out.println("++++++++++++++++++++++++++++++++++++++++++++++++++++++");
        test.simpleQuery();
        System.out.println("++++++++++++++++++++++++++++++++++++++++++++++++++++++");
        test.query();
        System.out.println("++++++++++++++++++++++++++++++++++++++++++++++++++++++");
        test.callProcedure();
        HibernateUtil.sessionFactory.close();
    }

    // 執行簡單的命名SQL查詢
    private void simpleQuery() {
        // 打開Session和事務
        Session session = HibernateUtil.currentSession();
        Transaction tx = session.beginTransaction();
        // 調用命名查詢，直接傳回結果
        List list = session.getNamedQuery("simpleQuery").list();
        tx.commit();
        HibernateUtil.closeSession();
        // 周遊結果集
        for (Object ele : list) {
            // 每個集合元素是Student對象
            Student s = (Student) ele;
            System.out.println(s.getName() + "\t");
        }
    }

    // 執行命名SQL查詢
    private void query() {
        // 打開Session和事務
        Session session = HibernateUtil.currentSession();
        Transaction tx = session.beginTransaction();
        // 調用命名查詢，直接傳回結果
        List list = session.getNamedQuery("queryTest").setInteger("targetYear", 2005).list();
        tx.commit();
        HibernateUtil.closeSession();
        // 周遊結果集
        for (Object ele : list) {
            // 每個集合元素是Student、Enrolment
            // 和stuName三個元素的數組
            Object[] objs = (Object[]) ele;
            Student s = (Student) objs[0];
            Enrolment e = (Enrolment) objs[1];
            Course c = (Course) objs[2];
            String stuName = (String) objs[3];
            System.out.println(s.getName() + "\t" + e.getYear() + "\t" + e.getSemester() + "\t="
                    + e.getCourse().getName() + "=\t" + stuName);
        }
    }

    // 調用存儲過程
    private void callProcedure() {
        // 打開Session和事務
        Session session = HibernateUtil.currentSession();
        Transaction tx = session.beginTransaction();
        // 調用命名查詢，直接傳回結果
        List list = session.getNamedQuery("callProcedure").list();
        tx.commit();
        HibernateUtil.closeSession();
        // 周遊結果集
        for (Object ele : list) {
            // 每個集合元素是Student對象
            Student s = (Student) ele;
            System.out.println(s.getName());
        }
    }
}

四資料腳本

drop database if exists hibernate;

create database hibernate;

use hibernate;

CREATE TABLE course_inf (
  course_code varchar(255) NOT NULL,
  name varchar(255) default NULL,
  PRIMARY KEY  (course_code)
);

INSERT INTO course_inf VALUES
('001','瘋狂Java講義'),
('002','輕量級Java EE企業應用實戰'),
('003','瘋狂Android講義');

CREATE TABLE student_inf (
  student_id int NOT NULL,
  name varchar(255) NOT NULL,
  PRIMARY KEY  (student_id)
);

INSERT INTO student_inf VALUES
(20050231,'孫悟空'),
(20050232,'豬八戒'),
(20050233,'牛魔王');



CREATE TABLE enrolment_inf (
  enrolment_id int(11) NOT NULL auto_increment,
  semester int(11) NOT NULL,
  year int(11) NOT NULL,
  student_id int default NULL,
  course_code varchar(255) default NULL,
  PRIMARY KEY  (enrolment_id),
  KEY FKEB4882C47EDE09EE (course_code),
  KEY FKEB4882C4109881D8 (student_id),
  FOREIGN KEY (student_id) REFERENCES student_inf (student_id),
  FOREIGN KEY (course_code) REFERENCES course_inf (course_code)
);

INSERT INTO enrolment_inf VALUES
(1,3,2005,20050232,'001'),
(2,2,2005,20050232,'003'),
(3,2,2005,20050233,'002'),
(4,3,2005,20050233,'003'),
(5,1,2005,20050231,'002');

-- 建立一個簡單的存儲過程
create procedure select_all_student()
select *
from student_inf;

Hibernate實戰——命名SQL查詢

五測試

Hibernate:
    select
        s.student_id ,
        s.name
    from
        student_inf s
孫悟空     
豬八戒     
牛魔王     
++++++++++++++++++++++++++++++++++++++++++++++++++++++
Hibernate:
    select
        s.*,
        e.*,
        c.*
    from
        student_inf s,
        enrolment_inf e,
        course_inf c
    where
        s.student_id = e.student_id
        and e.course_code = c.course_code
        and e.year=?
豬八戒     2005 3    =瘋狂Java講義=   豬八戒
豬八戒     2005 2    =瘋狂Android講義=     豬八戒
牛魔王     2005 2    =輕量級Java EE企業應用實戰=  牛魔王
牛魔王     2005 3    =瘋狂Android講義=     牛魔王
孫悟空     2005 1    =輕量級Java EE企業應用實戰=  孫悟空
++++++++++++++++++++++++++++++++++++++++++++++++++++++
Hibernate:
    {call select_all_student()}
孫悟空
豬八戒
牛魔王

Hibernate實戰——命名SQL查詢

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