Hibernate实战——命名SQL查询

比眉伴天荒 2021-07-24 23:20 554阅读 0赞

一 配置文件

  1. <?xml version="1.0" encoding="GBK"?>
  2. <!-- 指定Hibernate配置文件的DTD信息 -->
  3. <!DOCTYPE hibernate-configuration PUBLIC
  4.      "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
  5.      "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
  6. <!-- hibernate-configuration是配置文件的根元素 -->
  7. <hibernate-configuration>
  8.      <session-factory>
  9.            <!-- 指定连接数据库所用的驱动 -->
  10.            <property  name="connection.driver_class">com.mysql.jdbc.Driver</property>
  11.            <!-- 指定连接数据库的url，其中hibernate是本应用连接的数据库名 -->
  12.            <property  name="connection.url">jdbc:mysql://localhost/hibernate</property>
  13.            <!-- 指定连接数据库的用户名 -->
  14.            <property name="connection.username">root</property>
  15.            <!-- 指定连接数据库的密码 -->
  16.            <property name="connection.password">32147</property>
  17.            <!-- 指定连接池里最大连接数 -->
  18.            <property  name="hibernate.c3p0.max_size">20</property>
  19.            <!-- 指定连接池里最小连接数 -->
  20.            <property name="hibernate.c3p0.min_size">1</property>
  21.            <!-- 指定连接池里连接的超时时长 -->
  22.            <property  name="hibernate.c3p0.timeout">5000</property>
  23.            <!-- 指定连接池里最大缓存多少个Statement对象 -->
  24.            <property  name="hibernate.c3p0.max_statements">100</property>
  25.            <property  name="hibernate.c3p0.idle_test_period">3000</property>
  26.            <property  name="hibernate.c3p0.acquire_increment">2</property>
  27.            <property  name="hibernate.c3p0.validate">true</property>
  28.            <!-- 指定数据库方言 -->
  29.            <property  name="dialect">org.hibernate.dialect.MySQL5InnoDBDialect</property>
  30.            <!-- 根据需要自动创建数据库 -->
  31.            <property name="hbm2ddl.auto">update</property>
  32.            <!-- 显示Hibernate持久化操作所生成的SQL -->
  33.            <property name="show_sql">true</property>
  34.            <!-- 将SQL脚本进行格式化后再输出 -->
  35.            <property name="hibernate.format_sql">true</property>
  36.            <!-- 罗列所有持久化类的类名 -->
  37.            <mapping class="org.crazyit.app.domain.Enrolment"/>
  38.            <mapping class="org.crazyit.app.domain.Student"/>
  39.            <mapping class="org.crazyit.app.domain.Course"/>
  40.      </session-factory>
  41. </hibernate-configuration>

二 PO

Student

  1. package org.crazyit.app.domain;
  3. import java.util.*;
  4. import javax.persistence.*;
  6. @Entity
  7. @Table(name="student_inf")
  8. public class Student
  9. {
  10.     // 代表学生学号的成员变量，将作为标识属性
  11.     @Id @Column(name="student_id")
  12.     private Integer studentNumber;
  13.     // 代表学生姓名的成员变量
  14.     private String name;
  15.     // 该学生的所有选课记录对应的关联实体
  16.     @OneToMany(targetEntity=Enrolment.class
  17.         , mappedBy="student" , cascade=CascadeType.REMOVE)
  18.     private Set<Enrolment> enrolments
  19.         = new HashSet<>();
  21.     // 无参数的构造器
  22.     public Student()
  23.     {
  24.     }
  25.     // 初始化全部成员变量的构造器
  26.     public Student(Integer studentNumber , String name)
  27.     {
  28.         this.studentNumber = studentNumber;
  29.         this.name = name;
  30.     }
  32.     // studentNumber的setter和getter方法
  33.     public void setStudentNumber(Integer studentNumber)
  34.     {
  35.         this.studentNumber = studentNumber;
  36.     }
  37.     public Integer getStudentNumber()
  38.     {
  39.         return this.studentNumber;
  40.     }
  42.     // name的setter和getter方法
  43.     public void setName(String name)
  44.     {
  45.         this.name = name;
  46.     }
  47.     public String getName()
  48.     {
  49.         return this.name;
  50.     }
  52.     // enrolments的setter和getter方法
  53.     public void setEnrolments(Set<Enrolment> enrolments)
  54.     {
  55.         this.enrolments = enrolments;
  56.     }
  57.     public Set<Enrolment> getEnrolments()
  58.     {
  59.         return this.enrolments;
  60.     }
  61. }

Enrolment

  1. package org.crazyit.app.domain;
  2. import javax.persistence.*;
  4. @Entity
  5. @Table(name = "enrolment_inf")
  6. public class Enrolment
  7. {
  8.      // 定义标识属性
  9.      @Id
  10.      @Column(name = "enrolment_id")
  11.      @GeneratedValue(strategy = GenerationType.IDENTITY)
  12.      private Integer enrolmentId;
  13.      // 定义选课记录所属的学年
  14.      private int year;
  15.      // 定义选课记录所属的学期
  16.      private int semester;
  17.      // 定义选课记录关联的学生实体
  18.      @ManyToOne(targetEntity = Student.class)
  19.      @JoinColumn(name = "student_id")
  20.      private Student student;
  21.      // 定义选课记录关联的课程实体
  22.      @ManyToOne(targetEntity = Course.class)
  23.      @JoinColumn(name = "course_code")
  24.      private Course course;
  25.      // enrolmentId的setter和getter方法
  26.      public void setEnrolmentId(Integer enrolmentId) {
  27.            this.enrolmentId = enrolmentId;
  28.      }
  29.      public Integer getEnrolmentId() {
  30.            return this.enrolmentId;
  31.      }
  32.      // year的setter和getter方法
  33.      public void setYear(int year) {
  34.            this.year = year;
  35.      }
  36.      public int getYear() {
  37.            return this.year;
  38.      }
  39.      // semester的setter和getter方法
  40.      public void setSemester(int semester) {
  41.            this.semester = semester;
  42.      }
  43.      public int getSemester() {
  44.            return this.semester;
  45.      }
  46.      // student的setter和getter方法
  47.      public void setStudent(Student student) {
  48.            this.student = student;
  49.      }
  50.      public Student getStudent() {
  51.            return this.student;
  52.      }
  53.      // course的setter和getter方法
  54.      public void setCourse(Course course) {
  55.            this.course = course;
  56.      }
  57.      public Course getCourse() {
  58.            return this.course;
  59.      }
  60. }

Course

  1. package org.crazyit.app.domain;
  2. import javax.persistence.*;
  4. @Entity
  5. @Table(name="course_inf")
  6. public class Course
  7. {
  8.      // 代表课程编号的成员变量，将作为标识属性
  9.      @Id @Column(name="course_code")
  10.      private String courseCode;
  11.      // 代表课程名成员变量
  12.      private String name;
  13.      // 无参数的构造器
  14.      public Course()
  15.      {
  16.      }
  17.      // 初始化全部成员变量的构造器
  18.      public Course(String courseCode , String name)
  19.      {
  20.            this.courseCode = courseCode;
  21.            this.name = name;
  22.      }
  23.      // courseCode的setter和getter方法
  24.      public void setCourseCode(String courseCode)
  25.      {
  26.            this.courseCode = courseCode;
  27.      }
  28.      public String getCourseCode()
  29.      {
  30.            return this.courseCode;
  31.      }
  32.      // name的setter和getter方法
  33.      public void setName(String name)
  34.      {
  35.            this.name = name;
  36.      }
  37.      public String getName()
  38.      {
  39.            return this.name;
  40.      }
  41. }

三 VO

  1. package org.crazyit.app.vo;
  3. public class StudentCourse
  4. {
  5.      private String stuName;
  6.      private String courseName;
  7.      // stuName的setter和getter方法
  8.      public void setStuName(String stuName)
  9.      {
  10.            this.stuName = stuName;
  11.      }
  12.      public String getStuName()
  13.      {
  14.            return this.stuName;
  15.      }
  16.      // courseName的setter和getter方法
  17.      public void setCourseName(String courseName)
  18.      {
  19.            this.courseName = courseName;
  20.      }
  21.      public String getCourseName()
  22.      {
  23.            return this.courseName;
  24.      }
  25. }

四 测试

1 工具类

  1. package lee;
  3. import org.hibernate.*;
  4. import org.hibernate.cfg.*;
  5. import org.hibernate.service.*;
  6. import org.hibernate.boot.registry.*;
  8. public class HibernateUtil
  9. {
  10.     public static final SessionFactory sessionFactory;
  12.     static
  13.     {
  14.         try
  15.         {
  16.             // 使用默认的hibernate.cfg.xml配置文件创建Configuration实例
  17.             Configuration cfg = new Configuration()
  18.                 .configure();
  19.             // 以Configuration实例来创建SessionFactory实例
  20.             ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder()
  21.                 .applySettings(cfg.getProperties()).build();
  22.             sessionFactory = cfg.buildSessionFactory(serviceRegistry);
  23.         }
  24.         catch (Throwable ex)
  25.         {
  26.             System.err.println("Initial SessionFactory creation failed." + ex);
  27.             throw new ExceptionInInitializerError(ex);
  28.         }
  29.     }
  31.     // ThreadLocal可以隔离多个线程的数据共享，因此不再需要对线程同步
  32.     public static final ThreadLocal<Session> session
  33.         = new ThreadLocal<Session>();
  35.     public static Session currentSession()
  36.         throws HibernateException
  37.     {
  38.         Session s = session.get();
  39.         // 如果该线程还没有Session,则创建一个新的Session
  40.         if (s == null)
  41.         {
  42.             s = sessionFactory.openSession();
  43.             // 将获得的Session变量存储在ThreadLocal变量session里
  44.             session.set(s);
  45.         }
  46.         return s;
  47.     }
  49.     public static void closeSession()
  50.         throws HibernateException
  51.     {
  52.         Session s = session.get();
  53.         if (s != null)
  54.             s.close();
  55.         session.set(null);
  56.     }
  57. }

2 测试类

  1. package lee;
  3. import org.hibernate.*;
  4. import org.hibernate.transform.*;
  6. import java.util.*;
  8. import org.crazyit.app.domain.*;
  11. public class NamedSQLTest {
  12.     public static void main(String[] args) {
  13.         NamedSQLTest test = new NamedSQLTest();
  14.         System.out.println("++++++++++++++++++++++++++++++++++++++++++++++++++++++");
  15.         test.simpleQuery();
  16.         System.out.println("++++++++++++++++++++++++++++++++++++++++++++++++++++++");
  17.         test.query();
  18.         System.out.println("++++++++++++++++++++++++++++++++++++++++++++++++++++++");
  19.         test.callProcedure();
  20.         HibernateUtil.sessionFactory.close();
  21.     }
  23.     // 执行简单的命名SQL查询
  24.     private void simpleQuery() {
  25.         // 打开Session和事务
  26.         Session session = HibernateUtil.currentSession();
  27.         Transaction tx = session.beginTransaction();
  28.         // 调用命名查询，直接返回结果
  29.         List list = session.getNamedQuery("simpleQuery").list();
  30.         tx.commit();
  31.         HibernateUtil.closeSession();
  32.         // 遍历结果集
  33.         for (Object ele : list) {
  34.             // 每个集合元素是Student对象
  35.             Student s = (Student) ele;
  36.             System.out.println(s.getName() + "\t");
  37.         }
  38.     }
  40.     // 执行命名SQL查询
  41.     private void query() {
  42.         // 打开Session和事务
  43.         Session session = HibernateUtil.currentSession();
  44.         Transaction tx = session.beginTransaction();
  45.         // 调用命名查询，直接返回结果
  46.         List list = session.getNamedQuery("queryTest").setInteger("targetYear", 2005).list();
  47.         tx.commit();
  48.         HibernateUtil.closeSession();
  49.         // 遍历结果集
  50.         for (Object ele : list) {
  51.             // 每个集合元素是Student、Enrolment
  52.             // 和stuName三个元素的数组
  53.             Object[] objs = (Object[]) ele;
  54.             Student s = (Student) objs[0];
  55.             Enrolment e = (Enrolment) objs[1];
  56.             Course c = (Course) objs[2];
  57.             String stuName = (String) objs[3];
  58.             System.out.println(s.getName() + "\t" + e.getYear() + "\t" + e.getSemester() + "\t="
  59.                     + e.getCourse().getName() + "=\t" + stuName);
  60.         }
  61.     }
  63.     // 调用存储过程
  64.     private void callProcedure() {
  65.         // 打开Session和事务
  66.         Session session = HibernateUtil.currentSession();
  67.         Transaction tx = session.beginTransaction();
  68.         // 调用命名查询，直接返回结果
  69.         List list = session.getNamedQuery("callProcedure").list();
  70.         tx.commit();
  71.         HibernateUtil.closeSession();
  72.         // 遍历结果集
  73.         for (Object ele : list) {
  74.             // 每个集合元素是Student对象
  75.             Student s = (Student) ele;
  76.             System.out.println(s.getName());
  77.         }
  78.     }
  79. }

四 数据脚本

  1. drop database if exists hibernate;
  3. create database hibernate;
  5. use hibernate;
  7. CREATE TABLE course_inf (
  8.   course_code varchar(255) NOT NULL,
  9.   name varchar(255) default NULL,
  10.   PRIMARY KEY  (course_code)
  11. );
  13. INSERT INTO course_inf VALUES
  14. ('001','疯狂Java讲义'),
  15. ('002','轻量级Java EE企业应用实战'),
  16. ('003','疯狂Android讲义');
  18. CREATE TABLE student_inf (
  19.   student_id int NOT NULL,
  20.   name varchar(255) NOT NULL,
  21.   PRIMARY KEY  (student_id)
  22. );
  24. INSERT INTO student_inf VALUES
  25. (20050231,'孙悟空'),
  26. (20050232,'猪八戒'),
  27. (20050233,'牛魔王');
  31. CREATE TABLE enrolment_inf (
  32.   enrolment_id int(11) NOT NULL auto_increment,
  33.   semester int(11) NOT NULL,
  34.   year int(11) NOT NULL,
  35.   student_id int default NULL,
  36.   course_code varchar(255) default NULL,
  37.   PRIMARY KEY  (enrolment_id),
  38.   KEY FKEB4882C47EDE09EE (course_code),
  39.   KEY FKEB4882C4109881D8 (student_id),
  40.   FOREIGN KEY (student_id) REFERENCES student_inf (student_id),
  41.   FOREIGN KEY (course_code) REFERENCES course_inf (course_code)
  42. );
  44. INSERT INTO enrolment_inf VALUES
  45. (1,3,2005,20050232,'001'),
  46. (2,2,2005,20050232,'003'),
  47. (3,2,2005,20050233,'002'),
  48. (4,3,2005,20050233,'003'),
  49. (5,1,2005,20050231,'002');
  51. -- 创建一个简单的存储过程
  52. create procedure select_all_student()
  53. select *
  54. from student_inf;

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五 测试

  1. Hibernate:
  2.     select
  3.         s.student_id ,
  4.         s.name
  5.     from
  6.         student_inf s
  7. 孙悟空     
  8. 猪八戒     
  9. 牛魔王     
  10. ++++++++++++++++++++++++++++++++++++++++++++++++++++++
  11. Hibernate:
  12.     select
  13.         s.*,
  14.         e.*,
  15.         c.*
  16.     from
  17.         student_inf s,
  18.         enrolment_inf e,
  19.         course_inf c
  20.     where
  21.         s.student_id = e.student_id
  22.         and e.course_code = c.course_code
  23.         and e.year=?
  24. 猪八戒     2005 3    =疯狂Java讲义=   猪八戒
  25. 猪八戒     2005 2    =疯狂Android讲义=     猪八戒
  26. 牛魔王     2005 2    =轻量级Java EE企业应用实战=  牛魔王
  27. 牛魔王     2005 3    =疯狂Android讲义=     牛魔王
  28. 孙悟空     2005 1    =轻量级Java EE企业应用实战=  孙悟空
  29. ++++++++++++++++++++++++++++++++++++++++++++++++++++++
  30. Hibernate:
  31.     {call select_all_student()}
  32. 孙悟空
  33. 猪八戒
  34. 牛魔王

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