Создание таблиц из классов Entity в Hibernate
1. Цель статьи
Данная статья основана на:
Hibernate 5.2.2.Final
Eclipse 4.6 (MARS)
В данной статье я покажу вам как создать систему таблиц, основываясь на любой базе данных. (Oracle, MySQL, SQL Server, ..) основывая на классах Entity. Созданные таблицы будут полностью иметь ограничения (Constraints) по указаниям в классах Entity.
Заметьте, что Hibernate создан чтобы работать с любой базой данных. Поэтому, когда вы меняте базу данных вам не придется менять код программы. Но при этом, вам нужно создать систему таблицы в базе данных. Hibernate помогает вам создать систему таблицы из классов Entity.
Заметьте, что Hibernate создан чтобы работать с любой базой данных. Поэтому, когда вы меняте базу данных вам не придется менять код программы. Но при этом, вам нужно создать систему таблицы в базе данных. Hibernate помогает вам создать систему таблицы из классов Entity.
Данная статья является продолжением "Руководство программирования Hibernate для начинающих", которое вы можете посмотреть по ссылке:
2. Создать Maven Project & Объявить библиотеку
В pom.xml я объявляю библиотеку Hibernate 5, и библиотека JDBC для разных Database (Oracle, MySQL и SQL Server).
pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>org.o7planning</groupId>
<artifactId>HibernateGenerateTables</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>HibernateGenerateTables</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<repositories>
<!-- Repository for ORACLE JDBC Driver -->
<repository>
<id>codelds</id>
<url>https://code.lds.org/nexus/content/groups/main-repo</url>
</repository>
</repositories>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
<!-- Hibernate Core -->
<!-- https://mvnrepository.com/artifact/org.hibernate/hibernate-core -->
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>5.2.2.Final</version>
</dependency>
<!-- MySQL JDBC driver -->
<!-- http://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.34</version>
</dependency>
<!-- Oracle JDBC driver -->
<dependency>
<groupId>com.oracle</groupId>
<artifactId>ojdbc6</artifactId>
<version>11.2.0.3</version>
</dependency>
<!-- SQLServer JDBC driver (JTDS) -->
<!-- http://mvnrepository.com/artifact/net.sourceforge.jtds/jtds -->
<dependency>
<groupId>net.sourceforge.jtds</groupId>
<artifactId>jtds</artifactId>
<version>1.3.1</version>
</dependency>
</dependencies>
</project>
3. Классы Entity
Мы создаем классы Entity. Каждый Entity описывает таблицу в DB. Не говорите ничего, про то что имеется в этих таблицах.
- Department - Департамент
- Employee - Работник
- SalaryGrade - Зарплата
- Timekeeper - Хронометр, ведение учета прихода и ухода работников.
Department.java
package org.o7planning.tutorial.hibernate.entities;
import java.util.HashSet;
import java.util.Set;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.persistence.Table;
import javax.persistence.UniqueConstraint;
@Entity
@Table(name = "DEPARTMENT",
uniqueConstraints = { @UniqueConstraint(columnNames = { "DEPT_NO" }) })
public class Department {
private Integer deptId;
private String deptNo;
private String deptName;
private String location;
private Set<Employee> employees = new HashSet<Employee>(0);
public Department() {
}
public Department(Integer deptId, String deptName, String location) {
this.deptId = deptId;
this.deptNo = "D" + this.deptId;
this.deptName = deptName;
this.location = location;
}
@Id
@Column(name = "DEPT_ID")
public Integer getDeptId() {
return deptId;
}
public void setDeptId(Integer deptId) {
this.deptId = deptId;
}
@Column(name = "DEPT_NO", length = 20, nullable = false)
public String getDeptNo() {
return deptNo;
}
public void setDeptNo(String deptNo) {
this.deptNo = deptNo;
}
@Column(name = "DEPT_NAME", nullable = false)
public String getDeptName() {
return deptName;
}
public void setDeptName(String deptName) {
this.deptName = deptName;
}
@Column(name = "LOCATION")
public String getLocation() {
return location;
}
public void setLocation(String location) {
this.location = location;
}
@OneToMany(fetch = FetchType.LAZY, mappedBy = "department")
public Set<Employee> getEmployees() {
return employees;
}
public void setEmployees(Set<Employee> employees) {
this.employees = employees;
}
}
Employee.java
package org.o7planning.tutorial.hibernate.entities;
import java.util.Date;
import java.util.HashSet;
import java.util.Set;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.Lob;
import javax.persistence.ManyToOne;
import javax.persistence.OneToMany;
import javax.persistence.Table;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;
import javax.persistence.UniqueConstraint;
@Entity
@Table(name = "EMPLOYEE",
uniqueConstraints = { @UniqueConstraint(columnNames = { "EMP_NO" }) })
public class Employee {
private Long empId;
private String empNo;
private String empName;
private String job;
private Employee manager;
private Date hideDate;
private Float salary;
private byte[] image;
private Department department;
private Set<Employee> employees = new HashSet<Employee>(0);
public Employee() {
}
public Employee(Long empId, String empName, String job, Employee manager,
Date hideDate, Float salary, Float comm, Department department) {
this.empId = empId;
this.empNo = "E" + this.empId;
this.empName = empName;
this.job = job;
this.manager = manager;
this.hideDate = hideDate;
this.salary = salary;
this.department = department;
}
@Id
@Column(name = "EMP_ID")
public Long getEmpId() {
return empId;
}
public void setEmpId(Long empId) {
this.empId = empId;
}
@Column(name = "EMP_NO", length = 20, nullable = false)
public String getEmpNo() {
return empNo;
}
public void setEmpNo(String empNo) {
this.empNo = empNo;
}
@Column(name = "EMP_NAME", length = 50, nullable = false)
public String getEmpName() {
return empName;
}
public void setEmpName(String empName) {
this.empName = empName;
}
@Column(name = "JOB", length = 30, nullable = false)
public String getJob() {
return job;
}
public void setJob(String job) {
this.job = job;
}
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "MNG_ID")
public Employee getManager() {
return manager;
}
public void setManager(Employee manager) {
this.manager = manager;
}
@Column(name = "HIRE_DATE", nullable = false)
@Temporal(TemporalType.DATE)
public Date getHideDate() {
return hideDate;
}
public void setHideDate(Date hideDate) {
this.hideDate = hideDate;
}
@Column(name = "SALARY", nullable = false)
public Float getSalary() {
return salary;
}
public void setSalary(Float salary) {
this.salary = salary;
}
@Column(name = "IMAGE", length = 1111111, nullable = true)
@Lob
public byte[] getImage() {
return image;
}
public void setImage(byte[] image) {
this.image = image;
}
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "DEPT_ID", nullable = false)
public Department getDepartment() {
return department;
}
public void setDepartment(Department department) {
this.department = department;
}
@OneToMany(fetch = FetchType.LAZY, mappedBy = "empId")
public Set<Employee> getEmployees() {
return employees;
}
public void setEmployees(Set<Employee> employees) {
this.employees = employees;
}
}
SalaryGrade.java
package org.o7planning.tutorial.hibernate.entities;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;
@Entity
@Table(name = "SALARY_GRADE")
public class SalaryGrade {
private Integer grade;
private Float lowSalary;
private Float highSalary;
public SalaryGrade() {
}
public SalaryGrade(Integer grade, Float lowSalary, Float highSalary) {
this.grade = grade;
this.lowSalary = lowSalary;
this.highSalary = highSalary;
}
@Id
@Column(name = "GRADE")
public Integer getGrade() {
return grade;
}
public void setGrade(Integer grade) {
this.grade = grade;
}
@Column(name = "LOW_SALARY", nullable = false)
public Float getLowSalary() {
return lowSalary;
}
public void setLowSalary(Float lowSalary) {
this.lowSalary = lowSalary;
}
@Column(name = "HIGH_SALARY", nullable = false)
public Float getHighSalary() {
return highSalary;
}
public void setHighSalary(Float highSalary) {
this.highSalary = highSalary;
}
}
Timekeeper.java
package org.o7planning.tutorial.hibernate.entities;
import java.util.Date;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;
import org.hibernate.annotations.GenericGenerator;
@Entity
@Table(name = "TIMEKEEPER")
public class Timekeeper {
public static final char IN = 'I';
public static final char OUT = 'O';
private String timekeeperId;
private Date dateTime;
private Employee employee;
// 'I' or 'O'
private char inOut;
@Id
@GeneratedValue(generator = "uuid")
@GenericGenerator(name = "uuid", strategy = "uuid2")
@Column(name = "Timekeeper_Id", length = 36)
public String getTimekeeperId() {
return timekeeperId;
}
public void setTimekeeperId(String timekeeperId) {
this.timekeeperId = timekeeperId;
}
@Column(name = "Date_Time", nullable = false)
@Temporal(TemporalType.TIMESTAMP)
public Date getDateTime() {
return dateTime;
}
public void setDateTime(Date dateTime) {
this.dateTime = dateTime;
}
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "EMP_ID", nullable = false)
public Employee getEmployee() {
return employee;
}
public void setEmployee(Employee employee) {
this.employee = employee;
}
@Column(name = "In_Out", nullable = false, length = 1)
public char getInOut() {
return inOut;
}
public void setInOut(char inOut) {
this.inOut = inOut;
}
}
4. hibernate-xxx.cfg.xml
Чтобы создать таблицы, вам нужен файл конфигурации базы данных database (hibernate-<datatype>.cfg.xml) и классы Entity.
hibernate-oracle.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">
<hibernate-configuration>
<session-factory>
<property name="hibernate.dialect">org.hibernate.dialect.OracleDialect</property>
<property name="hibernate.connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
<property name="hibernate.connection.url">jdbc:oracle:thin:@localhost:1521:db12c</property>
<property name="hibernate.connection.username">simplehr2</property>
<property name="hibernate.connection.password">12345</property>
<property name="hibernate.show_sql">true</property>
<property name="hibernate.connection.release_mode">auto</property>
<property name="current_session_context_class">thread</property>
<property name="hibernate.connection.autoReconnect">true</property>
<mapping class="org.o7planning.tutorial.hibernate.entities.Department" />
<mapping class="org.o7planning.tutorial.hibernate.entities.Employee" />
<mapping class="org.o7planning.tutorial.hibernate.entities.SalaryGrade" />
<mapping class="org.o7planning.tutorial.hibernate.entities.Timekeeper" />
</session-factory>
</hibernate-configuration>
hibernate-mysql.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">
<hibernate-configuration>
<session-factory>
<!-- Database connection settings -->
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="connection.url">jdbc:mysql://tran-vmware:3306/simplehr?serverTimezone=UTC</property>
<property name="connection.username">root</property>
<property name="connection.password">1234</property>
<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property>
<!-- SQL dialect -->
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<!-- Enable Hibernate's automatic session context management -->
<property name="current_session_context_class">thread</property>
<!-- Disable the second-level cache -->
<property name="cache.provider_class">org.hibernate.cache.internal.NoCacheProvider</property>
<!-- Echo all executed SQL to stdout -->
<property name="show_sql">true</property>
<mapping class="org.o7planning.tutorial.hibernate.entities.Department" />
<mapping class="org.o7planning.tutorial.hibernate.entities.Employee" />
<mapping class="org.o7planning.tutorial.hibernate.entities.SalaryGrade" />
<mapping class="org.o7planning.tutorial.hibernate.entities.Timekeeper" />
</session-factory>
</hibernate-configuration>
hibernate-sqlserver.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">
<hibernate-configuration>
<session-factory>
<!-- Database connection settings -->
<property name="connection.driver_class">net.sourceforge.jtds.jdbc.Driver</property>
<property name="connection.url">jdbc:jtds:sqlserver://localhost:1433/simplehr;instance=SQLEXPRESS</property>
<property name="connection.username">sa</property>
<property name="connection.password">1234</property>
<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property>
<!-- SQL dialect -->
<property name="dialect">org.hibernate.dialect.SQLServerDialect</property>
<!-- Enable Hibernate's automatic session context management -->
<property name="current_session_context_class">thread</property>
<!-- Disable the second-level cache -->
<property name="cache.provider_class">org.hibernate.cache.internal.NoCacheProvider</property>
<!-- Echo all executed SQL to stdout -->
<property name="show_sql">true</property>
<mapping class="org.o7planning.tutorial.hibernate.entities.Department" />
<mapping class="org.o7planning.tutorial.hibernate.entities.Employee" />
<mapping class="org.o7planning.tutorial.hibernate.entities.SalaryGrade" />
<mapping class="org.o7planning.tutorial.hibernate.entities.Timekeeper" />
</session-factory>
</hibernate-configuration>
Удостоверьтесь, что вы создали пустые Schema. (Пустые database) без таблиц. Например с Oracle я создаю новую Schema с названием simplehr2.
-- ORACLE
Create user simplehr2 identified by 12345;
grant dba to simplehr2;
5. Создать таблицы из Entity
SchemaGeneratorDemo.java
package org.o7planning.generatetables;
import java.io.File;
import java.util.EnumSet;
import org.hibernate.boot.Metadata;
import org.hibernate.boot.MetadataSources;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.service.ServiceRegistry;
import org.hibernate.tool.hbm2ddl.SchemaExport;
import org.hibernate.tool.schema.TargetType;
// Hibernate 5.
public class SchemaGeneratorDemo {
public static final String SCRIPT_FILE = "exportScript.sql";
private static SchemaExport getSchemaExport() {
SchemaExport export = new SchemaExport();
// Script file.
File outputFile = new File(SCRIPT_FILE);
String outputFilePath = outputFile.getAbsolutePath();
System.out.println("Export file: " + outputFilePath);
export.setDelimiter(";");
export.setOutputFile(outputFilePath);
// No Stop if Error
export.setHaltOnError(false);
//
return export;
}
public static void dropDataBase(SchemaExport export, Metadata metadata) {
// TargetType.DATABASE - Execute on Databse
// TargetType.SCRIPT - Write Script file.
// TargetType.STDOUT - Write log to Console.
EnumSet<TargetType> targetTypes = EnumSet.of(TargetType.DATABASE, TargetType.SCRIPT, TargetType.STDOUT);
export.drop(targetTypes, metadata);
}
public static void createDataBase(SchemaExport export, Metadata metadata) {
// TargetType.DATABASE - Execute on Databse
// TargetType.SCRIPT - Write Script file.
// TargetType.STDOUT - Write log to Console.
EnumSet<TargetType> targetTypes = EnumSet.of(TargetType.DATABASE, TargetType.SCRIPT, TargetType.STDOUT);
SchemaExport.Action action = SchemaExport.Action.CREATE;
//
export.execute(targetTypes, action, metadata);
System.out.println("Export OK");
}
public static void main(String[] args) {
// Using Oracle Database.
String configFileName = "hibernate-oracle.cfg.xml";
// Create the ServiceRegistry from hibernate-xxx.cfg.xml
ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder()//
.configure(configFileName).build();
// Create a metadata sources using the specified service registry.
Metadata metadata = new MetadataSources(serviceRegistry).getMetadataBuilder().build();
SchemaExport export = getSchemaExport();
System.out.println("Drop Database...");
// Drop Database
dropDataBase(export, metadata);
System.out.println("Create Database...");
// Create tables
createDataBase(export, metadata);
}
}
Запуск примера:
Смотрим файл Script:
Руководства Java Hibernate
- Запрос Java Hibernate
- Установите JBoss Tools для Eclipse
- Используйте инструменты Hibernate для создания классов Entity из таблиц
- Создание таблиц из классов Entity в Hibernate
- Разбиение по страницам (Pagination) в Java Hibernate
- Руководство Java Hibernate для начинающих
Show More