Hibernate 5 示例

蔚落 2023-09-30 11:04 4阅读 0赞

我们将尝试创建 Hibernate环境并编写执行一个 Hibernate 基本示例。

先决条件

*  Java 1.8
 *  IDE
 *  Maven 3.5.4

### **Hibernate 环境设置** ###

安装 Java 1.8 后，我们要设置 eclipse。对于 Maven 安装，请[单击此处][Link 1]。Maven 已经在 Eclipse 中进行了设置。所以我们可以在eclipse中创建包含maven的应用程序。或者，如果您愿意，可以单独安装。

安装 Java 1.8 后，我们要设置 eclipse。Maven 安装请点击这里。Maven 已经在 Eclipse 中设置好了。所以我们可以在eclipse中创建包含maven的应用程序。或者，如果您愿意，可以单独安装。

### **Hibernate 基本示例** ###

数据库设置

CREATE DATABASE IF NOT EXISTS `docsconsole`;
    
    
    CREATE TABLE IF NOT EXISTS `employees` (
      `emp_id` int(11) DEFAULT NULL,
      `emp_first_name` varchar(50) DEFAULT NULL,
      `emp_last_name` varchar(50) DEFAULT NULL
    ) ENGINE=InnoDB DEFAULT CHARSET=latin1;
    
    INSERT INTO `employees` (`emp_id`, `emp_first_name`, `emp_last_name`) VALUES
    (101, 'Raj', 'Madav'),	(102, 'Ram', 'Dev');

请按照以下在 Eclipse 中给出的步骤来创建 Maven Java 项目。

Click on File tab 
    --> New 
    --> Click on Maven Project 
    --> Please check on Create Simple Project (Skip architype selection) 
    --> Click on Next --> Enter the values docs.console.hibernate.com as Group Id, HibernateFirstExample as Artifact Id 
    --> Click on Finish

注意：包应该是jar。

现在我们已经成功创建了 Maven Java 项目。

接下来是为员工表创建域/实体类。

Right click on src/main/java 
    --> New 
    --> Click on Class 
    --> Enter value for Package as docs.console.hibernate.com.model and Enter value for Name Employee.

请为 Employee.java 编写下面给出的代码

Employee .java

package docs.console.hibernate.com.model;
    
    public class Employee {
    	
    	private static final long serialVersionUID = 1L;
    
    	private Integer empId;
    	private String empFirstName;
    	private String EmpLastName;
    
    	public Employee() {
    	}
    
    	public Employee(Integer empId, String empFirstName,String EmpLastName) {
    		this.empId = empId;
    		this.empFirstName = empFirstName;
    		this.EmpLastName = EmpLastName;
    	}
    
    	public Integer getEmpId() {
    		return empId;
    	}
    
    	public void setEmpId(Integer empId) {
    		this.empId = empId;
    	}
    
    	public String getEmpFirstName() {
    		return empFirstName;
    	}
    
    	public void setEmpFirstName(String empFirstName) {
    		this.empFirstName = empFirstName;
    	}
    
    	public String getEmpLastName() {
    		return EmpLastName;
    	}
    
    	public void setEmpLastName(String empLastName) {
    		EmpLastName = empLastName;
    	}
    
    	public static long getSerialversionuid() {
    		return serialVersionUID;
    	}
    
    	
    }

我们将更新 pom.xml 以获取所需的依赖 jar 文件。

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>com.docsconsole.tutorials</groupId>
        <artifactId>Hibernate-BasicExample-App-With-XML</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <packaging>jar</packaging>
    
        <name>Hibernate-BasicExample-App-With-XML</name>
    
    
        <dependencies>
    
    
            
            <dependency>
                <groupId>org.hibernate</groupId>
                <artifactId>hibernate-core</artifactId>
                <version>5.6.5.Final</version>
            </dependency>
    
            
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>8.0.28</version>
            </dependency>
    
            <dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
                <version>3.8.2</version>
                <scope>test</scope>
            </dependency>
        </dependencies>
    
        
        <build>
            <sourceDirectory>src/main/java</sourceDirectory>
            <plugins>
                <plugin>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <version>3.5.1</version>
                    <configuration>
                        <source>1.8</source>
                        <target>1.8</target>
                    </configuration>
                </plugin>
            </plugins>
        </build>
    </project>

现在我们将为hibernate创建配置文件。

Right click on src/main/resources 
    --> New 
    --> Click on Other 
    --> select XML File 
    --> Click Next 
    --> Enter value for File Name hibernate.cfg.xml

请在 hibernate.cfg.xml 中添加以下给定的 xml 标签。

hibernate.cfg.xml

<?xml version='1.0' encoding='utf-8'?>
    <!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD//EN" "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
    
    <hibernate-configuration>
    
        <session-factory>
            
            <property name="hibernate.connection.driver_class">com.mysql.cj.jdbc.Driver</property>
            <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/blog?autoReconnect=true&useSSL=false&useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai</property>
            <property name="hibernate.connection.username">root</property>
            <property name="hibernate.connection.password">root</property>
    
            
            <property name="connection.pool_size">1</property>
    
            
            <property name="dialect">org.hibernate.dialect.MySQL8Dialect</property>
    
            
            <property name="current_session_context_class">thread</property>
    
            
            <property name="show_sql">true</property>
    
            
            <property name="hbm2ddl.auto">update</property>
    
            
            <mapping resource="employee.hbm.xml" />
    
        </session-factory>
    
    </hibernate-configuration>

下一步我们将创建类 HibernateMainClient

Right click on src/main/java 
    --> New 
    --> Click on Class 
    --> Enter value for Package as docs.console.hibernate.com and Enter value for Name HibernateMainClient

请在下面找到 HibernateMainClient.java 的给定代码。

HibernateMainClient.java

package com.docsconsole.tutorials.client;
    
    import com.docsconsole.tutorials.entity.Employee;
    import java.util.List;
    
    import com.docsconsole.tutorials.util.HibernateUtil;
    import org.hibernate.Query;
    import org.hibernate.Session;
    import org.hibernate.SessionFactory;
    import org.hibernate.Transaction;
    
    public class HibernateMainClient {
    
        /*static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
    	static final String DB_URL = "jdbc:mysql://localhost/docsconsole";
    
    	static final String USERNAME = "root";
    	static final String PASSWORD = "";*/
        public static void main(String[] args) {
    
            System.out.println("::::::::::::::::--------------------Started main method here-------------------::::::::::::::::");
    
            SessionFactory sfactory = HibernateUtil.getSessionFactory();
            System.out.println("::::::::::::::::--------------------SessionFactory is created here-------------------::::::::::::::::");
            Session session = sfactory.getCurrentSession();
            Transaction tx = session.beginTransaction();
    
            Employee employee = new Employee();
            employee.setEmpFirstName("fname");
            employee.setEmpLastName("lname");
            session.save(employee);
            System.out.println("save Completed !");
    
            System.out.println("::::::::::::::::--------------------Transaction is created here-------------------::::::::::::::::");
            Query query = session.createSQLQuery("select emp_id, emp_first_name, emp_last_name FROM employee");
            List resultList = query.list();
    
            for (Object object : resultList) {
                Object[] objectArray = (Object[]) object;
                System.out.println("::::::::::::::::--------------------Employe Id:" + objectArray[0]);
                System.out.println("::::::::::::::::--------------------Employe First Name:" + objectArray[1]);
                System.out.println("::::::::::::::::--------------------Employe Last Name:" + objectArray[2]);
            }
            tx.commit();
    
        }
    }

为 Employee 实体类创建 hbm 文件。

Right click on docs.console.hibernate.com 
    --> New 
    --> Click on Other 
    --> select XML File 
    --> Click Next 
    --> Enter value for File Name Employee.hbm.xml

下面是 Employee.hbm.xml 的 xml 内容

Employee.hbm.xml

<?xml version="1.0"?>
    <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
    "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
    
    <hibernate-mapping>
    	<class name="docs.console.com.model.Employee" table="employees"
    		catalog="docsconsole">
    		<id name="empId" type="java.lang.Integer">
    			<column name="emp_id" />
    			<generator class="identity" />
    		</id>
    		<property name="empFirstName" type="string">
    			<column name="emp_first_name" length="10" not-null="true"
    				unique="true" />
    		</property>
    		<property name="EmpLastName" type="string">
    			<column name="emp_last_name" length="20" not-null="true"
    				unique="true" />
    		</property>
    	</class>
    </hibernate-mapping>

现在我们将为 HibernateUtil.java 创建文件

Right click on src/main/java 
    --> New 
    --> Click on Class 
    --> Enter value for Package as docs.console.hibernate.com.util and Enter value for Name HibernateUtil.

请在下面找到 HibernateUtil.java 的给定代码。

HibernateUtil.java

package docs.console.hibernate.com.util;
    
    import org.hibernate.SessionFactory;
    import org.hibernate.cfg.Configuration;
    
    public class HibernateUtil {
    	private static final SessionFactory sessionFactory = buildSessionFactory();
    
    	private static SessionFactory buildSessionFactory() {
    		
    		try {
    			
    			// Create the SessionFactory from hibernate.cfg.xml
    			return new Configuration().configure().buildSessionFactory();
    		}
    		catch (Throwable ex) {
    			// Make sure you log the exception, as it might be swallowed
    			System.err.println("Initial SessionFactory creation failed." + ex);
    			throw new ExceptionInInitializerError(ex);
    		}
    	}
    
    	public static SessionFactory getSessionFactory() {
    		return sessionFactory;
    	}
    }

创建项目后，最终架构将如下所示。

![76bf3c7ae53cdb74dc3078e8d6728188.png][]

NetBeans:

![watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBAYWxsd2F5Mg_size_13_color_FFFFFF_t_70_g_se_x_16][]

当我们执行 HibernateMainClient 时，我们将得到低于给定的输出。

![800cc3b5d3751e1f56ec5d1266dd6875.png][]

请在此处参考 Github 存储库[Hibernate-BasicExample-App-With-XML][]

[Link 1]: https://docsconsole.com/spring-boot/spring-boot-helloworld-app-with-maven
[76bf3c7ae53cdb74dc3078e8d6728188.png]: https://img-blog.csdnimg.cn/img_convert/76bf3c7ae53cdb74dc3078e8d6728188.png
[watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBAYWxsd2F5Mg_size_13_color_FFFFFF_t_70_g_se_x_16]: https://img-blog.csdnimg.cn/c866f733723b4f5ab7ee00101a108a56.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBAYWxsd2F5Mg==,size_13,color_FFFFFF,t_70,g_se,x_16
[800cc3b5d3751e1f56ec5d1266dd6875.png]: https://img-blog.csdnimg.cn/img_convert/800cc3b5d3751e1f56ec5d1266dd6875.png
[Hibernate-BasicExample-App-With-XML]: https://github.com/Docsconsole/Hibernate-BasicExample-App-With-XML