Spring Orm 简明教程

Spring ORM - Quick Guide

Spring ORM - Overview

Spring 框架与 Hibernate、Java 持久化 API (JPA)、Java 数据对象 (JDO) 和 iBATIS SQL 映射等 ORM 框架很好地集成。Spring 提供资源管理、数据访问对象 (DAO) 实现和事务策略。Spring 允许通过依赖项管理配置 ORM 库功能。Spring 为其支持的所有 ORM 库维护统一的 DAO 异常层次结构和通用的事务管理。

Spring IoC 容器促进了 ORM 配置和轻松部署。以下是使用 Spring 框架创建 ORM DAO 的主要优点。

  1. Easy to Test −使用 Spring IoC，可以轻松配置 ORM 实现。可以孤立地测试持久单元的每一部分。

  2. Common Data Access Exception −Spring 将 ORM 工具异常包装到一个通用运行时异常（比如 DataAccessException）。此方法可帮助在相应图层中处理大多数持久化异常（不可恢复）。无需处理 ORM 特定的样板捕捉/抛出/异常声明。

  3. General Resource Management −Spring 应用程序上下文轻松地管理持久化对象及其配置。例如，Hibernate SessionFactory 实例、JPA EntityManagerFactory 实例、JDBC DataSource 实例、iBatis SQL 映射配置对象和其他相关对象。Spring 本身处理本地以及 JTA 事务管理。

  4. Integrated transaction management −Spring AOP 可用于使用声明式面向 AOP 的拦截器（例如 @Transaction 注释或在 XML 配置文件中指定事务 AOP 建议）将 ORM 代码包装起来。Spring 处理事务语义、异常处理、回滚等。Spring 允许在不影响 ORM 代码的情况下交换事务管理器。

Spring ORM - Environment Setup

本章将在您开始使用 Spring 框架时，指导您如何准备开发环境。它还将教您在设置 Spring 框架之前如何在您的机器上设置 JDK、Maven 和 Eclipse −

Setup Java Development Kit (JDK)

你可以从 Oracle 的 Java 站点下载 SDK 的最新版本 − Java SE Downloads. 你在下载文件中可以找到安装 JDK 的说明，按照给定的说明进行安装和配置。最后设置 PATH 和 JAVA_HOME 环境变量以引用包含 java 和 javac 的目录，通常分别为 java_install_dir/bin 和 java_install_dir。

如果您运行的是 Windows 且在 C:\jdk-11.0.11 中安装了 JDK，那么您将不得不把以下代码行放入您的 C:\autoexec.bat 文件中。

set PATH=C:\jdk-11.0.11;%PATH%
set JAVA_HOME=C:\jdk-11.0.11

或者，在 Windows NT/2000/XP 中，你必须右键单击我的电脑，选择属性 → 高级 → 环境变量。然后，你将不得不更新 PATH 值并单击确定按钮。

在 Unix（Solaris、Linux 等）中，如果 SDK 安装在 /usr/local/jdk-11.0.11 且您使用 C shell，那么您将不得不把以下代码行放入您的 .cshrc 文件中。

setenv PATH /usr/local/jdk-11.0.11/bin:$PATH
setenv JAVA_HOME /usr/local/jdk-11.0.11

或者，如果你使用诸如 Borland JBuilder、Eclipse、IntelliJ IDEA 或 Sun ONE Studio 这样的集成开发环境 (IDE)，则必须编译并运行一个简单程序来确认 IDE 知道你在何处安装了 Java。否则，你必须按照 IDE 文档中给出的内容执行正确的设置。

Setup Eclipse IDE

本教程中的所有示例都是使用 Eclipse IDE 编写的。因此，我们建议你应该在你机器上安装 Eclipse 的最新版本。

要安装 Eclipse IDE，请从 www.eclipse.org/downloads/ 下载最新的 Eclipse 二进制文件。下载安装文件后，将二进制分发解压缩到合适的目录中。例如，在 Windows 中的 C:\eclipse 或 Linux/Unix 中的 /usr/local/eclipse 中，最后适当设置 PATH 变量。

可以通过在 Windows 机器上执行以下命令启动 Eclipse，或者你只需双击 eclipse.exe

%C:\eclipse\eclipse.exe

可以通过在 Unix（Solaris、Linux 等）机器上执行以下命令启动 Eclipse −

$/usr/local/eclipse/eclipse

成功启动后，如果一切正常，它应该显示以下结果 −

eclipsehomepage

Install MySQL Database

当然，您将需要最重要的实际运行数据库，其中包含您可以查询和修改的表。

  1. MySQL DB − MySQL 是一个开源数据库。您可以从 MySQL Official Site 下载。我们建议您下载完整的 Windows 安装程序。此外，还要下载并安装 MySQL Administrator 和 MySQL Query Browser. 。这些基于 GUI 的工具将使您的开发变得更加容易。最后，下载 MySQL Connector/J （MySQL JDBC 驱动程序）并将它解压到一个方便的目录中。出于本教程的目的，我们将假设您已将驱动程序安装在 C:\Program Files\MySQL\mysql-connector-java-5.1.8 中。因此，将 CLASSPATH 变量设置为 C:\Program Files\MySQL\mysql-connector-java-5.1.8\mysql-connector-java-5.1.8-bin.jar。您的驱动程序版本可能会因安装而异。

Set Database Credential

当我们安装 MySQL 数据库时，它的管理员 ID 设置为 root ，并提供设置密码的选项。

使用 root ID 和密码，您可以创建另一个用户 ID 和密码，也可以为您的 JDBC 应用程序使用 root ID 和密码。

有各种数据库操作，例如数据库创建和删除，这需要管理员 ID 和密码。

如果您没有足够权限创建新用户，那么您可以请求数据库管理员 (DBA) 为您创建用户 ID 和密码。

Create Database

要创建 TUTORIALSPOINT 数据库，请执行以下步骤 −

Step 1

打开 Command Prompt 并更改到安装目录，如下所示 −

C:\>
C:\>cd Program Files\MySQL\bin
C:\Program Files\MySQL\bin>

Note − mysqld.exe 的路径可能因系统上 MySQL 的安装位置而异。您还可以查看有关如何启动和停止数据库服务器的文档。

Step 2

如果数据库服务器尚未运行，请执行以下命令以下启动数据库服务器。

C:\Program Files\MySQL\bin>mysqld
C:\Program Files\MySQL\bin>

Step 3

通过执行以下命令创建 TUTORIALSPOINT 数据库 −

C:\Program Files\MySQL\bin> create database TUTORIALSPOINT;

Note − mysqld.exe 的路径可能因系统上 MySQL 的安装位置而异。您还可以查看有关如何启动和停止数据库服务器的文档。

要全面了解 MySQL 数据库，请学习 MySQL Tutorial 。

Set Maven

在本教程中，我们使用 maven 来运行和构建基于 Spring 的示例。请按照 Maven - Environment Setup 安装 maven。

Spring ORM - Create Project

使用 Eclipse 选择 File → New * → *Maven Project 。勾选 创建简单项目（跳过原型选择），然后单击下一步。

new maven project

输入详细信息，如下所示：

project details

单击完成按钮，将创建一个新项目。

spring application

现在我们的项目已经准备就绪，在下一章中，让我们在 pom.xml 中添加以下依赖项。

  1. Spring Framework

  2. Hibernate

  3. MySQL Connector

  4. Other related dependencies.

Spring ORM - Maven Hibernate

我们将在 pom.xml 中添加以下依赖项。

  1. Spring Framework

  2. Hibernate

  3. MySQL Connector

  4. Other related dependencies.

按照以下内容更新 pom.xml。

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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.tutorialspoint</groupId>
   <artifactId>springorm</artifactId>
   <version>0.0.1-SNAPSHOT</version>
   <name>Spring ORM</name>
   <description>Spring ORM Test Project</description>
   <properties>
      <org.springframework.version>4.3.7.RELEASE</org.springframework.version>
      <org.hibernate.version>5.2.9.Final</org.hibernate.version>
      <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
      <java.version>1.8</java.version>
   </properties>
   <dependencies>
      <dependency>
         <groupId>org.springframework</groupId>
         <artifactId>spring-context</artifactId>
         <version>${org.springframework.version}</version>
         <scope>compile</scope>
      </dependency>
      <dependency>
         <groupId>org.springframework</groupId>
         <artifactId>spring-orm</artifactId>
         <version>${org.springframework.version}</version>
      </dependency>
      <dependency>
         <groupId>org.hibernate</groupId>
         <artifactId>hibernate-core</artifactId>
         <version>${org.hibernate.version}</version>
      </dependency>
      <dependency>
         <groupId>org.hibernate</groupId>
         <artifactId>hibernate-entitymanager</artifactId>
         <version>${org.hibernate.version}</version>
      </dependency>
      <dependency>
         <groupId>org.apache.commons</groupId>
         <artifactId>commons-dbcp2</artifactId>
         <version>2.1.1</version>
      </dependency>
      <dependency>
         <groupId>mysql</groupId>
         <artifactId>mysql-connector-java</artifactId>
         <scope>runtime</scope>
         <version>8.0.13</version>
      </dependency>
      <dependency>
         <groupId>com.sun.activation</groupId>
         <artifactId>javax.activation</artifactId>
         <version>1.2.0</version>
      </dependency>
      <dependency>
         <groupId>javax.xml.bind</groupId>
         <artifactId>jaxb-api</artifactId>
         <version>2.3.1</version>
      </dependency>
      <dependency>
         <groupId>org.glassfish.jaxb</groupId>
         <artifactId>jaxb-runtime</artifactId>
         <version>2.3.1</version>
         <scope>runtime</scope>
      </dependency>
   </dependencies>
   <build>
      <plugins>
         <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.1</version>
            <configuration>
               <source>${java.version}</source>
               <target>${java.version}</target>
            </configuration>
         </plugin>
      </plugins>
   </build>
</project>

现在右键单击项目名称。选择 Maven → Update Project 下载所需的依赖项。

Spring ORM - Persistence Hibernate

persistence.xml 定义了与 Hibernate 相关的各个方面，如下所示。

  1. Persistence Unit − 包含所有详细信息的持久化单元。其名称用于获取 Spring 上下文中的引用。

  2. provider − org.hibernate.jpa.HibernatePersistenceProvider 类将用作提供程序。

  3. Database url and credentials − 在属性部分，我们传递与数据库相关的值。

  4. show_sql − 显示生成的 SQL 查询

  5. hbm2ddl − 允许 Hibernate 创建表。

在 src → main > resources > META-INF 文件夹中创建 persistence.xml。

persistence.xml

<persistence xmlns="http://xmlns.jcp.org/xml/ns/persistence"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence
   http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd" version="2.1">

   <persistence-unit name="Hibernate_JPA">
   <description> Spring Hibernate JPA Configuration Example</description>
   <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
   <properties>
      <property name="javax.persistence.jdbc.driver" value="com.mysql.cj.jdbc.Driver" />
      <property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/tutorialspoint?useSSL=false" />
      <property name="javax.persistence.jdbc.user" value="root" />
      <property name="javax.persistence.jdbc.password" value="root@123" />
      <property name="hibernate.show_sql" value="true" />
      <property name="hibernate.hbm2ddl.auto" value="create" />
   </properties>
   </persistence-unit>
</persistence>

Spring ORM - Update Project

让我们在相关的包中向项目添加以下类。

project structure

Employee 类，用于保留在数据库中。

Employee.java

package com.tutorialspoint.jpa.entity;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name = "Employees")
public class Employee {
   @Id
   @GeneratedValue(strategy = GenerationType.IDENTITY)
   private int id;

   @Column(name = "NAME")
   private String name;

   @Column(name = "SALARY")
   private double salary;

   @Column(name = "DESIGNATION")
   private String designation;

   public Employee( ) {
   }

   public Employee(String name, double salary, String designation) {
      this.name = name;
      this.salary = salary;
      this.designation = designation;
   }
   public int getId() {
      return id;
   }
   public void setId(int id) {
      this.id = id;
   }
   public String getName() {
      return name;
   }
   public void setName(String name) {
      this.name = name;
   }
   public double getSalary() {
      return salary;
   }
   public void setSalary(double salary) {
      this.salary = salary;
   }
   public String getDesignation() {
      return designation;
   }
   public void setDesignation(String designation) {
      this.designation = designation;
   }
}

Employee DAO 类，用于对数据库执行操作。

EmployeeDao.java

package com.tutorialspoint.jpa.dao;

import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Root;
import org.springframework.stereotype.Repository;
import com.tutorialspoint.jpa.entity.Employee;

@Repository
public class EmployeeDao {
   @PersistenceContext
   private EntityManager em;

   public void add(Employee employee) {
      em.persist(employee);
   }
   public List<Employee> listEmployees() {
      CriteriaQuery<Employee> criteriaQuery = em.getCriteriaBuilder().createQuery(Employee.class);
      @SuppressWarnings("unused")
      Root<Employee> root = criteriaQuery.from(Employee.class);
      return em.createQuery(criteriaQuery).getResultList();
   }
}

Employee Service 类，用于使用 Employee DAO 类。

EmployeeService.java

package com.tutorialspoint.jpa.service;

import java.util.List;
import javax.transaction.Transactional;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import com.tutorialspoint.jpa.dao.EmployeeDao;
import com.tutorialspoint.jpa.entity.Employee;

@Service
public class EmployeeService {
   @Autowired
   private EmployeeDao employeeDao;

   @Transactional
   public void add(Employee employee) {
      employeeDao.add(employee);
   }
   @Transactional()
   public List<Employee> listEmployees() {
      return employeeDao.listEmployees();
   }
}

Application Configuration，供 Spring 框架使用。

AppConfig.java

package com.tutorialspoint.jpa;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.ComponentScans;
import org.springframework.context.annotation.Configuration;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.LocalEntityManagerFactoryBean;
import org.springframework.transaction.annotation.EnableTransactionManagement;

@Configuration
@EnableTransactionManagement
@ComponentScans(value = { @ComponentScan("com.tutorialspoint.jpa.dao"),
@ComponentScan("com.tutorialspoint.jpa.service") })
public class AppConfig {
   @Bean
   public LocalEntityManagerFactoryBean geEntityManagerFactoryBean() {
      LocalEntityManagerFactoryBean factoryBean = new LocalEntityManagerFactoryBean();
      factoryBean.setPersistenceUnitName("Hibernate_JPA");
      return factoryBean;
   }
   @Bean
   public JpaTransactionManager geJpaTransactionManager() {
      JpaTransactionManager transactionManager = new JpaTransactionManager();
      transactionManager.setEntityManagerFactory(geEntityManagerFactoryBean().getObject());
      return transactionManager;
   }
}

Main Application，用于运行并测试功能。

MainApp.java

package com.tutorialspoint.jpa;

import java.sql.SQLException;
import java.util.List;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import com.tutorialspoint.jpa.entity.Employee;
import com.tutorialspoint.jpa.service.EmployeeService;


public class MainApp {
   public static void main(String[] args) throws SQLException {
      AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(AppConfig.class);
      EmployeeService employeeService = context.getBean(EmployeeService.class);

      employeeService.add(new Employee("Julie", 10000, "Technical Manager"));
      employeeService.add(new Employee("Robert", 20000, "Senior Manager"));
      employeeService.add(new Employee("Anil", 5000, "Software Engineer"));

      // Get Persons
      List<Employee> employees = employeeService.listEmployees();
      for (Employee employee : employees) {
         System.out.println("Id : "+employee.getId());
         System.out.println("Name : "+employee.getName());
         System.out.println("Salary = "+employee.getSalary());
         System.out.println("Designation = "+employee.getDesignation());
         System.out.println();
      }
      context.close();
   }
}

Spring ORM - Run & Test Hibernate

现在在 Eclipse 中，右键单击 MainApp.java，选择 Run As ，然后选择 Java Application 。检查 Eclipse 中的控制台日志。您会看到以下日志 −

...
Sep 27, 2021 9:16:52 AM org.springframework.orm.jpa.LocalEntityManagerFactoryBean createNativeEntityManagerFactory
INFO: Building JPA EntityManagerFactory for persistence unit 'Hibernate_JPA'
Sep 27, 2021 9:16:52 AM org.hibernate.jpa.internal.util.LogHelper logPersistenceUnitInformation
INFO: HHH000204: Processing PersistenceUnitInfo [name: Hibernate_JPA...]
...
INFO: HHH000400: Using dialect: org.hibernate.dialect.MySQL5Dialect
Hibernate: drop table if exists Employees
Sep 27, 2021 9:16:54 AM org.hibernate.resource.transaction.backend.jdbc.internal.DdlTransactionIsolatorNonJtaImpl getIsolatedConnection
INFO: HHH10001501: Connection obtained from JdbcConnectionAccess [org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator$ConnectionProviderJdbcConnectionAccess@2264ea32] for (non-JTA) DDL execution was not in auto-commit mode; the Connection 'local transaction' will be committed and the Connection will be set into auto-commit mode.
Hibernate: create table Employees (id integer not null auto_increment, DESIGNATION varchar(255), NAME varchar(255), SALARY double precision, primary key (id)) engine=MyISAM
Sep 27, 2021 9:16:54 AM org.hibernate.resource.transaction.backend.jdbc.internal.DdlTransactionIsolatorNonJtaImpl getIsolatedConnection
INFO: HHH10001501: Connection obtained from JdbcConnectionAccess [org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator$ConnectionProviderJdbcConnectionAccess@58740366] for (non-JTA) DDL execution was not in auto-commit mode; the Connection 'local transaction' will be committed and the Connection will be set into auto-commit mode.
Sep 27, 2021 9:16:54 AM org.hibernate.tool.schema.internal.SchemaCreatorImpl applyImportSources
INFO: HHH000476: Executing import script 'org.hibernate.tool.schema.internal.exec.ScriptSourceInputNonExistentImpl@4b74b35'
Sep 27, 2021 9:16:54 AM org.springframework.orm.jpa.LocalEntityManagerFactoryBean buildNativeEntityManagerFactory
INFO: Initialized JPA EntityManagerFactory for persistence unit 'Hibernate_JPA'
Hibernate: insert into Employees (DESIGNATION, NAME, SALARY) values (?, ?, ?)
Hibernate: insert into Employees (DESIGNATION, NAME, SALARY) values (?, ?, ?)
Hibernate: insert into Employees (DESIGNATION, NAME, SALARY) values (?, ?, ?)
Sep 27, 2021 9:16:55 AM org.hibernate.hql.internal.QueryTranslatorFactoryInitiator initiateService
INFO: HHH000397: Using ASTQueryTranslatorFactory
Hibernate: select employee0_.id as id1_0_, employee0_.DESIGNATION as DESIGNAT2_0_, employee0_.NAME as NAME3_0_, employee0_.SALARY as SALARY4_0_ from Employees employee0_
Id   : 1
Name : Julie
Salary = 10000.0
Designation = Technical Manager

Id   : 2
Name : Robert
Salary = 20000.0
Designation = Senior Manager

Id   : 3
Name : Anil
Salary = 5000.0
Designation = Software Engineer

Sep 27, 2021 9:16:55 AM org.springframework.context.annotation.AnnotationConfigApplicationContext doClose
INFO: Closing org.springframework.context.annotation.AnnotationConfigApplicationContext@18eed359: startup date [Mon Sep 27 09:16:51 IST 2021]; root of context hierarchy
Sep 27, 2021 9:16:55 AM org.springframework.orm.jpa.LocalEntityManagerFactoryBean destroy
INFO: Closing JPA EntityManagerFactory for persistence unit 'Hibernate_JPA'
Sep 27, 2021 9:16:55 AM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl stop
INFO: HHH10001008: Cleaning up connection pool [jdbc:mysql://localhost:3306/tutorialspoint?useSSL=false]

在此使用 Spring 配置构建并运行项目。创建一个 Employee 表并有三个记录。您可以使用 MySQL 控制台对此进行验证。

Enter password: ********
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 41
Server version: 8.0.23 MySQL Community Server - GPL

Copyright (c) 2000, 2021, Oracle and/or its affiliates.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> use tutorialspoint;
Database changed
mysql> select * from employees;
+----+-------------------+--------+--------+
| id | DESIGNATION       | NAME   | SALARY |
+----+-------------------+--------+--------+
|  1 | Technical Manager | Julie  |  10000 |
|  2 | Senior Manager    | Robert |  20000 |
|  3 | Software Engineer | Anil   |   5000 |
+----+-------------------+--------+--------+
3 rows in set (0.00 sec)

mysql>

Spring ORM - Maven EclipseLink

我们将在 pom.xml 中添加以下依赖项。

  1. Spring Framework

  2. EclipseLink

  3. MySQL Connector

  4. Other related dependencies.

按照以下内容更新 pom.xml。

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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.tutorialspoint</groupId>
   <artifactId>springorm</artifactId>
   <version>0.0.1-SNAPSHOT</version>
   <name>Spring ORM</name>
   <description>Spring ORM Test Project</description>
   <properties>
      <org.springframework.version>4.3.7.RELEASE</org.springframework.version>
      <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
      <java.version>1.8</java.version>
   </properties>
   <dependencies>
      <dependency>
         <groupId>org.springframework</groupId>
         <artifactId>spring-context</artifactId>
         <version>${org.springframework.version}</version>
         <scope>compile</scope>
      </dependency>
      <dependency>
         <groupId>org.springframework</groupId>
         <artifactId>spring-orm</artifactId>
         <version>${org.springframework.version}</version>
      </dependency>
      <dependency>
         <groupId>org.eclipse.persistence</groupId>
         <artifactId>eclipselink</artifactId>
         <version>2.5.1</version>
      </dependency>
      <dependency>
         <groupId>org.eclipse.persistence</groupId>
         <artifactId>javax.persistence</artifactId>
         <version>2.0.0</version>
      </dependency>
      <dependency>
         <groupId>javax.transaction</groupId>
         <artifactId>javax.transaction-api</artifactId>
         <version>1.3</version>
      </dependency>
      <dependency>
         <groupId>org.apache.commons</groupId>
         <artifactId>commons-dbcp2</artifactId>
         <version>2.1.1</version>
      </dependency>
      <dependency>
         <groupId>mysql</groupId>
         <artifactId>mysql-connector-java</artifactId>
         <scope>runtime</scope>
         <version>8.0.13</version>
      </dependency>
      <dependency>
         <groupId>com.sun.activation</groupId>
         <artifactId>javax.activation</artifactId>
         <version>1.2.0</version>
      </dependency>
      <dependency>
         <groupId>javax.xml.bind</groupId>
         <artifactId>jaxb-api</artifactId>
         <version>2.3.1</version>
      </dependency>
      <dependency>
         <groupId>org.glassfish.jaxb</groupId>
         <artifactId>jaxb-runtime</artifactId>
         <version>2.3.1</version>
         <scope>runtime</scope>
      </dependency>
   </dependencies>
   <build>
      <plugins>
         <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.1</version>
            <configuration>
               <source>${java.version}</source>
               <target>${java.version}</target>
            </configuration>
         </plugin>
      </plugins>
   </build>
</project>

现在右键单击项目名称。选择 Maven → Update Project 下载所需的依赖项。

Spring ORM - Persistence EclipseLink

persistence.xml 定义了与 EclipseLink 相关的各种方面，如下所示。

  1. Persistence Unit − 包含所有详细信息的持久化单元。其名称用于获取 Spring 上下文中的引用。

  2. provider − 组织 eclipse.persistence.jpa.PersistenceProvider 类将用作提供程序。

  3. Database url and credentials − 在属性部分，我们传递与数据库相关的值。

  4. class − 注册要持久化的类。

  5. eclipselink.ddl-generation − 允许 EclipseLink 创建表。

在 src → main > resources > META-INF 文件夹中创建 persistence.xml。

persistence.xml

<persistence xmlns="http://xmlns.jcp.org/xml/ns/persistence"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence
   http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd" version="2.1">

   <persistence-unit name="EclipseLink_JPA">
      <description> Spring EclipseLink JPA Configuration Example</description>
      <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
      <class>com.tutorialspoint.jpa.entity.Employee</class>
      <properties>
         <property name="javax.persistence.jdbc.driver" value="com.mysql.cj.jdbc.Driver" />
         <property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/tutorialspoint?useSSL=false" />
         <property name="javax.persistence.jdbc.user" value="root" />
         <property name="javax.persistence.jdbc.password" value="root@123" />
         <property name="eclipselink.logging.level" value="FINE"/>
         <property name="eclipselink.ddl-generation" value="create-tables"/>
      </properties>

   </persistence-unit>
</persistence>

Spring ORM - Update Project EclipseLink

现在，更新 AppConfig.java 以使用为 EclipseLink 创建的持久化单元。

AppConfig.java

package com.tutorialspoint.jpa;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.ComponentScans;
import org.springframework.context.annotation.Configuration;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.LocalEntityManagerFactoryBean;
import org.springframework.transaction.annotation.EnableTransactionManagement;

@Configuration
@EnableTransactionManagement
@ComponentScans(value = { @ComponentScan("com.tutorialspoint.jpa.dao"),
   @ComponentScan("com.tutorialspoint.jpa.service") })
   public class AppConfig {

   @Bean
   public LocalEntityManagerFactoryBean geEntityManagerFactoryBean() {
      LocalEntityManagerFactoryBean factoryBean = new LocalEntityManagerFactoryBean();
      factoryBean.setPersistenceUnitName("EclipseLink_JPA");
      return factoryBean;
   }
   @Bean
   public JpaTransactionManager geJpaTransactionManager() {
      JpaTransactionManager transactionManager = new JpaTransactionManager();
      transactionManager.setEntityManagerFactory(geEntityManagerFactoryBean().getObject());
      return transactionManager;
   }
}

现在重置数据库。

mysql> use tutorialspoint
Database changed
mysql> delete from employees;
Query OK, 3 rows affected (0.02 sec)

mysql> drop table employees;
Query OK, 0 rows affected (0.17 sec)

mysql>

Spring ORM - Test EclipseLink

现在在 Eclipse 中，右键单击 MainApp.java，选择 Run As ，然后选择 Java Application 。检查 Eclipse 中的控制台日志。您会看到以下日志 −

...
Sep 28, 2021 8:56:13 AM org.springframework.orm.jpa.LocalEntityManagerFactoryBean createNativeEntityManagerFactory
INFO: Building JPA EntityManagerFactory for persistence unit 'EclipseLink_JPA'
[EL Config]: metadata: 2021-09-28 08:56:13.763--ServerSession(712627377)--Thread(Thread[main,5,main])--The access type for the persistent class [class com.tutorialspoint.jpa.entity.Employee] is set to [FIELD].
[EL Config]: metadata: 2021-09-28 08:56:13.787--ServerSession(712627377)--Thread(Thread[main,5,main])--The alias name for the entity class [class com.tutorialspoint.jpa.entity.Employee] is being defaulted to: Employee.
[EL Config]: metadata: 2021-09-28 08:56:13.802--ServerSession(712627377)--Thread(Thread[main,5,main])--The column name for element [id] is being defaulted to: ID.
Sep 28, 2021 8:56:13 AM org.springframework.orm.jpa.LocalEntityManagerFactoryBean buildNativeEntityManagerFactory
INFO: Initialized JPA EntityManagerFactory for persistence unit 'EclipseLink_JPA'
[EL Info]: 2021-09-28 08:56:14.102--ServerSession(712627377)--Thread(Thread[main,5,main])--EclipseLink, version: Eclipse Persistence Services - 2.5.1.v20130918-f2b9fc5
[EL Fine]: connection: 2021-09-28 08:56:14.403--Thread(Thread[main,5,main])--Detected database platform: org.eclipse.persistence.platform.database.MySQLPlatform
[EL Config]: connection: 2021-09-28 08:56:14.423--ServerSession(712627377)--Connection(741883443)--Thread(Thread[main,5,main])--connecting(DatabaseLogin(
   platform=>MySQLPlatform
   user name=> "root"
   datasource URL=> "jdbc:mysql://localhost:3306/tutorialspoint?useSSL=false"
))
[EL Config]: connection: 2021-09-28 08:56:14.469--ServerSession(712627377)--Connection(2134915053)--Thread(Thread[main,5,main])--Connected: jdbc:mysql://localhost:3306/tutorialspoint?useSSL=false
   User: root@localhost
   Database: MySQL  Version: 8.0.23
   Driver: MySQL Connector/J  Version: mysql-connector-java-8.0.13 (Revision: 66459e9d39c8fd09767992bc592acd2053279be6)
[EL Info]: connection: 2021-09-28 08:56:14.539--ServerSession(712627377)--Thread(Thread[main,5,main])--file:/F:/Workspace/springorm/target/classes/_EclipseLink_JPA login successful
[EL Fine]: sql: 2021-09-28 08:56:14.602--ServerSession(712627377)--Connection(2134915053)--Thread(Thread[main,5,main])--CREATE TABLE Employees (ID INTEGER AUTO_INCREMENT NOT NULL, DESIGNATION VARCHAR(255), NAME VARCHAR(255), SALARY DOUBLE, PRIMARY KEY (ID))
[EL Fine]: sql: 2021-09-28 08:56:14.836--ClientSession(181326224)--Connection(2134915053)--Thread(Thread[main,5,main])--INSERT INTO Employees (DESIGNATION, NAME, SALARY) VALUES (?, ?, ?)
   bind => [Technical Manager, Julie, 10000.0]
[EL Fine]: sql: 2021-09-28 08:56:14.855--ClientSession(181326224)--Connection(2134915053)--Thread(Thread[main,5,main])--SELECT LAST_INSERT_ID()
[EL Fine]: sql: 2021-09-28 08:56:14.883--ClientSession(1573125303)--Connection(2134915053)--Thread(Thread[main,5,main])--INSERT INTO Employees (DESIGNATION, NAME, SALARY) VALUES (?, ?, ?)
   bind => [Senior Manager, Robert, 20000.0]
[EL Fine]: sql: 2021-09-28 08:56:14.885--ClientSession(1573125303)--Connection(2134915053)--Thread(Thread[main,5,main])--SELECT LAST_INSERT_ID()
[EL Fine]: sql: 2021-09-28 08:56:14.893--ClientSession(2054787417)--Connection(2134915053)--Thread(Thread[main,5,main])--INSERT INTO Employees (DESIGNATION, NAME, SALARY) VALUES (?, ?, ?)
   bind => [Software Engineer, Anil, 5000.0]
[EL Fine]: sql: 2021-09-28 08:56:14.896--ClientSession(2054787417)--Connection(2134915053)--Thread(Thread[main,5,main])--SELECT LAST_INSERT_ID()
[EL Fine]: sql: 2021-09-28 08:56:14.929--ServerSession(712627377)--Connection(2134915053)--Thread(Thread[main,5,main])--SELECT ID, DESIGNATION, NAME, SALARY FROM Employees
Id   : 1
Name : Julie
Salary = 10000.0
Designation = Technical Manager

Id   : 2
Name : Robert
Salary = 20000.0
Designation = Senior Manager

Id   : 3
Name : Anil
Salary = 5000.0
Designation = Software Engineer

Sep 28, 2021 8:56:14 AM org.springframework.context.annotation.AnnotationConfigApplicationContext doClose
INFO: Closing org.springframework.context.annotation.AnnotationConfigApplicationContext@5383967b: startup date [Tue Sep 28 08:56:12 IST 2021]; root of context hierarchy
[EL Config]: connection: 2021-09-28 08:56:14.935--ServerSession(712627377)--Connection(2134915053)--Thread(Thread[main,5,main])--disconnect
Sep 28, 2021 8:56:14 AM org.springframework.orm.jpa.LocalEntityManagerFactoryBean destroy
INFO: Closing JPA EntityManagerFactory for persistence unit 'EclipseLink_JPA'
[EL Info]: connection: 2021-09-28 08:56:14.936--ServerSession(712627377)--Thread(Thread[main,5,main])--file:/F:/Workspace/springorm/target/classes/_EclipseLink_JPA logout successful
[EL Config]: connection: 2021-09-28 08:56:14.936--ServerSession(712627377)--Connection(741883443)--Thread(Thread[main,5,main])--disconnect

在此使用 Spring 配置构建并运行项目。创建一个 Employee 表并有三个记录。您可以使用 MySQL 控制台对此进行验证。

Enter password: ********
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 41
Server version: 8.0.23 MySQL Community Server - GPL

Copyright (c) 2000, 2021, Oracle and/or its affiliates.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> use tutorialspoint;
Database changed
mysql> select * from employees;
+----+-------------------+--------+--------+
| id | DESIGNATION       | NAME   | SALARY |
+----+-------------------+--------+--------+
|  1 | Technical Manager | Julie  |  10000 |
|  2 | Senior Manager    | Robert |  20000 |
|  3 | Software Engineer | Anil   |   5000 |
+----+-------------------+--------+--------+
3 rows in set (0.00 sec)

mysql>