Spring boot hibernate Configuration Example

1. pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<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>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.5.RELEASE</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.howtodoinjava.demo</groupId>
    <artifactId>SpringBoot2Demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>SpringBoot2Demo</name>
    <description>Demo project for Spring Boot</description>
 
    <properties>
        <java.version>1.8</java.version>
    </properties>
 
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
 
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
 
        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
            <scope>runtime</scope>
        </dependency>
 
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>
 
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
 
</project>

spring-boot-starter-data-jpa 包含了 spring data, hibernate, HikariCP, JPA API, JPA Implementation (默认为hibernate), JDBC和其他库.

 h2数据库应用

2. Create JPA entity classes

EmployeeEntity.java

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
 
@Entity
@Table(name="TBL_EMPLOYEES")
public class EmployeeEntity {
 
    @Id
    @GeneratedValue
    private Long id;
     
    @Column(name="first_name")
    private String firstName;
     
    @Column(name="last_name")
    private String lastName;
     
    @Column(name="email", nullable=false, length=200)
    private String email;
     
    //Setters and getters left out for brevity.
 
    @Override
    public String toString() {
        return "EmployeeEntity [id=" + id + ", firstName=" + firstName +
                ", lastName=" + lastName + ", email=" + email   + "]";
    }
}

 @Entity  会让springboot自动扫描这个class

@Table(name="TBL_EMPLOYEES") 初始化表名为 TBL_EMPLOYEES


@id 标注table的id

@GeneratedValue id值自动产生

@Column 初始化表格列名

3. Create JPA Repository

继承JpaRepository接口

EmployeeRepository.java

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;
 
import com.howtodoinjava.demo.entity.EmployeeEntity;
 
@Repository
public interface EmployeeRepository extends JpaRepository<EmployeeEntity, Long> {
 
}

EmployeeEntity和id类型被指定作为 JpaRepository 参数。通过继承，EmployeeRepository就拥有存储、删除、查找Employee实体的功能了。

4. Properties Configuration

4.1. Data source

数据库连接

application.properties

spring.datasource.url=jdbc:h2:file:~/test
spring.datasource.driverClassName=org.h2.Driver
spring.datasource.username=sa
spring.datasource.password=
spring.jpa.database-platform=org.hibernate.dialect.H2Dialect
 
# Enabling H2 Console
spring.h2.console.enabled=true
 
# Custom H2 Console URL
spring.h2.console.path=/h2-console

 4.2. Hibernate print SQL and Logging

application.properties

#Turn Statistics on and log SQL stmts
 
spring.jpa.show-sql=true
spring.jpa.properties.hibernate.format_sql=true
 
#If want to see very extensive logging
spring.jpa.properties.hibernate.generate_statistics=true
logging.level.org.hibernate.type=trace
logging.level.org.hibernate.stat=debug

 4.3. Database Initialization

除了@Table那种初始化数据库的表形式外，还有一种是使用schema.sql创建数据库表。

 --1

application.properties

spring.jpa.hibernate.ddl-auto=none // 使用schema.sql创建数据库表

如：schema.sql

DROP TABLE IF EXISTS TBL_EMPLOYEES;
  
CREATE TABLE TBL_EMPLOYEES (
    id INT AUTO_INCREMENT  PRIMARY KEY,
    first_name VARCHAR(250) NOT NULL,
    last_name VARCHAR(250) NOT NULL,
    email VARCHAR(250) DEFAULT NULL
);

 5. Spring boot hibernate demo

SpringBoot2DemoApplication.java

package com.howtodoinjava.demo;
 
import java.util.Optional;
 
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
 
import com.howtodoinjava.demo.entity.EmployeeEntity;
import com.howtodoinjava.demo.repository.EmployeeRepository;
 
@SpringBootApplication
public class SpringBoot2DemoApplication implements CommandLineRunner {
 
    private Logger logger = LoggerFactory.getLogger(this.getClass());
     
    @Autowired
    EmployeeRepository repository;
     
    public static void main(String[] args) {
        SpringApplication.run(SpringBoot2DemoApplication.class, args);
    }
 
    @Override
    public void run(String... args) throws Exception
    {      
        Optional<EmployeeEntity> emp = repository.findById(2L);
 
        logger.info("Employee id 2 -> {}", emp.get());
    }
}

 原文链接