SpringDataJPA是Spring Data的一个子项目，通过提供基于JPA的Repository极大的减少了JPA作为数据访问方案的代码量，你仅仅需要编写一个接口集成下SpringDataJPA内部定义的接口即可完成简单的CRUD操作。
前言
本篇文章引导你通过Spring Boot，Spring Data JPA和MySQL实现设置@id @generatedvalue初始值从10000自增。
准备
- JDK 1.8 或更高版本
- Maven 3 或更高版本
- MySQL Server 5.6
技术栈
- Spring Data JPA
- Spring Boot
- MySQL
目录结构
父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>
<groupId>cn.merryyou</groupId>
<artifactId>jpa-example</artifactId>
<version>1.0-SNAPSHOT</version>
<modules>
<module>one-to-one-foreignkey</module>
<module>one-to-one-primarykey</module>
<module>one-to-many</module>
<module>many-to-many</module>
<module>many-to-many-extra-columns</module>
<module>initial-value-generator</module>
</modules>
<packaging>pom</packaging>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>io.spring.platform</groupId>
<artifactId>platform-bom</artifactId>
<version>Brussels-SR6</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
</project>
@id @generatedvalue设置初始值
目录结构
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">
<parent>
<artifactId>jpa-example</artifactId>
<groupId>cn.merryyou</groupId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>initial-value-generator</artifactId>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</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>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.6.1</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
</plugins>
</build>
</project>
db.sql
SET FOREIGN_KEY_CHECKS=0;
-- ----------------------------
-- Table structure for address
-- ----------------------------
DROP TABLE IF EXISTS `address`;
CREATE TABLE `address` (
`id` bigint(20) NOT NULL,
`city` varchar(255) DEFAULT NULL,
`state` varchar(255) DEFAULT NULL,
`street` varchar(255) DEFAULT NULL,
`zip` varchar(255) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
-- ----------------------------
-- Records of address
-- ----------------------------
-- ----------------------------
-- Table structure for app_seq_store
-- ----------------------------
DROP TABLE IF EXISTS `app_seq_store`;
CREATE TABLE `app_seq_store` (
`APP_SEQ_NAME` varchar(255) NOT NULL,
`APP_SEQ_VALUE` int(11) NOT NULL,
PRIMARY KEY (`APP_SEQ_NAME`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
-- ----------------------------
-- Records of app_seq_store
-- ----------------------------
INSERT INTO `app_seq_store` VALUES ('LISTENER_PK', '10000');
实体类
Address
@Entity
public class Address {
@Id
@Column( name = "ID" )
@TableGenerator(
name = "AppSeqStore",
table = "APP_SEQ_STORE",
pkColumnName = "APP_SEQ_NAME",
pkColumnValue = "LISTENER_PK",
valueColumnName = "APP_SEQ_VALUE",
initialValue = 10000,
allocationSize = 1 )
@GeneratedValue( strategy = GenerationType.TABLE, generator = "AppSeqStore" )
private long id;
private String street;
private String city;
private String state;
private String zip;
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public String getStreet() {
return street;
}
public void setStreet(String address) {
this.street = address;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
public String getState() {
return state;
}
public void setState(String state) {
this.state = state;
}
public String getZip() {
return zip;
}
public void setZip(String zip) {
this.zip = zip;
}
public String toString() {
return "Address id: " + getId() + ", street: " + getStreet() + ", city: " + getCity()
+ ", state: " + getState() + ", zip: " + getZip();
}
@Table声明此对象映射到数据库的数据表，通过它可以为实体指定表(talbe),目录(Catalog)和schema的名字。该注释不是必须的，如果没有则系统使用默认值(实体的短类名)。@Id声明此属性为主键。该属性值可以通过应该自身创建，但是Hibernate推荐通过Hibernate生成-
@GeneratedValue指定主键的生成策略。- TABLE：使用表保存id值
- IDENTITY：identitycolumn
- SEQUENCR ：sequence
- AUTO：根据数据库的不同使用上面三个
@Column声明该属性与数据库字段的映射关系。name声明该表主键生成策略的名称，它被引用在@GeneratedValue中设置的“generator”值中;table声明表生成策略所持久化的表名;pkColumnName声明在持久化表中，该主键生成策略所对应键值的名称;valueColumnName声明在持久化表中，该主键当前所生成的值，它的值将会随着每次创建累加;pkColumnValue声明在持久化表中，该生成策略所对应的主键。initialValue声明主键初识值，默认为0allocationSize声明每次主键值增加的大小
Spring Data JPA Repository
AddressRepository
public interface AddressRepository extends JpaRepository<Address, Integer> {
}
Spring Data JPA包含了一些内置的Repository，实现了一些常用的方法：findone，findall，save等。
application.yml
spring:
datasource:
url: jdbc:mysql://localhost/initial-value-generator
username: root
password: admin
driver-class-name: com.mysql.jdbc.Driver
jpa:
show-sql: true
properties:
hibernate:
enable_lazy_load_no_trans: true
# hibernate:
# ddl-auto: create
AddressRepositoryTest
@RunWith(SpringRunner.class)
@SpringBootTest
@Slf4j
public class AddressRepositoryTest {
@Autowired
private AddressRepository addressRepository;
@Test
public void testSave(){
Address address = new Address();
address.setCity("beijing");
address.setState("02");
address.setStreet("street");
address.setZip("aa.zip");
Address result = addressRepository.save(address);
Assert.assertNotNull(result);
Assert.assertNotNull(result.getId());
Assert.assertTrue(result.getId()>=10000);
}
}
代码下载
从我的 github 中下载，https://github.com/longfeizheng/jpa-example/tree/master/initial-value-generator
- JPA关系映射系列一：one-to-one外键关联
- JPA关系映射系列二：one-to-one主键关联
- JPA关系映射系列三：one-to-many和many-to-one
- JPA关系映射系列四：many-to-many 关联映射
- JPA关系映射系列五：many-to-many 关联表存在额外字段关系映射
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