Spring Data項(xiàng)目是Spring用來解決數(shù)據(jù)訪問問題的一攬子解決方案。包含了大量了關(guān)系型數(shù)據(jù)庫(kù)及非關(guān)系型數(shù)據(jù)庫(kù)的解決方案。
1.Spring Data主要的包含的子項(xiàng)目
Spring Data Commons - Core Spring concepts underpinning every Spring Data project.
Spring Data Gemfire - Provides easy configuration and access to GemFire from Spring applications.
Spring Data JPA - Makes it easy to implement JPA-based repositories.
Spring Data KeyValue - Map-based repositories and SPIs to easily build a Spring Data module for key-value stores.
Spring Data LDAP - Provides Spring Data repository support for Spring LDAP.
Spring Data MongoDB - Spring based, object-document support and repositories for MongoDB.
Spring Data REST - Exports Spring Data repositories as hypermedia-driven RESTful resources.
Spring Data Redis - Provides easy configuration and access to Redis from Spring applications.
Spring Data for Apache Cassandra - Spring Data module for Apache Cassandra.
Spring Data for Apache Solr - Spring Data module for Apache Solr.
2.Spring Data Commons
Spring Data Commons是以上子項(xiàng)目的底層。它提供了統(tǒng)一的API。并且封裝了Spring Data Repository抽象類。
不同的子項(xiàng)目在分別實(shí)現(xiàn)了自己的Repository。比如Spring Data JPA是JpaRepository。Spring Data MongoDB是MongoRepository等等。
Spring Data還是提供了根據(jù)屬性進(jìn)行計(jì)數(shù)、刪除、查詢等方法。
3.Spring Data Jpa（重點(diǎn)）
JPA即 Java Persistence API。JPA是基于O/R映射的標(biāo)準(zhǔn)規(guī)范。JPA主要實(shí)現(xiàn)由：Hibernate、EclipseLink、OpenJPA等實(shí)現(xiàn)。
- 1.創(chuàng)建數(shù)據(jù)庫(kù)
CREATE DATABASE IF NOT EXISTS springbootstudy CHARSET utf8 COLLATE utf8_general_ci;
- 2.創(chuàng)建表
CREATE TABLE person(
id BIGINT(20) NOT NULL AUTO_INCREMENT PRIMARY KEY COMMENT '自增主鍵',
NAME VARCHAR(50) NOT NULL DEFAULT '' COMMENT '姓名',
age TINYINT NOT NULL DEFAULT 0 COMMENT '年齡',
gmt_create DATE COMMENT '創(chuàng)建時(shí)間',
gmt_modified DATE COMMENT '更新時(shí)間'
)ENGINE=INNODB
3.1 Spring Boot的支持
1.JDBC的配置
查看spring-boot-starter-data-jpa的pom文件可以看到該jar需要依賴于spring-boot-starter-jdbc。而Spring Boot對(duì)于JDBC的自動(dòng)配置在org.springframework.boot.autoconfigure.jdbc包中。
通過查看DataSourceProperties類，得知通過spring.datasource為前綴的屬性自動(dòng)配置JDBC
Spring Boot對(duì)于JPA的自動(dòng)配置放置在org.springframework.boot.autoconfigure.orm.jpa里。使用spring.jpa前綴進(jìn)行配置。也通過源碼看到Spring Boot默認(rèn)的JPA的實(shí)現(xiàn)是Hibernate
3.2 實(shí)戰(zhàn)代碼配置
- 配置spring.datasource
spring.datasource.username=root
spring.datasource.data-password=xxxx
spring.datasource.url=jdbc:mysql://localhost:3306/springdbootstudy?serverTimezone=Asia/Shanghai
spring.datasource.driverClassName = com.mysql.jdbc.Driver
- 配置spring.jpa
# hibernate提供了根據(jù)實(shí)體類自動(dòng)維護(hù)數(shù)據(jù)庫(kù)表結(jié)構(gòu)的功能。而none代表不做任何處理
spring.jpa.hibernate.ddl-auto=none
#顯示真實(shí)的sql
spring.jpa.show-sql=true
#讓控制臺(tái)輸出的json字符串格式更加美觀
spring.jackson.serialization.indent-output=true
- 1.創(chuàng)建person實(shí)體類
@Entity //@Entity注解指明這是一個(gè)和數(shù)據(jù)庫(kù)表影射的實(shí)體類
@Table(name = "person")//@Table代表類名稱和數(shù)據(jù)庫(kù)表名稱一致。
public class Person implements Serializable {
private static final long serialVersionUID = -6082167954080285357L;
/**
* 自增id
*/
@Id //@Id注解指明這個(gè)屬性映射為數(shù)據(jù)庫(kù)的主鍵
@GeneratedValue(strategy = GenerationType.AUTO) //@GeneratedValue注解默認(rèn)使用主鍵生成方式為自增
private long id;
/**
* 姓名
*/
private String name;
/**
* 年齡
*/
private Integer age;
/**
* 創(chuàng)建時(shí)間
*/
@Column(name = "gmt_create")//@Cloumn注解來表明映射屬性名和字段名。不注解的表明屬性名稱跟數(shù)據(jù)庫(kù)表字段名稱一致。
private Date create;
/**
* 更新時(shí)間
*/
@Column(name = "gmt_modified")
private Date modified;
//省略getter/setter
@Override
public String toString() {
return "Person{" +
"id=" + id +
", name='" + name + '\'' +
", age=" + age +
", create=" + create +
", modified=" + modified +
'}';
}
}
- 2.創(chuàng)建repository
public interface PersonRepository extends JpaRepository<Person, Long> {
/**
* 常規(guī)查詢。根據(jù)屬性名稱來定義查詢方法
*
* @param name
* @return
*/
List<Person> findByName(String name);
/**
* 查詢多個(gè)屬性之間用And連接
*
* @param name
* @param age
* @return
*/
List<Person> findByNameAndAge(String name, String age);
/**
* 通過名稱Like查詢
*
* @param name
* @return
*/
List<Person> findByNameLike(String name);
/**
* 使用@Query查詢，參數(shù)按照名稱綁定
*
* @param name
* @param age
* @return
*/
@Query("select p from Person p where p.name= :name and p.age= :age")
Person withNameAndAgeQuery(@Param("name") String name, @Param("age") Integer age);
}
- 測(cè)試
@RequestMapping("save")
public String insert() {
String msg = null;
try {
Person p = new Person();
p.setName("張三");
p.setAge(18);
p.setCreate(new Date());
personRepository.save(p);
msg = "成功";
} catch (Exception ex) {
msg = ex.getMessage();
}
return msg;
}
@RequestMapping("find")
public String find() {
try {
//List<Person> ss=personRepository.findByName("張三");
//List<Person> ss=personRepository.withNameAndAge("張三",19);
// for (Person p:ss){
// System.out.println(p.toString());
// }
Person p = personRepository.withNameAndAgeQuery("張三", 18);
System.out.println(p.toString());
} catch (Exception ex) {
System.out.println(ex.getMessage());
}
return "sa";
}
