在开发中我们通常会对数据库的数据进行操作，SpringBoot对关系性和非关系型数据库的访问操作都提供了非常好的整合支持。SpringData是spring提供的一个用于简化数据库访问、支持云服务的开源框架。它是一个伞状项目，包含大量关系型和非关系型数据库数据访问解决方案，让我们快速简单的使用各种数据访问技术，springboot默认采用整合springdata方式统一的访问层，通过添加大量的自动配置，引入各种数据访问模板Trmplate以及统一的Repository接口，从而达到简化数据访问操作。
这里我们分别对MyBatis、Redis进行整合。
mybatis作为目前操作数据库的流行框架，spingboot并没有给出依赖支持，但是mybaitis开发团队自己提供了启动器mybatis-spring-boot-starter依赖。
MyBatis是一款优秀的持久层框架，它支持定制sql、存储过程、高级映射、避免JDBC代码和手动参数以及获取结果集。mybatis不仅支持xml而且支持注解。
我们创建一个简单的数据库并插入一些数据用于我们下面的操作。
# 创建数据库CREATE DATABASE studentdata;# 选择使用数据库USE studentdata;# 创建表并插入相关数据DROP TABLE IF EXISTS `t_student`;CREATE TABLE `t_student` ( `id` int(20) NOT NULL AUTO_INCREMENT, `name` varchar(20) DEFAULT NULL, `age` int(8), PRIMARY KEY (`id`)) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;INSERT INTO `t_student` VALUES ('1', 'hjk', '18');INSERT INTO `t_student` VALUES ('2', '小何', '20');按照之前的方式创建一个springboot项目，并在pom.xml里导入依赖。我们创建一个名为springboot-01的springboot项目。并且导入阿里的数据源
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>2.2.2</version> </dependency> <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java --> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>8.0.28</version> </dependency> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid-spring-boot-starter</artifactId> <version>1.2.8</version> </dependency>我们可以在IDEA右边连接上数据库，便于我们可视化操作，这个不连接也不会影响我们程序的执行，只是方便我们可视化。
创建Student的实体类
package com.hjk.pojo;public class Student { private Integer id; private String name; private Integer age; public Student(){ } public Student(String name,Integer age){ this.id = id; this.name = name; this.age = age; } public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public Integer getAge() { return age; } public void setAge(Integer age) { this.age = age; } @Override public String toString() { return "Student{" + "id=" + id + ", name='" + name + '\'' + ", age=" + age + '}'; }}在application.properties里编写数据库连接配置。这里我们使用druid数据源顺便把如何配置数据源写了，用户名和密码填写自己的。使用其他数据源需要导入相关依赖，并且进行配置。springboot2.x版本默认使用的是hikari数据源。
## 选着数据库驱动类型spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driverspring.datasource.url=jdbc:mysql://localhost:3306/studentdata?serverTimezone=UTC## 用户名spring.datasource.username=root## 密码spring.datasource.password=123456spring.datasource.type=com.alibaba.druid.pool.DruidDataSource## 初始化连接数spring.datasource.druid.initial-size=20## 最小空闲数spring.datasource.druid.min-idle=10## 最大连接数spring.datasource.druid.max-active=100然后我们编写一个配置类，把durid数据源属性值注入，并注入到spring容器中
创建一个config包，并创建名为DataSourceConfig类
package com.hjk.config;import com.alibaba.druid.pool.DruidDataSource;import org.springframework.boot.context.properties.ConfigurationProperties;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import javax.sql.DataSource;@Configuration //将该类标记为自定义配置类public class DataSourceConfig { @Bean //注入一个Datasource对象 @ConfigurationProperties(prefix = "spring.datasource") //注入属性 public DataSource getDruid(){ return new DruidDataSource(); }}目前整个包结构
创建一个mapper包，并创建一个StudentMapper接口并编写代码。mapper其实就和MVC里的dao包差不多。
package com.hjk.mapper;import com.hjk.pojo.Student;import org.apache.ibatis.annotations.*;import java.util.List;@Mapper //这个注解是一个mybatis接口文件，能被spring扫描到容器中public interface StudentMapper { @Select("select * from t_student where id = #{id}") public Student getStudentById(Integer id) ; @Select("select * from t_student") public List<Student> selectAllStudent(); @Insert("insert into t_student values (#{id},#{name},#{age})") public int insertStudent(Student student); @Update("update t_student set name=#{name},age=#{age} where id = #{id}") public int updataStudent(Student student); @Delete("delete from t_student where id=#{id}") public int deleteStudent(Integer id);}package com.hjk;import com.hjk.mapper.StudentMapper;import com.hjk.pojo.Student;import org.junit.jupiter.api.Test;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.boot.test.context.SpringBootTest;import java.util.List;@SpringBootTestclass Springdata01ApplicationTests { @Autowired private StudentMapper studentMapper; @Test public void selectStudent(){ Student studentById = studentMapper.getStudentById(1); System.out.println(studentById.toString()); } @Test public void insertStudent(){ Student student = new Student("你好",16); int i = studentMapper.insertStudent(student); List<Student> students = studentMapper.selectAllStudent(); for (Student student1 : students) { System.out.println(student1.toString()); } } @Test public void updateStudent(){ Student student = new Student("我叫hjk",20); student.setId(1); int i = studentMapper.updataStudent(student); System.out.println(studentMapper.getStudentById(1).toString()); } @Test public void deleteStudent(){ studentMapper.deleteStudent(1); List<Student> students = studentMapper.selectAllStudent(); for (Student student : students) { System.out.println(student.toString()); } }}## 开启驼峰命名匹配映射mybatis.configuration.map-underscore-to-camel-case=true这里使用注解实现了整合mybatis。mybatis虽然在写一些简单sql比较方便，但是写一些复杂的sql还是需要xml配置。
我们使用xml要先在application.properties里配置一下,不然springboot识别不了。
## 配置Mybatis的XML配置路径mybatis.mapper-locations=classpath:mapper/*.xml## 配置XML指定实体类别名mybatis.type-aliases-package=com.hjk.pojo我们重新书写StudentMapper类，然后使用xml实现数据访问。这里我们就写两个方法，剩下的基本一样。
package com.hjk.mapper;import com.hjk.pojo.Student;import org.apache.ibatis.annotations.Mapper;import java.util.List;@Mapper //这个注解是一个mybatis接口文件，能被spring扫描到容器中public interface StudentMapper { public Student getStudentById(Integer id) ; public List<Student> selectAllStudent();}我们在resources目录下创建一个mapper包，并在该包下编写StudentMapper.xml文件。
我们在写的时候可以去mybatis文档中哪复制模板，然后再写也可以记录下来，方便下次写
<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"><mapper namespace="com.hjk.mapper.StudentMapper"><!--这里namespace写对应mapper的全路径名--> <select id="getStudentById" resultType="Student"> select * from t_student where id = #{id} </select> <select id="selectAllStudent" resultType="Student"> select * from t_student; </select></mapper>编写测试
package com.hjk;import com.hjk.mapper.StudentMapper;import com.hjk.pojo.Student;import org.junit.jupiter.api.Test;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.boot.test.context.SpringBootTest;import java.util.List;@SpringBootTestclass Springdata01ApplicationTests { @Autowired private StudentMapper studentMapper; @Test public void selectStudent(){ Student studentById = studentMapper.getStudentById(2); System.out.println(studentById.toString()); } @Test public void selectAllStudent(){ List<Student> students = studentMapper.selectAllStudent(); for (Student student : students) { System.out.println(student.toString()); } }}注解方便，书写简单，但是不方便写复杂的sql。
xml虽然比较麻烦，但是它的可定制化强，能够实现复杂的sql语言。
两者结合使用会有比较好的结果。
Redis是一个开源的、内存中的数据结构存储系统，它可以作用于数据库、缓存、消息中间件，并提供多种语言的API。redis支持多种数据结构，String、hasher、lists、sets、等。同时内置了复本replication、LUA脚本LUA scripting、LRU驱动时间LRU eviction、事务Transaction和不同级别的磁盘持久化persistence、并且通过Redis Sentinel和自动分区提供高可用性。
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-redis</artifactId> <version>2.6.6</version> </dependency>Family类
package com.hjk.pojo;import org.springframework.data.redis.core.index.Indexed;public class Family { @Indexed private String type; @Indexed private String userName; public String getType() { return type; } public void setType(String type) { this.type = type; } public String getUserName() { return userName; } public void setUserName(String userName) { this.userName = userName; } @Override public String toString() { return "Family{" + "type='" + type + '\'' + ", userName='" + userName + '\'' + '}'; }}Adderss类
package com.hjk.pojo;import org.springframework.data.redis.core.index.Indexed;public class Address { @Indexed private String city; @Indexed private String country; public String getCity() { return city; } public void setCity(String city) { this.city = city; } public String getCountry() { return country; } public void setCountry(String country) { this.country = country; } @Override public String toString() { return "Address{" + "city='" + city + '\'' + ", country='" + country + '\'' + '}'; }}Person类
package com.hjk.pojo;import org.springframework.data.annotation.Id;import org.springframework.data.redis.core.RedisHash;import org.springframework.data.redis.core.index.Indexed;import java.util.List;@RedisHash("person")public class Person { @Id private String id; @Indexed private String firstName; @Indexed private String lastName; private Address address; private List<Family> familyList; public String getId() { return id; } public void setId(String id) { this.id = id; } public String getFirstName() { return firstName; } public void setFirstName(String firstName) { this.firstName = firstName; } public String getLastName() { return lastName; } public void setLastName(String lastName) { this.lastName = lastName; } public Address getAddress() { return address; } public void setAddress(Address address) { this.address = address; } public List<Family> getFamilyList() { return familyList; } public void setFamilyList(List<Family> familyList) { this.familyList = familyList; } @Override public String toString() { return "Person{" + "id='" + id + '\'' + ", firstName='" + firstName + '\'' + ", lastName='" + lastName + '\'' + ", address=" + address + ", familyList=" + familyList + '}'; }}编写Repository接口，创建repository包并创建PersonRepository类
package com.hjk.repository;import com.hjk.pojo.Person;import org.springframework.data.domain.Page;import org.springframework.data.domain.Pageable;import org.springframework.data.repository.CrudRepository;import java.util.List;public interface PersonRepository extends CrudRepository<Person,String> { List<Person> findByLastName(String lastName); Page<Person> findPersonByLastName(String lastName, Pageable pageable); List<Person> findByFirstNameAndLastName(String firstName,String lastName); List<Person> findByAddress_City(String city); List<Person> findByFamilyList_UserName(String userName);}添加配置文件
在application.properties中添加redis数据库连接配置。
## redis服务器地址spring.redis.host=127.0.0.1## redis服务器练级端口spring.redis.port=6379## redis服务器密码默认为空spring.redis.password=编写测试类，在测试文件下创建一个名为RedisTests的类
package com.hjk;import com.hjk.pojo.Address;import com.hjk.pojo.Family;import com.hjk.pojo.Person;import com.hjk.repository.PersonRepository;import org.junit.jupiter.api.Test;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.boot.test.context.SpringBootTest;import java.util.ArrayList;import java.util.List;@SpringBootTestpublic class RedisTests { @Autowired private PersonRepository repository; @Test public void redisPerson(){ //创建按对象 Person person = new Person(); person.setFirstName("王"); person.setLastName("nihao"); Address address = new Address(); address.setCity("北京"); address.setCountry("china"); person.setAddress(address); ArrayList<Family> list = new ArrayList<>(); Family family = new Family(); family.setType("父亲"); family.setUserName("你爸爸"); list.add(family); person.setFamilyList(list); //向redis数据库添加数据 Person save = repository.save(person); System.out.println(save); } @Test public void selectPerson(){ List<Person> list = repository.findByAddress_City("北京"); for (Person person : list) { System.out.println(person); } } @Test public void updatePerson(){ Person person = repository.findByFirstNameAndLastName("王", "nihao").get(0); person.setLastName("小明"); Person save = repository.save(person); System.out.println(save); } @Test public void deletePerson(){ Person person = repository.findByFirstNameAndLastName("王", "小明").get(0); repository.delete(person); }}我们分别对mybatis和redis进行整合。
mybaitis：
注解：导入依赖->创建实体类->属性配置->编写配置类->编写mapper接口->进行测试。
xml：导入依赖->创建实体类->属性配置（配置数据库等，配置xml路径）->mapper接口->xml实现->测试
redis：导入依赖->实体类->实现接口->配置redis属性->测试