数据持久化(Dao---Entity---mapper)
配置(application.yml)
server:
port: 10086
spring:
datasource:
driver-class-name: com.mysql.cj.jdbc.Driver
url: jdbc:mysql://127.0.0.1:3306/wiki?useUnicode=true&characterEncoding=utf8&autoReconnect=true&zeroDateTimeBehavior=convertToNull&serverTimezone=UTC&useSSL=true
username: root
password: jia******
mybatis:
mapper-locations: classpath:/mapper/*.xml
写创建库表语句
drop table if exists `demo`;
create table `demo`
(
`id` bigint not null comment 'id',
`name` varchar(50) comment '名称',
`other_name` vachar(50) comment '代替名',
primary key (`id`)
) engine = innodb default charset utf8mb4 comment ='测试';
insert into `demo` (id, name,other_name)VALUES (1, '测试', 'text');
写相应的实体
//使用lombok写实体---我是用的方式,build创建实体很方便
import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;
/**
* @author Rui
* @description demo实体类
* @create 2024/7/5 16:58
*/
@Data
@Builder
@AllArgsConstructor
@NoArgsConstructor
public class DemoEntity {
private Integer id;
private String name;
private String otherName;
}
//使用getter,setter
/**
* @author Rui
* @description demo实体类
* @create 2024/7/5 16:58
*/
public class DemoEntity {
private Integer id;
private String name;
private String otherName;
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 String getOtherName() { return otherName; }
public void setOtherName(String otherName) { this.otherName = otherName; }
public DemoEntity() { }
public DemoEntity(Integer id, String name, String otherName) {
this.id = id;
this.name = name;
this.otherName = otherName;
}
}
写mapper
<?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.jiawa.wiki.dao.DemoDao">
<resultMap id ="dateMap" type="com.jiawa.wiki.domain.DemoEntity">
<id column="id" property="id"/>
<result column="name" property="name"/>
<result column="password" property="password"/>
</resultMap>
<select id="queryAllDemoDate" resultType="com.jiawa.wiki.domain.DemoEntity">
select * from `demo`
</select>
</mapper>
写dao接口
import com.jiawa.wiki.domain.DemoEntity;
import org.apache.ibatis.annotations.Mapper;
import java.util.List;
/**
* @author Rui
* @description 提供给服务层service的接口
* @create 2024/7/5 17:01
*/
@Mapper
public interface DemoDao {
List<DemoEntity> queryAllDemoDemo();
}
服务层对数据持久层的数据做处理
service
import com.jiawa.wiki.dao.DemoDao;
import com.jiawa.wiki.domain.DemoEntity;
import org.springframework.stereotype.Service;
import javax.annotation.Resource;
import java.util.List;
/**
* @author Rui
* @description 为controller层提供服务,对数据层的数据处理
* @create 2024/7/5 17:19
*/
@Service
public class DemoService {
@Resource
private DemoDao DemoDao;
public List<DemoEntity> selectAllDateDemo(){
List<DemoEntity> DemoEntities = DemoDao.queryAllDemoDate();
return DemoEntities;
}
}
控制层接收服务层提供的数据,或者向服务层传递前端的数据
controller
import com.jiawa.wiki.domain.DemoEntity;
import com.jiawa.wiki.service.DemoService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import javax.annotation.Resource;
import java.util.List;
/**
* @author Rui
* @description 接收服务层的数据,像服务层传递数据
* @description return出去的数据,浏览器就可以接收到了,几乎所有格式
* @create 2024/7/5 14:53
*/
@Slf4j
@RestController
//注意是rest风格的controller
public class DemoController {
@Resource
private DemoService DemoService;
//get方法和post方法效果相同,但是post可以在url中不显示参数
@RequestMapping(value = "/hello", method = RequestMethod.GET)
public String Hello() {
return "Hello world";
}
//除了post、get还有delete很多方法
@RequestMapping(value = "/hello/post", method = RequestMethod.POST)
public String HelloPost(String name) {
return "Hello world " +name;
}
@RequestMapping(value = "/hello/queryAll", method = RequestMethod.GET)
public List<DemoEntity> queryAllDateDemo() {
return DemoService.selectAllDateDemo();
}
}