(1)mysql数据表准备
首先,准备一张news的表,表的结构为:
image
数据中的表的内容为:
image
2.相关配置
2.1配置pom文件
由于在spring boot 中整合mybatis,需要修改pom.xml(maven 项目),添加mybatis 跟mysql 的设置:
在vscode 中,选择pom.xml 文件,右键选择Edit starters
image
输入同时勾选mysql、mybatis选项,如图:
image
更新后,pom.xml 中多了这两项的依赖选项:
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>2.0.1</version>
<scope>compile</scope>
</dependency>
2.2配置 application.properties选项
在application.properties配置文件中填写数据库账号,密码,连接字符串等配置:
#application.properties
spring.datasource.url=jdbc:mysql://localhost:3306/zlfj?allowMultiQueries=true&useUnicode=true&characterEncoding=UTF-8
spring.datasource.username=root
spring.datasource.password=${你的数据库密码}
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
2.3 创建entity类
项目文件目录为图所示:
image
创建newsentity类,用来java文件与sql 表的映射;
//NewsEntity.java
public class NewsEntity implements Serializable{
private static final long serialVersionUID = 1L;
private Long id;
private String title;
private String content;
private Date gmttime;
/*
**省略getset 方法,记得写
*/
}
2.4创建Dao层定义具体数据操作
(1)利用注解的方式
在dao层中定义了NewsDao.java 然后将注解写在方法中来实现数据库操作:
@Mapper
public interface NewsDao{
/**
* 查询单个
* @return
*/
@Select("SELECT * from news WHERE id=#{id}")
NewsEntity queryObject(@Param("id") Long id);
}
如果是传入的是entity 类,则需要对查询结果进行注解映射:
/**
* 保存
* @return
*/
@Results(
{
@Result(property = "id", column = "id", id = true),
@Result(property = "title", column = "title"),
@Result(property = "content", column = "content"),
@Result(property = "gmttime", column = "gmtTime")
}
)
@Insert("insert into news (title,content,gmtTime) values(#{title},#{content},#{gmttime})")
void save(NewsEntity news);
/**
* 修改
* @return
*/
@Results(
{
@Result(property = "id", column = "id", id = true),
@Result(property = "title", column = "title"),
@Result(property = "content", column = "content"),
@Result(property = "gmttime", column = "gmtTime")
}
)
@Update("update news set `title`=#{title},`content`=#{content},`gmtTime`=#{gmttime} where id=#{id}")
void update(NewsEntity news);
(2)利用xml的方式
首先定义dao层的各个操作,同时将dao添加mapper注解:
package com.zhb.nongboot.dao;
import java.util.List;
import java.util.Map;
import com.zhb.nongboot.entity.NewsEntity;
import org.apache.ibatis.annotations.Mapper;
@Mapper
public interface NewsDao{
/**
* 查询
* @return
*/
NewsEntity queryObject(Long id);
/**
* 查询列表
* @return
*/
List<NewsEntity> queryList(Map<String, Object> map);
/**
* 查询总数
* @return
*/
int queryTotal(Map<String, Object> map);
/**
* 保存
* @return
*/
void save(NewsEntity news);
/**
* 修改
* @return
*/
void update(NewsEntity news);
/**
* 删除
* @return
*/
void delete(Long id);
}
在NewsDao.java 的同级目录下,新增NewsDao.xml文件,定义其数据库具体sql操作:
<?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.zhb.nongboot.dao.NewsDao">
<resultMap id="newsMap" type="com.zhb.nongboot.entity.NewsEntity">
<result property="id" column="id"/>
<result property="title" column="title"/>
<result property="content" column="content"/>
<result property="gmttime" column="gmtTime"/>
</resultMap>
<select id="queryObject" resultType="com.zhb.nongboot.entity.NewsEntity">
select * from news where id = #{value}
</select>
<select id="queryList" resultType="com.zhb.nongboot.entity.NewsEntity">
select * from news where 1=1
<choose>
<when test="sidx != null and sidx.trim() != ''">
order by ${sidx} ${order}
</when>
<otherwise>
order by id desc
</otherwise>
</choose>
<if test="offset != null and limit != null">
limit #{offset}, #{limit}
</if>
</select>
<select id="queryTotal" resultType="int">
select count(*) from news where 1=1
</select>
<insert id="save" parameterType="com.zhb.nongboot.entity.NewsEntity" useGeneratedKeys="true" keyProperty="id">
insert into news
(
`title`,
`content`,
`gmtTime`
)
values
(
#{title},
#{content},
#{gmttime}
)
</insert>
<update id="update" parameterType="com.zhb.nongboot.entity.NewsEntity">
update news
<set>
<if test="title != null">`title` = #{title},</if>
<if test="content != null">`content` = #{content},</if>
<if test="gmttime != null">`gmtTime` = #{gmttime}</if>
</set>
where id = #{id}
</update>
<delete id="delete">
delete from news where id = #{value}
</delete>
<delete id="deleteBatch">
delete from news where id in
<foreach item="id" collection="array" open="(" separator="," close=")">
#{id}
</foreach>
</delete>
</mapper>
2.5定义service层接口方法与实现(具体业务层逻辑)
这里我们对news 这个表进行增删改操作,所以定义其接口:
NewsService.java
import java.util.List;
import java.util.Map;
import com.zhb.nongboot.entity.NewsEntity;
import org.springframework.stereotype.Service;
public interface NewsService{
/**
* 查询
* @return
*/
NewsEntity queryObject(Long id);
/**
* 查询列表
* @return
*/
List<NewsEntity> queryList(Map<String, Object> map);
/**
* 查询总数
* @return
*/
int queryTotal(Map<String, Object> map);
/**
* 保存
* @return
*/
void save(NewsEntity news);
/**
* 修改
* @return
*/
void update(NewsEntity news);
/**
* 删除
* @return
*/
void delete(Long id);
}
service 的具体实现:
//NewsServiceImpl.java
package com.zhb.nongboot.service.impl;
import java.util.List;
import java.util.Map;
import com.zhb.nongboot.dao.NewsDao;
import com.zhb.nongboot.entity.NewsEntity;
import com.zhb.nongboot.service.NewsService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
@Service
public class NewsServiceImpl implements NewsService{
@Autowired
private NewsDao newsDao;
@Override
public NewsEntity queryObject(Long id){
NewsEntity entity = newsDao.queryObject(id);
return entity;
}
@Override
public List<NewsEntity> queryList(Map<String, Object> map){
List<NewsEntity> list = newsDao.queryList(map);
return list;
}
@Override
public int queryTotal(Map<String, Object> map){
return newsDao.queryTotal(map);
}
@Override
public void save(NewsEntity news){
newsDao.save(news);
}
@Override
public void update(NewsEntity news){
newsDao.update(news);
}
@Override
public void delete(Long id){
newsDao.delete(id);
}
}
注意:因为在这里我们定义了一个service,在spring 中,这个NewsService要注册到spring,交由spring统一管理其容器(IOC控制反转)
所以在public class NewsServiceImpl implements NewsService定义中,记得加上@Service 注解
@Service
public class NewsServiceImpl implements NewsService{
不然spring会报错无法找到其服务.
2.6controller层:注册路由与接收参数
在这里我们简单测试一下查询方法跟保存方法是否正常:
import java.util.Date;
import java.util.HashMap;
import com.zhb.nongboot.entity.NewsEntity;
import com.zhb.nongboot.service.NewsService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
@RequestMapping("news")
public class NewsController {
@Autowired
private NewsService newsService;
/**
* 信息
*/
@RequestMapping("/info/{id}")
public NewsEntity info(@PathVariable("id") Long id){
NewsEntity news = newsService.queryObject(id);
return news;
}
@RequestMapping("save/{name}")
public HashMap<String,String> save(@PathVariable("name") String name){
NewsEntity news = new NewsEntity();
news.setTitle(name);
news.setContent("新增通知成功");
news.setGmttime(new Date());
newsService.save(news);
return (HashMap<String, String>) new HashMap<>().put("message", "ok");
}
当访问/news/info/2的时候,返回的是id为2的news表的行记录.
当访问/news/save/titlename的时候,新增一条title 为titlename的记录.
测试:
查询单行记录:
image
保存
image
image
测试成功;
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