Mybatis学习
正式进入框架学习
一 . 环境搭建及测试
1 . 导入依赖
在IDEA中创建一个maven项目
在根目录的 pom.xml 文件夹下导入依赖 mybatis mysql junit
<!--导入依赖-->
<dependencies>
<!-- mybatis -->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.7</version>
</dependency>
<!-- mysql -->
<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.18</version>
</dependency>
<!-- junit -->
<!-- https://mvnrepository.com/artifact/junit/junit -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.13.1</version>
<scope>test</scope>
</dependency>
</dependencies>2 . mapper文件
在 src --> main --> resources 下创建 mybatis-config.xml 文件
此文件是连接数据库 和 让Mybatis扫描对应的mapper文件
<?xml version="1.0" encoding="UTF8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="com.mysql.cj.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/atanycosts?useSSL=false&useUnicode=true&characterEncoding=utf-8&serverTimezone=GMT"/>
<property name="username" value="root"/>
<property name="password" value="root"/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="mapper/userMapper.xml"/>
</mappers>
</configuration>再 在src --> main --> resources 下创建 mapper 文件夹,里创建 userMapper.xml 文件
此文件里写的是 SQL语句
<?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="UserEntity">
<select id="getByUsers" resultType="com.atanycosts.entity.UserEntity">
select * from user
</select>
</mapper>3 . 实体类
src --> main --> com --> atanycosts --> entity
写入对应数据库的字段
package com.atanycosts.entity;
//实体类
public class UserEntity {
private Long id;
private String name;
private String address;
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "UserEntity{" +
"id=" + id +
", name='" + name + '\'' +
", address='" + address + '\'' +
'}';
}
}
4 . Test类
package atanycosts.dao;
import com.atanycosts.entity.UserEntity;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
public class UserdaoTest {
@Test
public void test() throws IOException {
// 1.读取加载mybatis-config.xml
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
// 2.获取到获取到
SqlSession sqlSession = sqlSessionFactory.openSession();
// 3.根据 mapper id=getByUsers 执行该s ql 语句 通过 sql语句得到我们的对象 orm
List<UserEntity> userEntitys = sqlSession.selectList("getByUsers", UserEntity.class);
System.out.println(userEntitys);
sqlSession.close();
}
}
二 . Mapper 代理开发模式
1 . 在实体类层
创建 UserFlight
package com.atanycosts.entity;
import java.util.Date;
//UserFlight实体类
public class UserFlight {
private Integer id; //id
private String flight_id ; //航号
private String company ; //航空公司
private String departure_airport ; //出发机场
private String arrive_airport ; //达到机场
private Date departure_time; //出发时间
private Date arrive_time; //到达时间
private String model; //机型
private Integer is_delete; //是否隐藏0显示 1隐藏
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getFlight_id() {
return flight_id;
}
public void setFlight_id(String flight_id) {
this.flight_id = flight_id;
}
public String getCompany() {
return company;
}
public void setCompany(String company) {
this.company = company;
}
public String getDeparture_airport() {
return departure_airport;
}
public void setDeparture_airport(String departure_airport) {
this.departure_airport = departure_airport;
}
public String getArrive_airport() {
return arrive_airport;
}
public void setArrive_airport(String arrive_airport) {
this.arrive_airport = arrive_airport;
}
public Date getDeparture_time() {
return departure_time;
}
public void setDeparture_time(Date departure_time) {
this.departure_time = departure_time;
}
public Date getArrive_time() {
return arrive_time;
}
public void setArrive_time(Date arrive_time) {
this.arrive_time = arrive_time;
}
public String getModel() {
return model;
}
public void setModel(String model) {
this.model = model;
}
public Integer getIs_delete() {
return is_delete;
}
public void setIs_delete(Integer is_delete) {
this.is_delete = is_delete;
}
}
2 . 创建mapper层
并创建 getByFlightAll getByFlightID 接口
src --> main --> com --> atanycosts --> mapper -->UserMapper
package com.atanycosts.mapper;
import com.atanycosts.entity.UserEntity;
import com.atanycosts.entity.UserFlight;
import java.util.List;
public interface UserMapper {
List<UserEntity> getByUsers(); //环境测试接口
List<UserFlight> getByFlightAll(); //航班接口
UserFlight getByFlightID(Integer id); //获取对应ID
}
3 . 创建service层
src --> main --> com --> atanycosts --> service -->FlightService
package com.atanycosts.service;
import com.atanycosts.entity.UserFlight;
import com.atanycosts.mapper.UserMapper;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
//flight业务逻辑层
public class FlightService {
private UserMapper flightMapper;
private SqlSession sqlSession;
public FlightService() throws IOException {
// 1.读取加载mybatis-config.xml
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
// 2.获取到获取到
sqlSession = sqlSessionFactory.openSession();
flightMapper = sqlSession.getMapper(UserMapper.class);
// sqlSession.close();
}
/**
* 获取所有
* @return
*/
public List<UserFlight> getByFlightAll(){
return flightMapper.getByFlightAll();
}
/**
* 获取对应ID
* @param id
* @return
*/
public UserFlight getByFlightID(Integer id){
return flightMapper.getByFlightID(id);
}
}
4 . 在测试类中创建对应方法
package atanycosts.dao;
import com.atanycosts.entity.UserEntity;
import com.atanycosts.entity.UserFlight;
import com.atanycosts.mapper.UserMapper;
import com.atanycosts.service.FlightService;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;
import java.io.IOException;
import java.io.InputStream;
import java.util.Date;
import java.util.List;
public class UserdaoTest {
/**
* 环境测试
*
* @throws IOException
*/
@Test
public void test01() throws IOException {
// 1.读取加载mybatis-config.xml
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
SqlSession sqlSession = sqlSessionFactory.openSession();
/**
* 接口
* getByUsers
*/
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
List<UserEntity> byUsers = mapper.getByUsers();
System.out.println(byUsers);
sqlSession.close();
}
/**
* flight测试
* 获取所有
*
* @throws IOException
*/
@Test
public void test02() throws IOException {
FlightService flightService = new FlightService();
List<UserFlight> byFlightAll = flightService.getByFlightAll();
System.out.println(byFlightAll);
// sqlSession.close();
}
/**
* flight测试
* 获取对应ID
*
* @throws IOException
*/
@Test
public void getByUsersID() throws IOException {
FlightService flightService = new FlightService();
UserFlight byFlightID = flightService.getByFlightID(1);
System.out.println(byFlightID);
}
}
5 . 对应的SQL
<?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.atanycosts.mapper.UserMapper">
<select id="getByFlightAll" resultType="com.atanycosts.entity.UserFlight">
select *
from flight
</select>
<select id="getByFlightID" resultType="com.atanycosts.entity.UserFlight" parameterType="int">
select *
from flight
where id = #{id}
</select>
</mapper>当数据库的字段与Java的属性对应不上时在userMapper.xml下写入如下代码
column 数据库字段 property Java属性
id 用 id 包裹
其他用 result
<resultMap id="test" type="com.atanycosts.entity.UserEntity">
<id column="id" property="id"></id>
<result column="Database Field" property="Java property"></result>
</resultMap>三 . 增删改查
1 . 实体类
实体类中构造增删改所需要的方法
/**
* 插入数据
* @param flight_id
* @param company
* @param departure_airport
* @param arrive_airport
* @param departure_time
* @param arrive_time
* @param model
* @param is_delete
*/
public UserFlight(String flight_id, String company, String departure_airport, String arrive_airport, Date departure_time, Date arrive_time, String model, Integer is_delete) {
this.flight_id = flight_id;
this.company = company;
this.departure_airport = departure_airport;
this.arrive_airport = arrive_airport;
this.departure_time = departure_time;
this.arrive_time = arrive_time;
this.model = model;
this.is_delete = is_delete;
}
/**
* 更新数据
* @param id
* @param flight_id
* @param company
* @param departure_airport
* @param arrive_airport
* @param departure_time
* @param arrive_time
* @param model
* @param is_delete
*/
public UserFlight(Integer id, String flight_id, String company, String departure_airport, String arrive_airport, Date departure_time, Date arrive_time, String model, Integer is_delete) {
this.id = id;
this.flight_id = flight_id;
this.company = company;
this.departure_airport = departure_airport;
this.arrive_airport = arrive_airport;
this.departure_time = departure_time;
this.arrive_time = arrive_time;
this.model = model;
this.is_delete = is_delete;
}
/**
* 删除数据
* @param id
*/
public UserFlight(Integer id) {
this.id = id;
}2 . 在接口文件中写入
/**
* 插入数据
* @param userFlight
* @return
*/
boolean insertFlight(UserFlight userFlight);
/**
* 修改数据
* @param userFlight
* @return
*/
boolean updateFlight(UserFlight userFlight);
/**
* 删除数据
* @param userFlight
* @return
*/
boolean deleteByIdFlight(UserFlight userFlight);3 . 在Service层写入
/**
* 插入数据
* @param userFlight
* @return
*/
public boolean insertFlight(UserFlight userFlight){
// 艹了 , 插入时 , 要提交事务
boolean result = flightMapper.insertFlight(userFlight);
sqlSession.commit();
sqlSession.close();
return result;
}
/**
* 更新数据
* @param userFlight
* @return
*/
public boolean updateFlight(UserFlight userFlight){
boolean result = flightMapper.updateFlight(userFlight);
sqlSession.commit();
sqlSession.close();
return result;
}
/**
* 删除数据
* @param userFlight
* @return
*/
public boolean deleteByIdFlight(UserFlight userFlight){
boolean result = flightMapper.deleteByIdFlight(userFlight);
sqlSession.commit();
sqlSession.close();
return result;
}4 . 测试类
/**
* flight测试
* 插入数据
*
* @throws IOException
*/
@Test
public void insertFlight() throws IOException {
FlightService flightService = new FlightService();
UserFlight userFlight = new UserFlight("1", "1", "1", "1", new Date(), new Date(), "1", 0);
boolean b = flightService.insertFlight(userFlight);
System.out.println(b);
}
/**
* flight测试
* 更新数据
*
* @throws IOException
*/
@Test
public void updateFlight() throws IOException {
FlightService flightService = new FlightService();
UserFlight userFlight = new UserFlight(12, "2", "2", "2", "2", new Date(), new Date(), "更改成功", 0);
boolean b = flightService.updateFlight(userFlight);
System.out.println(b);
}
/**
* 删除数据
*
* @throws IOException
*/
@Test
public void deleteByIdFlight() throws IOException {
FlightService flightService = new FlightService();
UserFlight userFlight = new UserFlight(13);
boolean b = flightService.deleteByIdFlight(userFlight);
System.out.println(b);
}5 . 对应的SQL
<!-- userMapper.xml文件 -->
<insert id="insertFlight" parameterType="com.atanycosts.entity.UserFlight" useGeneratedKeys="true" keyProperty="id">
INSERT INTO atanycosts.flight (`id`, `flight_id`, `company`, `departure_airport`, `arrive_airport`,`departure_time`, `arrive_time`, `model`, `is_delete`) VALUES (null, #{flight_id}, #{company}, #{departure_airport}, #{arrive_airport}, #{departure_time},#{arrive_time}, #{model}, #{is_delete});
</insert>
<update id="updateFlight" parameterType="com.atanycosts.entity.UserFlight">
UPDATE atanycosts.flight
SET `id`=#{id},
`flight_id`=#{flight_id},
`company`=#{company},
`departure_airport`=#{departure_airport},
`arrive_airport`=#{arrive_airport},
`departure_time`=#{departure_time},
`arrive_time`=#{arrive_time},
`model`=#{model},
`is_delete`=#{is_delete}
WHERE (`id` = #{id});
</update>
<delete id="deleteByIdFlight" parameterType="int">
delete from atanycosts.flight where id=#{id};
</delete>