Mybatis入门

目录

Mybatis简介

准备工作

Mybatis入门

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Mybatis简介

MyBatis 是一款优秀的持久层框架，它支持定制化SQL、存储过程以及高级映射，MyBatis 避免了几乎所有的 JDBC 代码和手动设置参数以及获得结果集。

准备工作

?创建SpringBoot工程?

注意勾选下面两种依赖

?点击finish完成工程的创建

??pom.xml文件内容如下

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.7.5</version>
        <relativePath/>
        <!--  lookup parent from repository  -->
    </parent>
    <groupId>com.itheima</groupId>
    <artifactId>springboot-mybatis-quickstart</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>springboot-mybatis-quickstart</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>11</java.version>
    </properties>
    <dependencies>
        <!-- mybatis的起步依赖 -->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.2.2</version>
        </dependency>
        <!--  mysql驱动包 , 刚刚发布的最新版本的驱动包 -->
        <dependency>
            <groupId>com.mysql</groupId>
            <artifactId>mysql-connector-j</artifactId>
            <scope>runtime</scope>
        </dependency>
        <!-- 上一个版本的驱动包 -->
        <!-- <dependency>
                    <groupId>mysql</groupId>
                    <artifactId>mysql-connector-java</artifactId>
                    <scope>runtime</scope>
                </dependency> -->
        <!-- springboot单元测试 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

连接数据库

注意Database的名称，一会需要填到resources.application.properties文件中?

创建User表

create table user(
    id int unsigned primary key auto_increment comment 'ID',
    name varchar(100) comment '姓名',
    age tinyint unsigned comment '年龄',
    gender tinyint unsigned comment '性别, 1:男, 2:女',
    phone varchar(11) comment '手机号'
) comment '用户表';
insert into user(id, name, age, gender, phone) VALUES (null,'白眉鹰王',55,'1','18800000000');
insert into user(id, name, age, gender, phone) VALUES (null,'金毛狮王',45,'1','18800000001');
insert into user(id, name, age, gender, phone) VALUES (null,'青翼蝠王',38,'1','18800000002');
insert into user(id, name, age, gender, phone) VALUES (null,'紫衫龙王',42,'2','18800000003');
insert into user(id, name, age, gender, phone) VALUES (null,'光明左使',37,'1','18800000004');
insert into user(id, name, age, gender, phone) VALUES (null,'光明右使',48,'1','18800000005');

创建User类

目录结构如下

User.java内容如下

package com.hi1220.demo.pojo;

public class User {
    private Integer id;
    private String name;
    private short age;
    private short gender;
    private String phone;

    public User() {
    }

    public User(Integer id, String name, short age, short gender, String phone) {
        this.id = id;
        this.name = name;
        this.age = age;
        this.gender = gender;
        this.phone = phone;
    }

    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 short getAge() {
        return age;
    }

    public void setAge(short age) {
        this.age = age;
    }

    public short getGender() {
        return gender;
    }

    public void setGender(short gender) {
        this.gender = gender;
    }

    public String getPhone() {
        return phone;
    }

    public void setPhone(String phone) {
        this.phone = phone;
    }
}

?在resources.application.properties文件中配置数据库的连接信息

#驱动类名称
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
#数据库连接的url
spring.datasource.url=jdbc:mysql://localhost:3306/mybatis
#连接数据库的用户名
spring.datasource.username=root
#连接数据库的密码
spring.datasource.password=root

Mybatis入门

目录结构如下

?UserMapper.interface文件内容如下

package com.hi1220.demo.mapper;

import com.hi1220.demo.pojo.User;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;
import java.util.List;

@Mapper
public interface UserMapper {
    //查询全部用户信息

    @Select("select * from user")
    public List<User> list ();

}

?test目录下的ApplicationTests.java文件内容如下

package com.hi1220.demo;

import com.hi1220.demo.mapper.UserMapper;
import com.hi1220.demo.pojo.User;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

import java.util.List;

@SpringBootTest
class DemoApplicationTests {

    @Autowired
    private UserMapper userMapper;

    @Test
    public void testListUser(){
        List<User> userList = userMapper.list();
        userList.stream().forEach(user -> {
            System.out.println(user);
        });
    }
}

运行结果如下