简单使用mybatis(idea中使用)

Posted 2021-01-12 邦☆杠

首先创建一个maven项目

第一步：在pom.xml中添加依赖

<dependencies>
        <!--mybatis-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.6</version>
        </dependency>
        <!--数据库相关 jar 包-->
        <dependency>
            <groupId>org.mariadb.jdbc</groupId>
            <artifactId>mariadb-java-client</artifactId>
            <version>2.3.0</version>
        </dependency>
        <!-- JUnit单元测试工具 -->
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.10</version>
    </dependency>
    </dependencies>

第二步：创建数据库表

CREATE TABLE BOOK(
ID INT AUTO_INCREMENT PRIMARY KEY,
NAME VARCHAR(20),
NUMBER int );
insert into BOOK(NAME,NUMBER) VALUES
(\'Java程序设计\',10),
(\'数据结构\',10),
(\'设计模式\',10)

第三步：在main目录下的java源代码写代码

实体类Book

package com.wbg.entity;

public class Book {
    int id;
    String name;
    int number;

    @Override
    public String toString() {
        return "Book{" +
                "id=" + id +
                ", name=\'" + name + \'\\\'\' +
                ", number=" + number +
                \'}\';
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public Book() {
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getNumber() {
        return number;
    }

    public void setNumber(int number) {
        this.number = number;
    }

    public Book(int id, String name, int number) {
        this.id = id;
        this.name = name;
        this.number = number;
    }
}

View Code

bookMapper接口

package com.wbg.dao;

import com.wbg.entity.Book;

public interface bookMapper {
    Book selectBookById();
}

BookDao

package com.wbg.dao;

import com.wbg.entity.Book;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import java.io.InputStream;

public class BookDao {
    public Book getBookById(int id){
        //使用类加载器加载mybatis的配置文件
        InputStream inputStream=BookDao.class.getClassLoader().getResourceAsStream("config.xml");
        //构建sqlSession的工厂
        SqlSessionFactory sqlSessionFactory=new SqlSessionFactoryBuilder().build(inputStream);
        //创建能执行映射文件中的sql
        SqlSession sqlSession=sqlSessionFactory.openSession();

        Book book=sqlSession.selectOne("com.wbg.dao.bookMapper.selectBookById",2);
          return book;
    }

    public static void main(String[] args) {
        BookDao bookDao=new BookDao();
        System.out.println(bookDao.getBookById(1));
    }
}

View Code

第四步：在resources中创建config.xml配置资源文件

<?xml version="1.0" encoding="UTF-8" ?>
<!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="org.mariadb.jdbc.Driver"/>
                <property name="url" value="jdbc:mariadb://localhost:3306/stu"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="mapper/bookMapper.xml"/>
    </mappers>
</configuration>

第五步：在resources中创建mapper目录，在目录下创建bookMapper.xml配置文件

<?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.wbg.dao.bookMapper">
    <select id="selectBookById" resultType="com.wbg.entity.Book">
        select * from Book where id=#{id}
    </select>
</mapper>

测试

 

 项目下载地址：https://github.com/weibanggang/mybatistest