MyBatis学习笔记1

<dependency>
    <groupId>org.mybatisgroupId>
    <artifactId>mybatisartifactId>
    <version>3.5.6version>
dependency>

GitHub:https://github.com/mybatis/mybatis-3/releases/tag/mybatis-3.5.13

创建MyBatis

1.新建一个普通的maven项目

2.删除src

3.导入Maven依赖

!--导入依赖-->
    <dependencies>
        
        <dependency>
            <groupId>mysqlgroupId>
            <artifactId>mysql-connector-javaartifactId>
            <version>5.1.46version>
        dependency>
        
        <dependency>
            <groupId>org.mybatisgroupId>
            <artifactId>mybatisartifactId>
            <version>3.5.6version>
        dependency>
        
        <dependency>
            <groupId>junitgroupId>
            <artifactId>junitartifactId>
            <version>4.12version>
        dependency>
    dependencies>

创建一个模块

编写核心配置文件

DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "https://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.jdbc.Driver"/>
            <property name="url" value="jdbc:mysql://localhost:3306/mybatis?serverTimezone=Asia/Beijing&useSSL=false&useUnicode=true&characterEncoding=UTF-8"/>
            <property name="username" value="root"/>
            <property name="password" value="123456"/>
        dataSource>
    environment>
        
    environments>

configuration>

编写MyBatis工具类

package utils;

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.InputStream;

public class MybatisUtils {
    private static SqlSessionFactory sqlSessionFactory;
    static {
        try {//使用MyBatis第一步获取sqlSessionFactory对象
            String resource = "mybatis-config.xml";
            InputStream inputStream = Resources.getResourceAsStream(resource);
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

        } catch (Exception e) {
            e.printStackTrace();
        }

    }
    public static SqlSession getSqlSession(){
        return sqlSessionFactoryopenSession();
    }
}

实体类

package pojo;

public class User {
    private int id;
    private String name;
    private  String pwd;
    public User(){
    }

    public User(int id, String name, String pwd) {
        this.id = id;
        this.name = name;
        this.pwd = pwd;
    }

    public int getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

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

    public String getPwd() {
        return pwd;
    }

    public void setPwd(String pwd) {
        this.pwd = pwd;
    }

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

dao接口

package dao;

import pojo.User;

import java.util.List;

public interface UserDao  {
    List<User> getUserList();
}

接口实现类转变为一个Mapper配置文件

DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "https://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="dao.UserDao">
    <select id="getUserList" resultType="pojo.User">
        select * from mybatis.user
    select>
mapper>

测试

junit测试

org.apache.ibatis.binding.BindingException: Type interface dao.UserDao is not known to the MapperRegistry.

MapperRegistry注册

  <mappers>
      <mapper resource="dao/UserMapper.xml"/>
  mappers>

    <build>
        <resources>
            <resource>
                <directory>src/main/resourcesdirectory>
                <includes>
                    <include>**/*.propertiesinclude>
                    <include>**/*.xmlinclude>
                includes>
            resource>
            <resource>
                <directory>src/main/javadirectory>
                <includes>
                    <include>**/*.propertiesinclude>
                    <include>**/*.xmlinclude>
                includes>
            resource>
        resources>
    build>