【MyBatis框架】Mybatis实战之基础篇

这里写目录标题

一：结构框架
二：开发流程

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项目代码：
链接：https://pan.baidu.com/s/1POo7Gscj3JgnUji9sXmWbw
提取码：6666
–来自百度网盘超级会员V3的分享

一：结构框架

mapper下的xml文件都会被package识别。
pojo下的所有类都会被package识别。
所以递归也会识别。
在这里插入图片描述

二：开发流程

1.基本配置：

1.1配置Application.properties

jdbc.driver=com.mysql.cj.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/Stu?serverTimezone=Asia/Shanghai&useUnicode=true&characterEncoding=utf-8
#jdbc.url=jdbc:mysql://localhost:3306/?????????????serverTimezone=Asia/Shanghai&useUnicode=true&characterEncoding=utf-8
jdbc.username=root
jdbc.password=XXXXXXXX
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1.2.配置mybatis-config


DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>

    
    <properties resource="Application.properties" />

    <settings>
        <setting name="logImpl" value="STDOUT_LOGGING"/>
    settings>

    
    
    
    <typeAliases>
        <package name="com.mybatis.ch01.pojo"/>
    typeAliases>


    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            
            <dataSource type="POOLED">
                <property name="driver" value="${jdbc.driver}"/>
                <property name="url" value="${jdbc.url}"/>
                <property name="username" value="${jdbc.username}"/>
                <property name="password" value="${jdbc.password}"/>
            dataSource>
        environment>
    environments>

    
    
    <mappers>
        <package name="com.mybatis.ch01.mapper"/>
    mappers>
configuration>
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1.3配置MyBatisUtil工具类

package com.mybatis.ch01.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.IOException;
import java.io.InputStream;

/**
 *  工具类：创建SqlSession对象
 */
public class MyBatisUtil {

    private static SqlSessionFactory factory  = null;

    static {

        String config= "mybatis-config.xml";
        try {
            InputStream inputStream  =Resources.getResourceAsStream(config);
            factory  = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    //创建方法，获取SqlSession对象
    public static SqlSession getSqlSession(){
        SqlSession session = null;
        if( factory != null ){
            session =factory.openSession(true);// openSession(true);
        }
        return session;
    }

}
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1.4配置pom.xml

build标签：

 
 <resources>
   <resource>
     <directory>src/main/javadirectory>
     <includes>
       <include>**/*.propertiesinclude>
       <include>**/*.xmlinclude>
     includes>
     <filtering>falsefiltering>
   resource>
 resources>
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dependencies标签

	//Test测试使用
    <dependency>
      <groupId>junitgroupId>
      <artifactId>junitartifactId>
      <version>4.11version>
      <scope>testscope>
    dependency>
	//JDBC使用
    <dependency>
      <groupId>mysqlgroupId>
      <artifactId>mysql-connector-javaartifactId>
      <version>8.0.30version>
    dependency>

	//mybatis依赖
    <dependency>
      <groupId>org.mybatisgroupId>
      <artifactId>mybatisartifactId>
      <version>3.4.6version>
    dependency>
	
	//@Data注解需要
    <dependency>
      <groupId>org.projectlombokgroupId>
      <artifactId>lombokartifactId>
      <version>1.18.12version>
      <scope>providedscope>
    dependency>
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2.编写pojo层（对应数据库中的表||导出的类）

Student.java

package com.mybatis.ch01.pojo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;

@Data
@AllArgsConstructor
@NoArgsConstructor
@ToString
public class Student {
    private Integer id;
    private String name;
    private String email;
    private Integer age;
}

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Teacher.java

package com.mybatis.ch01.pojo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;

@Data
@AllArgsConstructor
@NoArgsConstructor
@ToString
public class Teacher {
    private Integer id;
    private String name;
    private String tno;
    private String classname;
    private Integer money;
}

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ST.java:导出类

package com.mybatis.ch01.pojo.utils;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;

@Data
@AllArgsConstructor
@NoArgsConstructor
@ToString
public class ST {
    private Integer studentid;
    private String studentname;
    private Integer teacherid;
    private String teachername;

}
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3.编写mapper层

StudentMapper.java

package com.mybatis.ch01.mapper.student;

import com.mybatis.ch01.pojo.Student;
import org.apache.ibatis.annotations.Param;

import java.util.List;
import java.util.Map;

public interface StudentMapper {
    //传入一个简单类型的参数
    Student selectByIdOne(Integer id);

    //传入多个简单类型的参数
    List<Student> selectByNameEmailTwo (@Param("myName") String name,
                                        @Param("myEmail") String email
                                        );
    //传入一个对象
    List<Student> selectByNameEmailTwo2 (Student student);

    //使用位置，获取参数
    List<Student> selectByNameEmailTwo3 (String name,String email);

    //参数是一个Map
    List<Student> selectByNameEmailTwo4 (Map<String,Object> data);

}
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StudentMapper.xml


DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.mybatis.ch01.mapper.student.StudentMapper">
    
    <select id="selectByIdOne" resultType="Student">
        select * from student where id = #{myId}
    select>

    
    <select id="selectByNameEmailTwo" resultType="Student">
         select * from student where email = #{myEmail} and name = #{myName}
    select>

    
    <select id="selectByNameEmailTwo2" resultType="Student">
        select * from student where email = #{email} and name = #{name}
    select>

    
    <select id="selectByNameEmailTwo3" resultType="Student">
        select * from student where name = #{arg0} and email = #{arg1}
    select>

    
    <select id="selectByNameEmailTwo4" resultType="Student">
        select * from student where name = #{name} and email = #{email}
    select>
mapper>
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TeacherMapper.java

package com.mybatis.ch01.mapper.teacher;

import com.mybatis.ch01.pojo.Teacher;
import org.apache.ibatis.annotations.Param;

import java.util.List;
import java.util.Map;

public interface TeacherMapper {
    List<Teacher> selectByTows(Map<String,Object> data);
}

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TeacherMapper.xml


DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.mybatis.ch01.mapper.teacher.TeacherMapper">
    <select id="selectByTows" resultType="Teacher">
        select * from teacher where classname = #{classname} and money = #{money}
  select>
mapper>
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重点：
STMapper.java

package com.mybatis.ch01.mapper.utils;

import com.mybatis.ch01.pojo.utils.ST;

import java.util.List;

public interface STMapper {
    List<ST> getList();
}

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DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.mybatis.ch01.mapper.utils.STMapper">
    <select id="getList" resultType="ST">
        select s.id studentid,s.name studentname,t.id teacherid,t.name teachername from student s,teacher t where s.id = t.id
    select>
mapper>
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4.测试：

package com.mybatis.ch01;

import static org.junit.Assert.assertTrue;

import com.mybatis.ch01.mapper.student.StudentMapper;
import com.mybatis.ch01.mapper.teacher.TeacherMapper;
import com.mybatis.ch01.mapper.utils.STMapper;
import com.mybatis.ch01.pojo.Student;
import com.mybatis.ch01.pojo.Teacher;
import com.mybatis.ch01.pojo.utils.ST;
import com.mybatis.ch01.utils.MyBatisUtil;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * Unit test for simple App.
 */
public class AppTest 
{
    /**
     * 传入一个简单类型的参数
     */
    @Test
    public void selectByIdOne()
    {
        //1.获取SqlSession
        SqlSession session = MyBatisUtil.getSqlSession();
        //2.获取dao的代理
        StudentMapper dao = session.getMapper(StudentMapper.class);
        Student stu  = dao.selectByIdOne(1007);

        System.out.println(stu);
        //3.关闭SqlSession对象
        session.close();
    }

    /**
     * 传入多个简单类型的参数
     */
    @Test
    public void selectByNameEmailTwo()
    {
        SqlSession session = MyBatisUtil.getSqlSession();
        StudentMapper dao = session.getMapper(StudentMapper.class);
        List<Student> stus = dao.selectByNameEmailTwo("yxc1007","yxc1@qq.com");
        for (Student student:stus){
            System.out.println("stu==" + student);
        }
        session.close();
    }

    /**
     * 传入一个对象
     */
    @Test
    public void selectByNameEmailTwo2()
    {
        SqlSession session = MyBatisUtil.getSqlSession();
        StudentMapper dao = session.getMapper(StudentMapper.class);
        Student student = new Student();
        student.setName("yxc1007");
        student.setEmail("yxc1@qq.com");
        List<Student> stus = dao.selectByNameEmailTwo2(student);
        for (Student stu:stus){
            System.out.println("stu==" + stu);
        }
        session.close();
    }

    /**
     * 使用位置，获取参数
     */
    @Test
    public void selectByNameEmailTwo3()
    {
        SqlSession session = MyBatisUtil.getSqlSession();
        StudentMapper dao = session.getMapper(StudentMapper.class);
        List<Student> stus = dao.selectByNameEmailTwo3("yxc1007","yxc1@qq.com");
        for (Student stu:stus){
            System.out.println("stu==" + stu);
        }
        session.close();
    }
    /*
       使用Map作为参数
     */
    @Test
    public void selectByNameEmailTwo4()
    {
        SqlSession session = MyBatisUtil.getSqlSession();
        StudentMapper dao = session.getMapper(StudentMapper.class);
        Map<String,Object> data = new HashMap<>();
        data.put("name","yxc1007");
        data.put("email","yxc1@qq.com");
        List<Student> stus = dao.selectByNameEmailTwo4(data);
        for (Student stu:stus){
            System.out.println("stu==" + stu);
        }
        session.close();
    }

    /*
       使用Map作为参数(练习2)
     */
    @Test
    public void selectByTwos()
    {
        SqlSession session = MyBatisUtil.getSqlSession();
        TeacherMapper dao = session.getMapper(TeacherMapper.class);
        Map<String,Object> data = new HashMap<>();
        data.put("classname","计科");
        data.put("money",3000);
        List<Teacher> teachers = dao.selectByTows(data);
        for (Teacher tea:teachers){
            System.out.println("tea==" + tea);
        }
        session.close();
    }

    /**
     * 返回多表的数据
     */
    @Test
    public void getList()
    {
        SqlSession session = MyBatisUtil.getSqlSession();
        STMapper dao = session.getMapper(STMapper.class);
        List<ST> sts = dao.getList();
        for (ST s:sts){
            System.out.println("st==" + s);
        }
        session.close();
    }
}

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原文地址：https://blog.csdn.net/qq_52384627/article/details/126653154