1、MyBatis面向接口编程

1、在mybatis数据库下创建employee数据表

create table employee(
id int primary key auto_increment,
name varchar(50),
gender varchar(1)
);

2、创建Employee对象

package com.mi.pojo;

public class Employee {

    private int id;
    private String name;
    private String gender;

    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 getGender() {
        return gender;
    }

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

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

3、创建EmployeeMapper接口

package com.mi.dao;

import com.mi.pojo.Employee;

public interface EmployeeMapper {

    public Employee getEmployeeById(int id);
}

4、创建pom.xml

<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0modelVersion>

    <groupId>com.migroupId>
    <artifactId>mybatisartifactId>
    <version>1.0-SNAPSHOTversion>


    <dependencies>
        <dependency>
            <groupId>org.mybatisgroupId>
            <artifactId>mybatisartifactId>
            <version>3.5.2version>
        dependency>
        <dependency>
            <groupId>mysqlgroupId>
            <artifactId>mysql-connector-javaartifactId>
            <version>5.1.6version>
        dependency>
        <dependency>
            <groupId>junitgroupId>
            <artifactId>junitartifactId>
            <version>RELEASEversion>
            <scope>testscope>
        dependency>

    dependencies>


project>

5、创建mybatis-config.xml主配置文件

<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"/>
                <property name="username" value="root"/>
                <property name="password" value="root"/>
            dataSource>
        environment>
    environments>
    <mappers>
        <mapper resource="mapper/EmployeeMapper.xml"/>
    mappers>
configuration>

6、创建EmployeeMapper.xml

<mapper namespace="com.mi.dao.EmployeeMapper">
    
    <select id="getEmployeeById" resultType="com.mi.pojo.Employee">
        select * from employee where id = #{id}
    select>
mapper>

7、创建TestMybatis测试类

package com.mi.test;

import com.mi.dao.EmployeeMapper;
import com.mi.pojo.Employee;
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;

public class TestMybatis {

    public SqlSessionFactory getSqlSessionFactory() throws IOException {
        String resource  = "mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        return new SqlSessionFactoryBuilder().build(inputStream);
    }

    @Test
    public void test() throws IOException {
        //1、获取SqlSessionFactory对象
        SqlSessionFactory sqlSessionFactory = getSqlSessionFactory();
        //2、获取Sqlsesion对象
        SqlSession sqlSession = sqlSessionFactory.openSession();

        try {
            //3、获取接口的实现类对象
            //会为接口自动创建一个代理对象，代理对象去执行增删改查方法
            EmployeeMapper mapper = sqlSession.getMapper(EmployeeMapper.class);
            Employee employee = mapper.getEmployeeById(1);
            System.out.println(employee);
        }finally {
            sqlSession.close();
        }
    }
}