1、MyBatis面向接口編程

1、在mybatis數據庫下創建employee數據表

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

2、創建Employee對象

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、創建EmployeeMapper接口

package com.mi.dao;

import com.mi.pojo.Employee;

public interface EmployeeMapper {

    public Employee getEmployeeById(int id);
}

4、創建pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<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>4.0.0</modelVersion>

    <groupId>com.mi</groupId>
    <artifactId>mybatis</artifactId>
    <version>1.0-SNAPSHOT</version>


    <dependencies>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.2</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.6</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>RELEASE</version>
            <scope>test</scope>
        </dependency>

    </dependencies>


</project>

5、創建mybatis-config.xml主配置文件

<?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="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、創建EmployeeMapper.xml

<?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">
<!--指定爲接口的全類名-->
<mapper namespace="com.mi.dao.EmployeeMapper">
    <!--id 爲接口的方法名-->
    <select id="getEmployeeById" resultType="com.mi.pojo.Employee">
        select * from employee where id = #{id}
    </select>
</mapper>

7、創建TestMybatis測試類

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、獲取SqlSessionFactory對象
        SqlSessionFactory sqlSessionFactory = getSqlSessionFactory();
        //2、獲取Sqlsesion對象
        SqlSession sqlSession = sqlSessionFactory.openSession();

        try {
            //3、獲取接口的實現類對象
            //會爲接口自動創建一個代理對象，代理對象去執行增刪改查方法
            EmployeeMapper mapper = sqlSession.getMapper(EmployeeMapper.class);
            Employee employee = mapper.getEmployeeById(1);
            System.out.println(employee);
        }finally {
            sqlSession.close();
        }
    }
}