MyBatis学习笔记-1 Idea配置MyBatis

一、创建工程

    1、创建Java项目，勾选Java EE，Next，修改名称，Finish

    2、在WEB-INF下创建两个文件夹classes和lib，分别用作输出文件目录和库文件目录

    3、File-Project Structure， Modules-Path中将Out path和Test Out path更改为classes

    4、Module-Dependencies添加Jars or Directories选中lib文件夹，添加Library选中Tomcat

    

    5、打开Edit Configuration，创建一个Tomcat Server

    6、点击运行，能打开index.jsp，配置完成

二、准备数据库

    1、创建数据库MyBatis

CREATE DATABASE mybatis DEFAULT CHARACTER  SET utf8 COLLATE utf8_general_ci;

    2、创建数据表

use mybatis;

CREATE TABLE IF NOT EXISTS country (
id int NOT NULL AUTO_INCREMENT,
countryname varchar(255) NULL,
countrycode varchar(255) NULL,
PRIMARY KEY (id));

insert country(countryname, countrycode)
values ('中国','CN'),('美国','US'),('俄罗斯','RU'),
('英国','GB'),('法国','FR');

三、配置MyBatis

    1、添加MySQL、MyBatis及其依赖库包至lib下，右键Add As Library

        

    2、创建config目录，创建jdbc.properties文件，放置配置信息

jdbc.DriverClassName=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://127.0.0.1:3306/mybatis
jdbc.username=root
jdbc.password=password

    3、在config目录下，创建mybatis.xml文件

    4、在src目录下创建实体类Country.java

package model;

public class Country {
    private Long id;
    private String countryname;
    private String countrycode;

    public String getCountryname() {
        return countryname;
    }

    public void setCountryname(String countryname) {
        this.countryname = countryname;
    }

    public String getCountrycode() {
        return countrycode;
    }

    public void setCountrycode(String countrycode) {
        this.countrycode = countrycode;
    }

    public Long getId() {
        return id;
    }

    @Override
    public String toString() {
        return "Country{" +
                "id=" + id +
                ", countryname='" + countryname + '\'' +
                ", countrycode='" + countrycode + '\'' +
                '}';
    }
}

    5、在config下创建mapper文件Country.xml，存放SQL语句及其映射

    

    
    
        SELECT * FROM country
    

    6、配置Log4j（可选，若不配置，最后运行会报WARN）

# Configure logging for testing: optionally with log file
log4j.rootLogger=WARN, stdout
# log4j.rootLogger=WARN, stdout, logfile

log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d %p [%c] - %m%n

log4j.appender.logfile=org.apache.log4j.FileAppender
log4j.appender.logfile.File=target/spring.log
log4j.appender.logfile.layout=org.apache.log4j.PatternLayout
log4j.appender.logfile.layout.ConversionPattern=%d %p [%c] - %m%n

7、编写测试代码Demo1.java

package test;

import model.Country;
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.BeforeClass;
import org.junit.Test;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

public class Demo1 {
    private static SqlSessionFactory sqlSessionFactory;

    //使用junit4
    @BeforeClass
    public static void init(){
        try{
            //将mybatis.xml读入InputStream
            InputStream inputStream = Resources.getResourceAsStream("mybatis.xml");
            //通过SqlSessionFactoryBuilder创建sqlSessionFactory
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
            inputStream.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    //测试
    @Test
    public void testSelectAll(){
        //打开会话
        SqlSession sqlSession = sqlSessionFactory.openSession();
        try {
            List countryList = sqlSession.selectList("model.Country.selectAll");
            printCountryList(countryList);
        }finally {
            //关闭会话
            sqlSession.close();
        }
    }

    private void printCountryList(ListcountryList){
        for (Country country : countryList){
            System.out.println(country);
        }
    }
}

项目结构：

运行结果如下：