mybatis 3.4.5 HelloWorld 01

在SSH框架盛行的时代，ORM和持久层框架都不断响彻在耳边，今天如歌就带领大家一起来认识另一种持久层框架；

官网api

搭建开发环境

<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/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion>
<groupId>com.ruge</groupId>
<artifactId>mybatis</artifactId>
<packaging>war</packaging>
<version>1.0-SNAPSHOT</version>
<name>mybatis Maven Webapp</name>
<url>http://maven.apache.org</url>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.4.5</version>
</dependency>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis-spring</artifactId>
<version>1.3.1</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.45</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17.redhat-3</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
</dependency>
</dependencies>
<build>
<finalName>mybatis</finalName>
</build>
</project>

创建数据库

/*
Navicat MySQL Data Transfer

Source Server         : 爱丽丝、如歌
Source Server Version : 50717
Source Host           : localhost:3306
Source Database       : mybatis

Target Server Type    : MYSQL
Target Server Version : 50717
File Encoding         : 65001

Date: 2017-12-20 15:23:16
*/

SET FOREIGN_KEY_CHECKS=0;

-- ----------------------------
-- Table structure for `tbl_emp`
-- ----------------------------
DROP TABLE IF EXISTS `tbl_emp`;
CREATE TABLE `tbl_emp` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(255) DEFAULT NULL,
`gender` varchar(255) DEFAULT NULL,
`email` varchar(255) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of tbl_emp
-- ----------------------------
INSERT INTO `tbl_emp` VALUES ('1', '张三', 'gen', '1@qq.com');

mybatis-config.xml

<?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/Emp.xml"/>
</mappers>
</configuration>

Controller

package com.ruge.mybatis.controller;

import com.ruge.mybatis.entity.Emp;
import com.ruge.mybatis.mapper.EmpMapper;
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.InputStream;
import java.util.List;

/**
* @author 爱丽丝、如歌
* @Description: TODO
* @date 2017/12/20 11:07
*/
public class EmpController {
@Test
public void Conn() throws Exception{
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

SqlSession session = sqlSessionFactory.openSession();
try {
EmpMapper mapper = session.getMapper(EmpMapper.class);
List<Emp> ee = mapper.select(1);
System.out.println(ee);
} finally {
session.close();
}

}
}

Mapper

package com.ruge.mybatis.mapper;

import com.ruge.mybatis.entity.Emp;

import java.util.List;

/**
* @author 爱丽丝、如歌
* @Description: TODO
* @date 2017/12/20 11:19
*/
public interface EmpMapper {
public List<Emp> select ();
}

entity

package com.ruge.mybatis.entity;

/**
* @author 爱丽丝、如歌
* @Description: TODO
* @date 2017/12/20 10:56
*/
public class Emp {
private int id;
private String name;
private String gender;
private String email;

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;
}

public String getEmail() {
return email;
}

public void setEmail(String email) {
this.email = email;
}

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

Emp.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">
<mapper namespace="com.ruge.mybatis.mapper.EmpMapper">
<select id="select" resultType="com.ruge.mybatis.entity.Emp">
select * from tbl_emp where id = #{id}
</select>
</mapper>

总结

         mybatis是Apache下的顶级项目，是一个持久层框架，是一个不完全的ORM框架；

        mybatis使得程序将主要精力放在了sql上，它通过自身提供的映射方式，自由且灵活地生成满足程序需要的sql语句（半自动化，大部分需要程序员自己编写）;

        mybatis可以将向PreparedStatement中输入的参数自动进行输入映射，将查询结果集灵活映射成Java对象（输出映射）；

      以上是如歌对mybatis基础的整理，希望能帮大家更好的了解MyBatis！如有更好的建议或者意见，请留言！