mybatis01--初识MyBatis

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近日要开始MyBatis的学习了，首先第一件事当然是看官方文档啦

附上官方文档http://www.mybatis.org/mybatis-3/zh/index.html

创建maven工程

名称任意，创一个最简单的maven工程就好了

引入MyBatis

在pom.xml中加入MyBatis依赖和数据库驱动，我这里用的是mysql

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<dependency>
  <groupId>org.mybatis</groupId>
  <artifactId>mybatis</artifactId>
  <version>x.x.x</version>
</dependency>
<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.46</version>
</dependency>

x.x.x填的是MyBatis的版本号，目前最新稳定版是3.4.6

编写配置文件

由xml构建SqlSessionFactory,首先编写XML配置，以下所有中文均改成自己的配置

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<?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="数据库驱动"/>
        <property name="url" value="url地址"/>
        <property name="username" value="用户名"/>
        <property name="password" value="密码"/>
      </dataSource>
    </environment>
  </environments>
  <mappers>
    <mapper resource="mapper路径"/>
  </mappers>
</configuration>

编写mapper配置文件：

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<?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="org.mybatis.example.BlogMapper">
  <select id="selectUser" resultType="com.yhzl.bean.User">
    select * from User where id = #{id}
  </select>
</mapper>

编写实体类及测试类

实体类：

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package com.yhzl.bean;

/**
 * @author chsm
 * @date 2018年4月4日上午8:30:32
 * @version 1.0
 */
public class User {

	private Integer id;
	private String username;
	private String password;

	public Integer getId() {
		return id;
	}

	public void setId(Integer id) {
		this.id = id;
	}

	public String getUsername() {
		return username;
	}

	public void setUsername(String username) {
		this.username = username;
	}

	public String getPassword() {
		return password;
	}

	public void setPassword(String password) {
		this.password = password;
	}

	@Override
	public String toString() {
		return "User [id=" + id + ", username=" + username + ", password="
				+ password + "]";
	}

}

测试类:

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package com.yhzl.test;

import java.io.IOException;
import java.io.InputStream;

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 com.yhzl.bean.User;

/**
 * @author chsm
 * @date  2018年4月4日上午8:33:13
 * @version 1.0
 */
public class Test {
	
	public static void main(String[] args) throws IOException {
		InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");
		SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
		SqlSession session = sessionFactory.openSession();
		User user = session.selectOne("org.mybatis.example.BlogMapper.selectUser", 1);
		System.out.println(user);
	}
	
}

对代码的编写已经完成了此时可以运行了，如果出现报错等情况，请检查下代码看看有没有写错