Mybatis入门（一）

driver   = com.mysql.jdbc.Driver
url      = jdbc:mysql://127.0.0.1:3306/Howl
username = root
password =

<?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">

<!-- 根标签 -->
<configuration>

    <!-- 加载properties文件 -->
    <properties resource="db.properties">   

    <!-- 环境，可以配置多个，default：指定采用哪个环境，和spring整合后environments将废除 -->
    <environments default="default">
        <!-- id：唯一标识 -->
        <environment id="default">
            <!-- 事务管理器，JDBC类型的事务管理器 -->
            <transactionManager type="JDBC" />
            <!-- 数据源，池类型的数据源 -->
            <dataSource type="POOLED">
                <property name="driver" value="${driver}" />
                <property name="url" value="${url}" />
                <property name="username" value="${username}" />
                <property name="password" value="${password}" />
            </dataSource>
        </environment>
    </environments>
    
    <!-- 引入mapper文件的位置 -->
    <mappers>
        <mapper resource="mapper/user.xml"/>
    </mappers>
    
</configuration>

CREATE TABLE `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `email` varchar(20) NOT NULL,
  `password` text NOT NULL,
  `name` text NOT NULL,
  PRIMARY KEY (`id`) USING BTREE,
  UNIQUE KEY `email` (`email`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

package com.howl;

public class user {
    
    private int id;
    private String email;
    private String password;
    private String name;
    
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = email;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    @Override
    public String toString() {
        return "user [id=" + id + ", email=" + email + ", password=" + password + ", name=" + name + "]";
    }
}

<?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">
  
<!-- 命名空间 ,方便和其他JavaBean类的语句名称区分-->
<mapper namespace="user">

    <!-- id唯一表示语句 -->
    <!-- parameterType参数类型 -->
    <!-- resultType返回结果类型，这里的结果类型为上面创建的JavaBean-->
    <!-- #{}解析传进的参数占位符，预编译 -->
    <!-- ${}原样拼接，易mysql注入 -->
    <!-- <insert>/<select>/<update>/<delete>标签互用，但建议各用各 -->
    
    <select id="findUserById" parameterType="Integer" resultType="com.howl.user">
        select * from user where id = #{id};
    </select>
    
    <select id="findUser" resultType="com.howl.user">
        select * from user;
    </select>
    
    <insert id="addUser" parameterType="com.howl.user">
        insert into user (`email`,`password`,`name`) values (#{email},#{password},#{name})
    </insert>
    
</mapper>

//1.mybatis的配置文件地址  
String resource = "mybatis-config.xml";

//2.获取配置文件流
InputStream inputStream = Resources.getResourceAsStream(resource);

//3.根据配置文件流创建工厂----工厂模式
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

//4.根据工厂创建sqlsession
SqlSession sqlSession = sqlSessionFactory.openSession();

user user = sqlSession.select("user.findUserById",1);
List<user> users = sqlSession.selectList("user.findUser");
int ifSuccess = sqlSession.insert("user.addUser");

//mybatis默认关闭自动提交
//除了select语句，其他语句都需要commit提交，
sqlSession.commit();
//关闭sqlSession
sqlSession.close();