SSM框架之---Mybatis框架（单表操作）入门案例---xml配置

首先环境搭建
1、建立一个maven项目和一个简单的java模块
2、然后建立相应的包，并且进行相关的设置
3、然后数据库建表，建立一个简单的用户表
4、新建一个jdbc的properties配置文件，用于数据库连接
5、然后编写好实体类User（注意需要实现序列化）

基本目录结构

导入相关的依赖

目录结构详情

数据库建表

jdbc.properties配置文件

创建用户实体类

详情代码
1、实体类

package com.mybatis.domain;

import java.io.Serializable;

public class User implements Serializable {
    private int id;
    private String username;
    private String password;

    public int getId() {
        return id;
    }

    public void setId(int 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 + '\'' +
                '}';
    }
}

2、DAO层接口（单表的增删改查）

package com.mybatis.dao;

import com.mybatis.domain.User;

import java.util.List;

/**
 * 单表的增删该查
 */
public interface IUserDAO {
    public List<User> findAll();
    public List<User> findByUserName();
    public void saveUser(User user);
    public void deleteUser(int id);
    public void updateUser(User user);
}

3、这里是重点，创建SqlSession工具类，在Mybatis中用户增删改查的一个类就是Sqlsseion接口

package com.mybatis.utils;

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 java.io.IOException;

public class MySqlSessionUtil {
  private static SqlSessionFactory sqlSessionFactory;
  static {
        SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
      try {
          sqlSessionFactory = builder.build(Resources.getResourceAsStream("sqlMapperConfig.xml"));
      } catch (IOException e) {
          e.printStackTrace();
      }
  }
  public static SqlSession getSqlSession(){
      return sqlSessionFactory.openSession();
  }
}

4、然后在resources文件夹下创建主配置文件
用于加载相关数据库连接以及查找相关映射文件

<?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>
    <properties resource="jdbc.properties"></properties>
    <typeAliases>
        <package name="com.mybatis.dao"></package>
        <package name="com.mybatis.domain"></package>
    </typeAliases>
    <environments default="mysql">
        <environment id="mysql">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="${db.driver}"/>
                <property name="url" value="${db.url}"/>
                <property name="username" value="${db.username}"/>
                <property name="password" value="${db.password}"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <package name="com.mybatis.dao"></package>
    </mappers>
</configuration>

5、配置映射文件，进行相关的单表增删改查

<?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.mybatis.dao.IUserDAO">
    <resultMap id="userMap" type="User">
        <id property="id" column="id"></id>
        <result property="username" column="user_name"></result>
        <result property="password" column="user_pwd"></result>
    </resultMap>
    <select id="findAll" resultMap="userMap">
        select * from usertb;
    </select>
</mapper>

6、编写测试类

package com.mybatis.web;

import com.mybatis.dao.IUserDAO;
import com.mybatis.domain.User;
import com.mybatis.utils.MySqlSessionUtil;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.List;

public class UserServletTest {
    @Test
    public void findAllTest(){
        SqlSession sqlSession = MySqlSessionUtil.getSqlSession();
        IUserDAO mapper = sqlSession.getMapper(IUserDAO.class);
        List<User> all = mapper.findAll();
        for (User user : all) {
            System.out.println(user);
        }
    }
}

7、测试（查询所有）

该项目链接
链接：https://pan.baidu.com/s/16iQMrYa-U1Qi7146ZXL3AQ
提取码：2qxa

单表操作所有代码（全面）
链接：https://pan.baidu.com/s/1hIqJ8lbGxSKXypLfCBuNzQ
提取码：c51f