mybatis 基于配置文件的demo

项目工程如图：

创建数据库：

CREATE TABLE myuser(
    id     INT PRIMARY KEY,
    username VARCHAR(20),
    age     INT,
    PASSWORD VARCHAR(20)
);

mybatis加载文件：configuration.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>

  <!-- 指定properties配置文件，数据库相关 -->
  <properties resource="mysql.properties"></properties>
  
  <!-- 指定Mybatis使用log4j -->
  <settings>
     <setting name="logImpl" value="LOG4J"/>
  </settings>
      
  <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/my_DB"/>
        <property name="username" value="root"/>
        <property name="password" value="123456"/>
         
         <!-- 上面指定了数据库配置文件， 配置文件里面也是对应的这四个属性 -->
         <!-- <property name="driver" value="${driver}"/>
         <property name="url" value="${url}"/>
         <property name="username" value="${username}"/>
         <property name="password" value="${password}"/> -->
         
      </dataSource>
    </environment>
  </environments>
  
  
  <mappers>
    <mapper resource="mapping.xml"/>
  </mappers>
  
</configuration>

映射文件：mapping.xml

<?xml version="1.0" encoding="UTF-8" ?>   
<!DOCTYPE mapper   
PUBLIC "-//ibatis.apache.org//DTD Mapper 3.0//EN"  
"http://ibatis.apache.org/dtd/ibatis-3-mapper.dtd"> 
<mapper namespace="dao.UserDao">

    <select id="updateById" parameterType="entity.MyUser">
        UPDATE myuser SET age=#{age} WHERE id=#{id}
    </select>

    <select id="deleteById" parameterType="int">
        DELETE FROM myuser WHERE id=#{id}
    </select>

    <select id="insert" parameterType="entity.MyUser">
        INSERT INTO myuser VALUES(#{id},#{username},#{age},#{password})
    </select>

    <resultMap type="entity.MyUser" id="ResultListUser">
        <id column="id" property="id" />
        <result column="age" property="age" />
        <result column="username" property="username" />
        <result column="password" property="password" />
    </resultMap>

    <select id="findAllUser" parameterType="string" resultMap="ResultListUser">
        SELECT * FROM myuser WHERE PASSWORD LIKE "%"#{PASSWORD}"%"
    </select>

   <select id="getUserById" parameterType="int" resultType="entity.MyUser" > 
      select * from myuser where id = #{id}
   </select>

</mapper>

创建接口：UserDao.java

package dao;

import java.util.List;

import entity.MyUser;

public interface UserDao {

    public void updateById(MyUser user);
    
    public void deleteById(int id);
    
    public void insert(MyUser user);
    
    public MyUser getUserById(int id);
    
    public List<MyUser> findAllUser(String str);
    
}

创建与数据库表字段对应的类：MyUser.java

package entity;

public class MyUser {

    private int id;
    private int age;
    private String username;
    private String password;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    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 "MyUser [id=" + id + ", age=" + age + ", username=" + username + ", password=" + password + "]";
    }
    
    
    
}

进行测试:UserDaoTest.java

package dao;

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

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 entity.MyUser;

public class UserDaoTest {

    @Test
    public void testUpdateByid() {
        
        SqlSession sqlSession = getSessionFactory().openSession();  
        try {
            UserDao userDao = sqlSession.getMapper(UserDao.class);  
            MyUser user = userDao.getUserById(3);
            user.setAge(12);
            userDao.updateById(user);
            sqlSession.commit();
        
        }
        finally {
            sqlSession.close();
        }
        
    }
    
    @Test
    public void testDeleteById() {
        
        SqlSession sqlSession = getSessionFactory().openSession();  
        try {
            UserDao userDao = sqlSession.getMapper(UserDao.class);  
            userDao.deleteById(8);
            sqlSession.commit();
        
        }
        finally {
            sqlSession.close();
        }
        
    }
    
    @Test
    public void testInsert() {
        
        MyUser user = new MyUser();
        user.setAge(90);
        user.setId(8);
        user.setUsername("tyu");
        user.setPassword("458");
        
        SqlSession sqlSession = getSessionFactory().openSession();  
        try {
            UserDao userDao = sqlSession.getMapper(UserDao.class);  
            userDao.insert(user);
            sqlSession.commit();
        
        }
        finally {
            sqlSession.close();
        }
        
    }
    
    @Test
    public void testFindAllUser() {
        
        SqlSession sqlSession = getSessionFactory().openSession();  
        try {
            UserDao userDao = sqlSession.getMapper(UserDao.class);  
            List<MyUser> list = userDao.findAllUser("3");
            for(MyUser user:list) {
                System.out.println(user.toString());
            }
        
        }
        finally {
            sqlSession.close();
        }
        
    }
    
    @Test
    public void testGetUserById() {
        
        SqlSession sqlSession = getSessionFactory().openSession();  
        try {
            UserDao userDao = sqlSession.getMapper(UserDao.class);  
            MyUser user = userDao.getUserById(2); 
            System.out.println(user.toString());
        
        }
        finally {
            sqlSession.close();
        }
    
    }

     //Mybatis 通过SqlSessionFactory获取SqlSession, 然后才能通过SqlSession与数据库进行交互
    private static SqlSessionFactory getSessionFactory() {  
        SqlSessionFactory sessionFactory = null;  
        String resource = "configuration.xml";  
        try {  
            sessionFactory = new SqlSessionFactoryBuilder().build(Resources  
                    .getResourceAsReader(resource));
        } catch (IOException e) {  
            e.printStackTrace();  
        }  
        return sessionFactory;  
    }  
    
}