MyBatis 增、删、改、查操作-蒲公英云

示例：【MyBatis 增、删、改、查操作】

项目结构如下：

创建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>
    <!-- 默认的环境id为mysql -->
    <environments default="mysql">
        <environment id="mysql">
            <!-- 指定事务管理类型 -->
            <transactionManager type="jdbc"/>
            <!-- 配置数据库连接 -->
            <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>
    <!-- 配置Mapper的位置 -->
    <mappers>
        <mapper resource="com/mapper/UserMapper.xml"/>
    </mappers>
</configuration>

创建SessionFactory

package com.factory;
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;
public class SessionFactory {
    private static SqlSessionFactory sessionFactory=null;
    //初始化创建SqlSessionFactory对象
    static {        
                try {
                    //读取配置文件
                    InputStream    is = Resources.getResourceAsStream("mybatis-config.xml");
                    //根据配置文件构建SqlSessionFactory
                    sessionFactory=new SqlSessionFactoryBuilder().build(is);
                } catch (IOException e) {
                    e.printStackTrace();
                }                
    }
    //获取SqlSession对象
    public static SqlSession getSqlSession() {
        return sessionFactory.openSession();
    }
    // 获取SqlSessionFactory
    public static SqlSessionFactory getSqlSessionFactory() {
        return sessionFactory;
    }
}

创建UserMapper.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">
<!-- 用户自定义命名空间 -->
<mapper namespace="com.mapper.UserMapper">    
    <!-- 添加用户 -->
    <insert id="addUser" parameterType="com.po.User">
        insert into t_user(username,password) values(#{username},#{password})
    </insert>
    <!-- 删除用户 -->
    <delete id="deleteUser" parameterType="int">
        delete from t_user where uid=#{uid}
    </delete>
    <!-- 更新用户 -->
    <update id="updateUser" parameterType="com.po.User">
        update t_user set username=#{username},password=#{password} where uid=#{uid}
    </update>
    <!-- 查询用户 -->
    <select id="getUserById" parameterType="Integer" resultType="com.po.User">
        select * from t_user where uid=#{uid}
    </select>
    <!-- 查询所有用户 -->
    <select id="getUsers" resultType="com.po.User">
        select * from t_user
    </select>
    <!-- 模糊查询 -->
    <select id="findUser" resultType="com.po.User" parameterType="String">
        select * from t_user where username like CONCAT('%',#{username},'%')
    </select>
</mapper>

创建UserDao

package com.dao;
import java.util.List;
import org.apache.ibatis.session.SqlSession;
import com.factory.SessionFactory;
import com.po.User;
public class UserDao {
    private SqlSession session=SessionFactory.getSqlSession();
    private User user;
    private List<User> users;    
    public SqlSession getSession() {
        return session;
    }
    //增加用户
    public void addUser(User user) {
        session.insert("com.mapper.UserMapper.addUser",user);
        session.commit();
        session.close();
    }
    //删除用户
    public void deleteUser(int id) {
        session.delete("com.mapper.UserMapper.deleteUser", id);
        session.commit();
        session.close();
    }
    //根据 id查询用户
    public User getUserById(Integer id) {
        user=session.selectOne("com.mapper.UserMapper.getUserById", id);
        session.commit();
        session.close();
        return user;
    }
    //查询所有用户
    public List<User> getUsers(){
        users=session.selectList("com.mapper.UserMapper.getUsers");
        session.commit();
        session.close();
        return users;
    }
    //模糊查询
    public List<User> findUser(String username){
        users=session.selectList("com.mapper.UserMapper.findUser",username);
        session.commit();
        session.close();
        return users;
    }
    //更新用户
    public void updateUser(User user,int id) {
        User u=new User();
        u=session.selectOne("com.mapper.UserMapper.getUserById", id);
        u.setUsername(user.getUsername());
        u.setPassword(user.getPassword());
        session.update("com.mapper.UserMapper.updateUser", u);
        session.commit();
        session.close();
    }
}

创建Test

package com.test;
import java.util.List;
import com.dao.UserDao;
import com.po.User;
public class Test {
    public static void main(String[] args) {
    }
}

增加用户

public static void main(String[] args) {
        UserDao userDao=new UserDao();
        User user=new User();
        user.setUsername("user");
        user.setPassword("user123");
        userDao.addUser(user);
    }

70 1

删除用户

public static void main(String[] args) {
        UserDao userDao=new UserDao();
        userDao.deleteUser(12);
    }

70 2

修改用户

public static void main(String[] args) {
        UserDao userDao=new UserDao();
        User user=new User();
        user.setUsername("李四");
        user.setPassword("5622");
        userDao.updateUser(user, 3);
    }

70 3

根据id查询用户

public static void main(String[] args) {
        UserDao userDao=new UserDao();
        User user=userDao.getUserById(1);
        System.out.println(user);
    }

70 4

模糊查询用户

public static void main(String[] args) {
        UserDao userDao=new UserDao();
        List<User> users=userDao.findUser("an");
        for (User u : users) {
            System.out.println(u);
        }
    }