mybatis入门demo

1. mysql创建user表

   CREATE TABLE `user`  (
     `id` int(32) NOT NULL COMMENT 'id\r\n',
     `name` varchar(60) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
     `sex` varchar(1) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
     `birthday` date NULL DEFAULT NULL,
     PRIMARY KEY (`id`) USING BTREE
   ) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;
   
   SET FOREIGN_KEY_CHECKS = 1;

2. 创建maven普通工程mybatis-parent，删除src目录，添加mybatis依赖。

   
       <dependencies>
           <dependency>
               <groupId>mysqlgroupId>
               <artifactId>mysql-connector-javaartifactId>
               <version>5.1.47version>
           dependency>
           <dependency>
               <groupId>org.mybatisgroupId>
               <artifactId>mybatisartifactId>
               <version>3.5.3version>
           dependency>
           <dependency>
               <groupId>junitgroupId>
               <artifactId>junitartifactId>
               <version>4.12version>
           dependency>
           <dependency>
               <groupId>log4jgroupId>
               <artifactId>log4jartifactId>
               <version>1.2.17version>
           dependency>
       dependencies>

3. 创建子模块mybatis-01
4. resources目录下创建配置文件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>
       <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/mybatis?useSSL=false&useUnicode=true&characterEncoding=UTF-8"/>
                   <property name="username" value="root"/>
                   <property name="password" value="root"/>
               dataSource>
           environment>
       environments>
       <mappers>
           <mapper resource="com/qiaob/mapper/UserMapper.xml"/>
       mappers>
   configuration>

5. 封装mybatis工具类

   package com.qiaob.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 org.junit.Test;
   
   import java.io.IOException;
   import java.io.InputStream;
   
   public class MybatisUtils {
       static {
           //使用mybatis第一步：获取sqlSessionFactory对象
           try {
               String resource = "mybatis-config.xml";
               InputStream inputStream = null;
               inputStream = Resources.getResourceAsStream(resource);
               sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
           } catch (IOException e) {
               e.printStackTrace();
           }
   
       }
   
       private static SqlSessionFactory sqlSessionFactory;
   
       public static SqlSession getSqlSession() {
           return sqlSessionFactory.openSession();
       }
   
   
   }

6. 生成pojo实体类

   package com.qiaob.pojo;
   
   import java.util.Date;
   
   public class User {
       private int id;
       private String name;
       private String sex;
       private Date birthday;
   
       public User() {
       }
   
       @Override
       public String toString() {
           return "User{" +
                   "id=" + id +
                   ", name='" + name + '\'' +
                   ", sex='" + sex + '\'' +
                   ", birthday=" + birthday +
                   '}';
       }
   
       public int getId() {
           return id;
       }
   
       public void setId(int id) {
           this.id = id;
       }
   
       public String getName() {
           return name;
       }
   
       public void setName(String name) {
           this.name = name;
       }
   
       public String getSex() {
           return sex;
       }
   
       public void setSex(String sex) {
           this.sex = sex;
       }
   
       public Date getBirthday() {
           return birthday;
       }
   
       public void setBirthday(Date birthday) {
           this.birthday = birthday;
       }
   }

7. 生成mapper数据层接口

   package com.qiaob.mapper;
   
   import com.qiaob.pojo.User;
   
   import java.util.ArrayList;
   
   public interface UserMapper {
       //查询所有
       public ArrayList getUserList();
   
       //根据id查询某个
       public User getUserById(int id);
   
   
       //插入用户
       public int addUser(User user);
   
       //更新用户
       public int updateUser(User user);
   
       //删除用户
       public int deleteUser(int id);
   
   }

8.　　在resources相同层级目录下创建UserMapper.xml

:代表实现哪个mapper的接口方法

id="getUserList" :对应mapper的方法名

resultType="com.qiaob.pojo.User":对应返回集类型

parameterType="com.qiaob.pojo.User":sql中可以直接调用属性

sqlSession.commit()：mybatis要手工提交事务才生效

<?xml version="1.0" encoding="UTF-8" ?>
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">


    
    select * from mybatis.user
  

    
        select * from mybatis.user where id = #{id}
    

    
      insert into mybatis.user(id, name, sex, birthday) values (#{id},#{name},#{sex},#{birthday})
    
    
        update mybatis.user set birthday = #{birthday}  where  id=#{id};
    
    
        delete from mybatis.user where id =#{id}
    

9.创建单元测试类

• 获得指定日期的方法

 SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        Date d =null;
        try {
             d = sdf.parse("2018-03-09");
        } catch (ParseException e) {
            e.printStackTrace();
        }

package com.qiaob.dao;

import com.qiaob.mapper.UserMapper;
import com.qiaob.pojo.User;
import com.qiaob.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;

public class UserDaoTest {
    @Test
    public void testUserList(){
        //第一步：获得sqlSession对象
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        //第二步：执行sql
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);

        ArrayList userList = mapper.getUserList();
        for (User user : userList) {
            System.out.println(user);
        }

        //第三步：关闭sqlSession
        sqlSession.close();
    }


    @Test
    public  void testGetUserById(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();

        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        User user = mapper.getUserById(1);
        System.out.println(user);

        sqlSession.close();
    }

    @Test
    public  void testSaveUser(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();

        UserMapper mapper = sqlSession.getMapper(UserMapper.class);

        User user = new User(3, "乔逸之", "1", new Date());
        int num = mapper.addUser(user);

        System.out.println(num);

        sqlSession.commit();
        sqlSession.close();
    }

    @Test
    public void testUpdate(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();

        UserMapper mapper = sqlSession.getMapper(UserMapper.class);

        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        Date d =null;
        try {
             d = sdf.parse("2018-03-09");
        } catch (ParseException e) {
            e.printStackTrace();
        }

        mapper.updateUser(new User(3,"乔逸之","1",d));

        sqlSession.commit();
        sqlSession.close();
    }


    @Test
    public void testDeleteUser( ){
        SqlSession sqlSession = MybatisUtils.getSqlSession();

        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        mapper.deleteUser(3);
        sqlSession.commit();
        sqlSession.close();
    }

}

 补充：如果想将mapper.xml和mapper放在同一路径下，则需要在pom文件中增加导出过滤，见博客《》。