mybatis的简单实现

准备:

导入mybatis,及数据库驱动jar包,下面是maven依赖

<dependency> <groupId>com.mybatis</groupId> <artifactId>mybatis</artifactId> <version>3.3.0</version> </dependency> <dependency> <groupId>com.oracle</groupId> <artifactId>ojdbc7</artifactId> <version>10.2</version> </dependency>

创建三层架构包

 

TUser实体类,属性与数据库中存储的字段名相对应,可以相同也可以不相同,推荐相同

我的数据库表截图:

 

 

User实体类

package com.mybatis.bean;   /**  * @author TH  */ public class TUser {        private int id;         private String name;         private String gender;       public TUser() {     }       public TUser(int id, String name, String gender) {         this.id = id;         this.name = name;         this.gender = gender;     }       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 == null ? null : name.trim();     }         public String getGender() {         return gender;     }       public void setGender(String gender) {         this.gender = gender == null ? null : gender.trim();     } }

 

创建TUserMapper接口和TUserMapper.xml文件,文件名可以不一致,推荐一致.

package com.mybatis.dao;   import com.mybatis.bean.TUser; import java.util.List;   public interface TUserMapper {     //下面是一些普通方法定义,实现数据库的增删改查操作     int deleteByPrimaryKey(int id);       int insert(TUser record);         TUser selectByPrimaryKey(int id);         List<TUser> selectAll();       int updateByPrimaryKey(TUser record); }

 

<?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.TUserMapper">   <resultMap id="BaseResultMap" type="com.mybatis.bean.TUser">     <id column="ID" jdbcType="DECIMAL" property="id" />     <result column="NAME" jdbcType="VARCHAR" property="name" />     <result column="GENDER" jdbcType="VARCHAR" property="gender" />   </resultMap> <!--  这里的ID属性要与接口的方法名一致 -->   <delete id="deleteByPrimaryKey" parameterType="int">     delete from HGH.T_USER     where ID = #{id,jdbcType=DECIMAL}   </delete>     <insert id="insert" parameterType="com.mybatis.bean.TUser">     insert into HGH.T_USER (ID, NAME, GENDER       )     values (#{id,jdbcType=DECIMAL}, #{name,jdbcType=VARCHAR}, #{gender,jdbcType=VARCHAR}       )   </insert>   <update id="updateByPrimaryKey" parameterType="com.mybatis.bean.TUser">     update HGH.T_USER     set NAME = #{name,jdbcType=VARCHAR},       GENDER = #{gender,jdbcType=VARCHAR}     where ID = #{id,jdbcType=DECIMAL}   </update>   <select id="selectByPrimaryKey" parameterType="int" resultMap="BaseResultMap">     select ID, NAME, GENDER     from HGH.T_USER     where ID = #{id,jdbcType=DECIMAL}   </select>   <select id="selectAll" resultMap="BaseResultMap">       select ID, NAME, GENDER     from HGH.T_USER   </select> </mapper>

 

创建mybatis-config.xml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> <!--    引入配置文件-->     <properties resource="jdbc.properties"/>     <settings>         <!-- Globally enables or disables any caches configured in any mapper under this configuration -->         <setting name="cacheEnabled" value="false"/>         <!-- Sets the number of seconds the driver will wait for a response from the database -->         <setting name="defaultStatementTimeout" value="5"/>         <!-- Enables automatic mapping from classic database column names A_COLUMN to camel case classic Java property names aColumn -->         <setting name="mapUnderscoreToCamelCase" value="true"/>         <!-- Allows JDBC support for generated keys. A compatible driver is required.         This setting forces generated keys to be used if set to true,          as some drivers deny compatibility but still work -->         <setting name="useGeneratedKeys" value="true"/>     </settings>       <!-- Continue editing here --> <!--    给类起别名-->     <typeAliases>         <package name="com.mybatis"/>     </typeAliases> <!--    配置数据源     ${jdbc.driverClassName}使用该表达式获取properties配置文件写好的数据源配置 -->     <environments default="development">         <environment id="development">             <transactionManager type="JDBC"/>             <dataSource type="POOLED">                 <property name="driver" value="${jdbc.driverClassName}" />                 <property name="url" value="${jdbc.url}" />                 <property name="username" value="${jdbc.username}" />                 <property name="password" value="${jdbc.password}" />             </dataSource>         </environment>     </environments>   <!--    注册mapper.xml文件,这里使用的时包注册,就是说注册com.mybatis包下的所有xml文件-->     <mappers>         <package name="com.mybatis"/>     </mappers>   </configuration>

properties配置文件:

jdbc.driverClassName=oracle.jdbc.driver.OracleDriver jdbc.url=jdbc:oracle:thin:@localhost:1521:XE jdbc.username=hgh jdbc.password=orcl1234

创建TUserService接口和TUserServiceImpl实现类

package com.mybatis.service;   import com.mybatis.bean.TUser;   import java.util.List;   public interface TUserService {       int deleteByPrimaryKey(int id);       int insert(TUser record);       TUser selectByPrimaryKey(int id);       List<TUser> selectAll();       int updateByPrimaryKey(TUser record); }

 

package com.mybatis.service.impl;   import com.mybatis.MybatisSqlSessionFactory; import com.mybatis.bean.TUser; import com.mybatis.dao.TUserMapper; import com.mybatis.service.TUserService; import org.apache.ibatis.session.SqlSession;   import java.util.List;   /**  * @author TH  */ public class UserServiceImpl implements TUserService {     @Override     public int deleteByPrimaryKey(int id) { //这里MybatisSqlSessionFactory是自己创建的工厂类         try(SqlSession session = MybatisSqlSessionFactory.getSqlSessionFactory().openSession()) {             TUserMapper tUserMapper = session.getMapper(TUserMapper.class);             int result = tUserMapper.deleteByPrimaryKey(id);             session.commit();             return result;         }     }       @Override     public int insert(TUser record) {         try(SqlSession session = MybatisSqlSessionFactory.getSqlSessionFactory().openSession()) {             TUserMapper tUserMapper = session.getMapper(TUserMapper.class);             int result = tUserMapper.insert(record);             session.commit();             return result;         }     }       @Override     public TUser selectByPrimaryKey(int id) {         try(SqlSession session = MybatisSqlSessionFactory.getSqlSessionFactory().openSession()) {             TUserMapper tUserMapper = session.getMapper(TUserMapper.class);             TUser result = tUserMapper.selectByPrimaryKey(id);             return result;         }     }       @Override     public List<TUser> selectAll() {         try(SqlSession session = MybatisSqlSessionFactory.getSqlSessionFactory().openSession()) {             TUserMapper tUserMapper = session.getMapper(TUserMapper.class);             List<TUser> result = tUserMapper.selectAll();             return result;         }     }       @Override     public int updateByPrimaryKey(TUser record) {         try(SqlSession session = MybatisSqlSessionFactory.getSqlSessionFactory().openSession()) {             TUserMapper tUserMapper = session.getMapper(TUserMapper.class);             int result = tUserMapper.updateByPrimaryKey(record);             session.commit();             return result;         }     } }

 

工厂类

package com.mybatis;   import org.apache.ibatis.io.Resources; import org.apache.ibatis.session.SqlSessionFactory; import org.apache.ibatis.session.SqlSessionFactoryBuilder;   import java.io.IOException; import java.io.InputStream;   /**  * @author TH  */ public class MybatisSqlSessionFactory {     private static InputStream is;     static {         try {             is = Resources.getResourceAsStream("mybatis-config.xml");         } catch (IOException e) {             e.printStackTrace();         }     }       private MybatisSqlSessionFactory() {     }       public static SqlSessionFactory getSqlSessionFactory(){         return Singer.S_INSTANCE;     }     private static class Singer{         private static final SqlSessionFactory S_INSTANCE = new SqlSessionFactoryBuilder().build(MybatisSqlSessionFactory.is);     } }

 

1. 开始测试啦:

package com.mybatis;   import com.mybatis.bean.TUser;   import com.mybatis.service.impl.UserServiceImpl;   public class Test {     public static void main(String[] args) {         UserServiceImpl service = new UserServiceImpl();         service.updateByPrimaryKey(new TUser(2,"mt","female"));     } } //这里就可以成功修改数据库数据了,执行其他操作只需要调用相应的方法即可

如果实现过程中遇到什么问题可评论区留言,会尽快回复.