MyBatis的简单操作

2022-09-15 17:13:30

这里将的是简单的增、删、改、查等基本操作

首先创建java项目，导入相应的依赖包，这里可以参考上一篇博客

1、添加数据

在jike.book.pojo包中，新建java类

JiKeUser.java:

 package jike.book.pojo;

 public class JiKeUser {

     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;

     }

 }

在jike.book.map中有：

MyBatisConfig.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>

 <!-- 定义别名 ,必须放在environments之前-->

   <typeAliases>

       <typeAlias alias="JiKeUser" type="jike.book.pojo.JiKeUser"/>

   </typeAliases>

   <environments default="development">

      <environment id="development">

        <transactionManager type="JDBC">

        </transactionManager>

        <dataSource type="POOLED">

              <property name="driver" value="com.mysql.jdbc.Driver"/>

              <property name="url" value="jdbc:mysql://localhost:3306/jikebook"/>

              <property name="username" value="root"/>

              <property name="password" value=""/>

        </dataSource>

      </environment>

   </environments>

   <mappers>

         <mapper resource="jike/book/map/jikeUser.xml"/>

   </mappers>

 </configuration>

jikeUser.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">

 <mapper namespace="/">

   <select id="findById"  parameterType="int"  resultType="jike.book.pojo.JiKeUser">

         select * from jikeUser where id=#{id}

   </select>

   <insert id="insertUser" parameterType="JiKeUser" statementType="PREPARED"

      keyProperty="id" useGeneratedKeys="true">

      insert into JikeUser (userName,password) values(#{userName},#{password})

   </insert>

 </mapper>

新建测试类：

TestUpdate.java

 package jike.book.test;

 import java.io.IOException;

 import java.io.Reader;

 import jike.book.map.InterfaceJiKeUserMap;

 import jike.book.pojo.JiKeUser;

 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 TestUpdate {

     public static void main(String[] args) {

         String resource = "jike/book/map/MyBatisConfig.xml";

         Reader reader = null;

         SqlSession session;

         try {

             reader = Resources.getResourceAsReader(resource);

         } catch (IOException e) {

             e.printStackTrace();

         }

         SqlSessionFactory sqlMapper = new SqlSessionFactoryBuilder()

                 .build(reader);

         session = sqlMapper.openSession();

         try{

     /* 添加  */

             JiKeUser jku = new JiKeUser();

             jku.setUserName("jike001");

             jku.setPassword("");

             session.insert("insertUser",jku);

 session.commit();

         }catch(Exception e){

             e.printStackTrace();

         }finally{

             session.close();

         }

     }

 }

执行java测试类即可

2、修改

修改数据和添加数据差不多，在jikeUser.xml中添加

 <update id="updateUser" parameterType="JiKeUser">

     update JiKeUser set userName = #{userName},password=#{password}

     where id=#{id}

  </update>

然后将测试类改为：

package jike.book.test;

import java.io.IOException;

import java.io.Reader;

import jike.book.map.InterfaceJiKeUserMap;

import jike.book.pojo.JiKeUser;

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 TestUpdate {

    public static void main(String[] args) {

        String resource = "jike/book/map/MyBatisConfig.xml";

        Reader reader = null;

        SqlSession session;

        try {

            reader = Resources.getResourceAsReader(resource);

        } catch (IOException e) {

            e.printStackTrace();

        }

        SqlSessionFactory sqlMapper = new SqlSessionFactoryBuilder()

                .build(reader);

        session = sqlMapper.openSession();

        try{

            /* 修改  */

            JiKeUser jku2 = new JiKeUser();

            jku2.setUserName("jike00100");

            jku2.setPassword("");

            jku2.setId();

            session.update("updateUser", jku2);

            session.commit();

        }catch(Exception e){

            e.printStackTrace();

        }finally{

            session.close();

        }

    }

}

即可

3、删除

删除操作稍微有些不同，首先在jike.book.map中新建一个接口

InterfaceJiKeUserMap.java,采用注解方式

 package jike.book.map;

 import org.apache.ibatis.annotations.Delete;

 public interface InterfaceJiKeUserMap {

     @Delete("delete from JiKeUser where id=#{id}" )

     public void deleteUser(Integer id);

 }

在MyBatisConfig.xml中加入map映射

 <mapper class="jike.book.map.InterfaceJiKeUserMap" />

然后修改测试类

 package jike.book.test;

 import java.io.IOException;

 import java.io.Reader;

 import jike.book.map.InterfaceJiKeUserMap;

 import jike.book.pojo.JiKeUser;

 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 TestUpdate {

     public static void main(String[] args) {

         String resource = "jike/book/map/MyBatisConfig.xml";

         Reader reader = null;

         SqlSession session;

         try {

             reader = Resources.getResourceAsReader(resource);

         } catch (IOException e) {

             e.printStackTrace();

         }

         SqlSessionFactory sqlMapper = new SqlSessionFactoryBuilder()

                 .build(reader);

         session = sqlMapper.openSession();

         try{

             /* 删除  */

             InterfaceJiKeUserMap ijum = session.getMapper(InterfaceJiKeUserMap.class);

             ijum.deleteUser();

             session.commit();

         }catch(Exception e){

             e.printStackTrace();

         }finally{

             session.close();

         }

     }

 }

即可

4、查询

查询比较麻烦，分为查询一条数据和查询多条数据

4.1 查询一条语句（两种方式：利用HashMap 和利用 JiKeUser对象）

4.1.1 利用hashmap实现

在jikeUser.xml下添加语句

<select id="loginSelect" resultType="JiKeUser" parameterType="hashmap">

      select * from JiKeUser where userName=#{userName} and password=#{password}

  </select>

然后修改测试类

package jike.book.test;

import java.io.IOException;

import java.io.Reader;

import java.util.HashMap;

import java.util.List;

import jike.book.pojo.JiKeUser;

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 TestSelect {

    public static void main(String[] args) {

        String resource = "jike/book/map/MyBatisConfig.xml";

        Reader reader = null;

        SqlSession session;

        try {

            reader = Resources.getResourceAsReader(resource);

        } catch (IOException e) {

            e.printStackTrace();

        }

        SqlSessionFactory sqlMapper = new SqlSessionFactoryBuilder()

                .build(reader);

        session = sqlMapper.openSession();

        try{

            /*

             * 查询一条记录

             * */

            /*  利用HashMap  */

            HashMap<String,String> hm = new HashMap();

            hm.put("userName", "jike00100");

            hm.put("password", "");

            JiKeUser temp = session.selectOne("loginSelect",hm);

            if(temp!=null){

                System.out.println("登陆成功！");

            }

        }catch(Exception e){

            e.printStackTrace();

        }finally{

            session.close();

        }

    }

}

4.1.2 利用 JiKeUser对象
在jikeUser.xml下添加语句

<select id="login2" resultType="JiKeUser" parameterType="JiKeUser">

     select * from JiKeUser where userName=#{userName} and password=#{password}

  </select>

修改测试类：

package jike.book.test;

import java.io.IOException;

import java.io.Reader;

import java.util.HashMap;

import java.util.List;

import jike.book.pojo.JiKeUser;

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 TestSelect {

    public static void main(String[] args) {

        String resource = "jike/book/map/MyBatisConfig.xml";

        Reader reader = null;

        SqlSession session;

        try {

            reader = Resources.getResourceAsReader(resource);

        } catch (IOException e) {

            e.printStackTrace();

        }

        SqlSessionFactory sqlMapper = new SqlSessionFactoryBuilder()

                .build(reader);

        session = sqlMapper.openSession();

        try{

            /*

             * 查询一条记录

             * */

            /*  利用 JiKeUser对象   */

            JiKeUser jku = new JiKeUser();

            jku.setUserName("jike00100");

            jku.setPassword("");

            JiKeUser onetemp = session.selectOne("login2",jku);

            if(onetemp!=null){

                System.out.println("登陆成功");

            }

        }catch(Exception e){

            e.printStackTrace();

        }finally{

            session.close();

        }

    }

}

4.2 查询多条数据（利用resultType 和利用resultMap）

4.2.1 利用resultType

在jikeUser.xml下添加语句

<select id="selectJiKeUserList" resultType="JiKeUser">

     select * from JiKeUser

  </select>

修改测试类

 package jike.book.test;

 import java.io.IOException;

 import java.io.Reader;

 import java.util.HashMap;

 import java.util.List;

 import jike.book.pojo.JiKeUser;

 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 TestSelect {

     public static void main(String[] args) {

         String resource = "jike/book/map/MyBatisConfig.xml";

         Reader reader = null;

         SqlSession session;

         try {

             reader = Resources.getResourceAsReader(resource);

         } catch (IOException e) {

             e.printStackTrace();

         }

         SqlSessionFactory sqlMapper = new SqlSessionFactoryBuilder()

                 .build(reader);

         session = sqlMapper.openSession();

         try{

             /*

              * 查询多条记录

              * */

             /* 利用resultType */

             List<JiKeUser> ap = session.selectList("selectJiKeUserList");

             for(JiKeUser temp:ap){

                 System.out.println("用户名="+temp.getUserName()+"密码="+temp.getPassword());

             }

         }catch(Exception e){

             e.printStackTrace();

         }finally{

             session.close();

         }

     }

 }

4.2.2 利用resultMap

在jikeUser.xml下添加语句

 <resultMap type="JiKeUser" id="JiKeUserMap">

       <id property="id" column="id"></id>

       <result property="userName" column="userName"/>

       <result property="password" column="password"/>

   </resultMap>

   <select id="selectUsers" resultMap="JiKeUserMap">

      select id,userName,password from JiKeUser

   </select>

测试类：

package jike.book.test;

import java.io.IOException;

import java.io.Reader;

import java.util.HashMap;

import java.util.List;

import jike.book.pojo.JiKeUser;

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 TestSelect {

    public static void main(String[] args) {

        String resource = "jike/book/map/MyBatisConfig.xml";

        Reader reader = null;

        SqlSession session;

        try {

            reader = Resources.getResourceAsReader(resource);

        } catch (IOException e) {

            e.printStackTrace();

        }

        SqlSessionFactory sqlMapper = new SqlSessionFactoryBuilder()

                .build(reader);

        session = sqlMapper.openSession();

        try{

            /*

             * 查询多条记录

             * */

            /* 利用resultMap */

            List<JiKeUser> ap1 = session.selectList("selectUsers");

            for(JiKeUser temp:ap1){

                System.out.println("用户名="+temp.getUserName());

            }

        }catch(Exception e){

            e.printStackTrace();

        }finally{

            session.close();

        }

    }

}

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