myBatis实例

一.搭建环境,

建立数据库

 CREATE TABLE user(
        id int(11) not NULL AUTO_INCREMENT,
        userName varchar(50) DEFAULT NULL,
        userAge int(11) DEFAULT NULL,
        userAddress varchar(200) DEFAULT NULL,
        PRIMARY KEY(id)
 )ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;

建立一个myBatis的java项目(不需要web项目)

然后倒入jar包

建总配置文件:

在src下建configration包.在建Configurations.xml文件

代码如下:

 <?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>
     <typeAliases>
         <typeAlias type="com.user.User" alias="User"/>
     </typeAliases>
     <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://127.0.0.1:3306/mybatis"/>
                 <property name="username" value="root"/>
                 <property name="password" value="123"/>
             </dataSource>
         </environment>
     </environments>

     <mappers>
         <mapper resource="configration/User.xml"/>

　　　　</mappers>
 </configuration>

建user的实体类和映射文件:

com.user.User代码:

 package com.user;

 public class User {
     private int id;
     private String userName;
     private String userAge;
     private String userAddress;
     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 getUserAge() {
         return userAge;
     }
     public void setUserAge(String userAge) {
         this.userAge = userAge;
     }
     public String getUserAddress() {
         return userAddress;
     }
     public void setUserAddress(String userAddress) {
         this.userAddress = userAddress;
     }

 }

configration包下见User.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="User">
    <select id="selectUserById" parameterType="int" resultType="User">
        select * from user where id=#{id}
    </select>
    <select id="selectUserList" parameterType="int" resultType="User">
        select * from user
    </select>
 <insert id="insertUser" keyProperty="id" useGeneratedKeys="true"  parameterType="user">
    insert into user
        (userName,userAge)
        values
        (#{userName},#{userName})
    </insert>
</mapper>

建测试类

 package test;

 import java.io.Reader;
 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 com.user.User;

 public class Test {
     private static SqlSessionFactory sqlSessionFactory;
     private static Reader reader;

     static {
         try {
             reader = Resources.getResourceAsReader("configration/Configurations.xml");
             sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
         } catch (Exception e) {
             e.printStackTrace();
         }
     }
     public static void main(String[] args) {
         SqlSession session = sqlSessionFactory.openSession();
         try {
             //User user = (User) session.selectOne("User.selectUserById", 2);
             List<User> list=session.selectList("User.selectUserList");
             for(User user:list){
                 System.out.println("姓名:"+user.getUserName());
                 System.out.println("年龄"+user.getUserAge());
                 System.out.println("地址:"+user.getUserAddress());
                 System.out.println("-----------------------------------------------------------");
             }

         } catch (Exception e) {
             System.out.println("出现异常了.....");
             e.printStackTrace();
         } finally {
             session.close();
         }
     }
 }

当你查看到从数据库中读取的数据时,说明环境搭建完毕了

如何获取插入数据的主键值呢?

package test;

import java.io.Reader;
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 com.user.User;

public class Run {
    private static SqlSessionFactory sqlSessionFactory;
    private static Reader reader;

    static {
        try {
            reader = Resources.getResourceAsReader("mybatis.xml");
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    public static void main(String[] args) {
        SqlSession session = sqlSessionFactory.openSession();
        try {
            User u=new User();
            u.setUserAge(255);
            u.setUserName("思思博士");
            int count=session.insert("User.insertUser",u);//count受影响的行数
            session.commit();
            System.out.println("插入数据的id值:>>>>>>>>"+u.getId());
        } catch (Exception e) {
            System.out.println("出现异常了.....");
            e.printStackTrace();
        } finally {
            session.close();
        }
    }
}

上面的count是受影响的行数

u.getId()才是插入数据的主键的id值

二.用接口的方式实现编程.

建立IUserOperation.java

 package inter;

 import java.util.List;

 import com.user.User;

 public interface IUserOperation {
     public User selectUserById(int id);
     public List<User> selectUserList();
 }

建立IUser.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="inter.IUserOperation">
     <select id="selectUserById" parameterType="int" resultType="User">
         select * from user where id=#{id}
     </select>
     <select id="selectUserList" resultType="User">
         select * from user
     </select>
 </mapper>

注意这个地方的namspace就不可以随意取名字了.必须是实现接口的地址.

在总配置文件中mappers添加一条xml:<mapper resource="configration/IUser.xml"/>

添加测试类:

 package test;

 import inter.IUserOperation;

 import java.io.Reader;
 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 com.user.User;

 /**
  * 以接口的方式编程
  * 如果以这种方式的话,那么对应的sql的xml配置文件中的namespace必须是实现接口的具体地址
  */
 public class TestInterface {
     private static SqlSessionFactory sqlSessionFactory;
     private static Reader reader;

     static {
         try {
             reader = Resources.getResourceAsReader("configration/Configurations.xml");
             sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
         } catch (Exception e) {
             e.printStackTrace();
         }
     }
     public static void main(String[] args) {
         SqlSession session = sqlSessionFactory.openSession();
         try {
             IUserOperation userOperation=session.getMapper(IUserOperation.class);
             /*User user=userOperation.selectUserById(3);
             System.out.println(user.getUserAddress());
             System.out.println(user.getUserName());*/

             List<User> list=userOperation.selectUserList();
             for(User user:list){
                 System.out.println("姓名:"+user.getUserName());
                 System.out.println("年龄:"+user.getUserAge());
                 System.out.println("地址:"+user.getUserAddress());
                 System.out.println("--------------------------------");
             }

         } catch (Exception e) {
             System.out.println("出现异常了.....");
             e.printStackTrace();
         } finally {
             session.close();
         }
     }
 }

三,使用myBatis完成增删改查.

重新修改以下文件.

IUser.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="inter.IUserOperation">
 <!-- 返回list数据集时使用的返回map -->
     <resultMap type="User" id="resultListUserMap">
         <id column="id" property="id" />
         <result column="userName" property="userName"/>
         <result column="userAge" property="userAge"/>
         <result column="userAddress" property="userAddress"/>
     </resultMap>
     <select id="selectUserById" parameterType="int" resultType="User">
         select * from user where id=#{id}
     </select>
     <select id="selectUsers" parameterType="String" resultMap="resultListUserMap">
         select * from user where userName like #{userName}
     </select>
     <!--
         执行增加操作的SQL语句.id和parameterType分别与IUserOperation接口中的
         adUser方法的名字和参数类型一致.以#{name}的形式引用User参数的name属性.
         myBatis将使用反射读取User参数的此属性.#{name}中name大小写敏感.
         seGeneratedKeys设置为true,表明要myBatis获取自由数据库自动生成的主键;
         keyProperty="id"指定把获取到的主键值注入到User的id属性
      -->
     <insert id="addUser" parameterType="User" useGeneratedKeys="true" keyProperty="id">
         insert into user(userName,userAge,userAddress)
         values(#{userName},#{userAge},#{userAddress});
     </insert>

     <update id="updateUser" parameterType="User">
         update user set userName=#{userName},userAge=#{userAge},userAddress=#{userAddress}
         where id=#{id}
     </update>

     <delete id="deleteUser" parameterType="int">
         delete from user where id=#{id}
     </delete>

 </mapper>

IUserOperation.java

 package inter;

 import java.util.List;

 import com.user.User;

 public interface IUserOperation {
     public User selectUserById(int id);
     public List<User> selectUsers(String userName);
     public void addUser(User user);
     public void updateUser(User user);
     public void deleteUser(int id);
 }

Test1.java

 package test;

 import inter.IUserOperation;

 import java.io.Reader;
 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 com.user.User;

 public class Test1 {
     private static SqlSessionFactory sqlSessionFactory;
     private static Reader reader;
     static {
         try {
             reader = Resources
                     .getResourceAsReader("configration/Configurations.xml");
             sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
         } catch (Exception e) {
             e.printStackTrace();
         }
     }
     public void getUserList(String userName){
         SqlSession session=sqlSessionFactory.openSession();
         try {
             IUserOperation userOperation=session.getMapper(IUserOperation.class);
         List<User> users=userOperation.selectUsers(userName);
         for(User user:users){
             System.out.println("id:"+user.getId());
             System.out.println("name:"+user.getUserName());
             System.out.println("age:"+user.getUserAge());
             System.out.println("address:"+user.getUserAddress());
             System.out.println("-----------------");
         }
         } catch (Exception e) {
             System.out.println("查询出错了......");
         }finally{
             session.close();
         }

     }

     /**
      * 添加数据,必须提交事务,否则不会写入dao数据库
      * @param args
      */
     public void addUser(){
         User user=new User();
         user.setUserAddress("安徽,舒城");
         user.setUserAge(26);
         user.setUserName("思思博士");
         SqlSession session=sqlSessionFactory.openSession();
         try {
             IUserOperation userOperation=session.getMapper(IUserOperation.class);
             userOperation.addUser(user);
             session.commit();
             System.out.println("当前增加的id为:"+user.getId());
         } catch (Exception e) {
             System.out.println("添加出现异常啦........");
         }finally{
             session.close();
         }
     }

     /**
      *
      * @param args
      */
     public void updateUser(){
         User user=new User();
         user.setUserAddress("安徽,舒城,千人桥镇");
         user.setUserAge(260);
         user.setUserName("思思博士");
         user.setId(4);
         SqlSession session=sqlSessionFactory.openSession();
         try {
             IUserOperation userOperation=session.getMapper(IUserOperation.class);
             userOperation.updateUser(user);
             session.commit();
             //System.out.println("当前增加的id为:"+user.getId());
         } catch (Exception e) {
             System.out.println("更新出现异常啦........");
         }finally{
             session.close();
         }
     }

     /**
      * 删除数据
      * @param args
      */
     public void deleteUser(int id){
         SqlSession session=sqlSessionFactory.openSession();
         try {
             IUserOperation userOperation=session.getMapper(IUserOperation.class);
             userOperation.deleteUser(id);
             session.commit();
             System.out.println("数据删除成功");
         } catch (Exception e) {
             System.out.println("数据删除失败啦.....");
         }
         finally{
             session.close();
         }
     }

     public static void main(String[] args) {
         Test1 test1=new Test1();
         //查询列表
         test1.getUserList("%");
         //test1.addUser();//添加数据
         //test1.updateUser();//更新数据
         //test1.deleteUser(3);//删除数据
     }
 }

四.联合查询:

IJoinUser.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="inter.IUserJoinOperation">
     <resultMap type="User" id="resultListUserMapss">
         <id column="id" property="id" />
         <result column="userName" property="userName"/>
         <result column="userAge" property="userAge"/>
         <result column="userAddress" property="userAddress"/>
     </resultMap>
     <!-- User联合文章进行查询方法之一的配置(多对一的方式) -->
     <resultMap type="News" id="resultUserNewsListMap">
         <id property="id" column="Id" />
         <result property="title" column="title" />
         <result property="content" column="content" />
         <association property="user" javaType="User">
             <id property="id" column="id" />
             <result property="userName" column="userName"/>
             <result property="userAddress" column="userAddress"/>
         </association>
     </resultMap>

     <select id="getUserNewsList" parameterType="int" resultMap="resultUserNewsListMap">
         select user.id,user.userName,user.userAge,user.userAddress,
         news.id,news.userId,news.title,news.content
         from user,news
         where user.id=news.userId and user.id=#{id}
     </select>

 </mapper>

IUserOperation.java

 package inter;

 import java.util.List;

 import com.user.News;

 public interface IUserJoinOperation {
     public List<News> getUserNewsList(int userId);
 }

测试类:

 package test;

 import inter.IUserJoinOperation;
 import inter.IUserOperation;

 import java.io.Reader;
 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 com.user.News;
 import com.user.User;

 public class Test2 {
     private static SqlSessionFactory sqlSessionFactory;
     private static Reader reader;
     static {
         try {
             reader = Resources
                     .getResourceAsReader("configration/Configurations.xml");
             sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
         } catch (Exception e) {
             e.printStackTrace();
         }
     }
     /**
      * 联合查询
      * @param args
      */
     public void getUserNews(int userId){
         SqlSession session=sqlSessionFactory.openSession();
         try {
             IUserJoinOperation joinOperation=session.getMapper(IUserJoinOperation.class);
             List<News> newsList=joinOperation.getUserNewsList(userId);
             for(News news:newsList){
                 System.out.println("id:"+news.getId());
                 System.out.println("title:"+news.getTitle());
                 System.out.println("content:"+news.getContent());
                 System.out.println("userId:"+news.getUser().getId());
                 System.out.println("name:"+news.getUser().getUserName());
                 System.out.println("age:"+news.getUser().getUserAge());
                 System.out.println("address:"+news.getUser().getUserAddress());
                 System.out.println("------------------------------------");
             }
             System.out.println("输出完毕....");
         } catch (Exception e) {
             System.out.println("联合查询失败啦.......");
         }
         finally{
             session.close();
         }
     }

     public static void main(String[] args) {
         Test2 test2=new Test2();
         //查询列表
         test2.getUserNews(4);
     }
 }

其实还可以用另外一种方法:

修改IJoinUser.xml文件

 <?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="inter.IUserJoinOperation">
     <resultMap type="User" id="resultListUserMapss">
         <id column="id" property="id" />
         <result column="userName" property="userName"/>
         <result column="userAge" property="userAge"/>
         <result column="userAddress" property="userAddress"/>
     </resultMap>
     <!-- User联合文章进行查询方法之一的配置(多对一的方式) -->
     <resultMap type="News" id="resultUserNewsListMap">
         <id property="id" column="Id" />
         <result property="title" column="title" />
         <result property="content" column="content" />
         <association property="user" resultMap="resultListUserMapss" javaType="User" />
         <!-- <association property="user" javaType="User">
             <id property="id" column="id" />
             <result property="userName" column="userName"/>
             <result property="userAddress" column="userAddress"/>
         </association> -->
     </resultMap>

     <select id="getUserNewsList" parameterType="int" resultMap="resultUserNewsListMap">
         select user.id,user.userName,user.userAge,user.userAddress,
         news.id,news.userId,news.title,news.content
         from user,news
         where user.id=news.userId and user.id=#{id}
     </select>

 </mapper>

这个地方我测试了一下,不知道为什么总是只能查出一条语句,但是sql语句直接在mysql中查询的话,可以查询多条的,哪位大神知道答案的,请告知啊.

本文非原创:

http://blog.csdn.net/techbirds_bao/article/details/9233599/