MyBatis总结（一）

一、创建测试项目工程

二、导包（一个myBatis所需的包，以及一个数据库操作的包）

三、创建实体类

四、配置文件的建立（最佳命名为（SqlMapConfig.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>

    <properties resource="datasource.properties"></properties>

    <typeAliases>

        <typeAlias type="com.lovo.pojo.User" alias="User"/>

    </typeAliases>

    <environments default="development">

    <environment id="development">

        <transactionManager type="JDBC" />

        <dataSource type="POOLED">

                <property name="driver" value="${jdbc.driver}" />

                <property name="url" value="${jdbc.url}" />

                <property name="username" value="${jdbc.username}" />

                <property name="password" value="${jdbc.password}" />

            </dataSource>

    </environment>

    </environments>

    <mappers>

    <mapper resource="com/lovo/mapper/UserMapper.xml"/>

    </mappers>

</configuration>

用以上方式配置需要先创立配置文件（datasource.properties）

配置文件代码如下：

jdbc.driver=com.mysql.jdbc.Driver

jdbc.url=jdbc:mysql://localhost:3306/myBatis?useUnicode=true&characterEncoding=UTF-8

jdbc.username=root

jdbc.password=123

然后创建一个获得连接对象的类，我习惯命名为DbUtil放在util包中，代码如下：

public class DbUtil {

    private static SqlSessionFactory sessionFactory = null;

    private DbUtil() {

        InputStream in = null;

        try {

            in = Resources.getResourceAsStream("SqlMapConfig.xml");

            sessionFactory = new SqlSessionFactoryBuilder().build(in);

        } catch (IOException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        }

    }

    public static SqlSession getSession() {

        if (sessionFactory == null) {

            new DbUtil();

        }

        return sessionFactory.openSession();

    }

然后再对实体pojo配置一个XML文件和一个接口：

XML最好与接口同名，以便自己好辨识

xml文件如下：

<?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" >

<!--namespace与mapper接口相对应  -->

<mapper namespace="com.lovo.mapper.UserMapper">

    <resultMap  type="User" id="UserMap">

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

    <result property="userName" column="username" javaType="java.lang.String"/>

    <result property="userPwd" column="pwd" javaType="java.lang.String"/>

    <result property="state" column="state" javaType="int"/>

    </resultMap>

    <insert id="addUser" parameterType="User">

    insert into user values(null,#{User.userName},#{User.userPwd},#{User.state})

    </insert>

    <delete id="delUserById" parameterType="int">

        delete from user where id=#{id}

    </delete>

    <select id="findUserById" parameterType="int" resultMap="UserMap">

    select * from user where id=#{id}

    </select>

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

        update  user set  username=#{User.userName},pwd=#{User.userPwd},state=#{User.state} where id=#{User.id}

    </update>

    <select id="FindAllUser" resultMap="UserMap">

        select * from user

    </select>

    <select id="findUserCount" resultType="int">

        select count(*) from user

    </select>

    <select id="FindUserByState" resultMap="UserMap">

        select * from user where state=#{state}

    </select>

    <select id="sumOfState" resultType="int">

        select sum(state) from user

    </select>

</mapper>

接口如下：

public interface UserMapper {

    public int addUser(@Param("User") User user);

    public int delUserById(@Param("id") int id);

    public int updateUser(@Param("User") User user);

    public User findUserById(@Param("id") int id);

    public List<User> FindAllUser();

    public int findUserCount();

    public List<User> FindUserByState(@Param("state") int state);

    public int sumOfState();

}

这里的@param("User")为别名，除参数只有单个，且为基本数据类型外，都需要给于别名。

最后在建立service层

如：

public class UserServiceImpl implements UserService {

    SqlSession sqlSession=DbUtil.getSession();

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

    @Override

    public int addUser(User user) {

        // TODO Auto-generated method stub

        int num=0;

        num=mapper.addUser(user);

        sqlSession.commit();

        return num;

    }

巴特西

MyBatis总结（一）

最新文章

热门文章