mybatis入门程序

package xyz.db361.mybatis.pojo;

import java.io.Serializable;
import java.util.Date;

public class User implements Serializable {
/**
*
*/
private static final long serialVersionUID = 1L;
private Integer id;
private String username;// 用户姓名
private String sex;// 性别
private Date birthday;// 生日
private String address;// 地址

public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
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;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "User [id=" + id + ", username=" + username + ", sex=" + sex
+ ", birthday=" + birthday + ", address=" + address + "]";
}
}

<?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：命名空间，用于隔离sql，还有一个很重要的作用，后面会讲 -->
<!-- 写Sql语句 -->
<mapper namespace="xyz.db361.mybatis.mapper.UserMapper">
<!-- 通过id查询一个用户 -->
<select id="findUserById" parameterType="Integer"
resultType="xyz.db361.mybatis.pojo.User">
select * from user where id = #{v}
</select>

<!-- #{}占位符 ？ = ‘ ’ = ‘五’ ${} 字符串拼接 不带单引号 = ‘%五%’ -->
<select id="findUserByUserName" parameterType="String"
resultType="User">
select * from user where username like '%${value}%'
<!-- select * from user where username like "%"#{value}"%" -->
</select>

<!-- 添加用户 -->
<!-- User运用了别名 -->
<insert id="insertUser" parameterType="User">
<selectKey keyProperty="id" resultType="Integer" order="AFTER">
select LAST_INSERT_ID()
</selectKey>
insert into
user(username, birthday, address, sex) values(#{username},
#{birthday}, #{address}, #{sex})
</insert>

<!-- 更新 -->
<update id="updateUserById" parameterType="User">

update user set
username = #{username}, sex = #{sex},
birthday = #{birthday},
address =
#{address} where id = #{id}

</update>

<!-- 删除 -->
<delete id="deleteUserById" parameterType="Integer">
delete from user where
id = #{id}
</delete>
</mapper>

<?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 res
4000
ource="jdbc.properties"/>
<!-- 别名 -->
<typeAliases>
<!-- <typeAlias type="xyz.db361.mybatis.pojo.User" alias="User"/> -->
<!-- User  user 都对 -->
<package name="xyz.db361.mybatis.pojo"/>
</typeAliases>
<!-- 和spring整合后 environments配置将废除 -->
<environments default="development">
<environment id="development">
<!-- 使用jdbc事务管理 -->
<transactionManager type="JDBC" />
<!-- 数据库连接池 -->
<dataSource type="POOLED">
<property name="driver" value="${jdbc.driver}" />
<property name="url"
value="jdbc:mysql://localhost:3306/mybatis?characterEncoding=utf-8" />
<property name="username" value="root" />
<property name="password" value="root" />
</dataSource>
</environment>
</environments>

<!-- 告诉Mapper文件的位置 -->
<mappers>
<!-- resource class url其中一个 -->
<mapper resource="sqlmap/User.xml"/>
<!-- 要求mapper名称和映射文件相同且在同意目录下 -->
<!-- <mapper class="xyz.db361.mybatis.mapper.UserMapper"/> -->

</mappers>

</configuration>

package xyz.db361.mybatis.mapper;

import xyz.db361.mybatis.pojo.User;

public interface UserMapper {
/**
* 遵循四个原则
* 接口方法名 = User.xml文件中的id名
* 返回值类型与xml文件中返回类型一致
* 方法的入参类型与xml文件中入参的类型要一致
* 接口和xml文件绑定(在xml文件中进行)
* */
public User findUserById(Integer id);
public Integer deleteUserById(Integer id);
}

@Test
public void testMapper() throws IOException {
// 加载核心配置文件
String resource = "SqlMapConfig.xml";
// Resources.get
InputStream in = Resources.getResourceAsStream(resource);
// 创建SqlSessionFactory
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(in);
// 创建SqlSession
SqlSession sqlSession = sqlSessionFactory.openSession();

//SqlSession帮我生成一个实现类(给接口)
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
User u = userMapper.findUserById(34);
System.out.println(u);
}