Mybatis基础入门学习
mybatis架构分析
搭建测试mybatis架构
（1）下载并导入mybatis3.2.7.jar（架构），mysql-connector-java-5.1.7-bin.jar（数据库驱动），junit-4.9.jar（单元测试）
（2）测试mybatis项目搭建
（3）Jdbc资源文件
jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3307/mybatis?characterEncoding=utf-8
jdbc.username=root
jdbc.password=admins
（4）Mybatis核心配置文件
<?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>
<!-- 数据库资源文件 -->
<properties resource="jdbc.properties"/> <!-- 别名：方便映射文件调用 -->
<typeAliases>
<!-- 这个有弊端：有多少pojo就要配置多少个 -->
<!--<typeAlias type="com.pojo.User" alias="user"/>-->
<!-- 所以用包的方式：扫描该包及其子包的所有pojo，并取别名为（如:user或User） -->
<package name="com.pojo"/>
</typeAliases> <!-- 数据库环境,与Spring整合后，environments标签将废除-->
<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="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/mybatis"/>
<property name="username" value="root"/>
<property name="password" value="admins"/>--> <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> <!-- 映射器的位置 -->
<mappers>
<!--<mapper resource="com/mapper/UserMapper.xml"/>-->
<!-- 3个属性只能取一个，当为class时，xml文件和接口文件必须文件名一样且在同一个包下 -->
<!--<mapper class="com.mapper.UserMapper"/>-->
<!-- url:该属性指定mapper在盘符下的绝对路径，不建议使用 --> <!-- 上面的弊端还是会太多配置，导包的原则和class一样 -->
<package name="com.mapper"/>
</mappers>
</configuration>
（5）日志文件
#日志文件
log4j.rootLogger=DEBUG,stdout
log4j.logger.org.mybatis=DEBUG
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p %d %C: %m%n
（6）创建一个User类
package com.pojo; import java.io.Serializable;
import java.util.Date; /**
* Serializable:序列化接口
*/
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 + "]";
}
}
（7）User类的映射器
<?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">
<!-- 命名空间：用于区分；如test.findUserById -->
<mapper namespace="com.mapper.UserMapper">
<!-- 通过ID查询一个用户 -->
<select id="findUserById" parameterType="Integer" resultType="User">
<!-- #{}:表示占位符 -->
select * from user where id=#{v}
</select> <!-- 根据用户名模糊查询用户 -->
<select id="findUserByName" parameterType="String" resultType="com.pojo.User">
<!-- ${}:表示字符串拼接 -->
-- select * from user where username like '%${value}%'
<!-- 防sql注入 -->
select * from user where username like "%"#{value}"%"
</select> <!-- 添加用户 -->
<insert id="addUser" parameterType="com.pojo.User">
<!-- 获取最新的ID主键 -->
<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> <!-- 更新用户 -->
<update id="updateUserById" parameterType="com.pojo.User">
update user
set username=#{username},birthday=#{birthday},address=#{address},sex=#{sex}
where id=#{id}
</update> <!-- 删除用户 -->
<delete id="delUserById" parameterType="Integer">
delete from user where id=#{id}
</delete>
</mapper>
（8）与映射器绑定的接口
package com.mapper; import com.pojo.User; /**
* @author: XDZY
* @date: 2018/8/30 10:02
* @description: 实现用户增删改查的接口(映射器)
* 遵循四个原则
* 1）接口方法名与xml文件标签id一样
* 2）方法返回值类型与xml文件一样
* 3）方法的参数与xml文件一样
* 4）xml文件命名空间与该接口绑定
*/
public interface UserMapper {
public User findUserById(Integer id);
}
（9）测试mybatis实现增删改查
package com.junit; import com.pojo.User;
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 org.junit.Test; import java.io.InputStream;
import java.util.Date;
import java.util.List; /**
* @author: XDZY
* @date: 2018/8/29 23:18
* @description: 单元测试mybatis的增删改查
*/
public class UnitTest {
//根据用户ID查询用户
@Test
public void testMybatis() throws Exception{
//加载核心配置文件
String resource="sqlMapConfig.xml";
InputStream in= Resources.getResourceAsStream(resource);
//创建sqlSessionFactory
SqlSessionFactory sqlSessionFactory=new SqlSessionFactoryBuilder().build(in);
//创建sqlSession
SqlSession sqlSession=sqlSessionFactory.openSession();
//执行sql语句
User user=sqlSession.selectOne("com.mapper.UserMapper.findUserById",10);
System.out.println(user);
} //根据用户名模糊查询用户
@Test
public void testFindUserByName() throws Exception{
//加载核心配置文件
String resource="sqlMapConfig.xml";
InputStream in= Resources.getResourceAsStream(resource);
//创建sqlSessionFactory
SqlSessionFactory sqlSessionFactory=new SqlSessionFactoryBuilder().build(in);
//创建sqlSession
SqlSession sqlSession=sqlSessionFactory.openSession();
//执行sql语句
List<User> users=sqlSession.selectList("com.mapper.UserMapper.findUserByName","五");
for (User user:users){
System.out.println(user);
}
} //添加用户
@Test
public void testAddUser() throws Exception{
//加载核心配置文件
String resource="sqlMapConfig.xml";
InputStream in= Resources.getResourceAsStream(resource);
//创建sqlSessionFactory
SqlSessionFactory sqlSessionFactory=new SqlSessionFactoryBuilder().build(in);
//创建sqlSession
SqlSession sqlSession=sqlSessionFactory.openSession();
//执行sql语句
User user=new User();
user.setUsername("judy");
user.setSex("男");
user.setBirthday(new Date());
user.setAddress("珠海");
int i=sqlSession.insert("com.mapper.UserMapper.addUser",user);
//提交事务
sqlSession.commit();
System.out.println(user.getId());
} //更新用户
@Test
public void testUpdateUserById() throws Exception{
//加载核心配置文件
String resource="sqlMapConfig.xml";
InputStream in= Resources.getResourceAsStream(resource);
//创建sqlSessionFactory
SqlSessionFactory sqlSessionFactory=new SqlSessionFactoryBuilder().build(in);
//创建sqlSession
SqlSession sqlSession=sqlSessionFactory.openSession();
//执行sql语句
User user=new User();
user.setId(28);
user.setUsername("judy");
user.setSex("女");
user.setBirthday(new Date());
user.setAddress("珠海");
int i=sqlSession.update("com.mapper.UserMapper.updateUserById",user);
//提交事务
sqlSession.commit();
} //删除用户
@Test
public void testDelUserById() throws Exception{
//加载核心配置文件
String resource="sqlMapConfig.xml";
InputStream in= Resources.getResourceAsStream(resource);
//创建sqlSessionFactory
SqlSessionFactory sqlSessionFactory=new SqlSessionFactoryBuilder().build(in);
//创建sqlSession
SqlSession sqlSession=sqlSessionFactory.openSession();
//执行sql语句
sqlSession.delete("com.mapper.UserMapper.delUserById",28);
//提交事务
sqlSession.commit();
}
}