Mybatis项目创建流程
一、创建maven项目
1、删除src文件
2、在pom.xml中配置
<dependencies>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.20</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.12</version>
</dependency>
</dependencies>
<build>
<!--在 build中配置resources，来防止我们资源导出失败的问题-->
<resources>
<resource>
<directory>src/main/resources</directory>
<includes>
<include>**/*.properties</include>
<include>**/*.xml</include>
</includes>
<filtering>true</filtering>
</resource>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.properties</include>
<include>**/*.xml</include>
</includes>
<filtering>true</filtering>
</resource>
</resources>
</build>
二、创建module项目
1、配置pox.xml
<dependencies>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.2</version>
</dependency>
</dependencies>
2、在 resources 资源文件下创建 核心配置 文件
2.1 db.properties
driver=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://localhost:3306/数据库名?useSSL=false&useUnicode=true&characterEncoding=UTF-8&serverTimezone=UTC
username=root
password=td725430
2.2 mybatis-config.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核心配置文件-->
<configuration>
<!--引用外部配置文件-->
<properties resource="db.properties"/>
<settings>
<!--标准的日志工厂实现-->
<setting name="logImpl" value="STDOUT_LOGGING"/>
<!--开启驼峰命名自动映射-->
<setting name="mapUnderscoreToCamelCase" value="true"/>
</settings>
<!--可以给实体类写别名，
实体类比较少时，使用第一种。
实体类十分多时，建议使用第二种-->
<typeAliases>
<!--第一种可以DIY（自定义）别名-->
<!--<typeAlias type="com.tenton.pojo.User" alias="User"/>-->
<!--第二种不能DIY（自定义）别名，如果非要改，需要在实体上增加注解-->
<package name="com.tenton.pojo"/>
</typeAliases>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="${driver}"/>
<property name="url" value="${url}"/>
<property name="username" value="${username}"/>
<property name="password" value="${password}"/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper class="com.tenton.dao.接口名"/>
</mappers>
</configuration>
3、在Java目录(com.tenton.utils)下创建工具类 MybatisUtils
public class MybatisUtils {
//提升作用域
private static SqlSessionFactory sqlSessionFactory;
//初始就加载
static {
try {
//使用mybatis
// 第一步 Resources获取全局配置文件（核心配置文件）mybatis-config.xml
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
/**
*第二步 SqlSessionFactoryBuilder（sqlSession工厂构造器）通过构造器 build
* build 调用 build方法
* build 方法 XMLConfigBuilder（XML配置构造器）类，解析了流、环境及配置文件 （inputStream, environment, properties）
* 解析完成之后，赋值给configuratiion对象（所有配置文件对象）
* 然后给 build 方法传递一个 Configuration 对象解析 Resources 获取到的全局配置文件流inputStream
*第三步 SqlSessionFactoryBuilder（sqlSession工厂构造器）调用 build 方法实例化 sqlSessionFactory（sqlSession工厂）
*/
sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
} catch (IOException e) {
e.printStackTrace();
}
}
//既然有了 SqlSessionFactory，顾名思义，我们可以从中获得 SqlSession 的实例。
// SqlSession 提供了在数据库执行SQL 命令所需的所有方法。
public static SqlSession getSqlSession(){
return sqlSessionFactory.openSession(true);
}
}
4、在Java目录(com.tenton.pojo)下创建实体类 User.java
@Data
@NoArgsConstructor
@AllArgsConstructor
public class User {
private int id;
private String name;
private String pwd;
}
5、在Java目录(com.tenton.dao)下创建接口 IUserMapper及对应实现接口中方法的xml文件 IUserMapper.xml
注意： IUserMapper接口和IUserMapper.xml 要在一个包路径下
5.1 IUserMapper接口：
package com.tenton.dao;
import com.tenton.pojo.User;
import java.util.List;
import java.util.Map;
public interface IUserMapper {
/**
* 模糊查询
*/
List<User> getUserLike(String value);
/**
*获取全部用户
*/
List<User> getUserList();
/**
* 根据ID查询用户
*/
User getUsetById(int id);
/**
* 增加一个用户
*/
int addUser(User user);
int addUser2(Map<String, Object> map);
/**
* 根据ID删除用户
*/
int deleteUser(int id);
/**
* 修改用户
*/
int updateUser(User user);
}
5.2 IUserMapper.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="com.tenton.dao.IUserMapper">
<!--select语句查询：id : 对应namespace中接口中的方法名"
resultType:sql语句执行的返回值-->
<select id="getUserList" resultType="com.tenton.pojo.User">
select * from mybatis.user;
</select>
<select id="getUsetById" resultType="com.tenton.pojo.User">
select * from mybatis.user where id = #{id};
</select>
<select id="getUserLike" resultType="com.tenton.pojo.User">
select * from mybatis.user where name like #{value};
</select>
<!--对象中的属性，可以直接取出来-->
<insert id="addUser" parameterType="com.tenton.pojo.User">
insert into user(id,name,pwd) values (#{id},#{name},#{pwd});
</insert>
<insert id="addUser2" parameterType="map">
insert into user(id,name,pwd) values (#{userid},#{username},#{userpwd});
</insert>
<update id="updateUser" parameterType="com.tenton.pojo.User">
update user set name=#{name},pwd=#{pwd} where id=#{id};
</update>
<delete id="deleteUser" parameterType="com.tenton.pojo.User">
delete from user where id=#{id};
</delete>
</mapper>
6、在test目录下创建测试类 IUserMapperTest.java
package com.tenton.dao;
import com.tenton.pojo.User;
import com.tenton.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class UserDaoTest {
@Test
public void getUserList(){
SqlSession sqlSession =null;
try {
//第一步：获取sqlSession对象
sqlSession = MybatisUtils.getSqlSession();
//执行SQL(两种)
//第一种：getMapper 推荐
IUserMapper mapper = sqlSession.getMapper(IUserMapper.class);
List<User> userList = mapper.getUserList();
//第二种（不推荐）
// List<User> userList = sqlSession.selectList("com.tenton.dao.IUserMapper.getUserList");
for (User user:userList){
System.out.println(user);
}
}catch (Exception e){
e.printStackTrace();
}finally {
//关闭sqlSession
sqlSession.close();
}
}
@Test
public void getUserLike(){
SqlSession sqlSession = MybatisUtils.getSqlSession();
IUserMapper mapper = sqlSession.getMapper(IUserMapper.class);
List<User> userList = mapper.getUserLike("%尚%");
for (User user:userList) {
System.out.println(user);
//关闭sqlSession
sqlSession.close();
}
}
@Test
public void getUsetById(){
SqlSession sqlSession = MybatisUtils.getSqlSession();
IUserMapper mapper = sqlSession.getMapper(IUserMapper.class);
User user = mapper.getUsetById(1);
System.out.println(user);
sqlSession.close();
}
@Test
public void addUser(){
SqlSession sqlSession = MybatisUtils.getSqlSession();
IUserMapper mapper = sqlSession.getMapper(IUserMapper.class);
int result = mapper.addUser(new User(4, "尚琼", "lsq01197867"));
if (result > 0){
System.out.println("插入成功！");
}
//提交事务
sqlSession.commit();
sqlSession.close();
}
@Test
public void addUser2(){
SqlSession sqlSession = MybatisUtils.getSqlSession();
IUserMapper mapper = sqlSession.getMapper(IUserMapper.class);
Map<String,Object> map = new HashMap<String,Object>();
map.put("userid",3);
map.put("username","唐东");
map.put("userpwd","td725430");
mapper.addUser2(map);
sqlSession.commit();
sqlSession.close();
}
@Test
public void updateUser(){
SqlSession sqlSession = MybatisUtils.getSqlSession();
IUserMapper mapper = sqlSession.getMapper(IUserMapper.class);
int result = mapper.updateUser(new User(2, "尚琼", "lsq01197867"));
if (result > 0){
System.out.println("修改成功！");
}
//提交事务
sqlSession.commit();
sqlSession.close();
}
@Test
public void deleteUser(){
SqlSession sqlSession = MybatisUtils.getSqlSession();
IUserMapper mapper = sqlSession.getMapper(IUserMapper.class);
int result = mapper.deleteUser(4);
if (result > 0){
System.out.println("删除成功！");
}
//提交事务
sqlSession.commit();
sqlSession.close();
}
}
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