Mybatis入门
Mybatis入门
搭建环境
创建数据库
/*
Navicat Premium Data Transfer
Source Server : localhost
Source Server Type : MySQL
Source Server Version : 50716
Source Host : localhost:3306
Source Schema : mybatis
Target Server Type : MySQL
Target Server Version : 50716
File Encoding : 65001
Date: 05/09/2020 12:29:50
*/
SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;
-- ----------------------------
-- Table structure for user
-- ----------------------------
DROP TABLE IF EXISTS `user`;
CREATE TABLE `user` (
`id` int(8) NOT NULL,
`name` varchar(20) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;
-- ----------------------------
-- Records of user
-- ----------------------------
INSERT INTO `user` VALUES (1, 'zhang');
INSERT INTO `user` VALUES (2, 'wang');
INSERT INTO `user` VALUES (3, 'liu');
SET FOREIGN_KEY_CHECKS = 1;
创建Maven工程
导入依赖
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<!-- 父工程-->
<groupId>org.example</groupId>
<artifactId>MybatisDemo</artifactId>
<version>1.0-SNAPSHOT</version>
<!-- 导入依赖-->
<dependencies>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.47</version>
</dependency>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.5</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
</dependency>
</dependencies>
</project>
创建模块
删除默认的src目录，新建maven项目
├─.idea
└─Mybatis1
└─src
├─main
│ ├─java
│ └─resources
└─test
└─java
编写Mybatis的核心配置文件（resources目录下）
<?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>
<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://localhost:3306/mybatis?useSSL=true"/>
<property name="username" value="root"/>
<property name="password" value="qwe123"/>
</dataSource>
</environment>
</environments>
</configuration>
编写mybatis的工具类
新建一个package，编写工具类代码
package com.ivy.utils;
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 java.io.IOException;
import java.io.InputStream;
public class MybatisUtils {
private static SqlSessionFactory sqlSessionFactory;
static {
try {
// 配置文件的路径
String resource = "mybatis-config.xml";
InputStream resourceAsStream = Resources.getResourceAsStream(resource);
sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
} catch (IOException e) {
e.printStackTrace();
}
}
public static SqlSession getSqlSessionFactory() {
return sqlSessionFactory.openSession();
}
}
创建数据库对应的实体类
package com.ivy.pojo;
public class User {
private int id;
private String name;
public User() {
}
public User(int id, String name) {
this.id = id;
this.name = name;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", name='" + name + '\'' +
'}';
}
}
创建接口类
package com.ivy.dao;
import com.ivy.pojo.User;
import java.util.List;
public interface UserDao {
List<User> getUserList();
}
创建mapper的配置文件
放在resources目录下可以跳过一些资源过滤的坑
<?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写上接口类的类路径-->
<mapper namespace="com.ivy.dao.UserDao">
<!-- id写上对应的方法 resultType为返回值类型的类路径-->
<select id="getUserList" resultType="com.ivy.pojo.User">select * from mybatis.user</select>
</mapper>
注册mapper到mybatis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>
<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://localhost:3306/mybatis?useSSL=true"/>
<property name="username" value="root"/>
<property name="password" value="qwe123"/>
</dataSource>
</environment>
</environments>
<mappers>
<!-- 这里写上你的mapper文件的路径-->
<mapper resource="UserMapper.xml"/>
</mappers>
</configuration>
编写测试类
package com.ivy.dao;
import com.ivy.pojo.User;
import com.ivy.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;
import java.util.List;
public class UserDaoTest {
@Test
public void test() {
// 获取sqlSession对象
SqlSession sqlSession = MybatisUtils.getSqlSession();
// 获取mapper对象
UserDao mapper = sqlSession.getMapper(UserDao.class);
List<User> userList = mapper.getUserList();
for (User user : userList) {
System.out.println(user);
}
sqlSession.close();
}
}
运行
User{id=1, name='zhang'}
User{id=2, name='wang'}
User{id=3, name='liu'}
最后整个项目结构
└─Mybatis1
└─src
├─main
│ ├─java
│ │ └─com
│ │ └─ivy
│ │ ├─dao
│ │ ├─pojo
│ │ └─utils
│ └─resources
└─test
└─java
└─com
└─ivy
└─dao
基本的CRUD
实体类
package com.ivy.dao;
import com.ivy.pojo.User;
import java.util.List;
public interface UserDao {
List<User> getUserList();
User getUserById(int id);
void createUser(User user);
void updateUser(User user);
void deleteUserById(int id);
}
配置文件
<?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">
<!--namespace写上接口类的类路径-->
<mapper namespace="com.ivy.dao.UserDao">
<!-- id写上对应的方法 resultType为返回值类型的类路径-->
<select id="getUserList" resultType="com.ivy.pojo.User">select * from mybatis.user</select>
<select id="getUserById" resultType="com.ivy.pojo.User" parameterType="int">select * from mybatis.user where id = #{id}</select>
<insert id="createUser" parameterType="com.ivy.pojo.User">
insert into mybatis.user (`id`, `name`) values (#{id}, #{name})
</insert>
<update id="updateUser" parameterType="com.ivy.pojo.User">
update mybatis.user set `name`=#{name} where id = #{id}
</update>
<delete id="deleteUserById" parameterType="int">
delete from mybatis.user where id=#{id}
</delete>
</mapper>
测试类
package com.ivy.dao;
import com.ivy.pojo.User;
import com.ivy.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;
import java.util.List;
public class UserDaoTest {
@Test
public void getUserList() {
// 获取sqlSession对象
SqlSession sqlSession = MybatisUtils.getSqlSession();
// 获取mapper对象
UserDao mapper = sqlSession.getMapper(UserDao.class);
List<User> userList = mapper.getUserList();
for (User user : userList) {
System.out.println(user);
}
sqlSession.close();
}
@Test
public void getUserById() {
// 获取sqlSession对象
SqlSession sqlSession = MybatisUtils.getSqlSession();
// 获取mapper对象
UserDao mapper = sqlSession.getMapper(UserDao.class);
User user = mapper.getUserById(1);
System.out.println(user);
sqlSession.close();
}
@Test
public void createUser() {
// 获取sqlSession对象
SqlSession sqlSession = MybatisUtils.getSqlSession();
// 获取mapper对象
UserDao mapper = sqlSession.getMapper(UserDao.class);
mapper.createUser(new User(4, "wangwu"));
sqlSession.commit();
sqlSession.close();
}
@Test
public void updateUser() {
// 获取sqlSession对象
SqlSession sqlSession = MybatisUtils.getSqlSession();
// 获取mapper对象
UserDao mapper = sqlSession.getMapper(UserDao.class);
mapper.updateUser(new User(4, "xxxxx"));
sqlSession.commit();
sqlSession.close();
}
@Test
public void deleteUserById() {
// 获取sqlSession对象
SqlSession sqlSession = MybatisUtils.getSqlSession();
// 获取mapper对象
UserDao mapper = sqlSession.getMapper(UserDao.class);
mapper.deleteUserById(4);
sqlSession.commit();
sqlSession.close();
}
}
最后注意，对数据体进行增删改的操作的时候要提交事务。
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