标签：Mapper java ibatis apache session org MyBatis import 搭建
一、MyMyBatis工程搭建
新建Maven项目：mybatis-demo
准备数据源
1 # 删除mybatis_demo数据库 2 drop database if exists mybatis_demo; 3 4 # 创建mybatis_demo数据库 5 create database mybatis_demo; 6 7 # 使用mybatis_demo数据库 8 use mybatis_demo; 9 10 # 创建account表 11 create table user ( 12 id int auto_increment primary key, 13 username varchar(20), 14 age int, 15 score int 16 ); 17 18 # 新增数据 19 insert into user (id, username, age, score) values 20 (1,'peter', 18, 100), (2,'pedro', 24, 200), 21 (3,'jerry', 28, 500), (4,'mike', 12, 300), 22 (5,'tom', 27, 1000);
连接数据库
1 <dependencies> 2 <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java --> 3 <dependency> 4 <groupId>mysql</groupId> 5 <artifactId>mysql-connector-java</artifactId> 6 <version>8.0.23</version> 7 </dependency> 8 </dependencies>
代码结构图：
代码编写：
JDBCDemo.java
1 import java.sql.Connection;
2 import java.sql.DriverManager;
3 import java.sql.PreparedStatement;
4 import java.sql.ResultSet;
5
6 public class JDBCDemo {
7 public static void main(String[] args) throws Exception {
8 //1.注册驱动
9 Class.forName("com.mysql.cj.jdbc.Driver");
10 //2.获取连接
11 Connection connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/mybatis_demo", "root", "root");
12 //3.获取Statement对象
13 PreparedStatement preparedStatement = connection.prepareStatement("select * from user WHERE id = ?");
14 preparedStatement.setInt(1, 1);
15 //4.执行SQL语句返回结果集
16 ResultSet resultSet = preparedStatement.executeQuery();
17 //5.遍历结果集
18 while (resultSet.next()) {
19 System.out.println("username: " + resultSet.getString("username"));
20 System.out.println("age: " + resultSet.getString("age"));
21 }
22 //6.释放资源
23 resultSet.close();
24 preparedStatement.close();
25 connection.close();
26 }
27 }
执行结果：
引入MyBatis依赖
1 <!-- https://mvnrepository.com/artifact/org.mybatis/mybatis --> 2 <dependency> 3 <groupId>org.mybatis</groupId> 4 <artifactId>mybatis</artifactId> 5 <version>3.5.6</version> 6 </dependency> 7 <!-- https://mvnrepository.com/artifact/ch.qos.logback/logback-classic --> 8 <dependency> 9 <groupId>ch.qos.logback</groupId> 10 <artifactId>logback-classic</artifactId> 11 <version>1.3.0-alpha5</version> 12 <scope>test</scope> 13 </dependency>
删除JDBC连接：JDBCDemo.java
新建文件：StartNoXml.java
1 import org.apache.ibatis.datasource.pooled.PooledDataSource;
2 import org.apache.ibatis.mapping.Environment;
3 import org.apache.ibatis.session.Configuration;
4 import org.apache.ibatis.session.SqlSession;
5 import org.apache.ibatis.session.SqlSessionFactory;
6 import org.apache.ibatis.session.SqlSessionFactoryBuilder;
7 import org.apache.ibatis.transaction.jdbc.JdbcTransactionFactory;
8
9 import java.sql.PreparedStatement;
10 import java.sql.ResultSet;
11 import java.sql.SQLException;
12
13 @SuppressWarnings({"SqlResolve", "SqlNoDataSourceInspection", "Duplicates"})
14 public class StartNoXml {
15 public static void main(String[] args) throws SQLException {
16 // 准备jdbc事务类
17 JdbcTransactionFactory jdbcTransactionFactory = new JdbcTransactionFactory();
18 // 配置数据源
19 PooledDataSource dataSource = new PooledDataSource(
20 "com.mysql.cj.jdbc.Driver",
21 "jdbc:mysql://localhost:3306/mybatis_demo?useSSL=false",
22 "root",
23 "root");
24 // 配置环境，向环境中指定环境id、事务和数据源
25 Environment environment = new Environment.Builder("development")
26 .transactionFactory(jdbcTransactionFactory)
27 .dataSource(dataSource).build();
28 // 新建 MyBatis 配置类
29 Configuration configuration = new Configuration(environment);
30 // 得到 SqlSessionFactory 核心类
31 SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(configuration);
32 // 开始一个 sql 会话
33 SqlSession session = sqlSessionFactory.openSession();
34 // 得到 sql 连接并运行 sql 语句
35 PreparedStatement preStatement = session
36 .getConnection()
37 .prepareStatement("SELECT * FROM user WHERE id = ?");
38 preStatement.setInt(1, 1);
39 ResultSet result = preStatement.executeQuery();
40 // 验证结果
41 while (result.next()) {
42 System.out.println("username: " + result.getString("username"));
43 System.out.println("age: " + result.getString("age"));
44 }
45 // 关闭会话
46 session.close();
47 }
48 }
执行结果：
配置文件：mybatis-config.xml
1 <?xml version="1.0" encoding="UTF-8" ?> 2 <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"> 3 <configuration> 4 <!-- 环境变量 --> 5 <environments default="development"> 6 <environment id="development"> 7 <!-- 事务管理器 --> 8 <transactionManager type="JDBC"/> 9 <!-- 数据源 --> 10 <dataSource type="POOLED"> 11 <property name="driver" value="com.mysql.cj.jdbc.Driver"/> 12 <property name="url" value="jdbc:mysql://localhost:3306/mybatis_demo?useSSL=false"/> 13 <property name="username" value="root"/> 14 <property name="password" value="123456"/> 15 </dataSource> 16 </environment> 17 </environments> 18 <!-- mapper配置 --> 19 <mappers> 20 <mapper class="mapper.UserMapper"/> 21 </mappers> 22 </configuration>
修改StartNoXml.java类名：StartWithXml.java
1 import org.apache.ibatis.datasource.pooled.PooledDataSource;
2 import org.apache.ibatis.io.Resources;
3 import org.apache.ibatis.mapping.Environment;
4 import org.apache.ibatis.session.Configuration;
5 import org.apache.ibatis.session.SqlSession;
6 import org.apache.ibatis.session.SqlSessionFactory;
7 import org.apache.ibatis.session.SqlSessionFactoryBuilder;
8 import org.apache.ibatis.transaction.jdbc.JdbcTransactionFactory;
9
10 import java.io.IOException;
11 import java.io.InputStream;
12 import java.sql.PreparedStatement;
13 import java.sql.ResultSet;
14 import java.sql.SQLException;
15
16 @SuppressWarnings({"SqlResolve", "SqlNoDataSourceInspection", "Duplicates"})
17 public class StartWithXml {
18 public static void main(String[] args) throws SQLException, IOException {
19 // 读取配置文件
20 InputStream configuration = Resources.getResourceAsStream("mybatis-config.xml");
21 // 得到 SqlSessionFactory 核心类
22 SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(configuration);
23 // 开始一个 sql 会话
24 SqlSession session = sqlSessionFactory.openSession();
25 // 得到 sql 连接并运行 sql 语句
26 PreparedStatement preStatement = session
27 .getConnection()
28 .prepareStatement("SELECT * FROM user WHERE id = ?");
29 preStatement.setInt(1, 1);
30 ResultSet result = preStatement.executeQuery();
31 // 验证结果
32 while (result.next()) {
33 System.out.println("username: " + result.getString("username"));
34 System.out.println("age: " + result.getString("age"));
35 }
36 // 关闭会话
37 session.close();
38 }
39 }
执行结果：
二、MyBatis实现Mapper配置查询
注解方式使用Mapper
代码编写：
在mybatis-config.xml配置文件中加入mapper配置
1 <!-- mapper配置 --> 2 <mappers> 3 <mapper class="mapper.UserMapper"/> 4 </mappers>
新建mapper包，新建一个UserMapper.java类
UserMapper.java
1 package mapper;
2
3 import entity.User;
4 import org.apache.ibatis.annotations.Select;
5
6 public interface UserMapper {
7 /**
8 * 通过用户id查询用户名称
9 *
10 * @param id 用户id
11 * @return 用户名称
12 */
13 //通过#{**}的方式来查询
14 @Select("SELECT username FROM user WHERE id = #{id}")
15 String selectUsernameById(Integer id);
16 /**
17 * 通过用户id查询用户年龄
18 *
19 * @param id 用户id
20 * @return 用户年龄
21 */
22 Integer selectUserAgeById(Integer id);
23
24 /**
25 * 通过用户id查询用户信息
26 *
27 * @param id
28 * @return
29 */
30 User selectUserById(Integer id);
31
32 }
UserTest.java
1 import entity.User;
2 import mapper.UserMapper;
3 import org.apache.ibatis.io.Resources;
4 import org.apache.ibatis.session.SqlSession;
5 import org.apache.ibatis.session.SqlSessionFactory;
6 import org.apache.ibatis.session.SqlSessionFactoryBuilder;
7
8 import java.io.IOException;
9 import java.io.InputStream;
10 import java.sql.SQLException;
11
12 @SuppressWarnings({"SqlResolve", "SqlNoDataSourceInspection", "Duplicates"})
13 public class UserTest {
14 public static void main(String[] args) throws IOException, SQLException {
15 // 读取配置文件
16 InputStream configuration = Resources.getResourceAsStream("mybatis-config.xml");
17 // 得到 SqlSessionFactory 核心类
18 SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(configuration);
19 // 开始一个 sql 会话
20 SqlSession session = sqlSessionFactory.openSession();
21 // 得到 mapper
22 UserMapper mapper = session.getMapper(UserMapper.class);
23 // 调用注解的SQL
24 String username = mapper.selectUsernameById(1);
25 System.out.println("username: " + username);
26 // 调用XML的SQL
27 Integer age = mapper.selectUserAgeById(1);
28 System.out.println("age: " + age);
29
30 // 调用通过用户id查询用户信息的方法
31 User user = mapper.selectUserById(1);
32 System.out.println(user);
33 // 关闭会话
34 session.close();
35 }
36 }
执行结果：
标签：Mapper,java,ibatis,apache,session,org,MyBatis,import,搭建 来源： https://www.cnblogs.com/suisui2021/p/14592242.html
本站声明： 1. iCode9 技术分享网（下文简称本站）提供的所有内容，仅供技术学习、探讨和分享； 2. 关于本站的所有留言、评论、转载及引用，纯属内容发起人的个人观点，与本站观点和立场无关； 3. 关于本站的所有言论和文字，纯属内容发起人的个人观点，与本站观点和立场无关； 4. 本站文章均是网友提供，不完全保证技术分享内容的完整性、准确性、时效性、风险性和版权归属；如您发现该文章侵犯了您的权益，可联系我们第一时间进行删除； 5. 本站为非盈利性的个人网站，所有内容不会用来进行牟利，也不会利用任何形式的广告来间接获益，纯粹是为了广大技术爱好者提供技术内容和技术思想的分享性交流网站。