一、Mybatis HelloWorld
1. 应用 Maven 创立一个我的项目, 我的项目目录如下
2. 在 maven 的 pom.xml 引入依赖
次要包含 mybatis,mysql,junit 的依赖,而后就可进行开发了。
<?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>
<groupId>org.example</groupId>
<artifactId>test03</artifactId>
<version>1.0-SNAPSHOT</version>
<properties>
<maven.compiler.source>8</maven.compiler.source>
<maven.compiler.target>8</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.7</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.22</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.13.2</version>
<scope>test</scope>
</dependency>
</dependencies>
</project>
3. 编写 mybatis 配置文件 mybatis-config.xml 文件
次要是用来配置数据源 和 配置相干 mapper*.xml 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.cj.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/test?serverTimezone=UTC"/>
<property name="username" value="root"/>
<property name="password" value="123456"/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="UserMapper.xml"/>
</mappers>
</configuration>
4. 创立用户表, 编写 User 类
package com.jt;
public class User {
private int id;
private String username;
private String password;
public int getId() {return id;}
public void setId(int id) {this.id = id;}
public String getUsername() {return username;}
public void setUsername(String username) {this.username = username;}
public String getPassword() {return password;}
public void setPassword(String password) {this.password = password;}
@Override
public String toString() {
return "User{" +
"id=" + id +
", username='" + username + '\'' +
", password='" + password + '\'' +
'}';
}
}
5. 编写 UserMapper 类
package com.jt;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;
import java.util.Map;
public interface UserMapper {public User selectUser(int id);
public User selectUserByIdAndName(@Param("id") Integer id,@Param("username") String username);
public User selectUserByIdAndNameUseMap(Map map);
public Integer insertUser(User user);
public boolean updateUser(User user);
public Integer deleteUserById(int id);
}
6. 编写 UserMapper.xml 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">
<mapper namespace="com.jt.UserMapper">
<select id="selectUser" resultType="com.jt.User">
select * from test01 where id = #{id}
</select>
<select id="selectUserByIdAndName" resultType="com.jt.User">
select * from test01 where id = #{id} and username=#{username}
</select>
<select id="selectUserByIdAndNameUseMap" resultType="com.jt.User">
select * from test01 where id = #{id} and username=#{username}
</select>
<insert id="insertUser" useGeneratedKeys="true" keyProperty="id">
insert into test01 (username,password) values(#{username},#{password})
</insert>
<update id="updateUser" parameterType="com.jt.User">
update test01 set username=#{username} where id=#{id}
</update>
<delete id="deleteUserById">
delete from test01 where id=#{id}
</delete>
</mapper>
7. 编写测试类
import com.jt.User;
import com.jt.UserMapper;
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.IOException;
import java.io.InputStream;
import java.util.LinkedHashMap;
import java.util.Map;
public class HelloTest {
@Test
public void selectTest() throws IOException {
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory =
new SqlSessionFactoryBuilder().build(inputStream);
try (SqlSession session = sqlSessionFactory.openSession()) {UserMapper userMapper = session.getMapper(UserMapper.class);
User user = userMapper.selectUser(1);
System.out.println(user);
}finally {sqlSessionFactory.openSession();
}
}
@Test
public void selectByIdAndNameTest() throws IOException {
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory =
new SqlSessionFactoryBuilder().build(inputStream);
try (SqlSession session = sqlSessionFactory.openSession()) {UserMapper userMapper = session.getMapper(UserMapper.class);
User user = userMapper.selectUserByIdAndName(5,"3");
System.out.println(user);
}finally {sqlSessionFactory.openSession();
}
}
@Test
public void selectByIdAndNameUseMapTest() throws IOException {
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory =
new SqlSessionFactoryBuilder().build(inputStream);
try (SqlSession session = sqlSessionFactory.openSession()) {UserMapper userMapper = session.getMapper(UserMapper.class);
Map map = new LinkedHashMap();
map.put("id",5);
map.put("username","3");
User user = userMapper.selectUserByIdAndNameUseMap(map);
System.out.println(user);
}finally {sqlSessionFactory.openSession();
}
}
@Test
public void insertTest() throws IOException {
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory =
new SqlSessionFactoryBuilder().build(inputStream);
try (SqlSession session = sqlSessionFactory.openSession()) {UserMapper userMapper = session.getMapper(UserMapper.class);
User user01 = new User();
user01.setUsername("4");
user01.setPassword("4");
userMapper.insertUser(user01);
System.out.println(user01.getId());
}finally {sqlSessionFactory.openSession();
}
}
@Test
public void updateTest() throws IOException {
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory =
new SqlSessionFactoryBuilder().build(inputStream);
try (SqlSession session = sqlSessionFactory.openSession()) {UserMapper userMapper = session.getMapper(UserMapper.class);
User user01 = new User();
user01.setId(2);
user01.setUsername("批改 1");
boolean res = userMapper.updateUser(user01);
System.out.println(res);
}finally {sqlSessionFactory.openSession();
}
}
@Test
public void deleteTest() throws IOException {
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory =
new SqlSessionFactoryBuilder().build(inputStream);
try (SqlSession session = sqlSessionFactory.openSession()) {UserMapper userMapper = session.getMapper(UserMapper.class);
int res = userMapper.deleteUserById(1);
System.out.println(res);
}finally {sqlSessionFactory.openSession();
}
}
}