Mybatis配置数据库连接
首先resources下的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">
<!--核心配置文件-->
<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/ssms?useSSL=true&useUnicode=true&characterEncoding=UTF-8"/>
<property name="username" value="root"/>
<property name="password" value="123456"/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="cn/zmxy/dao/UsersMapper.xml"/>
</mappers>
</configuration>
pojo实现类层的Java类(对应数据库表),比如Users表
public class Users {
private int id;
private String name;
private String pwd;
public Users(){}
}
dao层的映射xml和Interface接口
UsersMapper.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">
<!--namespace 命名空间 保定一个对应的dao/mapper接口-->
<mapper namespace="cn.zmxy.dao.UsersMapper">
<select id="getUserList" resultType="cn.zmxy.pojo.Users">
SELECT * FROM ssms.users
</select>
<select id="getUserById" resultType="cn.zmxy.pojo.Users" parameterType="int">
SELECT * FROM ssms.users WHERE id = #{id}
</select>
<insert id="addUser" parameterType="cn.zmxy.pojo.Users">
INSERT INTO ssms.users (id, name, pwd) VALUES (#{id}, #{name}, #{pwd})
</insert>
<update id="updateUser" parameterType="cn.zmxy.pojo.Users">
UPDATE ssms.users SET name = #{name}, pwd = #{pwd} WHERE id = #{id}
</update>
<delete id="deleteUser" parameterType="int">
DELETE FROM ssms.users WHERE id = #{id}
</delete>
</mapper>
UsersMapper.java
package cn.zmxy.dao;
import cn.zmxy.pojo.Users;
import java.util.List;
public interface UsersMapper {
// 查询全部用户
public List<Users> getUserList();
// 根据ID查询用户
public Users getUserById(int id);
// 添加用户
public int addUser(Users user);
// 修改用户
public int updateUser(Users user);
// 删除用户
public int deleteUser(int id);
}
写一个utils类,获取SqlSession
MyBatisUtils.java
package cn.zmxy.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 {
String resource = "mybatis-config.xml";
InputStream is = Resources.getResourceAsStream(resource);
sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
} catch (IOException e) {
e.printStackTrace();
} }
public static SqlSession getSqlSession()
{ return sqlSessionFactory.openSession();
}}
最后就可以调用了,写一个test类
UserMapperTest.java
package cn.zmxy.dao;
import cn.zmxy.pojo.Users;
import cn.zmxy.utils.MyBatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;
import java.util.List;
public class UserDaoTest {
@Test
public void test()
{ // 第一步,获取SqlSession对象
SqlSession sqlSession = MyBatisUtils.getSqlSession();
// 第二步,执行SQL
UsersMapper usersMapper = sqlSession.getMapper(UsersMapper.class);
List<Users> userList = usersMapper.getUserList();
// 打印users
for (Users users : userList) {
System.out.println(users);
} // 关闭SqlSession
sqlSession.close();
}
@Test
public void getUserById()
{ // 第一步,获取SqlSession对象
SqlSession sqlSession = MyBatisUtils.getSqlSession();
UsersMapper mapper = sqlSession.getMapper(UsersMapper.class);
Users user = mapper.getUserById(1);
System.out.println(user);
// 关闭SqlSession
sqlSession.close();
}
@Test
public void addUser()
{ // 第一步,获取SqlSession对象
SqlSession sqlSession = MyBatisUtils.getSqlSession();
UsersMapper mapper = sqlSession.getMapper(UsersMapper.class);
int num = mapper.addUser(new Users(0, "露露", "1234"));
System.out.println("受影响行数:" + num);
sqlSession.commit();
// 关闭SqlSession
sqlSession.close();
}
@Test
public void updateUser()
{ // 第一步,获取SqlSession对象
SqlSession sqlSession = MyBatisUtils.getSqlSession();
UsersMapper mapper = sqlSession.getMapper(UsersMapper.class);
int num = mapper.updateUser(new Users(3, "露露", "1234"));
System.out.println("受影响行数:" + num);
sqlSession.commit();
// 关闭SqlSession
sqlSession.close();
}
@Test
public void deleteUser()
{ // 第一步,获取SqlSession对象
SqlSession sqlSession = MyBatisUtils.getSqlSession();
UsersMapper mapper = sqlSession.getMapper(UsersMapper.class);
int num = mapper.deleteUser(11);
System.out.println("受影响行数:" + num);
sqlSession.commit();
// 关闭SqlSession
sqlSession.close();
}
}