mybatis入门（实现增删改查）
目录
1.查询数据库中id=1的记录
2.通过用户名模糊查询记录
3.插入数据
4.根据id修改用户名
5.根据id删除记录
6.使用mybatis开发dao层（查询id为1的记录。对比上面的）
新建javaProject
导入数据库驱动包：
导入mybatis包和它的依赖包：
配置约束：https://blog.csdn.net/qq_40323256/article/details/89705297
项目文件如下：
数据库：
全局配置(SqlMapConfig.xml)
注意：SqlMapConfig.xml中还可以使用读取配置文件（db.properties）的方式连接数据库，如下：
db.properties:
jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/web01
jdbc.username=root
jdbc.password=root1.查询数据库中id=1的记录
UserMapper.xml:
User.java:
package com.sikiedu.bean;
public class User {
private Integer id;
private String username;
private String password;
public Integer getId() {
return id;
}
public void setId(Integer 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 + "]";
}
}
HelloMyBatis.java:
package test;
import java.io.IOException;
import java.io.InputStream;
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 com.sikiedu.bean.User;
public class HelloMyBatis {
@Test
public void Test() throws IOException{
String resource="sqlMapConfig.xml";
InputStream in = Resources.getResourceAsStream(resource);
SqlSessionFactoryBuilder ssfb=new SqlSessionFactoryBuilder();
SqlSessionFactory ssf=ssfb.build(in);
SqlSession session = ssf.openSession();
User user = session.selectOne("UserMapper.selectUserById",1);
System.out.println(user);
}
}
运行结果：
2.通过用户名模糊查询记录
HelloBatis.java:
@Test
public void Test2() throws IOException{
String resource="sqlMapConfig.xml";
InputStream in = Resources.getResourceAsStream(resource);
SqlSessionFactoryBuilder ssfb=new SqlSessionFactoryBuilder();
SqlSessionFactory ssf=ssfb.build(in);
SqlSession session = ssf.openSession();
List list = session.selectList("UserMapper.selectUserByName", "李");
for (User u : list) {
System.out.println(u);
}
} UserMapper.xml:
运行结果：
3.插入数据
HelloMyBatis.java:
@Test
public void Test3() throws IOException{
String resource="sqlMapConfig.xml";
InputStream in = Resources.getResourceAsStream(resource);
SqlSessionFactoryBuilder ssfb=new SqlSessionFactoryBuilder();
SqlSessionFactory ssf=ssfb.build(in);
SqlSession session = ssf.openSession();
User user=new User();
user.setUsername("小明");
user.setPassword("1");
session.insert("UserMapper.insertUser",user);
session.commit();
}UserMapper.xml:
insert into user values(null,#{username},#{password})
运行结果：
4.根据id修改用户名
HelloMyBatis.java:
@Test
public void Test4() throws IOException{
String resource="sqlMapConfig.xml";
InputStream in = Resources.getResourceAsStream(resource);
SqlSessionFactoryBuilder ssfb=new SqlSessionFactoryBuilder();
SqlSessionFactory ssf=ssfb.build(in);
SqlSession session = ssf.openSession();
User user=new User();
user.setId(14);
user.setUsername("小疆");
session.insert("UserMapper.updateUser",user);
session.commit();
}UserMapper.xml:
update user set username=#{username} where id=#{id}
运行结果：
5.根据id删除记录
HelloMyBatis.java:
@Test
public void Test5() throws IOException{
String resource="sqlMapConfig.xml";
InputStream in = Resources.getResourceAsStream(resource);
SqlSessionFactoryBuilder ssfb=new SqlSessionFactoryBuilder();
SqlSessionFactory ssf=ssfb.build(in);
SqlSession session = ssf.openSession();
session.delete("UserMapper.deleteUser",14);
session.commit();
}UserMapper.xml:
delete from user where id=#{id}
运行结果：id=14的记录被删除了
6.使用mybatis开发dao层（查询id为1的记录。对比上面的）
UserDao.java:
package com.sikiedu.dao;
import com.sikiedu.bean.User;
public interface UserDao {
User getUserById(Integer id);
}
UserDaolmpl.java:
package com.sikiedu.dao;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import com.sikiedu.bean.User;
public class UserDaolmpl implements UserDao {
SqlSessionFactory ssf;
public UserDaolmpl(SqlSessionFactory ssf) {
super();
this.ssf = ssf;
}
@Override
public User getUserById(Integer id) {
SqlSession session = ssf.openSession();
return session.selectOne("UserMapper.selectUserById",id);
}
}
UserDaoTest.java:
package test;
import java.io.IOException;
import java.io.InputStream;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;
import com.sikiedu.bean.User;
import com.sikiedu.dao.UserDao;
import com.sikiedu.dao.UserDaolmpl;
public class UserDaoTest {
private static SqlSessionFactory ssf;
static{
String resource="sqlMapConfig.xml";
InputStream in;
try {
in = Resources.getResourceAsStream(resource);
SqlSessionFactoryBuilder ssfb=new SqlSessionFactoryBuilder();
ssf=ssfb.build(in);
in.close();
} catch (IOException e) {
e.printStackTrace();
}
}
@Test
public void DaoTest(){
UserDao dao=new UserDaolmpl(ssf);
User user=dao.getUserById(1);
System.out.println(user);
}
}
运行结果：
7.包装类
UserVo.java:
package com.sikiedu.bean;
public class UserVo {
private User user;
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
}
UserMapper.java:
public User selectUserByUserVo(UserVo vo);UserMapper.xml:
MapperTest.java:
@Test
public void Test3() throws IOException{
String resource="sqlMapConfig.xml";
InputStream in = Resources.getResourceAsStream(resource);
SqlSessionFactoryBuilder ssfb=new SqlSessionFactoryBuilder();
SqlSessionFactory ssf=ssfb.build(in);
SqlSession session = ssf.openSession();
UserMapper mapper = session.getMapper(UserMapper.class);
UserVo vo=new UserVo();
User u=new User();
u.setId(1);
vo.setUser(u);
User user = mapper.selectUserByUserVo(vo);
System.out.println(user);
}运行结果：
