mybatis入门（实现增删改查）

悠悠 2021-09-19 04:20 556阅读 0赞

**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：

![20190430100003118.png][]

导入mybatis包和它的依赖包：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70][]![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 1][]

配置约束：[https://blog.csdn.net/qq\_40323256/article/details/89705297][https_blog.csdn.net_qq_40323256_article_details_89705297]

项目文件如下：

![20190430121915938.png][]           数据库：![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 2][]

![20190430125512784.png][]

全局配置(SqlMapConfig.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">
     
    <configuration>
    	
    
    	<environments default="development">
    		<environment id="development">
    			
    			<transactionManager type="JDBC"></transactionManager>
    			
    			<dataSource type="POOLED">
    				<property name="driver" value="com.mysql.jdbc.Driver"/>
    				<property name="url" value="jdbc:mysql://localhost:3306/web01"/>
    				<property name="username" value="root"/>
    				<property name="password" value="root"/>
    			</dataSource>
    		</environment>
    	</environments>
    	
    	<mappers>
    		<mapper resource="mapper/UserMapper.xml"/>
    
    
    	
    	</mappers>
    	
    </configuration>

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：

<?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>
    
    	<properties resource="db.properties"></properties>
    
    	
    
    	<environments default="development">
    		<environment id="development">
    			
    			<transactionManager type="JDBC"></transactionManager>
    			
    			<dataSource type="POOLED">
    				<property name="driver" value="${jdbc.driver}"/>
    				<property name="url" value="${jdbc.url}"/>
    				<property name="username" value="${jdbc.username}"/>
    				<property name="password" value="${jdbc.password}"/>
    			</dataSource>
    		</environment>
    	</environments>
    	
    	<mappers>
    		<mapper resource="mapper/UserMapper.xml"/>
    
    	
    	</mappers>
    	
    </configuration>

db.properties:

jdbc.driver=com.mysql.jdbc.Driver
    jdbc.url=jdbc:mysql://localhost:3306/web01
    jdbc.username=root
    jdbc.password=root

#   1.查询数据库中id=1的记录 #

UserMapper.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">
     
    <mapper namespace="UserMapper">
    
    	<select id="selectUserById" parameterType="Integer" resultType="com.sikiedu.bean.User">
    		SELECT * FROM user WHERE id =#{id}
    	</select>
    </mapper>

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：

![20190430122407482.png][]

# 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<User> list = session.selectList("UserMapper.selectUserByName", "李");
    		for (User u : list) {
    			System.out.println(u);
    		}
    	}

UserMapper.xml:

<select id="selectUserByName" parameterType="String" resultType="com.sikiedu.bean.User">
    
    			SELECT * FROM user WHERE username like "%"#{name}"%"
    	</select>

运行结果：

![20190430123730137.png][]

# 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 id="insertUser" parameterType="com.sikiedu.bean.User">
    		insert into user values(null,#{username},#{password})
    	</insert>

运行结果：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 3][]

# 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 id="updateUser" parameterType="com.sikiedu.bean.User">
    		update user set username=#{username} where id=#{id}
    	</update>

运行结果：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 4][]

# 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 id="deleteUser" parameterType="Integer">
    		delete from user where id=#{id}
    	</delete>

运行结果：id=14的记录被删除了

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 5][]

# 6.使用mybatis开发dao层（查询id为1的记录。对比上面的） #

![20190430201201666.png][]

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：

![20190430201319553.png][]

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:

<select id="selectUserByUserVo" parameterType="com.sikiedu.bean.UserVo" resultType="com.sikiedu.bean.User">
    		SELECT * FROM user WHERE id =#{user.id}
    	</select>

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：

![20190501121711213.png][]

[20190430100003118.png]: /images/20210725/ddf7d64166fa496f85baa14c647d05ed.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20190430100110376.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 1]: /images/20210725/209ab11c94644cb38e4442073c78b08b.png
[https_blog.csdn.net_qq_40323256_article_details_89705297]: https://blog.csdn.net/qq_40323256/article/details/89705297
[20190430121915938.png]: https://img-blog.csdnimg.cn/20190430121915938.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 2]: /images/20210725/a154ae89078040fd86f8d6100d72f1a5.png
[20190430125512784.png]: /images/20210725/591ca583b8b443f598370662313dd2f5.png
[20190430122407482.png]: /images/20210725/c986ac9c0b71442c81ce67a299931a6d.png
[20190430123730137.png]: /images/20210725/71921a24a63e497a835a8faa755d559f.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 3]: /images/20210725/8de4fe261f2d4d36bae676753070a62d.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 4]: /images/20210725/29100b0e71774353a170f6e27e01dd35.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 5]: /images/20210725/27a8f94e646949a5b0d40216f9cd3e87.png
[20190430201201666.png]: /images/20210725/c07dc199df6e4930a77d4108978c19dd.png
[20190430201319553.png]: /images/20210725/444394a363fb404b862ba9cc8883f8cf.png
[20190501121711213.png]: /images/20210725/d84b0fe1ed6046f382f0c8b636f5e7b5.png