Mybatis使用（一）

- 日理万妓 2022-01-23 02:31 209阅读 0赞

# Mybatis使用（一） #

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NtMTYxMTE_size_16_color_FFFFFF_t_70][]

![20190601225055516.png][]

下面就实现用户的增删改查来举例说明mybatis的使用

a\}导入相关jar包

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还有数据库驱动包

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NtMTYxMTE_size_16_color_FFFFFF_t_70 2][]

**需要jar包的同志评论里打call。。。**

b）编写核心配置文件mybatis.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" />
    			
    			<dataSource type="POOLED">
    				<property name="driver" value="com.mysql.jdbc.Driver" />
    				<property name="url" value="jdbc:mysql://localhost:3306/test" />
    				<property name="username" value="root" />
    				<property name="password" value="*******" />
    			</dataSource>
    		</environment>
    	</environments>
    	<mappers>
    		
    		<mapper resource="com/bean/mapper.xml" />
    	</mappers>
    </configuration>

c）编写工具类mybatisulit.java

package com.util;
    
    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;
    
    
    public class MybatisUtil {
    	public static SqlSessionFactory getSqlSessionFactory() throws IOException{
    		String resource = "mybatis.xml";
    		InputStream inputStream = Resources.getResourceAsStream(resource); //解析mybatis.xml文件
    		SqlSessionFactory sqlSessionFactory =new SqlSessionFactoryBuilder().build(inputStream);
    		return sqlSessionFactory;
    	}
    	public static SqlSession getSqlSession() throws IOException{
    		SqlSessionFactory sqlSessionFactory = getSqlSessionFactory();
    		return sqlSessionFactory.openSession(); //获取sqlSession对象
    	}
    }

c）编写实体类User.java

package com.bean;
    
    public class User {
    	private int id;
    	private String name;
    	private int age;
    	public int getId() {
    		return id;
    	}
    	public void setId(int id) {
    		this.id = id;
    	}
    	public String getName() {
    		return name;
    	}
    	public void setName(String name) {
    		this.name = name;
    	}
    	public int getAge() {
    		return age;
    	}
    	public void setAge(int age) {
    		this.age = age;
    	}
    	@Override
    	public String toString() {
    		return "User [id=" + id + ", name=" + name + ", age=" + age + "]";
    	}
    	
    	
    }

d）编写sql语句的映射文件mapper.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="com.bean.Usermapper">
    	<select id="selectAll" resultType="com.bean.User">
    		select * from user 
    	</select>
    	<select id="selectUser" resultType="com.bean.User">
    		select * from user where id = #{id}
    	</select>
    	
    	<insert id="insertUser" parameterType="com.bean.User" useGeneratedKeys="true">
    		insert into user(name,age) values (#{name},#{age})
    	</insert>
    	<update id="updateUser" parameterType="com.bean.User">
    		update user set name=#{name} where id=#{id}
    	</update>
    	<delete id="deleteUser" >
    		delete from user where id = #{id}
    	</delete>
    </mapper>

e）编写dao操作类UserDao.java

package com.dao;
    
    import java.io.IOException;
    import java.util.List;
    
    import org.apache.ibatis.session.SqlSession;
    
    import com.bean.User;
    import com.util.MybatisUtil;
    
    public class UserDao {
    	public List getAll() throws IOException{ //查询全部
    		SqlSession sqlSession = MybatisUtil.getSqlSession();
    		List<User> user = sqlSession.selectList("com.bean.Usermapper.selectAll");//获取路径
    		sqlSession.close();
    		return user;
    	}
    	public User getbyId(int id) throws IOException{//查询一个
    		SqlSession sqlSession = MybatisUtil.getSqlSession();
    		User user = sqlSession.selectOne("com.bean.Usermapper.selectUser", id);
    		sqlSession.close();
    		return user;
    	}
    	public void insert(User user) throws IOException{//插入
    		SqlSession sqlSession = MybatisUtil.getSqlSession();
    		sqlSession.insert("com.bean.Usermapper.insertUser", user);
    		sqlSession.commit(); //提交确认
    		sqlSession.close();
    		
    	}
    	public void update(User user) throws IOException{//更新
    		SqlSession sqlSession = MybatisUtil.getSqlSession();
    		sqlSession.update("com.bean.Usermapper.updateUser", user);
    		sqlSession.commit();//提交确认
    		sqlSession.close();
    		
    	}
    	public void delete(int id) throws IOException{//删除
    		SqlSession sqlSession = MybatisUtil.getSqlSession();
    		sqlSession.delete("com.bean.Usermapper.deleteUser", id);
    		sqlSession.commit();//提交确认
    		sqlSession.close();
    		
    	}
    }

f)编写测试类Test.java测试实现效果

package com.test;
    
    import java.io.IOException;
    import java.util.List;
    
    import org.apache.ibatis.session.SqlSession;
    
    import com.bean.User;
    import com.dao.UserDao;
    import com.util.MybatisUtil;
    
    public class Test {
    	public static void main(String[] args) throws IOException {
    //		SqlSession sqlSession = MybatisUtil.getSqlSession();
    //		User user = sqlSession.selectOne("com.bean.Usermapper.selectUser", 2);
    		
    		//System.out.println(user.getId()+"...."+user.getName()+"...."+user.getAge());
    		//sqlSession.close();
    		
    //		System.out.println(userdao.getbyId(1));
    		UserDao userdao = new UserDao();
    		User user = new User();
    		user.setName("张三");
    		user.setAge(18);
    		userdao.insert(user);
    		System.out.println("插入成功");
    				
    		User user1 = userdao.getbyId(7);
    		user1.setName("李四");
    		userdao.update(user1);
    		System.out.println("修改成功");
    		
    		userdao.delete(11);
    		System.out.println("ok");
    		
    		List<User> list = userdao.getAll();
    		System.out.println("查询结果");
    			for(User u:list){
    				System.out.println(u);
    			}
    	}
    }

效果图

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NtMTYxMTE_size_16_color_FFFFFF_t_70 3][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NtMTYxMTE_size_16_color_FFFFFF_t_70 4][]

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[20190601225055516.png]: /images/20220123/2b45eaec8e0c42f9b360d2aac29df0b8.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NtMTYxMTE_size_16_color_FFFFFF_t_70 1]: /images/20220123/04b3b8d0539b4be2aa64d433757e255f.png
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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NtMTYxMTE_size_16_color_FFFFFF_t_70 4]: /images/20220123/03ad094b92194c0c9ab729ce7f8a652f.png