從零開始Mybatis連接數(shù)據(jù)庫的方法

更新時(shí)間：2023年02月27日 08:23:53 作者：赤葉秋楓

這篇文章主要介紹了Mybatis連接數(shù)據(jù)庫的方法，本文通過實(shí)例代碼給大家介紹的非常詳細(xì)，對(duì)大家的學(xué)習(xí)或工作具有一定的參考借鑒價(jià)值,需要的朋友可以參考下

從零開始Mybatis連接數(shù)據(jù)庫

創(chuàng)建Maven文件

File-->new-->project-->maven,點(diǎn)擊next

配置

在出現(xiàn)的pom.xml文件中<project>標(biāo)簽之間加入以下內(nèi)容

 <!--打包方式-->
<packaging>jar</packaging>

    <dependencies>
        <!--加載Mybatis核心-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.7</version>
        </dependency>

        <!--Junit測(cè)試-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>

        <!--mysql驅(qū)動(dòng)-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.3</version>
        </dependency>

    </dependencies>

在src-->main-->resources下創(chuàng)建文件mybatis-config.xml

在該文件中加入以下內(nèi)容:

<?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>
    <!--配置連接數(shù)據(jù)庫環(huán)境-->
    <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="自己的用戶名"/>
                <property name="password" value="自己的密碼"/>
            </dataSource>
        </environment>
    </environments>

</configuration>

注意將username和password的value值改成自己的,且在自己的數(shù)據(jù)庫中創(chuàng)建test庫

創(chuàng)建實(shí)體類

在main的java下創(chuàng)建我們需要與表中對(duì)應(yīng)的實(shí)體類,這里我們寫user類

public class User {
    //實(shí)體類
    
    //屬性與表中的各項(xiàng)對(duì)應(yīng),加入相應(yīng)的get,set方法
        int  userid;
        String username;
        String userpass;
        String usertel;
        int usercarad;

        public User() {
        }

        public User(int userid, String username, String userpass, String usertel, int usercarad) {
            this.userid = userid;
            this.username = username;
            this.userpass = userpass;
            this.usertel = usertel;
            this.usercarad = usercarad;
        }

        public int getUserid() {
            return userid;
        }

        public void setUserid(int userid) {
            this.userid = userid;
        }

        public String getUsername() {
            return username;
        }

        public void setUsername(String username) {
            this.username = username;
        }

        public String getUserpass() {
            return userpass;
        }

        public void setUserpass(String userpass) {
            this.userpass = userpass;
        }

        public String getUsertel() {
            return usertel;
        }

        public void setUsertel(String usertel) {
            this.usertel = usertel;
        }

        public int getUsercarad() {
            return usercarad;
        }

        public void setUsercarad(int usercarad) {
            this.usercarad = usercarad;
        }
    }

創(chuàng)建com.mapper包,并在包下創(chuàng)建UserMapper接口

這里我們簡單做一個(gè)添加內(nèi)容示例

package com.mapper;

public interface UserMapper {
    int insertUser();//返回值為改變的行數(shù)
}

創(chuàng)建UserMapper.xml映射文件

在resources文件夾下創(chuàng)建mapper文件夾(包)并在其中創(chuàng)建UserMapper.xml

并在其中加入以下內(nèi)容,這里要保證兩個(gè)一致

<?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">
<!--第一個(gè)一致,namespace對(duì)應(yīng)UserMapper接口全類名-->
<mapper namespace="com.mapper.UserMapper">

    <!--第二個(gè)一致,id對(duì)應(yīng)方法名   int  insertUser(); -->
   <insert id="insertUser">
       insert into user values (null,"tom","1234","111",22)
   </insert>

</mapper>

在mybatis-config.xml下<configuration>標(biāo)簽中最下面加入

<!--引入映射文件-->
    <mappers>
        <mapper resource="mapper/UserMapper.xml"/>
    </mappers>

創(chuàng)建測(cè)試類

創(chuàng)建Test類進(jìn)行測(cè)試

import com.mapper.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 java.io.IOException;
import java.io.Reader;

public class Test {
    public static void main(String[] args) throws IOException {
        //獲取配置文件
       Reader reader = Resources.getResourceAsReader("mybatis-config.xml");
       // 獲取SqlSessionFactoryBuilder獲取SqlSessionFactory工廠
       SqlSessionFactoryBuilder sqlSessionFactoryBuilder=new SqlSessionFactoryBuilder();
        //獲取SqlSessionFactory工廠
        SqlSessionFactory sqlSessionFactory= sqlSessionFactoryBuilder.build(reader);
        //利用工廠獲取sqlSession
        SqlSession sqlSession=sqlSessionFactory.openSession();//openSession()加入?yún)?shù)true,即可實(shí)現(xiàn)自動(dòng)提交事務(wù)
        //利用sqlSession的方法獲取接口的對(duì)象
        UserMapper userMapper=sqlSession.getMapper(UserMapper.class);
        //調(diào)用接口方法,從而調(diào)用映射文件的sql語句
       int num= userMapper.insertUser();
       //提交事務(wù)
        sqlSession.commit();
        System.out.println("改變行數(shù)"+num);


    }
}

運(yùn)行結(jié)果: