Mybatis搭建

2024-01-02 20:48:28

Mybatis学习

发现学完东西老忘还得重看一遍视频所以记录一下

第一步

首先在maven下面加入依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <!--父工程-->
    <groupId>com.com.su</groupId>
    <artifactId>Mybatis-Study</artifactId>
    <packaging>pom</packaging>
    <version>1.0-SNAPSHOT</version>
    <modules>
        <module>mybatis-01</module>
        <module>mybatis-02youhua</module>
    </modules>

    <!--导入依赖-->
    <dependencies>
<!--        mysql-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.46</version>
        </dependency>
<!--        mybatis-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.2.6</version>
        </dependency>
<!--        junit-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
    </dependencies>

<!-- 打包生成xml-->
    <build>
        <resources>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
        </resources>
    </build>

</project>

第二步

在resources下面加入mybatis-config.xml

根据自己需要修改url和用户名密码

<?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/mybatis?useSSL=true&amp;useUnicode=true&amp;characterEncoding=UTF-8"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="com/com.su/dao/UserMapper.xml"/>
    </mappers>
</configuration>

第三步

创建工具类：Mybatisuils

package com.su.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;
//SqlSessionFactory-->SqlSession 链接数据库
public class Mybatisutils {
    private  static SqlSessionFactory sqlSessionFactory;
    static {
        String resource = "mybatis-config.xml";
        InputStream inputStream = null;
        try {
            inputStream = Resources.getResourceAsStream(resource);
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }

    }
    //获取SqlSessionFactory中获得SqlSession的实例
    public static SqlSession getSqlSession(){
        SqlSession sqlSession = sqlSessionFactory.openSession();
        return sqlSession;
    }

}

第四步

创建实体类名字和数据库对上然后alt+insert 快速设置getset和tostring

package com.su.pojo;
//实体类
public class User {
    private int id;
    private String name;
    private String pwd;
    public User(){

    }

    public User(int id, String name, String pwd) {
        this.id = id;
        this.name = name;
        this.pwd = pwd;
    }

    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 String getPwd() {
        return pwd;
    }

    public void setPwd(String pwd) {
        this.pwd = pwd;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", pwd='" + pwd + '\'' +
                '}';
    }
}

第五步

创建Usermapper和Mapper.xml

package com.su.dao;

import com.su.pojo.User;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

public interface UserMapper {
    List<User> getUserList();//查

    List<User> getUserListByName(String value);//模糊查找

    User getUserByid(int id);//条件查

    User getuserByNameandPwd(Map<String,Object> map);



    int addUser(User user);

    int addUser2(Map<String,Object> map);

    int updateUser(User user);

    int deleteUser(User user);
}

<?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.com.su.dao.UserMapper">
    <select id="getUserList" resultType="com.com.su.pojo.User" >
        select * from user
    </select>

    <select id="getUserListByName" resultType="com.com.su.pojo.User">
        select * from user where name like #{value}
    </select>

    <select id="getUserByid" parameterType="int" resultType="com.com.su.pojo.User">
        select * from user where id = #{id}
    </select>

    <insert id="addUser" parameterType="com.com.su.pojo.User">
        insert into user(id,name,pwd) values (#{id},#{name},#{pwd})
    </insert>

    <insert id="addUser2" parameterType="map">
        insert into user(id,name,pwd) values (#{userid},#{username},#{userpwd})
    </insert>

    <select id="getuserByNameandPwd" parameterType="map" resultType="com.com.su.pojo.User">
        select * from user where name = #{username} and pwd = #{userpwd}
    </select>
    
    <update id="updateUser" parameterType="com.com.su.pojo.User">
        update user set name=#{name},pwd=#{pwd} where id = #{id} ;
    </update>

    <delete id="deleteUser" parameterType="com.com.su.pojo.User">
        delete from user where id = #{id}
    </delete>
</mapper>

解析一下代码

<mapper namespace="com.com.su.dao.UserMapper"> //绑定对应的Mapper接口
 <select id="getUserList" resultType="com.com.su.pojo.User" >//id是找Mapper中对应的方法 List<User> getUserList()
// resultType返回对应类型

超级重要：

每创建一个Mapper.xml就要在mybatis-config.xml加入注册

    <mappers>
        <mapper resource="com/com.su/dao/UserMapper.xml"/>
    </mappers>

第六步

junit测试

运行一下代码

首先在test里建立个UserDaoTest

package com.su.dao;

import com.su.pojo.User;
import com.su.utils.Mybatisutils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class UserDaoTest {

    @Test
    public void test(){
        //必写
       SqlSession sqlSession= Mybatisutils.getSqlSession();
       UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
//        System.out.println(userMapper.getUserByid(1));
//        List<User> userList = userMapper.getUserList();
//
//        for (User user : userList) {
//            System.out.println(user);
//        }

//        int test = userMapper.addUser(new User(4,"xjz","sb"));
//        if (test>0){
//            System.out.println("提交陈宫");
//        }

//        int test = userMapper.updateUser(new User(4,"xjz","zdsb"));
//        if (test>0){
//            System.out.println("修改陈宫");
//        }

//
//        int test = userMapper.deleteUser(new User(4,"xjz","zdsb"));
//        if (test>0){
//            System.out.println("删除陈宫");
//        }
//        Map map = new HashMap<String,Object>();
//        map.put("userid",4);
//        map.put("username","sbsbs");
//        map.put("userpwd","xjzsb");
//        int test = userMapper.addUser2(map);
//        if (test>0){
//            System.out.println("加入成功");
//        }
//
//        sqlSession.commit();
//
//        Map map = new HashMap<String,Object>();
//        map.put("username","sbsbs");
//        map.put("userpwd","xjzsb");
//        User user = userMapper.getuserByNameandPwd(map);
//        System.out.println(user);

        List<User> userList = userMapper.getUserListByName("%m%");

        for (User user : userList) {
            System.out.println(user);
        }

        sqlSession.close();
    }
}

如果报错：

检查maven是否有以下语句不然java文件夹里的xml不会一起导出

    <build>
        <resources>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
        </resources>
    </build>

码农公寓

Mybatis学习

第一步

第二步

第三步

第四步

第五步

第六步

junit测试

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