使用IDEA搭建mybatis

使用IDEA搭建mybatis

• 建立一个maven项目，导入所需要的依赖

1.mysql依赖
2.mybatis依赖
3.junit依赖
    <dependencies>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.47</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.2</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
        </dependency>
    </dependencies>

• 导入核心配配置文件一般放在resources中 官方给定文件名为 mybatis-config.xml

<?xml version="1.0" encoding="UTF8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">

<!-- configuration核心配置文件-->
<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="xxxxx"/>
                <property name="password" value="xxxxx"/>
            </dataSource>
        </environment>
    </environments>

    <mappers>
    这个是指向下面的dao中的xml 可以参考最下面的目录结构
        <mapper resource="cn/at99guoke/dao/UserMapper.xml"/>
    </mappers>
</configuration>

环境是可以有多套的，但只能使用一个
以防Maven读不到src中的xml、pro文件需要在pom.xml中加入配置

    <build>
        <resources>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.xml</include>
                    使用pro的需要在这个地方再加
                </includes>
                <filtering>true</filtering>
            </resource>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
        </resources>
    </build>

如果没有加会报以下异常

• 编写工具类获取 SqlSession

package cn.at99guoke.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;

public class MybatisUtils {
    private static SqlSessionFactory sqlSessionFactory;
    static {
        String resource = "mybatis-config.xml";
        try {
            InputStream inputStream = Resources.getResourceAsStream(resource);
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }


    public static SqlSession getSqlSession(){
        return sqlSessionFactory.openSession();
    }
}

• 编写Musql对应的实体类添加对应的set、get等方法

package cn.at99guoke.pojo;

public class User {
    private int id;
    private String name;
    private String pwd;

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

    public User() {
    }

    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 + '\'' +
                '}';
    }
}

• 编写接口

package cn.at99guoke.dao;

import cn.at99guoke.pojo.User;

import java.util.List;

public interface UserMapper {
    List<User> getUserMapper();
}

• 编写接口对应的xml文件

<?xml version="1.0" encoding="UTF8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="cn.at99guoke.dao.UserMapper">
    <select id="getUserMapper" resultType="cn.at99guoke.pojo.User">
    select * from User where 1=1
  </select>
</mapper>

• 编写测试

package cn.at99guoke.dao;

import cn.at99guoke.pojo.User;
import cn.at99guoke.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.List;

public class userMapperTses {

    @Test
    public void test01(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        List<User> userMapper = mapper.getUserMapper();
        for (User user : userMapper) {
            System.out.println(user);
        }
        sqlSession.close();

    }
}

• 在测试的时候可能会出现不支持版本5的异常
  

目录结构大概是这个样子的