Mybatis

Mybatis配置

1.新建 maven 项目

2. 打开 pom.xml 编辑

<?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>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
    </properties>

    <groupId>org.example</groupId>
    <artifactId>mybatis</artifactId>
    <version>1.0-SNAPSHOT</version>
    <dependencies>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.19</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.4</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.12</version>
        </dependency>
    </dependencies>

    <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>

 3. 创建 mybatis-config.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.cj.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/newuser?serverTimezone=UTC"/>
                <property name="username" value="root"/>
                <property name="password" value="test1234"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="com/mybatis/dao/UserMapper.xml"/>
    </mappers>
</configuration>

 

4. 创建 Mybatis 工具类

package com.mybatis.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();
    }
}

 

5. 创建实体类

package com.mybatis.pojo;

public class User {

    private long id;
    private String name;
    private String password;
    private String mailbox;
    private String website;


    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }


    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }


    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }


    public String getMailbox() {
        return mailbox;
    }

    public void setMailbox(String mailbox) {
        this.mailbox = mailbox;
    }


    public String getWebsite() {
        return website;
    }

    public void setWebsite(String website) {
        this.website = website;
    }

    @Override
    public String toString() {
        return "{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", password='" + password + '\'' +
                ", mailbox='" + mailbox + '\'' +
                ", website='" + website + '\'' +
                '}';
    }
}

 

6. 创建 Usermapper 接口

package com.mybatis.dao;

import com.mybatis.pojo.User;

import java.util.List;

public interface UserDao {
    List<User> getUserList();
}

7. 创建 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="com.mybatis.dao.UserDao">
    <select id="getUserList" resultType="com.mybatis.pojo.User">
    select * from user
  </select>
</mapper>

 

8.创建测试类

package com.mybatis.dao;

import com.mybatis.pojo.User;
import com.mybatis.utils.mybatisutils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.List;

public class UserDaoTest {
    @Test
    public void test() {
        SqlSession sqlSession = mybatisutils.getSqlSession();

        UserDao mapper = sqlSession.getMapper(UserDao.class);
        List<User> userList = mapper.getUserList();

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

} }

 无法打包xml文件在pom.xml配置

<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>

 增删改需提交事务

sqlSession.commit();

万能Map

1.接口

add(Map<String,Object> map);

2.xml文件

<insert id="add" parameterType="map">
        insert into student (name,password,age,phone)
        values (#{a1},#{a2},#{a3},#{a4})
</insert>

3.测试类

public class myadd {
    @Test
    public void test(){
        SqlSession sqlSession= MybatisUtils.getSqlSession();
        StudentMapper studentMapper=sqlSession.getMapper(StudentMapper.class);
        Map<String,Object> map=new HashMap<String, Object>();
        map.put("a1",1);
        map.put("a2",1);
        map.put("a3",1);
        map.put("a4",1);
        studentMapper.add(map);
        sqlSession.close();
    }
}