01 mybatis开发步骤

最新推荐文章于 2025-01-12 10:02:06 发布

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本文详细介绍了如何在Maven项目中添加MyBatis的依赖，包括MySQL驱动和MyBatis本身。创建了`test_user`数据表，并展示了User实体类的定义。接着，提供了UserMapper.xml的映射文件，包含了查询所有用户的操作。最后，给出了核心配置文件sqlMapConfig.xml的配置，包括数据源连接和映射文件加载。在测试类中，实现了查询所有用户的功能。

添加MyBatis的坐标

pom.xml

主要是mysql及mybatis坐标

<?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>

    <groupId>chen.li.com</groupId>
    <artifactId>itheima_mybatis_quick</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.32</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.6</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>1.2.17</version>
        </dependency>
    </dependencies>


</project>

创建user数据表

CREATE TABLE test_user (	
	id INT ( 18 ) PRIMARY KEY auto_increment,-- 给id添加主键约束，并且主键自增长	
	userName VARCHAR ( 12 ),
	passWord INT(20),
	phone INT(11))

编写User实体类

package li.chen.com.business.entity;
public class User {   
    private Integer id;    
    private String userName;    
    private String passWord;    
    private String phone;    
    public Integer getId() {        
        return id;    
    }   
    public void setId(Integer id) {       
        this.id = id;    
    }    
    public String getUserName() {        
        return userName;   
    }   
    public void setUserName(String userName) {       
        this.userName = userName;    
    }    
    public String getPassWord() {       
        return passWord;   
    }    
    public void setPassWord(String passWord) {       
        this.passWord = passWord;    
    }    
    public String getPhone() {      
        return phone;    
    }    
    public void setPhone(String phone) {        
        this.phone = phone;   
    }    
    @Override   
    public String toString() {       
        return "User{" +               
            "id=" + id +              
            ", userName='" + userName + '\'' +              
            ", passWord='" + passWord + '\'' +              
            ", phone='" + phone + '\'' +               
            '}';  
    }
}

编写映射文件UserMapper.xml

对User表的增删改查操作
在 resource 文件下创建li.chen.com.mipper 目录，再创建普通文件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="userMapper">

    <!--查询操作 resultType 查询结果给他-->
    <select id="findAll" resultType="li.chen.com.business.entity.User">
        select * from test_user
    </select>

</mapper>

编写核心文件sqlMapConfig.xml

连接数据源，配置映射文件

<?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>
    <!--配置数据源环境-->
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/db1"/>
                <property name="username" value="root"/>
                <property name="password" value="root"/>

            </dataSource>
        </environment>
    </environments>

    <!--加载映射文件-->
    <mappers>
        <mapper resource="li.chen.com.mapper\UserMapper.xml"/>
    </mappers>

</configuration>

编写测试类

查询操作

import li.chen.com.business.entity.User;
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 org.junit.Test;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

public class MyBatisTest {

    //查询操作
    @Test
    public void test1() throws IOException {
        //获得核心配置文件
        InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");

        //获得session工厂对象
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);

        //获得session会话对象
        SqlSession sqlSession = sqlSessionFactory.openSession();

        //执行操作 参数：namespace+id
        List<User> userList = sqlSession.selectList("userMapper.findAll");

        //打印数据
        System.out.println(userList);

        //释放资源
        sqlSession.close();

    }

}