创建表

CREATE TABLE `post` (
    `id` VARCHAR(32) NOT NULL COLLATE 'utf8mb4_unicode_ci',
    `title` VARCHAR(128) NULL DEFAULT NULL COLLATE 'utf8mb4_unicode_ci',
    `content` VARCHAR(512) NULL DEFAULT NULL COLLATE 'utf8mb4_unicode_ci',
    `user_id` VARCHAR(32) NULL DEFAULT NULL COLLATE 'utf8mb4_unicode_ci',
    `create_time` DATETIME NULL DEFAULT NULL,
    PRIMARY KEY (`id`)
)
COLLATE='utf8mb4_unicode_ci'
ENGINE=InnoDB
;

导入数据：

INSERT INTO `post` (`id`, `title`, `content`, `user_id`, `create_time`) VALUES ('1', '如何学习mybatis', '学习mybatis的方法', '10001', '2020-11-08 10:43:40');
INSERT INTO `post` (`id`, `title`, `content`, `user_id`, `create_time`) VALUES ('2', 'java从入门到放弃', 'java的学习方法', '10001', '2020-11-08 13:50:17');
INSERT INTO `post` (`id`, `title`, `content`, `user_id`, `create_time`) VALUES ('3', '面试300问', '准备面试', '10002', '2020-11-08 13:51:15');

创建 Post 实体类

package org.malaoshi.entity;

import java.util.Date;

public class Post {
    private String id;
    private String title;
    private String content;
    private String userId;
    private Date createTime;

    public String getId() {
        return id;
    }

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

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }

    public String getUserId() {
        return userId;
    }

    public void setUserId(String userId) {
        this.userId = userId;
    }

    public Date getCreateTime() {
        return createTime;
    }

    public void setCreateTime(Date createTime) {
        this.createTime = createTime;
    }
}

创建 IPostMapper 接口

package org.malaoshi.mapper;


public interface IPostMapper {

}

创建 postMapper.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="org.malaoshi.mapper.IPostMapper" >

</mapper>

修改 mybatis-config.xml

增加下面代码

<mapper resource="mapper/postMapper.xml"></mapper>

全文是：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD SQL Map Config 3.0//EN"  
    "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>

    <!-- 给实体类起别名 -->
    <typeAliases>
        <package name="org.malaoshi.entity" />
    </typeAliases>
    <!-- 配置环境 。default名字随意起-->
    <environments default="mysql">
    <!--    id名字必须同上面default名    -->
        <environment id="mysql">
            <!-- 配置事务管理器类型，JDBC 是 JdbcTransactionFactory.class 的别名 -->
            <transactionManager type="JDBC"></transactionManager>
            <!-- 配置数据源。POOLED 是 PooledDataSourceFactory.class 的别名 -->
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3308/mybatis"/>
                <property name="username" value="root"/>
                <property name="password" value=""/>
            </dataSource>
        </environment>
    </environments>
<mappers>
    <mapper resource="mapper/userMapper.xml"></mapper>
    <mapper resource="mapper/postMapper.xml"></mapper>
</mappers>

</configuration>

原文出处：/show_1IXG7EgdTX.html