mybatis-plus入門筆記

java零基礎自學點擊瞭解:https://how2j.cn?p=81777

目錄

一:數據庫準備

二:創建springboot項目

三:安裝lombok插件

四:配置application.properties文件

五:寫代碼

---

一:數據庫準備

1.創建數據庫

 

create database mybatis_plus;

2.創建table

 

CREATE TABLE user(

    id BIGINT(20) NOT NULL COMMENT '主鍵ID',

    name VARCHAR(30) NULL DEFAULT NULL COMMENT '姓名',

    age INT(11) NULL DEFAULT NULL COMMENT '年齡',

    email VARCHAR(50) NULL DEFAULT NULL COMMENT '郵箱',

    PRIMARY KEY (id)

);

3.導入數據

 

INSERT INTO user(id,name,age,email)VALUES

(1,'Jone',18,'[email protected]'),

(2,'Jack',20,'[email protected]'),

(3,'Tom',28,'[email protected]'),

(4,'Sandy',24,'[email protected]'),

(5,'Billie',30,'[email protected]');

 

二:創建springboot項目

1:創建spring lnitializr形式的springboot項目mpdemo

 

2:複製下面代碼到pom文件

 

<dependencies>

    <dependency>

        <groupId>org.springframework.boot</groupId>

        <artifactId>spring-boot-starter</artifactId>

    </dependency>

​

    <dependency>

        <groupId>org.springframework.boot</groupId>

      <artifactId>spring-boot-starter-test</artifactId>

        <scope>test</scope>

        <exclusions>

            <exclusion>

                <groupId>org.junit.vintage</groupId>

                <artifactId>junit-vintage-engine</artifactId>

            </exclusion>

        </exclusions>

    </dependency>

    <!--mybatis-plus-->

    <dependency>

        <groupId>com.baomidou</groupId>

        <artifactId>mybatis-plus-boot-starter</artifactId>

        <version>3.0.5</version>

    </dependency>

    <!--mysql-->

    <dependency>

        <groupId>mysql</groupId>

        <artifactId>mysql-connector-java</artifactId>

    </dependency>

    <!--lombok用來簡化實體類-->

    <dependency>

        <groupId>org.projectlombok</groupId>

        <artifactId>lombok</artifactId>

   </dependency>

</dependencies>

3:點擊右下方import Change下載依賴

 

三:安裝lombok插件

1:操作步驟:file>seting...>plugins

2:搜索框搜索:lombok

 

3:重啓idea即可

四:配置application.properties文件

1:複製以下內容到.properties文件

 

spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

spring.datasource.url=jdbc:mysql://localhost:3306/mybatis_plus?serverTimezone=GMT%2B8

spring.datasource.username=root

spring.datasource.password=123456

2:修改自己數據量username和password

五:寫代碼

1:創建實體類entity.Uaer

 

import lombok.Data;

​

/**

 * @Author: ZhangDeChen

 * @Date: 2020/6/4 20:28

 */

@Data

public class User {

    private Long id;

    private String name;

    private Integer age;

    private String email;

}

2:創建mapper.UserMapper

 

​

3:在啓動類中添加:@MapperScan("xyz.dechen.mpdemo.mapper")括號中爲項目mapper包的路徑

 

4:在測試類中複製以下代碼,測試.

 

import org.junit.jupiter.api.Test;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.boot.test.context.SpringBootTest;

import xyz.dechen.mpdemo.entity.User;

import xyz.dechen.mpdemo.mapper.UserMapper;

​

import java.util.List;

​

@SpringBootTest

class MpdemoApplicationTests {

    @Autowired

    private UserMapper userMapper;

​

    //查詢user表中的所有數據

    @Test

    public void findAll() {

        List<User> users=userMapper.selectList(null);

        System.out.println(users);

    }

​

}

5:測試成功: