Mybatis Plus快速入门(一)

1. 环境准备

MySQL环境配置：5.7,可以参考我之前的文章使用docker或者直接安装在服务器上面。新建一张表user,使用Mybatis Plus官网提供表结构和数据。

DROP TABLE IF EXISTS `user`;

CREATE TABLE `user`
(
    id BIGINT NOT NULL COMMENT '主键ID',
    name VARCHAR(30) NULL DEFAULT NULL COMMENT '姓名',
    age INT NULL DEFAULT NULL COMMENT '年龄',
    email VARCHAR(50) NULL DEFAULT NULL COMMENT '邮箱',
    PRIMARY KEY (id)
);

DELETE FROM `user`;

INSERT INTO `user` (id, name, age, email) VALUES
(1, 'Jone', 18, 'test1@baomidou.com'),
(2, 'Jack', 20, 'test2@baomidou.com'),
(3, 'Tom', 28, 'test3@baomidou.com'),
(4, 'Sandy', 21, 'test4@baomidou.com'),
(5, 'Billie', 24, 'test5@baomidou.com');

2.简单介绍

MyBatis-Plus (opens new window)（简称 MP）是一个 MyBatis (opens new window)的增强工具，在 MyBatis 的基础上只做增强不做改变，为简化开发、提高效率而生。

3.开发环境准备

我们使用Spring Boot来快速搭建本次开发环境，父级模块主要用来引入基础包，父级模块中新建Mybtais plus学习子模块，如下：

父级项目pom.xml

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.7.18</version>
    <relativePath/> <!-- lookup parent from repository -->
</parent>

<groupId>com.wyz</groupId>
<artifactId>SpringStudy</artifactId>
<version>1.0</version>

<properties>
    <maven.compiler.source>8</maven.compiler.source>
    <maven.compiler.target>8</maven.compiler.target>
    <jackson.version>2.14.2</jackson.version>
    <mapstruct.version>1.5.5.Final</mapstruct.version>
    <lombok.version>1.18.30</lombok.version>
    <lombok-mapstruct-binding.version>0.2.0</lombok-mapstruct-binding.version>
    <hutool.version>5.8.24</hutool.version>
    <swagger.version>2.9.2</swagger.version>
</properties>
<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
        <scope>runtime</scope>
        <optional>true</optional>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <optional>true</optional>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
        <version>${jackson.version}</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-core</artifactId>
        <version>${jackson.version}</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-annotations</artifactId>
        <version>${jackson.version}</version>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
    </dependency>
    <dependency>
        <groupId>org.mapstruct</groupId>
        <artifactId>mapstruct</artifactId>
        <version>${mapstruct.version}</version>
    </dependency>
    <dependency>
        <groupId>cn.hutool</groupId>
        <artifactId>hutool-all</artifactId>
        <version>${hutool.version}</version>
    </dependency>
    <dependency>
        <groupId>io.springfox</groupId>
        <artifactId>springfox-swagger2</artifactId>
        <version>${swagger.version}</version>
    </dependency>
    <dependency>
        <groupId>io.springfox</groupId>
        <artifactId>springfox-swagger-ui</artifactId>
        <version>${swagger.version}</version>
    </dependency>
</dependencies>



<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
            <configuration>
                <excludes>
                    <exclude>
                        <groupId>org.projectlombok</groupId>
                        <artifactId>lombok</artifactId>
                    </exclude>
                </excludes>
            </configuration>
        </plugin>
        <!-- Maven 编译插件，提供给 MapStruct 使用 -->
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>${maven-compiler-plugin.version}</version>
            <configuration>
                <source>${java.version}</source>
                <target>${java.version}</target>
                <annotationProcessorPaths>
                    <!-- MapStruct 注解处理器 -->
                    <path>
                        <groupId>org.mapstruct</groupId>
                        <artifactId>mapstruct-processor</artifactId>
                        <version>${mapstruct.version}</version>
                    </path>
                    <!-- Lombok 注解处理器 -->
                    <path>
                        <groupId>org.projectlombok</groupId>
                        <artifactId>lombok</artifactId>
                        <version>${lombok.version}</version>
                    </path>
                    <!-- MapStruct 和 Lombok 注解绑定处理器 -->
                    <path>
                        <groupId>org.projectlombok</groupId>
                        <artifactId>lombok-mapstruct-binding</artifactId>
                        <version>${lombok-mapstruct-binding.version}</version>
                    </path>
                </annotationProcessorPaths>
            </configuration>
        </plugin>
    </plugins>
</build>

中间引入了一些其它依赖，比如：序列化（jackson）,工具包(hutool),MapStruct,Lombok,这些工具包在公司实际项目中也是比较常用。

MybatisPlusDemo模块中pom.xml文件如下：

<properties>
    <maven.compiler.source>8</maven.compiler.source>
    <maven.compiler.target>8</maven.compiler.target>
    <mybatis-plus.version>3.5.5</mybatis-plus.version>
    <mysql.version>5.1.49</mysql.version>
    <druid.version>1.2.20</druid.version>
</properties>

<dependencies>
    <dependency>
        <groupId>com.baomidou</groupId>
        <artifactId>mybatis-plus-boot-starter</artifactId>
        <version>${mybatis-plus.version}</version>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>${mysql.version}</version>
    </dependency>
    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid-spring-boot-starter</artifactId>
        <version>${druid.version}</version>
    </dependency>
</dependencies>

配置文件application.yml

server:
  port: 80
spring:
  application:
    name: MybatisPlusDemo
  datasource:
    druid:
      url: jdbc:mysql://localhost:3306/cloud_study?useSSL=false&serverTimezone=UTC&characterEncoding=utf8
      username: root
      password: 123456
      driver-class-name: com.mysql.jdbc.Driver

启动测试：

4.创建实体类和DAO层

@ToString
@Data
@TableName("user")
@ApiModel(value = "UserDO", description = "用户信息对象")
public class UserDO {
    @ApiModelProperty("ID")
    @TableId(type = IdType.AUTO)
    private Long id;

    @ApiModelProperty("姓名")
    @TableField("name")
    private String name;

    @ApiModelProperty("年龄")
    @TableField("age")
    private Integer age;

    @ApiModelProperty("邮箱地址")
    @TableField("email")
    private String email;
}

@Mapper
public interface UserMapper extends BaseMapper<UserDO> {
}

快速测试：

@SpringBootTest
public class MybatisPlusDemoTest {
    @Resource
    private UserMapper userMapper;

    @Test
    public void queryAllTest(){
        List<UserDO> userDOS = userMapper.selectList(null);
        System.out.println(userDOS);
    }
}