（二）springboot+mybatis plus快速构建项目

r囧r小猫 2022-01-12 09:53 277阅读 0赞

### （二）springboot+mybatis plus快速构建项目 ###

注明：我将通过一个Demo来阐述MyBatis-Plus的强大

我的环境

*  JDK1.8
 *  maven3.5.4
 *  开发工具idea
 *  springboot2.0.5
 *  mybatis-plus3.0.3
 *  mysql5.7

上面是我的环境版本。

[源码下载地址][Link 1]

### 对应的数据库脚本 ###

CREATE TABLE user
    (
    	id BIGINT(20) NOT NULL COMMENT '主键ID',
    	name VARCHAR(30) NULL DEFAULT NULL COMMENT '姓名',
    	age INT(11) NULL DEFAULT NULL COMMENT '年龄',
    	email VARCHAR(50) NULL DEFAULT NULL COMMENT '邮箱',
    	PRIMARY KEY (id)
    );

### 数据库data脚本 ###

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');

数据库准备完成后我们来通过springboot创建初始化一个工程。初始化工程的步骤我就不阐述了，有不知道的小伙伴自行baidu

### pom.xml展示 ###

<?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>com.lqf</groupId>
        <artifactId>springboot-mybatis-plus</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <packaging>jar</packaging>
    
        <name>springboot-mybatis-plus</name>
        <description>Demo project for Spring Boot</description>
    
        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>2.0.5.RELEASE</version>
            <relativePath/> 
        </parent>
    
        <properties>
            <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
            <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
            <java.version>1.8</java.version>
        </properties>
    
        <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>
            </dependency>
    
            
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
    
            
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <optional>true</optional>
            </dependency>
    
            
            <dependency>
                <groupId>com.baomidou</groupId>
                <artifactId>mybatis-plus-boot-starter</artifactId>
                <version>3.0.3</version>
            </dependency>
    
            
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-jdbc</artifactId>
            </dependency>
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <scope>runtime</scope>
            </dependency>
        </dependencies>
    
        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>
            </plugins>
        </build>
    
    
    </project>

### 注意 ###

引入 MyBatis-Plus 之后请不要再次引入 MyBatis 以及 MyBatis-Spring，以避免因版本差异导致的问题。
    如果springboot版本是SNAPSHOT快照版还需要添加仓库
    <repository>
        <id>snapshots</id>
        <url>https://oss.sonatype.org/content/repositories/snapshots/</url>
    </repository>

### applicaiton.yml配置 ###

# DataSource Config
    spring:
      datasource:
        driver-class-name: com.mysql.jdbc.Driver
        url: jdbc:mysql://******:3306/crm
        username: ****
        password: ****

数据库连接换成自己的就可以

### 在 Spring Boot 启动类中添加 @MapperScan 注解，扫描 Mapper 文件夹 ###

@MapperScan()内容填写你自己的mapper位置

package com.lqf.springbootmybatisplus;
    
    import org.mybatis.spring.annotation.MapperScan;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    
    @SpringBootApplication
    @MapperScan("com.lqf.springbootmybatisplus.dao.mapper")
    public class SpringbootMybatisPlusApplication { 
    
        public static void main(String[] args) { 
            SpringApplication.run(SpringbootMybatisPlusApplication.class, args);
        }
    }

### 对应数据库实体类编写 ###

@Data注解会给此类默认提供Getter,Setter,equals,hashCode,toString方法

@Data
    public class User { 
        private Long id;
        private String name;
        private Integer age;
        private String email;
    }

### 编写Mapper类 UserMapper.java ###

public interface UserMapper extends BaseMapper<User> { 
    
    }

### 测试类 ###

package com.lqf.springbootmybatisplus;
    
    import com.lqf.springbootmybatisplus.dao.mapper.UserMapper;
    import com.lqf.springbootmybatisplus.domain.entity.User;
    import org.junit.Assert;
    import org.junit.Test;
    import org.junit.runner.RunWith;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.boot.test.context.SpringBootTest;
    import org.springframework.test.context.junit4.SpringRunner;
    
    import java.util.List;
    
    @RunWith(SpringRunner.class)
    @SpringBootTest
    public class SpringbootMybatisPlusApplicationTests { 
    
        @Autowired
        private UserMapper userMapper;
    
        @Test
        public void testSelect() { 
            System.out.println(("----- selectAll method test ------"));
            List<User> userList = userMapper.selectList(null);
            Assert.assertEquals(5, userList.size());
            userList.forEach(System.out::println);
        }
    
    }

### 测试结果 ###

----- selectAll method test ------
    User(id=1, name=Jone, age=18, email=test1@baomidou.com)
    User(id=2, name=Jack, age=20, email=test2@baomidou.com)
    User(id=3, name=Tom, age=28, email=test3@baomidou.com)
    User(id=4, name=Sandy, age=21, email=test4@baomidou.com)
    User(id=5, name=Billie, age=24, email=test5@baomidou.com)

到这里一个简单的springboot+mybatis-plus就整合完成了，你会发现没有写mapper.xml，mapper.java中什么也没有。对的你没看错，这只是mybatis-plus的冰山一角，让我们看他后续的强大功能吧

转自：[https://blog.csdn.net/m0\_37034294/article/details/82892981][https_blog.csdn.net_m0_37034294_article_details_82892981]

[Link 1]: https://gitee.com/v_soul/springboot-mybatis-plus
[https_blog.csdn.net_m0_37034294_article_details_82892981]: https://blog.csdn.net/m0_37034294/article/details/82892981