SpringBoot集成MyBatis及使用mybatis-generator-plugin生成代码(完美，步骤巨详细)

以你之姓@ 2022-03-28 13:59 408阅读 0赞

> 该文主要记录SpringBoot集成MyBatis框架，以及如何使用mybatis-generator插件生成pojo、mapper等文件。中间踩坑无数，不过最终经过各种Google后还是搭建起来了，step by step。

### 文章目录 ###

*   *   *  一、新建项目
         *  二、\`pom.xml\`
         *   *  2.1 添加连接池依赖
             *  2.2 添加\`mybatis-generator\`插件及相关依赖
             *  2.3 \`pom.xml\`完整版
         *  三、\`application.properties\`或\`application.yml\`配置
         *  四、\`mybatis-generator\`插件配置
         *   *  4.1 \`generatorConfig.xml\`配置
             *  4.2 创建\`mybatis-generator\`命令快捷方式
         *  五、数据库相关
         *   *  5.1 创建数据库
             *  5.2 创建表
         *  六、执行\`generate\`，生成\`pojo\`及\`mapper\`
         *  七、编写\`Controller\`、\`Service\`
         *   *  7.1 编写\`Service\`
             *  7.2 新建\`controller\`
         *  九、启动测试
         *   *  9.1 启动应用
             *  9.2 访问\`controller\`映射的方法
         *  十、大功告成

### 一、新建项目 ###

新建步骤没啥好说的，直接上图，按照顺序来即可。  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTAzNTgxNjg_size_16_color_FFFFFF_t_70]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTAzNTgxNjg_size_16_color_FFFFFF_t_70 1]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTAzNTgxNjg_size_16_color_FFFFFF_t_70 2]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTAzNTgxNjg_size_16_color_FFFFFF_t_70 3]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTAzNTgxNjg_size_16_color_FFFFFF_t_70 4]

需要注意的是，除了引入`web`依赖外，还引入了`MyBatis`和`MySQL`依赖。

### 二、`pom.xml` ###

#### 2.1 添加连接池依赖 ####

该示例数据库连接池使用阿里的`durid`，其好处就不多说了，集合了所有连接池的好处，并且还提供了监控等功能，加大了可扩展性等等。

<dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>druid-spring-boot-starter</artifactId>
                <version>1.1.1</version>
            </dependency>

#### 2.2 添加`mybatis-generator`插件及相关依赖 ####

此处，除了需要添加`mybatis-generator-maven-plugin`插件外，还需要添加`mysql-connector`及`mybatis-generator-core`等依赖，方面后面再使用插件生成`pojo`和`mapper`文件时使用。如下：

<plugin>
                    <groupId>org.mybatis.generator</groupId>
                    <artifactId>mybatis-generator-maven-plugin</artifactId>
                    <version>1.3.2</version>
                    <configuration>
                        <configurationFile>${basedir}/src/main/resources/generator/generatorConfig.xml</configurationFile>
                        <overwrite>true</overwrite>
                        <verbose>true</verbose>
                    </configuration>
                    
                    <dependencies>
                        <dependency>
                            <groupId>mysql</groupId>
                            <artifactId>mysql-connector-java</artifactId>
                            <version>5.1.34</version>
                        </dependency>
                        <dependency>
                            <groupId>org.mybatis.generator</groupId>
                            <artifactId>mybatis-generator-core</artifactId>
                            <version>1.3.2</version>
                        </dependency>
                    </dependencies>
                </plugin>

#### 2.3 `pom.xml`完整版 ####

<?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>
        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>2.1.1.RELEASE</version>
            <relativePath/> 
        </parent>
        <groupId>com.happy.video</groupId>
        <artifactId>small_video</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <name>small_video</name>
        <description>Demo project for Spring Boot</description>
    
        <properties>
            <java.version>1.8</java.version>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>1.3.2</version>
            </dependency>
            
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <scope>runtime</scope>
            </dependency>
            
            
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>druid-spring-boot-starter</artifactId>
                <version>1.1.1</version>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </dependency>
        </dependencies>
    
        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>
                
                <plugin>
                    <groupId>org.mybatis.generator</groupId>
                    <artifactId>mybatis-generator-maven-plugin</artifactId>
                    <version>1.3.2</version>
                    <configuration>
                        <configurationFile>${basedir}/src/main/resources/generator/generatorConfig.xml</configurationFile>
                        <overwrite>true</overwrite>
                        <verbose>true</verbose>
                    </configuration>
                    
                    <dependencies>
                        <dependency>
                            <groupId>mysql</groupId>
                            <artifactId>mysql-connector-java</artifactId>
                            <version>5.1.34</version>
                        </dependency>
                        <dependency>
                            <groupId>org.mybatis.generator</groupId>
                            <artifactId>mybatis-generator-core</artifactId>
                            <version>1.3.2</version>
                        </dependency>
                    </dependencies>
                </plugin>
            </plugins>
        </build>
    
    </project>

### 三、`application.properties`或`application.yml`配置 ###

接下来就需要对`application`进行相关设置了，此处以`application.yml`为例，其与`.properties`配置项没区别，只不过语法稍微不一样而已。

此处不再一一展开，直接上配置文件，相关配置都有注释，可自行阅读：

# 设置端口
    server:
      port: 8080
    
    # 设置数据源
    spring:
      datasource:
        url: jdbc:mysql://localhost:3306/sb_mbg_demo
        username: root
        password: root
        # 连接池类型
        type: com.alibaba.druid.pool.DruidDataSource
        # 驱动
        driver-class-name: com.mysql.jdbc.Driver
        # 连接池配置
        druid:
          # 最小数
          min-idle: 5
          # 最大数
          max-active: 20
          # 初始大小
          initial-size: 5
          # 配置获取连接等待超时时间
          max-wait: 6000
          # 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒
          time-between-eviction-runs-millis: 60000
          # 配置一个连接在池中最小生存时间  单位为毫秒
          min-evictable-idle-time-millis: 300000
          validation-query: SELECT 1 FROM DUAL
          test-while-idle: true
          test-on-borrow: false
          test-on-return: false
          # 打开 PSCache，并且指定每个连接上PSCache的大小
          pool-prepared-statements: true
          max-pool-prepared-statement-per-connection-size: 20
          # 配置监控统计拦截的filters，去掉后监控界面sql无法统计，wall用于防火墙
          filters: stat,wall
    
    # 配置mybatis
    mybatis:
      mapper-locations: classpath:mappers/*.xml
      # 全局的映射，不用在xml文件写实体类的全路径
      type-aliases-package: com.happy.video.pojo
      configuration:
        # 开启驼峰映射
        map-underscore-to-camel-case: true

### 四、`mybatis-generator`插件配置 ###

#### 4.1 `generatorConfig.xml`配置 ####

不知道是否还记得在`pom.xml`中`mybatis-generator-plugin`中有过这样配置

<configurationFile>${basedir}/src/main/resources/generator/generatorConfig.xml</configurationFile>

其实这个就是其配置文件，根据配置，在`resources`目录下新建`generator`文件夹，并新建`generatorConfig.xml`配置文件。

该配置文件主要描述如下信息：数据库连接配置、类型转换、生成模型的包名及位置、生成映射文件的包名及位置、生成mapper文件的包名及位置、要生成的表等。

废话不多说，直接上代码，具体都有注释，可自行阅读：

<?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE generatorConfiguration
            PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
            "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">
    
    <generatorConfiguration>
        <context id="DB2Tables" targetRuntime="MyBatis3">
    
            <commentGenerator>
                <property name="suppressDate" value="true"/>
                
                <property name="suppressAllComments" value="true"/>
            </commentGenerator>
    
            
            <jdbcConnection driverClass="com.mysql.jdbc.Driver"
                            connectionURL="jdbc:mysql://localhost:3306/sb_mbg_demo"
                            userId="root"
                            password="root">
            </jdbcConnection>
    
            
            <javaTypeResolver>
                
                <property name="forceBigDecimals" value="false"/>
            </javaTypeResolver>
    
            
            <javaModelGenerator targetPackage="com.happy.video.pojo" targetProject="src/main/java">
                <property name="enableSubPackages" value="true"/>
                <property name="trimStrings" value="true"/>
            </javaModelGenerator>
    
            
            <sqlMapGenerator targetPackage="mappers" targetProject="src/main/resources">
                <property name="enableSubPackages" value="true"/>
            </sqlMapGenerator>
    
            
            <javaClientGenerator type="XMLMAPPER" targetPackage="com.happy.video.mapper" targetProject="src/main/java">
                <property name="enableSubPackages" value="true"/>
            </javaClientGenerator>
    
            
            <table tableName="user" domainObjectName="User" enableCountByExample="false" enableUpdateByExample="false"
                   enableDeleteByExample="false" enableSelectByExample="false" selectByExampleQueryId="false">
                <property name="useActualColumnNames" value="false"/>
                
                <generatedKey column="id" sqlStatement="Mysql" identity="true"/>
            </table>
        </context>
    
    </generatorConfiguration>

#### 4.2 创建`mybatis-generator`命令快捷方式 ####

该步骤是为了方便在后续直接通过运行命令方式来操作生成`mapper`、`pojo`等，就像运行`application`一样。

操作步骤如下：

![在这里插入图片描述][20190110174849904.png]

选中`Edit Configurations`，打开如下窗口：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTAzNTgxNjg_size_16_color_FFFFFF_t_70 5]

如果此处没有`Maven`条目，需要点击右上角`加号`，选中`Maven`：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTAzNTgxNjg_size_16_color_FFFFFF_t_70 6]

在右侧`Command line`中输入命令`mybatis-generator:generate -e`，并设置其`Name`，如下：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTAzNTgxNjg_size_16_color_FFFFFF_t_70 7]

此时，设置完成，点击`OK`即可。

### 五、数据库相关 ###

#### 5.1 创建数据库 ####

CREATE DATABASE sb_myb_demo charset utf8;

#### 5.2 创建表 ####

CREATE TABLE user(
      user_id INT NOT NULL PRIMARY KEY AUTO_INCREMENT,
      user_name VARCHAR(255) NOT NULL ,
      password VARCHAR(255) NOT NULL ,
      phone VARCHAR(255) NOT NULL
    ) ENGINE=INNODB AUTO_INCREMENT=1000 DEFAULT CHARSET=utf8;

### 六、执行`generate`，生成`pojo`及`mapper` ###

执行之前设置的`generate`命令，运行结果如下：

/Library/Java/JavaVirtualMachines/jdk1.8.0_111.jdk/Contents/Home/bin/java -Dmaven.multiModuleProjectDirectory=/Users/zhonglongquan/Project/IdeaProjects "-Dmaven.home=/Applications/IntelliJ IDEA.app/Contents/plugins/maven/lib/maven3" "-Dclassworlds.conf=/Applications/IntelliJ IDEA.app/Contents/plugins/maven/lib/maven3/bin/m2.conf" -Didea.launcher.port=7536 "-Didea.launcher.bin.path=/Applications/IntelliJ IDEA.app/Contents/bin" -Dfile.encoding=UTF-8 -classpath "/Applications/IntelliJ IDEA.app/Contents/plugins/maven/lib/maven3/boot/plexus-classworlds-2.5.2.jar:/Applications/IntelliJ IDEA.app/Contents/lib/idea_rt.jar" com.intellij.rt.execution.application.AppMain org.codehaus.classworlds.Launcher -Didea.version=2016.3.5 mybatis-generator:generate -e
    [INFO] Error stacktraces are turned on.
    [INFO] Scanning for projects...
    [INFO]                                                                         
    [INFO] ------------------------------------------------------------------------
    [INFO] Building small_video 0.0.1-SNAPSHOT
    [INFO] ------------------------------------------------------------------------
    [INFO] 
    [INFO] --- mybatis-generator-maven-plugin:1.3.2:generate (default-cli) @ small_video ---
    [INFO] Connecting to the Database
    [INFO] Introspecting table user
    log4j:WARN No appenders could be found for logger (org.mybatis.generator.internal.db.DatabaseIntrospector).
    log4j:WARN Please initialize the log4j system properly.
    log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
    [INFO] Generating Record class for table user
    [INFO] Generating Mapper Interface for table user
    [INFO] Generating SQL Map for table user
    [INFO] Saving file UserMapper.xml
    [INFO] Saving file User.java
    [INFO] Saving file UserMapper.java
    [WARNING] Column id, specified as an identity column in table user, does not exist in the table.
    [WARNING] Existing file /Users/***/Project/IdeaProjects/small_video/src/main/java/com/happy/video/pojo/User.java was overwritten
    [WARNING] Existing file /Users/***/Project/IdeaProjects/small_video/src/main/java/com/happy/video/mapper/UserMapper.java was overwritten
    [INFO] ------------------------------------------------------------------------
    [INFO] BUILD SUCCESS
    [INFO] ------------------------------------------------------------------------
    [INFO] Total time: 1.279 s
    [INFO] Finished at: 2019-01-10T17:56:32+08:00
    [INFO] Final Memory: 15M/155M
    [INFO] ------------------------------------------------------------------------
    
    Process finished with exit code 0

然后查看项目，发现`mapper`、`pojo`等已经生成好，并且生成了相关CRUD方法，如图:  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTAzNTgxNjg_size_16_color_FFFFFF_t_70 8]

生成代码就不在此罗列了，可自行尝试或者查看文章尾部的示例。

### 七、编写`Controller`、`Service` ###

#### 7.1 编写`Service` ####

新建`service`包及`UserService`接口，此处偷懒，直接复制`UserMapper`的方法了，内容如下：

package com.happy.video.service;
    
    import com.happy.video.pojo.User;
    
    /**
     * Created by *** on 2019/1/10.
     */
    public interface UserService {
        int deleteByPrimaryKey(Integer userId);
    
        int insert(User record);
    
        int insertSelective(User record);
    
        User selectByPrimaryKey(Integer userId);
    
        int updateByPrimaryKeySelective(User record);
    
        int updateByPrimaryKey(User record);
    }

在`service`包下新建`impl`包及`UserServiceImpl`类，如下：

package com.happy.video.service.impl;
    
    import com.happy.video.mapper.UserMapper;
    import com.happy.video.pojo.User;
    import com.happy.video.service.UserService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    
    /**
     * Created by *** on 2019/1/10.
     */
    @Service
    public class UserServiceImpl implements UserService {
    
        @Autowired
        private UserMapper userMapper;
    
        @Override
        public int deleteByPrimaryKey(Integer userId) {
            return userMapper.deleteByPrimaryKey(userId);
        }
    
        @Override
        public int insert(User record) {
            return userMapper.insert(record);
        }
    
        @Override
        public int insertSelective(User record) {
            return userMapper.insertSelective(record);
        }
    
        @Override
        public User selectByPrimaryKey(Integer userId) {
            return userMapper.selectByPrimaryKey(userId);
        }
    
        @Override
        public int updateByPrimaryKeySelective(User record) {
            return userMapper.updateByPrimaryKeySelective(record);
        }
    
        @Override
        public int updateByPrimaryKey(User record) {
            return userMapper.updateByPrimaryKey(record);
        }
    }

此时，注入的`userMapper`会报错，无视即可。

#### 7.2 新建`controller` ####

新建`controller`及`UserController`类，如下：

package com.happy.video.controller;
    
    import com.happy.video.pojo.User;
    import com.happy.video.service.impl.UserServiceImpl;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    /**
     * Created by *** on 2019/1/10.
     */
    @RestController()
    @RequestMapping("/user")
    public class UserController {
    
        @Autowired
        private UserServiceImpl userService;
    
        @RequestMapping("index")
        public String index() {
            return "hello user";
        }
    
        @RequestMapping("/queryUserById")
        public User selectUserById(int id) {
            System.out.println("id:" + id);
            User user = userService.selectByPrimaryKey(id);
            System.out.println(user.toString());
            return user;
        }
    
    }

八、`SpringBootApplication`入口类设置

在应用入口类添加`@MapperScan`注解，并指定要扫描的包，此处如果不加的话，需要在自动生成的`mapper`类中，添加`@Mapper`注解，这样就添加的太繁琐，建议使用`@MapperScan`注解的形式。

修改后的`SmallVideoApplication.java`内容如下：

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

### 九、启动测试 ###

#### 9.1 启动应用 ####

执行入口类的`main`方法，启动应用

#### 9.2 访问`controller`映射的方法 ####

之前在`UserController`中，添加了查询用户`queryUserById`的方法，那就来访问一下吧，在浏览器访问链接为：`http://localhost:8080/user/queryUserById?id=1`  
(之前偷偷在数据库添加了一条记录)  
显示结果如下：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTAzNTgxNjg_size_16_color_FFFFFF_t_70 9]

### 十、大功告成 ###

到此，SpringBoot集成Mybatis以及使用`mybatis-generator`插件生成`mapper`、`pojo`等已经完成，不得不说该插件大大减少了我们的工作量，爽的一批。

示例工程可以直接下载：[点我直达][Link 1]

如有问题，欢迎留言

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[20190110174849904.png]: /images/20220328/f96fc1d351884ba7b283726d981e463e.png
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[Link 1]: https://download.csdn.net/download/u010358168/10909393