使用maven mybatis generator自动生成mybatis实体以及查询代码 mapper代码详细教程

mybatis-generator-maven-plugin是mybatis 官方发布的maven插件,能够自动生成代码,在项目开发前期设计完数据库库后,需要大量编写实体类,使用maven插件省时省力,快速高效,来看看怎么自动生成代码.
码云参考代码下载地址:下载
在实验过多个idea第三方插件后尝试无果,最终还是选择官方maven插件,成功插入数据.mabatis官方文档地址能不能打开看缘分,来看看详细的使用教程吧.

1. 在pom文件中引入pom插件,引入dependency和plugin

<?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 https://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>2.2.6.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.springboot</groupId>
    <artifactId>blog</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>blog</name>
    <description>Spring Boot blog</description>

    <properties>
        <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>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>

        <!--mysql数据库驱动-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>

        <!--mybatis-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.2</version>
        </dependency>

        <dependency>
            <groupId>org.mybatis.generator</groupId>
            <artifactId>mybatis-generator-core</artifactId>
            <version>1.4.0</version>
        </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>1.4.0</version>
                <executions>
                    <execution>
                        <id>Generate MyBatis Artifacts</id>
                        <goals>
                            <goal>generate</goal>
                        </goals>
                    </execution>
                </executions>
                <dependencies>
                    <dependency>
                        <groupId>mysql</groupId>
                        <artifactId>mysql-connector-java</artifactId>
                        <version>8.0.19</version>
                    </dependency>
                </dependencies>
            </plugin>
        </plugins>
    </build>
</project>

2. 编写配置文件generatorConfig.xml

在resources目录下新建配置文件generatorConfig.xml编写数据库映射配置,包括需要映射的文件目录,以及需要映射的数据库表.来看下我的配置.

<?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="testTables" targetRuntime="MyBatis3Simple">
        <commentGenerator>
            <!-- 是否去除自动生成的注释 true：是 ： false:否 -->
            <property name="suppressAllComments" value="true" />
        </commentGenerator>
        <!--数据库连接的信息：驱动类、连接地址、用户名、密码 -->
        <jdbcConnection driverClass="com.mysql.cj.jdbc.Driver"
                        connectionURL="jdbc:mysql://127.0.0.1/springboot?serverTimezone=UTC&amp;nullCatalogMeansCurrent=true" userId="root"
                        password="root">
        </jdbcConnection>

        <!-- 默认false，把JDBC DECIMAL 和 NUMERIC 类型解析为 Integer，为 true时把JDBC DECIMAL 和
            NUMERIC 类型解析为java.math.BigDecimal -->
        <javaTypeResolver>
            <property name="forceBigDecimals" value="false" />
        </javaTypeResolver>

        <!-- targetProject:生成PO类的位置 -->
        <javaModelGenerator targetPackage="com.springboot.blog.entity"
                            targetProject="./src/main/java">
            <!-- enableSubPackages:是否让schema作为包的后缀 -->
            <property name="enableSubPackages" value="false" />
            <!-- 从数据库返回的值被清理前后的空格 -->
            <property name="trimStrings" value="true" />
        </javaModelGenerator>
        <!-- targetProject:mapper映射文件生成的位置xml -->
        <sqlMapGenerator targetPackage="mapping"
                         targetProject="./src/main/resources">
            <!-- enableSubPackages:是否让schema作为包的后缀 -->
            <property name="enableSubPackages" value="false" />
        </sqlMapGenerator>
        <!-- targetPackage：mapper接口生成的位置 -->
        <javaClientGenerator type="XMLMAPPER"
                             targetPackage="com.springboot.blog.mapper"
                             targetProject="./src/main/java">
            <!-- enableSubPackages:是否让schema作为包的后缀 -->
            <property name="enableSubPackages" value="false" />
        </javaClientGenerator>
        <!-- 指定数据库表 -->
        <table schema="springboot" tableName="article"></table>
        <table schema="springboot" tableName="article_tag"></table>
        <table schema="springboot" tableName="blogroll"></table>
        <table schema="springboot" tableName="category"></table>
        <table schema="springboot" tableName="comment"></table>
        <table schema="springboot" tableName="nav"></table>
        <table schema="springboot" tableName="tag"></table>
        <!-- 有些表的字段需要指定java类型
         <table schema="" tableName="">
            <columnOverride column="" javaType="" />
        </table> -->
    </context>
</generatorConfiguration>

3. 执行maven命令生成代码

执行mvn -Dmybatis.generator.overwrite=true mybatis-generator:generate生成代码,或者直接点击生成代码

4. 执行成功结果

等待执行成功后,会生成相应的文件,包括实体,mapper以及xml配置,

5.测试生成的代码是否可用.

以文章为例,我们再数据库中手动插入一条测试数据.
然后找到mapper/ArticleMapper 在类上添加@Mapper注解,自动生成的代码不带注解.

6.编写测试articleservice以及impl实现类是否可用.

public interface ArticleService {
    int deleteByPrimaryKey(Integer id);

    int insert(Article record);

    Article selectByPrimaryKey(Integer id);

    List<Article> selectAll();

    int updateByPrimaryKey(Article record);
}

@Service
public class ArticleServiceImpl implements ArticleService {
    @Resource//@Autowired或者使用
    private ArticleMapper mapper;

    @Override
    public int deleteByPrimaryKey(Integer id) {
        return 0;
    }

    @Override
    public int insert(Article record) {
        return 0;
    }

    @Override
    public Article selectByPrimaryKey(Integer id) {
        return mapper.selectByPrimaryKey(id);
    }

    @Override
    public List<Article> selectAll() {
        return null;
    }

    @Override
    public int updateByPrimaryKey(Article record) {
        return 0;
    }
}

7.编写测试articlecontroller.

@RestController
@RequestMapping("article")
public class ArticleController {

    @Autowired
    private ArticleService service;

    /**
     * 通过主键查询单条数据
     *
     * @param id 主键
     * @return 单条数据
     */
    @GetMapping("selectOne")
    public Article selectOne(Integer id) {
        return this.service.selectByPrimaryKey(id);
    }
}

请求地址:http://127.0.0.1:8080/article/selectOne?id=1

请求成功.