使用通用 Mapper 依据数据表生成实体类

使用 mappergenerator 可以很方便生成实体类，Mapper 接口以及对应的 XML 文件，不再手写。

以下使用 Spring boot，MySQL 以及 tk.mybatis

设计数据表

该 tabple_emp 表中有 4 个字段

CREATE TABLE `tabple_emp` (
  `emp_id` int(11) NOT NULL AUTO_INCREMENT,
  `emp_name` varchar(500) DEFAULT NULL,
  `emp_salary` double(15,5) DEFAULT NULL,
  `emp_age` int(11) DEFAULT NULL,
  PRIMARY KEY (`emp_id`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8

创建 SpringBoot 项目并引入tk.mybatis

以下是部分依赖，主要是引入了 tk.mybatis，与配置代码生成器

 <dependencies>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.1</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <!-- 引入依赖 -->
        <dependency>
            <groupId>tk.mybatis</groupId>
            <artifactId>mapper</artifactId>
            <version>4.1.5</version>
        </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>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <plugin>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>${java.version}</source>
                    <target>${java.version}</target>
                </configuration>
            </plugin>
            <!-- 生成器的配置 -->
            <plugin>
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-maven-plugin</artifactId>
                <version>1.3.6</version>
                <configuration>
                	<!-- 生成器所需的配置文件路径 -->
                    <configurationFile>
                        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>5.1.29</version>
                    </dependency>
                    <dependency>
                        <groupId>tk.mybatis</groupId>
                        <artifactId>mapper</artifactId>
                        <version>4.0.0</version>
                    </dependency>
                </dependencies>
            </plugin>
        </plugins>
    </build>
</project>

配置 generatorConfig.xml 与 config.properties

在上面 pom.xml 中设置的目录中，放置以下文件

generatorConfig.xml

该配置文件指定了将要生成的 model，mapper，与 mapper xml 的存放路径

<!DOCTYPE generatorConfiguration
        PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
        "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">

<generatorConfiguration>
    <properties resource="config.properties"/>

    <context id="Mysql" targetRuntime="MyBatis3Simple" defaultModelType="flat">
        <property name="beginningDelimiter" value="`"/>
        <property name="endingDelimiter" value="`"/>

        <plugin type="tk.mybatis.mapper.generator.MapperPlugin">
            <property name="mappers" value="tk.mybatis.mapper.common.Mapper"/>
            <property name="caseSensitive" value="true"/>
        </plugin>

        <jdbcConnection driverClass="${jdbc.driverClass}"
                        connectionURL="${jdbc.url}"
                        userId="${jdbc.user}"
                        password="${jdbc.password}">
        </jdbcConnection>

        <javaModelGenerator targetPackage="cn.duniqb.mappermbg.model"
                            targetProject="src/main/java"/>

        <sqlMapGenerator targetPackage="mapper"
                         targetProject="src/main/resources"/>

        <javaClientGenerator targetPackage="cn.duniqb.mappermbg.mapper"
                             targetProject="src/main/java"
                             type="XMLMAPPER"/>

		<!-- 数据库中数据表的名字 -->
        <table tableName="tabple_emp">
            <generatedKey column="id" sqlStatement="JDBC"/>
        </table>
    </context>
</generatorConfiguration>

config.properties

该配置文件指定了数据库的连接属性

# Database connection information
jdbc.driverClass=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://192.168.71.136:3306/test?useUnicode=true&characterEncoding=utf8
jdbc.user=root
jdbc.password=root
#c3p0
jdbc.maxPoolSize=50
jdbc.minPoolSize=10
jdbc.maxStatements=100
jdbc.testConnection=true
# mapper
mapper.plugin=tk.mybatis.mapper.generator.MapperPlugin
mapper.Mapper=tk.mybatis.mapper.common.Mapper

开始生成

单击 Maven 窗口的 mybatis-generator:generate 即可运行生成出目标代码。