mybatis-generator自动生成代码

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1.场景分析

在实际项目中，很多寻常的逻辑，例如：数据库表的增，删，改，查；这些徒手写确实有些费人力又费时间，今天笔者向大家介绍自动生成代码的插件：mybatis-generator

2.实现步骤

①在pom.xml中配置generator插件

<build>    <plugins>        <!-- Package the project as an executable jar -->        <plugin>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-maven-plugin</artifactId>            <!-- Set the character encoding for the JVM -->            <configuration>                <jvmArguments>-Dfile.encoding=UTF-8</jvmArguments>            </configuration>        </plugin>        <!--代码生成-->        <plugin>            <groupId>org.mybatis.generator</groupId>            <artifactId>mybatis-generator-maven-plugin</artifactId>            <version>1.3.5</version>            <dependencies>                <dependency>                    <groupId> mysql</groupId>                    <artifactId> mysql-connector-java</artifactId>                    <version> ${mysql-connector-java.version}</version>                </dependency>                <dependency>                    <groupId>org.mybatis.generator</groupId>                    <artifactId>mybatis-generator-core</artifactId>                    <version>1.3.5</version>                </dependency>            </dependencies>            <executions>                <execution>                    <id>Generate MyBatis Artifacts</id>                    <phase>package</phase>                    <goals>                        <goal>generate</goal>                    </goals>                </execution>            </executions>            <configuration>                <!--允许移动生成的文件 -->                <verbose>true</verbose>                <!-- 是否覆盖 -->                <overwrite>true</overwrite>                <!-- 自动生成的配置 -->                <configurationFile>                    src/main/resources/mybatis-generator.xml</configurationFile>            </configuration>        </plugin>    </plugins></build>

②在src/main/resources下创建mybatis-generator.xml

<?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>        <!--数据库链接地址账号密码-->        <jdbcConnection driverClass="com.mysql.jdbc.Driver"                         connectionURL="jdbc:mysql://127.0.0.1:3306/permission" userId="root" password="root">        </jdbcConnection>        <javaTypeResolver>            <property name="forceBigDecimals" value="false"/>        </javaTypeResolver>        <!--生成Model类存放位置-->        <javaModelGenerator targetPackage="com.zhangxing.model" targetProject="src/main/java">            <property name="enableSubPackages" value="true"/>            <property name="trimStrings" value="true"/>        </javaModelGenerator>        <!--生成映射文件存放位置-->        <sqlMapGenerator targetPackage="mapper" targetProject="src/main/resources">            <property name="enableSubPackages" value="true"/>        </sqlMapGenerator>        <!--生成Dao类存放位置-->        <!-- 客户端代码，生成易于使用的针对Model对象和XML配置文件 的代码                type="ANNOTATEDMAPPER",生成Java Model 和基于注解的Mapper对象                type="MIXEDMAPPER",生成基于注解的Java Model 和相应的Mapper对象                type="XMLMAPPER",生成SQLMap XML文件和独立的Mapper接口        -->        <javaClientGenerator type="XMLMAPPER" targetPackage="com.zhangxing.dao" targetProject="src/main/java">            <property name="enableSubPackages" value="true"/>        </javaClientGenerator>        <!--生成对应表及类名-->        <table tableName="user" domainObjectName="User" enableCountByExample="false" enableUpdateByExample="false" enableDeleteByExample="false" enableSelectByExample="false" selectByExampleQueryId="false"></table>        <table tableName="role" domainObjectName="Role" enableCountByExample="false" enableUpdateByExample="false" enableDeleteByExample="false" enableSelectByExample="false" selectByExampleQueryId="false"></table>        <table tableName="permission" domainObjectName="Permission" enableCountByExample="false" enableUpdateByExample="false" enableDeleteByExample="false" enableSelectByExample="false" selectByExampleQueryId="false"></table>        <table tableName="user_role" domainObjectName="UserRole" enableCountByExample="false" enableUpdateByExample="false" enableDeleteByExample="false" enableSelectByExample="false" selectByExampleQueryId="false"></table>        <table tableName="role_permission" domainObjectName="RolePermission" enableCountByExample="false" enableUpdateByExample="false" enableDeleteByExample="false" enableSelectByExample="false" selectByExampleQueryId="false"></table>    </context></generatorConfiguration>

自动创建的表来源

<jdbcConnection driverClass="com.mysql.jdbc.Driver"          connectionURL="jdbc:mysql://127.0.0.1:3306/permission" userId="root" password="root"></jdbcConnection>

自动创建的model目录

<javaModelGenerator targetPackage="com.zhangxing.model" targetProject="src/main/java">            <property name="enableSubPackages" value="true"/>            <property name="trimStrings" value="true"/></javaModelGenerator>

自动创建的dao目录

<javaClientGenerator type="XMLMAPPER" targetPackage="com.zhangxing.dao" targetProject="src/main/java">            <property name="enableSubPackages" value="true"/></javaClientGenerator>

自动创建的mapper映射目录

 <sqlMapGenerator targetPackage="mapper" targetProject="src/main/resources">            <property name="enableSubPackages" value="true"/> </sqlMapGenerator>

去除自动生成代码的注解（代码生成时间及dao层的所有注解）

<commentGenerator>     <property name="suppressDate" value="true"/>     <property name="suppressAllComments" value="true"/></commentGenerator>

申明数据库对应表名及对应的model名称

tableName="role_permission" domainObjectName="RolePermission"

自动生成代码样式的选择

<javaClientGenerator type="XMLMAPPER" targetPackage="com.zhangxing.dao" targetProject="src/main/java">            <property name="enableSubPackages" value="true"/>        </javaClientGenerator>

其中type可以有以下选择可供参考

<!-- 客户端代码，生成易于使用的针对Model对象和XML配置文件 的代码                type="ANNOTATEDMAPPER",生成Java Model 和基于注解的Mapper对象                type="MIXEDMAPPER",生成基于注解的Java Model 和相应的Mapper对象                type="XMLMAPPER",生成SQLMap XML文件和独立的Mapper接口  -->

有兴趣的伙伴可以逐一实践下效果；

③application.properities配置

# EMBEDDED SERVER CONFIGURATION (ServerProperties)server.port=8089server.session-timeout=1800server.context-path=server.tomcat.max-threads=0server.tomcat.uri-encoding=UTF-8server.tomcat.basedir=target/tomcat# HTTP encoding (HttpEncodingProperties)spring.http.encoding.charset=UTF-8spring.http.encoding.enabled=true spring.http.encoding.force=true#datasourcespring.datasource.url=jdbc:mysql://localhost/permission?useUnicode=true&characterEncoding=UTF-8spring.datasource.username=rootspring.datasource.password=rootspring.datasource.driverClassName=com.mysql.jdbc.Driver#mybatismybatis.type-aliases-package=com.zhangxing.modelmybatis.mapper-locations=classpath:mapper/*.xml#mappermapper.mappers=tk.mybatis.mapper.common.Mappermapper.not-empty=falsemapper.identity=MYSQL#pagehelperpagehelper.helperDialect=mysqlpagehelper.reasonable=truepagehelper.supportMethodsArguments=truepagehelper.params=count=countSql#logging#logging.level.root=INFO#logging.level.org.springframework.web=DEBUGlogging.level.org.zhangxing=DEBUGspring.velocity.suffix=.html

主要是mybatis实体类及映射mapper扫描

#mybatismybatis.type-aliases-package=com.zhangxing.modelmybatis.mapper-locations=classpath:mapper/*.xml

④Application启动类

@SpringBootApplication@MapperScan(basePackages = "com.zhangxing.dao")public class Application extends SpringBootServletInitializer{    public static void main(String[] args) {        SpringApplication.run(Application.class, args);    }}

dao层接口的扫描

@MapperScan(basePackages = "com.zhangxing.dao")

⑤然后点击Run-->Edit Configrations

⑥接着点击绿色的“+”号，选择Maven

⑦在界面的command line中添加命令

mybatis-generator:generate -e

⑧点击ok,执行配好的generator-auto

ok,执行效果如下

3.效果展示

①自动生成的映射mapper（以user为例）

②自动生成的model

③自动生成的dao

补充：dao层分析

package com.zhangxing.dao;import com.zhangxing.model.User;public interface UserMapper {    int deleteByPrimaryKey(Integer id);    int insert(User record);    int insertSelective(User record);    User selectByPrimaryKey(Integer id);    int updateByPrimaryKeySelective(User record);    int updateByPrimaryKey(User record);}

在dao层没有自动生成任何注解，也无需加注解；因为在Application启动类中，我们已经扫描了dao层的所有接口

测试类

@RunWith(SpringJUnit4ClassRunner.class)@SpringBootTest(classes = Application.class)public class ServiceTest {    @Autowired    private UserService userMapper;    @Test    public void test(){        User user = userMapper.selectByPrimaryKey(1);        System.out.println(user.getName());    }}

运行结果：

好了，自动生成代码就搞定了，这样可以节省大量的基础开发时间了；我是张星，欢迎加入博主技术交流群，群号：313145288

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