內建Mybatis通用Mapper以及代碼生成器

為什麼要學習Mybatis的通用Mapper，相信也不用我做太多介紹，總之他能簡化我們開發過程中對資料庫的單表操作。

這裡詳細講解一下Spring環境下配置Mybatis通用Mapper以及代碼生成器的過程

1. pom.xml中引入依賴

   <!--tk.mybatis/mapper -->
               <dependency>
                   <groupId>tk.mybatis</groupId>
                   <artifactId>mapper</artifactId>
                   <version>3.3.8</version>
               </dependency>
   
               <!--mybatis-generator-core -->
               <dependency>
                   <groupId>org.mybatis.generator</groupId>
                   <artifactId>mybatis-generator-core</artifactId>
                   <version>1.3.3</version>
               </dependency>
              

2. pom.xml中配置代碼生成器插件

   <properties>
           <!-- MyBatis Generator -->
   
           <!-- Java接口和實體類 -->
           <targetJavaProject>${basedir}/src/main/java</targetJavaProject>
           <!-- mapper接口的生成位置 -->
           <targetMapperPackage>fei.mapper</targetMapperPackage>
           <!-- 實體類的生成位置 -->
           <targetModelPackage>fei.entity</targetModelPackage>
   
           <!-- MyBatis Generator mapper.xml生成位置 -->
           <targetResourcesProject>${basedir}/src/main/resources</targetResourcesProject>
           <targetXMLPackage>fei.mapper</targetXMLPackage>
       </properties>
   
   		......
   
   	<!--通用mapper自動生成插件-->
           <plugin>
               <groupId>org.mybatis.generator</groupId>
               <artifactId>mybatis-generator-maven-plugin</artifactId>
               <version>1.3.2</version>
               <configuration>
                   <!--代碼生成器配置檔案路徑-->
                   <configurationFile>${basedir}/src/main/resources/generator/generatorConfig.xml</configurationFile>
                   <!--是否覆寫已經存在的檔案-->
                   <overwrite>true</overwrite>
                   <verbose>true</verbose>
               </configuration>
               <dependencies>
                   <dependency>
                       <groupId>mysql</groupId>
                       <artifactId>mysql-connector-java</artifactId>
                       <version>5.1.21</version>
                   </dependency>
                   <dependency>
                       <groupId>tk.mybatis</groupId>
                       <artifactId>mapper</artifactId>
                       <version>3.3.8</version>
                   </dependency>
               </dependencies>
           </plugin>
              

3. 編寫代碼生成器配置檔案

   generatorConfig.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>
   	 <!--加載配置檔案取值-->
       <properties resource="classpath:generator.properties"/>
   
       <context id="Mysql" targetRuntime="MyBatis3Simple" defaultModelType="flat">
           <property name="beginningDelimiter" value="`"/>
           <property name="endingDelimiter" value="`"/>
   
           <plugin type="${mapper.plugin}">
               <!--自定義通用Mapper接口，将來所有生成的mapper接口都會繼承這個接口-->
               <property name="mappers" value="${mapper.Mapper}"/>
               <!--強制生成注解，不管entity與表名是否一緻-->
               <property name="forceAnnotation" value="true"/>
               <!--區分大小寫-->
               <property name="caseSensitive" value="true"/>
           </plugin>
   
   		 <!--連接配接資料庫-->
           <jdbcConnection driverClass="${jdbc.driver}"
                           connectionURL="${jdbc.url}"
                           userId="${jdbc.username}"
                           password="${jdbc.password}">
           </jdbcConnection>
   
           <!--pom.xml配置的檔案生成路徑-->
           <javaModelGenerator targetPackage="${targetModelPackage}" targetProject="${targetJavaProject}"/>
   
           <sqlMapGenerator targetPackage="${targetXMLPackage}"  targetProject="${targetResourcesProject}"/>
   
           <javaClientGenerator targetPackage="${targetMapperPackage}" targetProject="${targetJavaProject}" type="XMLMAPPER" />
   
   		<!--可以指定資料庫中的某個表，%表示所有表-->
           <table tableName="%" >
               <generatedKey column="user_id" sqlStatement="Mysql" identity="true"/>
           </table>
   
       </context>
   </generatorConfiguration>
              

4. resources根目錄下定義需要加載的配置檔案

   generator.properties

   jdbc.driver=com.mysql.jdbc.Driver
   jdbc.url=jdbc:mysql://localhost:3306/mybatis?characterEncoding=utf-8
   jdbc.username=root
   jdbc.password=1111
   mapper.plugin = tk.mybatis.mapper.generator.MapperPlugin
   mapper.Mapper =fei.dao.BaseMapper
              

   注意我的

   fei.dao.BaseMapper

   繼承了

   extends Mapper<T>, MySqlMapper<T>

   ，前面配置了所有自動生成的mapper接口都繼承這個接口
5. 然後将原來mybatis-batis.xml檔案中的

   <!-- 配置Mapper接口掃描 -->
       <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
           <!-- 配置Mapper掃描包 -->
           <property name="basePackage" value="fei.mapper" />
       </bean>
              

   改成

   <!-- 配置Mapper接口掃描 -->
       <bean class="tk.mybatis.spring.mapper.MapperScannerConfigurer">
           <!-- 配置Mapper掃描包 -->
           <property name="basePackage" value="fei.mapper" />
       </bean>
              

6. 最後測試啟動

   

   沒有報錯，應該就在指定位置可以看到自動生成的實體類，Mapper接口，Mapper.xml檔案

   如自動幫我們生成的實體類

   @Table(name = "customer")
   public class Customer {
       @Id
       @Column(name = "cust_id")
       private Integer custId;
   
       @Column(name = "cust_name")
       private String custName;
   
       @Column(name = "cust_profession")
       private String custProfession;
   
       @Column(name = "cust_phone")
       private String custPhone;
       ......