探究Mybatis逆向工程的相關配置

一 項目構建

選擇構建Maven項目，這裏選擇webapp
輸入GroupId和ArtifectId
選擇項目所在目錄

二 項目目錄結構

三 項目的pom文件主要內容代碼

<properties>
        <org.springframework.version>4.0.0.RELEASE</org.springframework.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.apache.tomcat</groupId>
            <artifactId>tomcat-servlet-api</artifactId>
            <version>9.0.19</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${org.springframework.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-oxm</artifactId>
            <version>${org.springframework.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>${org.springframework.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-tx</artifactId>
            <version>${org.springframework.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>${org.springframework.version}</version>
        </dependency>

        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.9.5</version>
        </dependency>

        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjrt</artifactId>
            <version>1.9.5</version>
        </dependency>

        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>2.0.4</version>
        </dependency>

        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.1</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
            <scope>test</scope>
        </dependency>

        <dependency>
          <groupId>org.aspectj</groupId>
          <artifactId>aspectjrt</artifactId>
          <version>1.6.11</version>
        </dependency>

        <dependency>
          <groupId>commons-dbcp</groupId>
          <artifactId>commons-dbcp</artifactId>
          <version>1.4</version>
          <!--<scope>runtime</scope>-->
        </dependency>

        <dependency>
          <groupId>ch.qos.logback</groupId>
          <artifactId>logback-classic</artifactId>
          <version>1.1.2</version>
          <scope>compile</scope>
        </dependency>

        <dependency>
          <groupId>ch.qos.logback</groupId>
          <artifactId>logback-core</artifactId>
          <version>1.1.2</version>
          <scope>compile</scope>
        </dependency>

        <dependency>
          <groupId>mysql</groupId>
          <artifactId>mysql-connector-java</artifactId>
          <version>8.0.20</version>
        </dependency>

        <!-- mybatis pageHelper分頁插件 -->
        <dependency>
          <groupId>com.github.pagehelper</groupId>
          <artifactId>pagehelper</artifactId>
          <version>4.1.0</version>
        </dependency>

        <dependency>
          <groupId>com.github.miemiedev</groupId>
          <artifactId>mybatis-paginator</artifactId>
          <version>1.2.17</version>
        </dependency>

        <dependency>
          <groupId>com.github.jsqlparser</groupId>
          <artifactId>jsqlparser</artifactId>
          <version>0.9.4</version>
        </dependency>
     </dependencies>

  <build>
    <finalName>mark</finalName>
    <plugins>
      <!-- mybatis逆向工程插件-->
      <plugin>
        <groupId>org.mybatis.generator</groupId>
        <artifactId>mybatis-generator-maven-plugin</artifactId>
        <configuration>
          <verbose>true</verbose>
          <overwrite>true</overwrite>
        </configuration>
      </plugin>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <configuration>
          <source>1.8</source>
          <target>1.8</target>
          <encoding>UTF-8</encoding>
          <compilerArguments>
            <extdirs>${project.basedir}/src/main/webapp/WEB-INF/lib</extdirs>
          </compilerArguments>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>

四 generatorConfig.xml文件配置

<?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>
    <!--導入屬性配置-->
    <properties resource="datasource.properties"></properties>

    <!--指定特定數據庫的jdbc驅動jar包的位置-->
    <classPathEntry location="${db.driverLocation}"/>

    <context id="default" targetRuntime="MyBatis3">

        <!-- optional，旨在創建class時，對註釋進行控制 -->
        <commentGenerator>
            <property name="suppressDate" value="true"/>
            <property name="suppressAllComments" value="true"/>
        </commentGenerator>

        <!--jdbc的數據庫連接 -->
        <jdbcConnection
                driverClass="${db.driverClassName}"
                connectionURL="${db.url}"
                userId="${db.username}"
                password="${db.password}">
        </jdbcConnection>

        <!-- 非必需，類型處理器，在數據庫類型和java類型之間的轉換控制-->
        <javaTypeResolver>
            <property name="forceBigDecimals" value="false"/>
        </javaTypeResolver>

        <!-- Model模型生成器,用來生成含有主鍵key的類，記錄類 以及查詢Example類
            targetPackage     指定生成的model生成所在的包名
            targetProject     指定在該項目下所在的路徑
        -->
        <!--<javaModelGenerator targetPackage="com.mark.pojo" targetProject=".\src\main\java">-->
        <javaModelGenerator targetPackage="com.mark.pojo" targetProject="./src/main/java">
            <!-- 是否允許子包，即targetPackage.schemaName.tableName -->
            <property name="enableSubPackages" value="false"/>
            <!-- 是否對model添加 構造函數 -->
            <property name="constructorBased" value="true"/>
            <!-- 是否對類CHAR類型的列的數據進行trim操作 -->
            <property name="trimStrings" value="true"/>
            <!-- 建立的Model對象是否不可改變  即生成的Model對象不會有 setter方法，只有構造方法 -->
            <property name="immutable" value="false"/>
        </javaModelGenerator>

        <!--mapper映射文件生成所在的目錄 爲每一個數據庫的表生成對應的SqlMap文件 -->
        <!--<sqlMapGenerator targetPackage="mappers" targetProject=".\src\main\resources">-->
        <sqlMapGenerator targetPackage="mappers" targetProject="./src/main/resources">
            <property name="enableSubPackages" value="false"/>
        </sqlMapGenerator>

        <!-- 客戶端代碼，生成易於使用的針對Model對象和XML配置文件 的代碼
                type="ANNOTATEDMAPPER",生成Java Model 和基於註解的Mapper對象
                type="MIXEDMAPPER",生成基於註解的Java Model 和相應的Mapper對象
                type="XMLMAPPER",生成SQLMap XML文件和獨立的Mapper接口
        -->

        <!-- targetPackage：mapper接口dao生成的位置 -->
        <!--<javaClientGenerator type="XMLMAPPER" targetPackage="com.mark.dao" targetProject=".\src\main\java">-->
        <javaClientGenerator type="XMLMAPPER" targetPackage="com.mark.dao" targetProject="./src/main/java">
            <!-- enableSubPackages:是否讓schema作爲包的後綴 -->
            <property name="enableSubPackages" value="false" />
        </javaClientGenerator>
        <table tableName="mark_user" domainObjectName="User" enableCountByExample="false" enableUpdateByExample="false" enableDeleteByExample="false" enableSelectByExample="false" selectByExampleQueryId="false"></table>
        <!--mybatis插件的搭建 -->
    </context>
</generatorConfiguration>

五 UserMapper.xml文件配置

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<!--namespace名命空間，Mapper中Namespace的定義本身是沒有限制的，只要不重複即可，
但如果使用Mybatis的DAO接口動態代理，則namespace必須爲DAO接口的全路徑，
如com.mark.dao.UserMapper-->
<mapper namespace="com.mark.dao.UserMapper">
  <resultMap id="BaseResultMap" type="com.mark.pojo.User">
    <constructor>
      <idArg column="id" javaType="java.lang.Integer" jdbcType="INTEGER" />
      <arg column="username" javaType="java.lang.String" jdbcType="VARCHAR" />
      <arg column="password" javaType="java.lang.String" jdbcType="VARCHAR" />
      <arg column="email" javaType="java.lang.String" jdbcType="VARCHAR" />
      <arg column="phone" javaType="java.lang.String" jdbcType="VARCHAR" />
      <arg column="question" javaType="java.lang.String" jdbcType="VARCHAR" />
      <arg column="answer" javaType="java.lang.String" jdbcType="VARCHAR" />
      <arg column="role" javaType="java.lang.Integer" jdbcType="INTEGER" />
      <arg column="create_time" javaType="java.util.Date" jdbcType="TIMESTAMP" />
      <arg column="update_time" javaType="java.util.Date" jdbcType="TIMESTAMP" />
    </constructor>
  </resultMap>

  <sql id="Base">
    id, username, password, email, phone, question, answer, role, create_time, update_time
   </sql>

    <!--
        id：當前名稱空間下的statement的唯一標識(必須屬性)，可以隨意寫，
            但是使用動態代理要求id和mapper接口中的方法的名字一致
        parameterType:使用動態代理，需要和mapper中接口的參數保持一致
    -->
  <!--
       1.#{},預編譯的方式preparedstatement，使用佔位符替換，防止sql注入，
             一個參數的時候，任意參數名可以接收
       2.${},普通的Statement，字符串直接拼接，不可以防止sql注入，
             一個參數的時候，必須使用${value}接收參數
     -->
    <select id="selectByPrimaryKey" parameterType="java.lang.Integer" resultMap="BaseResultMap">
        select
        <include refid="Base" />
        from mark_user
        where id = #{id,jdbcType=INTEGER}
    </select>

  <insert id="insert" parameterType="com.mark.pojo.User">

    insert into mark_user (id, username, password, 
      email, phone, question, 
      answer, role, create_time, 
      update_time)

    values (#{id,jdbcType=INTEGER}, #{username,jdbcType=VARCHAR}, #{password,jdbcType=VARCHAR}, 
      #{email,jdbcType=VARCHAR}, #{phone,jdbcType=VARCHAR}, #{question,jdbcType=VARCHAR}, 
      #{answer,jdbcType=VARCHAR}, #{role,jdbcType=INTEGER}, #{createTime,jdbcType=TIMESTAMP}, 
      #{updateTime,jdbcType=TIMESTAMP})
  </insert>
</mapper>

總結：最後通過mybatis的逆向工程插件mybatis-generator就可以根據UserMapper.xml文件的配置信息生成對應的UserMapper接口和名爲User的javaBean。