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MyBatis reverse engineering analysis and simple tutorial (with code)

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php是最好的语言Original
2018-08-02 14:11:451971browse

MyBatis's reverse engineering

1: What is reverse engineering.

MyBatis是一款优秀的持久层框架,它支持定制化SQL、存储过程以及高级映射。MyBatis 避免了几乎所有的 JDBC 代码和手动设置参数以及获取结果集。MyBatis 可以使用简单的 XML 或注解来配置和映射原生信息,将接口和 Java 的 POJOs(Plain Old Java Objects,普通的 Java对象)映射成数据库中的记录。

当数据库表比较多的时候,重复的创建pojo对象和简单的数据库表的(CRUD)操作的mapper,效率低,官方给出了使用mybatis Generator用来根据数据库表逆向生成pojo和mapper文件,极大的方便开发。

2: Simple tutorial

  • Add plug-in to maven’s pom.xml

 <packaging>jar</packaging>
<dependencies>

        <!-- 添加对mybatis的依赖 -->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
        </dependency>
        <dependency>
            <groupId>com.github.miemiedev</groupId>
            <artifactId>mybatis-paginator</artifactId>
        </dependency>
        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper</artifactId>
        </dependency>
        <!-- MySql -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <!-- 连接池 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
        </dependency>

        <dependency>
            <groupId>org.mybatis.generator</groupId>
            <artifactId>mybatis-generator-core</artifactId>
            <version>1.3.6</version>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <!-- mybatis逆向工程 -->
            <plugin>
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-maven-plugin</artifactId>
                <version>1.3.7</version>
                <configuration>
                    <!--配置文件的位置-->
                    <configurationFile>src/main/resources/generatorConfig.xml</configurationFile>
                    <verbose>true</verbose>
                    <overwrite>true</overwrite>
                </configuration>
            </plugin>
        </plugins>
    </build>
  • Create the configuration file 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>
    <!--引入数据库配置文件方便修改-->
    <properties resource="jdbc.properties"/>
    <!--数据库驱动文件  需要修改 TODO-->
    <classPathEntry
            location="/Volumes/Tool/JAVA_Tool/maven/Maven_Repository/mysql/mysql-connector-java/5.1.32/mysql-connector-java-5.1.32.jar"/>

    <context id="context" targetRuntime="MyBatis3Simple">
        <commentGenerator>
            <!-- 是否去除自动生成的注释,true:是;false:否 -->
            <property name="suppressAllComments" value="true"/>
            <property name="suppressDate" value="false"/>
        </commentGenerator>
        <!--数据库连接的信息:驱动类、连接地址、用户名、密码 -->
        <jdbcConnection driverClass="${jdbc.driverClassName}"
                        connectionURL="${jdbc.url}"
                        userId="${jdbc.username}"
                        password="${jdbc.password}"/>
        <!--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 -->
        <!-- 非必需,类型处理器,在数据库类型和java类型之间的转换控制-->
        <javaTypeResolver>
            <property name="forceBigDecimals" value="false"/>
        </javaTypeResolver>
        <!--生成PO类的位置 配置生成的实体包-->
        <!--targetPackage:生成的实体包位置,默认存放在src目录下-->
        <!--targetProject:相对路径  路径拼接结果 src/main/java/one/domain -->
        <javaModelGenerator targetPackage="one.domain" 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>
        <!-- 实体包对应映射文件位置及名称,默认存放在src目录下 同上 -->
        <sqlMapGenerator targetPackage="MapperXml" 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 targetPackage="one.mapper" type="XMLMAPPER" targetProject="src/main/java">
            <!-- enableSubPackages:是否让schema作为包的后缀 -->
            <property name="enableSubPackages" value="false"/>
        </javaClientGenerator>
        <!--配置表-->
        <!--schema:不用填写-->
        <!--tableName: 表名 TODO-->
        <!--enableCountByExample、enableSelectByExample、enableDeleteByExample、enableUpdateByExample、selectByExampleQueryId:-->
        <!--去除自动生成的注释例子-->
        <table tableName="tb_user" enableCountByExample="false" enableDeleteByExample="false"
               enableSelectByExample="false" enableUpdateByExample="false"/>
    </context>
</generatorConfiguration>
  • Run the Generator class to generate

I have already completed the project and downloaded it You can run

Related articles:

Getting started with MyBatis (7)---Reverse Engineering

Spring SpringMVC MyBatis in-depth learning and construction ——MyBatis reverse engineering

Related videos:

MySQLi process-oriented quick introduction

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