I. Introduction to MyBatis Generator

MyBatis Generator is a code generator officially provided by MyBatis, which can generate xml, dao and entity.

See http://mybatis.org/generator for the official website/

II. Usage

MyBatis Generator can be used in four ways:

• Command line generation
• Maven mode generation
• Build with Ant task
• Using Java code generation

This article will use Intel IDEA+Maven method to generate code, because integration and use are relatively simple, after configuration, double-click directly to run.

Three, actual combat

First, create a new spring boot project, spring mybatis generator, and then follow the steps below.

1. Configure plugin in pom.xml

<!-- Introduce mybatis-generator Plug-in unit -->
<plugin>
    <groupId>org.mybatis.generator</groupId>
    <artifactId>mybatis-generator-maven-plugin</artifactId>
    <version>1.3.2</version>
    <configuration>
        <!-- mybatis-generator The configuration file of, adjust the location according to the situation -->
        <configurationFile>src/main/resources/mybatis-generator.xml</configurationFile>
        <verbose>true</verbose>
        <overwrite>true</overwrite>
    </configuration>
    <executions>
        <execution>
            <id>Generate MyBatis Artifacts</id>
            <goals>
                <goal>generate</goal>
            </goals>
        </execution>
    </executions>
    <dependencies>
        <dependency>
            <groupId>org.mybatis.generator</groupId>
            <artifactId>mybatis-generator-core</artifactId>
            <version>1.3.2</version>
        </dependency>
    </dependencies>
</plugin>

1. Modify mybatis-generator.xml file

In the previous step, a configuration file was specified in pom.xml. Therefore, create mybatis-generator.xml in the resources directory. Through this configuration file, MyBatis Generator can perform the following operations:

• How to connect to a database
• What objects to generate and how to generate them
• Which tables apply to object generation

There will be the complete contents below, and it should be noted that.

Say important things three times.

The complete contents of mybatis-generator.xml are as follows:

<?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>

    <!--JDBC drive jar Absolute path of package -->
    <!--JDBC drive jar Absolute path of package -->
    <!--JDBC drive jar Absolute path of package -->
    <classPathEntry location="C:\Users\java_suisui\.m2\repository\mysql\mysql-connector-java\5.1.39\mysql-connector-java-5.1.39.jar"/>

    <!--defaultModelType="flat" Big data field, regardless of table -->
    <context id="Mysql" targetRuntime="MyBatis3Simple" defaultModelType="flat">
        <property name="autoDelimitKeywords" value="true" />
        <property name="beginningDelimiter" value="`" />
        <property name="endingDelimiter" value="`" />
        <property name="javaFileEncoding" value="utf-8" />
        <plugin type="org.mybatis.generator.plugins.SerializablePlugin" />

        <plugin type="org.mybatis.generator.plugins.ToStringPlugin" />

        <!-- Notes -->
        <commentGenerator >
            <property name="suppressAllComments" value="true"/><!-- Cancel comment or not -->
            <property name="suppressDate" value="true" /> <!-- Generate comment generation timestamp or not-->
        </commentGenerator>

        <!--Database link address account password-->
        <jdbcConnection driverClass="com.mysql.jdbc.Driver"
                        connectionURL="jdbc:mysql://localhost:3306/demo"
                        userId="root"
                        password="123456">
        </jdbcConnection>

        <!-- Type conversion -->
        <javaTypeResolver>
            <!-- Whether to use bigDecimal， false The following types can be automatically converted( Long, Integer, Short, etc.) -->
            <property name="forceBigDecimals" value="false"/>
        </javaTypeResolver>

        <!--generate Model Class storage location-->
        <javaModelGenerator targetPackage="com.example.springbootmybatis.generator.entity" targetProject="src/main/java">
            <property name="enableSubPackages" value="true"/>
            <property name="trimStrings" value="true"/>
        </javaModelGenerator>

        <!-- generate mapxml file -->
        <sqlMapGenerator targetPackage="mapper" targetProject="src/main/resources" >
            <property name="enableSubPackages" value="false" />
        </sqlMapGenerator>

        <!-- generate mapxml Corresponding client，Interface dao -->
        <javaClientGenerator targetPackage="com.example.springbootmybatis.generator.dao" targetProject="src/main/java" type="XMLMAPPER" >
            <property name="enableSubPackages" value="false" />
        </javaClientGenerator>

        <table tableName="user" enableCountByExample="true" enableUpdateByExample="true" enableDeleteByExample="true" enableSelectByExample="true" selectByExampleQueryId="true">
            <generatedKey column="id" sqlStatement="Mysql" identity="true" />
        </table>

        <table tableName="user_role" enableCountByExample="true" enableUpdateByExample="true" enableDeleteByExample="true" enableSelectByExample="true" selectByExampleQueryId="true">
            <generatedKey column="id" sqlStatement="Mysql" identity="true" />
        </table>

    </context>
</generatorConfiguration>

1. Generate code

Click "Maven Projects" on the right side of IntelIDEA, find mybatis generator: generate under spring boot mybatis generator, double-click to run, and "BUILD SUCCESS" appears in the log to indicate that the code has been generated.

Running screenshot:

Generate code screenshot:

Operation log:

[INFO] Scanning for projects...
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building spring-boot-mybatis-generator 0.0.1-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO] 
[INFO] --- mybatis-generator-maven-plugin:1.3.2:generate (default-cli) @ spring-mybatis-generator ---
[INFO] Connecting to the Database
[INFO] Introspecting table user
log4j:WARN No appenders could be found for logger (org.mybatis.generator.internal.db.DatabaseIntrospector).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
[INFO] Introspecting table user_role
[INFO] Generating Record class for table user
[INFO] Generating Mapper Interface for table user
[INFO] Generating SQL Map for table user
[INFO] Generating Record class for table user_role
[INFO] Generating Mapper Interface for table user_role
[INFO] Generating SQL Map for table user_role
[INFO] Saving file UserMapper.xml
[INFO] Saving file UserRoleMapper.xml
[INFO] Saving file User.java
[INFO] Saving file UserMapper.java
[INFO] Saving file UserRole.java
[INFO] Saving file UserRoleMapper.java
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------

Now we have finished the introduction of using mybatis generator to generate code automatically. If you have any questions, please leave a message and communicate!

Full source address: https://github.com/suisui2019/springboot-study

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