Using MyBatis Generator for Code Generation and Practical CRUD Examples

The article provides a step‑by‑step guide for integrating MyBatis Generator into a Java backend project, including Maven plugin configuration, XML generator settings, JDBC properties, and practical usage examples.

1. Set up MyBatis Generator plugin environment

a. Add plugin dependency in pom.xml

<!--mybatis 逆向生成插件-->
<plugin>
    <groupId>org.mybatis.generator</groupId>
    <artifactId>mybatis-generator-maven-plugin</artifactId>
    <version>1.3.2</version>
    <configuration>
        <configurationFile>src/main/resources/generatorConfig.xml</configurationFile>
        <verbose>true</verbose>
        <overwrite>true</overwrite>
    </configuration>
    <executions>
        <execution>
            <id>Generate MyBatis Artifacts</id>
        </execution>
    </executions>
    <dependencies>
        <dependency>
            <groupId>org.mybatis.generator</groupId>
            <artifactId>mybatis-generator-core</artifactId>
            <version>1.3.2</version>
        </dependency>
    </dependencies>
</plugin>

b. Configure 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>
    <properties resource="jdbc.properties"/>
    <classPathEntry location="${jdbc_driverLocation}"/> <!-- specify JDBC driver jar -->
    
    <context id="default" targetRuntime="MyBatis3">
        <!-- comment generator settings -->
        <commentGenerator>
            <property name="suppressDate" value="true"/>
            <property name="suppressAllComments" value="true"/>
        </commentGenerator>
        
        <!-- JDBC connection -->
        <jdbcConnection driverClass="${jdbc_driverClass}" 
                         connectionURL="${jdbc_url}" 
                         userId="${jdbc_user}" 
                         password="${jdbc_pwd}"/>
        
        <!-- Java model generator -->
        <javaModelGenerator targetPackage="com.rambo.sdm.dao.pojo" 
                               targetProject="src/main/java">
            <property name="enableSubPackages" value="false"/>
            <property name="constructorBased" value="true"/>
            <property name="trimStrings" value="true"/>
            <property name="immutable" value="false"/>
        </javaModelGenerator>
        
        <!-- SQL map generator -->
        <sqlMapGenerator targetPackage="com.rambo.sdm.dao.mapper" 
                           targetProject="src/main/java">
            <property name="enableSubPackages" value="false"/>
        </sqlMapGenerator>
        
        <!-- Java client generator (XML mapper) -->
        <javaClientGenerator targetPackage="com.rambo.sdm.dao.inter" 
                               targetProject="src/main/java" 
                               type="XMLMAPPER">
            <property name="enableSubPackages" value="true"/>
        </javaClientGenerator>
        
        <!-- Table configuration example -->
        <table tableName="user" domainObjectName="UserPO">
            <generatedKey column="uuid" sqlStatement="SELECT REPLACE(UUID(),'-','') UUID FROM DUAL"/>
        </table>
    </context>
</generatorConfiguration>

c. Database configuration file jdbc.properties

jdbc_driverLocation=D:\Program Files\Repository\mysql\mysql-connector-java\5.1.38\mysql-connector-java-5.1.38.jar
jdbc_driverClass=com.mysql.jdbc.Driver
jdbc_url=jdbc:mysql://localhost:3306/db_test?useUnicode=true&characterEncoding=utf-8
jdbc_user=root
jdbc_pwd=123456
validationQuery = select 1

d. Plugin execution configuration (image omitted)

2. Practical project examples

The following code snippets illustrate how to use the generated MyBatis artifacts for common operations such as deleting a user, updating team information, and performing various queries.

a. Delete a specific user's information under a team

public int deleteUserApplyInfo(long user_id, long team_id){
    StudyTeamUserApplyInfoExample ue = new StudyTeamUserApplyInfoExample();
    ue.createCriteria().andUserIdEqualTo(new BigDecimal(user_id))
                      .andTeamIdEqualTo(new BigDecimal(team_id));
    return studyTeamUserApplyInfoDAO.deleteByExample(ue);
}

b. Update team information based on non‑primary‑key team ID

public int updateStudyTeamInfo(StudyTeamInfo st){
    StudyTeamInfoExample ste = new StudyTeamInfoExample();
    ste.createCriteria().andTeamIdEqualTo(st.getTeamId());
    return studyTeamInfoDAO.updateByExampleSelective(st, ste);
}

c. Various queries

(1) Fuzzy search with sorting

public List<StudyTeamInfo> getStudyTeamInfoByName(String team_name){
    StudyTeamInfoExample se = new StudyTeamInfoExample();
    se.createCriteria().andTeamNameLike("%"+team_name+"%")
                      .andEnableEqualTo((short)1);
    se.setOrderByClause("team_score desc");
    List<StudyTeamInfo> ls = studyTeamInfoDAO.selectByExample(se);
    if(ls != null && ls.size() > 0){
        return ls;
    }
    return null;
}

(2) Query for scores within a range

public StudyTeamLevel getStudyTeamLevel(long score){
    StudyTeamLevelExample le = new StudyTeamLevelExample();
    le.createCriteria().andNeedScoreLessThanOrEqualTo(score)
                        .andUpScoreGreaterThan(score);
    List<StudyTeamLevel> ls = studyTeamLevelDAO.selectByExample(le);
    if(ls != null && ls.size() > 0){
        return ls.get(0);
    }
    return null;
}

By following these configurations and examples, developers can quickly generate MyBatis model, mapper, and XML files, and perform typical CRUD and query operations without writing repetitive boilerplate code.