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Generate Java Code with MyBatis Generator

This is a note about how to use MyBatis to generate Java code by given database and configuration.

First, create your database tables or update them.

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alter table data_fun.bi_sheet add column joined_columns longtext after categories;
alter table data_fun.bi_sheet add column joined_sheets longtext after joined_columns;
alter table data_fun.bi_sheet add column joined_relations longtext after joined_sheets;

Then create or update the “src/main/resources/generatorConfig.xml” configuration file:

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<?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>
    <classPathEntry
            location="/home/user/mysql-connector-java-5.1.42-bin.jar"/>
    <context id="DB2Tables" targetRuntime="MyBatis3" defaultModelType ="flat" >
        <plugin type="org.mybatis.generator.plugins.SerializablePlugin"/>
        <plugin type="com.test.exp.util.MybatisLimitPlugin"/>

        <jdbcConnection driverClass="com.mysql.jdbc.Driver"
                        connectionURL="jdbc:mysql://192.168.177.79:3306/data_fun?characterEncoding=UTF8"
                        userId="user"
                        password="password">
        </jdbcConnection>

        <javaModelGenerator targetPackage="com.test.exp.orm.model" targetProject="/home/user/code/xdata/exp/src/main/java">
            <property name="enableSubPackages" value="true"/>
            <property name="trimStrings" value="true"/>
        </javaModelGenerator>

        <sqlMapGenerator targetPackage="com.test.exp.orm.mapper" targetProject="/home/user/code/xdata/exp/src/main/resources">
            <property name="enableSubPackages" value="true"/>
        </sqlMapGenerator>

        <javaClientGenerator type="XMLMAPPER" targetPackage="com.test.exp.orm.mapper" targetProject="/home/user/code/xdata/exp/src/main/java">
            <property name="enableSubPackages" value="true"/>
        </javaClientGenerator>

        <table schema="sq_slfile" tableName="bi_sheet" domainObjectName="Sheet">
            <property name="useActualColumnNames" value="false"/>
            <generatedKey column="id" sqlStatement="MYSQL" identity="true"/>
            <columnOverride column="sheet_type" javaType="Byte"/>
        </table>

    </context>
</generatorConfiguration>

The “pom.xml” file should have the following content to use the MyBatis Generator:

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<build>
    <plugins>
        <plugin>
            <groupId>org.mybatis.generator</groupId>
            <artifactId>mybatis-generator-maven-plugin</artifactId>
            <version>1.3.4</version>
            <configuration>
                <verbose>true</verbose>
                <overwrite>true</overwrite>
            </configuration>
            <dependencies>
                <dependency>
                    <groupId>com.exp</groupId>
                    <artifactId>pagination</artifactId>
                    <version>1.0.0</version>
                </dependency>
            </dependencies>
        </plugin>
    </plugins>
</build>

Note the “pagination” dependency here, you need to install it manually:

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mvn install:install-file -Dfile=/home/user/pagination-1.0.0.jar  -DgroupId=com.exp  -DartifactId=pagination -Dversion=1.0.0 -Dpackaging=jar

It contains only one class whose code is list below:

MybatisLimitPlugin.java
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package com.test.exp.util;

import org.mybatis.generator.api.IntrospectedTable;
import org.mybatis.generator.api.dom.java.Field;
import org.mybatis.generator.api.dom.java.FullyQualifiedJavaType;
import org.mybatis.generator.api.dom.java.JavaVisibility;
import org.mybatis.generator.api.dom.java.Method;
import org.mybatis.generator.api.dom.java.Parameter;
import org.mybatis.generator.api.dom.java.TopLevelClass;
import org.mybatis.generator.api.dom.xml.Attribute;
import org.mybatis.generator.api.dom.xml.XmlElement;

public class MybatisLimitPlugin extends org.mybatis.generator.api.PluginAdapter
{
  public MybatisLimitPlugin() {}
  
  public boolean validate(java.util.List<String> list)
  {
    return true;
  }
  
  public boolean modelExampleClassGenerated(TopLevelClass topLevelClass, IntrospectedTable introspectedTable)
  {
    org.mybatis.generator.api.dom.java.PrimitiveTypeWrapper integerWrapper = FullyQualifiedJavaType.getIntInstance().getPrimitiveTypeWrapper();
    
    Field limit = new Field();
    limit.setName("limit");
    limit.setVisibility(JavaVisibility.PRIVATE);
    limit.setType(integerWrapper);
    topLevelClass.addField(limit);
    
    Method setLimit = new Method();
    setLimit.setVisibility(JavaVisibility.PUBLIC);
    setLimit.setName("setLimit");
    setLimit.addParameter(new Parameter(integerWrapper, "limit"));
    setLimit.addBodyLine("this.limit = limit;");
    topLevelClass.addMethod(setLimit);
    
    Method getLimit = new Method();
    getLimit.setVisibility(JavaVisibility.PUBLIC);
    getLimit.setReturnType(integerWrapper);
    getLimit.setName("getLimit");
    getLimit.addBodyLine("return limit;");
    topLevelClass.addMethod(getLimit);
    
    Field offset = new Field();
    offset.setName("offset");
    offset.setVisibility(JavaVisibility.PRIVATE);
    offset.setType(integerWrapper);
    topLevelClass.addField(offset);
    
    Method setOffset = new Method();
    setOffset.setVisibility(JavaVisibility.PUBLIC);
    setOffset.setName("setOffset");
    setOffset.addParameter(new Parameter(integerWrapper, "offset"));
    setOffset.addBodyLine("this.offset = offset;");
    topLevelClass.addMethod(setOffset);
    
    Method getOffset = new Method();
    getOffset.setVisibility(JavaVisibility.PUBLIC);
    getOffset.setReturnType(integerWrapper);
    getOffset.setName("getOffset");
    getOffset.addBodyLine("return offset;");
    topLevelClass.addMethod(getOffset);
    
    return true;
  }
  
  public boolean sqlMapSelectByExampleWithoutBLOBsElementGenerated(XmlElement element, IntrospectedTable introspectedTable)
  {
    XmlElement ifLimitNotNullElement = new XmlElement("if");
    ifLimitNotNullElement.addAttribute(new Attribute("test", "limit != null"));
    
    XmlElement ifOffsetNotNullElement = new XmlElement("if");
    ifOffsetNotNullElement.addAttribute(new Attribute("test", "offset != null"));
    ifOffsetNotNullElement.addElement(new org.mybatis.generator.api.dom.xml.TextElement("limit ${offset}, ${limit}"));
    ifLimitNotNullElement.addElement(ifOffsetNotNullElement);
    
    XmlElement ifOffsetNullElement = new XmlElement("if");
    ifOffsetNullElement.addAttribute(new Attribute("test", "offset == null"));
    ifOffsetNullElement.addElement(new org.mybatis.generator.api.dom.xml.TextElement("limit ${limit}"));
    ifLimitNotNullElement.addElement(ifOffsetNullElement);
    
    element.addElement(ifLimitNotNullElement);
    
    return true;
  }
  
  public boolean sqlMapSelectByExampleWithBLOBsElementGenerated(XmlElement element, IntrospectedTable introspectedTable)
  {
    return sqlMapSelectByExampleWithoutBLOBsElementGenerated(element, introspectedTable);
  }
}

You can execute the following command under the directory where the “pom.xml” file is:

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mvn mybatis-generator:generate
[INFO] Scanning for projects...
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building exp 1.0.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO] 
[INFO] --- mybatis-generator-maven-plugin:1.3.4:generate (default-cli) @ exp ---
[INFO] Connecting to the Database
[INFO] Introspecting table sq_slfile.bi_sheet
[INFO] Generating Example class for table bi_sheet
[INFO] Generating Record class for table bi_sheet
[INFO] Generating Mapper Interface for table bi_sheet
[INFO] Generating SQL Map for table bi_sheet
[INFO] Saving file SheetMapper.xml
[INFO] Saving file SheetExample.java
[INFO] Saving file Sheet.java
[INFO] Saving file SheetMapper.java
[WARNING] Existing file /home/user/code/xdata/exp/src/main/java/com/test/exp/orm/model/SheetExample.java was overwritten
[WARNING] Existing file /home/user/code/xdata/exp/src/main/java/com/test/exp/orm/model/Sheet.java was overwritten
[WARNING] Existing file /home/user/code/xdata/exp/src/main/java/com/test/exp/orm/mapper/SheetMapper.java was overwritten
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1.879 s
[INFO] Finished at: 2017-05-09T15:18:58+08:00
[INFO] Final Memory: 11M/121M
[INFO] ------------------------------------------------------------------------

Now all the files(Java/XML and etc) are generated automatically.

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