MyBatis Generator的使用

時間  2019-12-13
標籤 mybatis generator 使用 欄目 MyBatis 简体版
原文   原文鏈接

Mybatis Generator使用

介紹

使用MyBatis Generator (MBG) 能夠減小重複代碼工做量，自動根據數據庫表的結構生成MyBatis的Model/Dao/XML。
本文主要介紹MBG如何根據Oralce數據庫表的結構生成相應文件的。同時經過MBG提供的插件擴展能力，實現兩個插件，用於在生成的Model中包含數據庫中定義的註釋和添加Lombok註解。html

項目結構

本演示項目使用IDE爲IDEA。首先建立一個簡單的Maven工程。
根據《IntelliJ IDEA 建立 Maven簡單項目》建立Maven工程。java

項目結構預覽：
下面是使用MBG生成MyBatis中的Model(Pojo)/Dao/XML各層的最終項目結構。mysql

com.zqq.dao 存放生成的MyBatis數據庫操做類
com.zqq.pojo 存放與數據庫表映射的數據庫模型bean
mappers/DemoPojoMapper.xml 存放與DAO包中的方法對應的sql操做語句文件git

配置文件（搭建Maven項目）

使用MBG不須要依賴於Spring等框架，只須要依賴基本的MBG插件便可。可是因爲是根據數據庫表生成MyBatis操做對象，所以還須要配置數據庫鏈接信息datasource.properties。同時，使用MBG時須要配置generatorConfig.xml文件。sql

注意oracle驅動與jdk的關係 ojdbc7 對應jdk 7 8 https://download.csdn.net/download/panhaigang123/10757085數據庫

//datasource.properties
#下面配置的是Oracle數據庫的鏈接信息，oracle url要使用域名：端口/實例
#驅動本地路徑
db.driverLocation=D:\\code\\private\\model_generator\\src\\main\\tools\\ojdbc7-12.1.0.2.jar
#驅動類路徑
db.driverClassName=oracle.jdbc.driver.OracleDriver

#數據庫鏈接信息
db.url=jdbc:oracle:thin:@host:1521/database
db.username=xxx
db.password=xxx
//generatorConfig.xml
<!--配置文件中的suppresscomment不要配置。type=MyCommentGenerator 要用全類名，不然可能找不到。屢次執行generate，生成的xml只能追加沒法覆蓋問題，使用插件解決-->

<?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">

        <!--可選配置，使用自定義插件，經過註解使每次重複執行時覆蓋原有的xml文件-->
        <!--<plugin type="OverIsMergeablePlugin"/>-->
        <!--可選配置，使用自定義插件，生成Lombok註解-->
        <plugin type="com.zqq.plugins.LombokPlugin">
            <property name="hasLombok" value="true"/>
        </plugin>

        <!-- 可選配置，旨在建立class時，對註釋進行控制 -->
        <!--MyCommentGenerator實現了對字段添加註釋功能-->
        <commentGenerator type="com.zqq.plugins.MyCommentGenerator">

            <!--<property name="suppressDate" value="true"/>-->
            <!--不能添加以下配置，不然沒法生成註釋-->
            <!--<property name="suppressAllComments" value="true"/>-->
        </commentGenerator>

        <!--jdbc的數據庫鏈接 -->
        <jdbcConnection
                driverClass="${db.driverClassName}"
                connectionURL="${db.url}"
                userId="${db.username}"
                password="${db.password}">
            <property name="remarksReporting" value="true"></property>
        </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.zqq.pojo" targetProject="./src/main/java">
            <!-- 是否容許子包，即targetPackage.schemaName.tableName -->
            <property name="enableSubPackages" value="false"/>
            <!-- 是否對model添加 構造函數 當immutable爲false時，此處設置纔有效-->
            <property name="constructorBased" value="false"/>
            <!-- 是否對類CHAR類型的列的數據進行trim操做 -->
            <property name="trimStrings" value="true"/>
            <!-- 創建的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 -->
            <!--該屬性用來配置實體類屬性是否可變，若是設置爲true，那麼constructorBased無論設置成什麼，都會使用構造方法入參，而且不會生成setter方法。若是爲false，實體類屬性就能夠改變。默認爲false。-->
            <property name="immutable" value="false"/>
        </javaModelGenerator>

        <!--mapper映射文件生成所在的目錄 爲每個數據庫的表生成對應的SqlMap文件 -->
        <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.zqq.dao" targetProject="./src/main/java">
            <!-- enableSubPackages:是否讓schema做爲包的後綴 -->
            <property name="enableSubPackages" value="false"/>
        </javaClientGenerator>

        <!--須要生成相應MyBatis操做dao/pojo/xml的數據庫表以及映射的pojo-->
        <table tableName="DEMO_TABLE" domainObjectName="DemoPojo"
               enableCountByExample="false" enableUpdateByExample="false" enableDeleteByExample="false"
               enableSelectByExample="false" selectByExampleQueryId="false"></table>

      
    </context>
</generatorConfiguration>

POM配置

下面給出pom.xml的配置。MBG要用1.3.3及之後版本 不然沒法生成類註釋addModelClassComment。apache

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com</groupId>
    <artifactId>MBG</artifactId>
    <packaging>war</packaging>
    <version>1.0-SNAPSHOT</version>
    <name>MBG DEMO</name>
    <url>http://maven.apache.org</url>


    <dependencies>
        <dependency>
            <groupId>org.mybatis.generator</groupId>
            <artifactId>mybatis-generator-core</artifactId>
            <version>1.3.5</version>
        </dependency>
    </dependencies>

    <build>
        <finalName>mmall</finalName>
        <plugins>
            <plugin>
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-maven-plugin</artifactId>
                <version>1.3.5</version>
                <configuration>
                    <verbose>true</verbose>
                    <overwrite>true</overwrite>
                </configuration>
            </plugin>

        </plugins>

    </build>
    
</project>

自定義插件

MBG提供的插件的擴展類PluginAdapter，能夠實現本身須要的特定功能。須要注意的是，MBG不一樣的版本提供的接口是不一樣的。下面分別給出，三個自定義插件的實現。api

LombokPlugin

該插件提供了在生成的POJO上面添加Lombok註解。mybatis

package com.zqq.plugins;

import org.mybatis.generator.api.IntrospectedColumn;
import org.mybatis.generator.api.IntrospectedTable;
import org.mybatis.generator.api.PluginAdapter;
import org.mybatis.generator.api.dom.java.Interface;
import org.mybatis.generator.api.dom.java.Method;
import org.mybatis.generator.api.dom.java.TopLevelClass;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;


public class LombokPlugin extends PluginAdapter
{

    @Override
    public boolean validate(List<String> list)
    {
        return true;
    }

    @Override
    public boolean modelBaseRecordClassGenerated(TopLevelClass topLevelClass, IntrospectedTable introspectedTable)
    {
        //添加domain的import
        topLevelClass.addImportedType("lombok.Data");
        topLevelClass.addImportedType("lombok.Builder");
        topLevelClass.addImportedType("lombok.NoArgsConstructor");
        topLevelClass.addImportedType("lombok.AllArgsConstructor");

        //添加domain的註解
        topLevelClass.addAnnotation("@Data");
        topLevelClass.addAnnotation("@Builder");
        topLevelClass.addAnnotation("@NoArgsConstructor");
        topLevelClass.addAnnotation("@AllArgsConstructor");
        return true;
    }

    @Override
    public boolean modelSetterMethodGenerated(Method method, TopLevelClass topLevelClass, IntrospectedColumn introspectedColumn, IntrospectedTable introspectedTable, ModelClassType modelClassType)
    {
        //不生成getter
        return false;
    }

    @Override
    public boolean modelGetterMethodGenerated(Method method, TopLevelClass topLevelClass, IntrospectedColumn introspectedColumn, IntrospectedTable introspectedTable, ModelClassType modelClassType)
    {
        //不生成setter
        return false;
    }

    private String date2Str(Date date)
    {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy/MM/dd");
        return sdf.format(date);
    }
}

MyCommentGenerator

原生的MBG沒法將數據庫中的表註釋及字段註釋添加到生成的POJO的類或字段上。該插件能夠提供該能力生成Oracle或MySQL數據庫表及字段的註釋。oracle

package com.zqq.plugins;

import static org.mybatis.generator.internal.util.StringUtility.isTrue;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Properties;
import java.util.Set;

import org.mybatis.generator.api.CommentGenerator;
import org.mybatis.generator.api.IntrospectedColumn;
import org.mybatis.generator.api.IntrospectedTable;
import org.mybatis.generator.api.dom.java.*;
import org.mybatis.generator.api.dom.xml.XmlElement;
import org.mybatis.generator.config.MergeConstants;
import org.mybatis.generator.config.PropertyRegistry;
import org.mybatis.generator.internal.util.StringUtility;

public class MyCommentGenerator implements CommentGenerator
{

    private Properties properties;
    private Properties systemPro;
    private boolean suppressDate;
    private boolean suppressAllComments;
    private String currentDateStr;

    public MyCommentGenerator()
    {
        super();
        properties = new Properties();
        systemPro = System.getProperties();
        suppressDate = false;
        suppressAllComments = false;
        currentDateStr = (new SimpleDateFormat("yyyy-MM-dd")).format(new Date());
    }

    @Override
    public void addJavaFileComment(CompilationUnit compilationUnit)
    {
        // add no file level comments by default
        return;
    }

    /**
     * Adds a suitable comment to warn users that the element was generated, and
     * when it was generated.
     */
    @Override
    public void addComment(XmlElement xmlElement)
    {
        return;
    }

    @Override
    public void addRootComment(XmlElement rootElement)
    {
        // add no document level comments by default
        return;
    }

    @Override
    public void addConfigurationProperties(Properties properties)
    {
        this.properties.putAll(properties);

        suppressDate = isTrue(properties.getProperty(PropertyRegistry.COMMENT_GENERATOR_SUPPRESS_DATE));

        suppressAllComments = isTrue(properties.getProperty(PropertyRegistry.COMMENT_GENERATOR_SUPPRESS_ALL_COMMENTS));
    }

    /**
     * This method adds the custom javadoc tag for. You may do nothing if you do
     * not wish to include the Javadoc tag - however, if you do not include the
     * Javadoc tag then the Java merge capability of the eclipse plugin will
     * break.
     *
     * @param javaElement the java element
     */
    protected void addJavadocTag(JavaElement javaElement, boolean markAsDoNotDelete)
    {
        javaElement.addJavaDocLine(" *");
        StringBuilder sb = new StringBuilder();
        sb.append(" * ");
        sb.append(MergeConstants.NEW_ELEMENT_TAG);
        if (markAsDoNotDelete)
        {
            sb.append(" do_not_delete_during_merge");
        }
        String s = getDateString();
        if (s != null)
        {
            sb.append(' ');
            sb.append(s);
        }
        javaElement.addJavaDocLine(sb.toString());
    }

    /**
     * This method returns a formated date string to include in the Javadoc tag
     * and XML comments. You may return null if you do not want the date in
     * these documentation elements.
     *
     * @return a string representing the current timestamp, or null
     */
    protected String getDateString()
    {
        String result = null;
        if (!suppressDate)
        {
            result = currentDateStr;
        }
        return result;
    }

    @Override
    public void addClassComment(InnerClass innerClass, IntrospectedTable introspectedTable)
    {
        if (suppressAllComments)
        {
            return;
        }
        StringBuilder sb = new StringBuilder();
        innerClass.addJavaDocLine("/**");
        sb.append(" * ");
        sb.append(introspectedTable.getFullyQualifiedTable());
        sb.append(" ");
        sb.append(getDateString());
        innerClass.addJavaDocLine(sb.toString());
        innerClass.addJavaDocLine(" */");
    }

    @Override
    public void addEnumComment(InnerEnum innerEnum, IntrospectedTable introspectedTable)
    {
        if (suppressAllComments)
        {
            return;
        }

        StringBuilder sb = new StringBuilder();

        innerEnum.addJavaDocLine("/**");
        //      addJavadocTag(innerEnum, false);
        sb.append(" * ");
        sb.append(introspectedTable.getFullyQualifiedTable());
        innerEnum.addJavaDocLine(sb.toString());
        innerEnum.addJavaDocLine(" */");
    }

    /**
     * 添加字段註釋
     *
     * @param field
     * @param introspectedTable
     * @return
     * @throws
     * @auther 
     * @since 11:58 2019/1/9
     */
    @Override
    public void addFieldComment(Field field, IntrospectedTable introspectedTable)
    {
        if (suppressAllComments)
        {
            return;
        }

        StringBuilder sb = new StringBuilder();

        field.addJavaDocLine("/**");
        sb.append(" * ");
        sb.append(introspectedTable.getFullyQualifiedTable());
        field.addJavaDocLine(sb.toString());
        field.addJavaDocLine(" */");
    }

    //字段添加ApiModelProperty
    @Override
    public void addFieldComment(Field field, IntrospectedTable introspectedTable, IntrospectedColumn introspectedColumn)
    {
        if (suppressAllComments)
        {
            return;
        }

        StringBuilder sb = new StringBuilder();

        field.addJavaDocLine("/**");
        sb.append(" * ");
        sb.append(introspectedColumn.getRemarks());
        field.addJavaDocLine(sb.toString());

        //      addJavadocTag(field, false);

        field.addJavaDocLine(" */");
        StringBuilder sb1 = new StringBuilder();
        //@ApiModelProperty(name = "approveStatus", notes = "審批狀態")
        sb1.append("@ApiModelProperty").append("(name = \"").append(field.getName())
                .append("\" , notes = \"").append(introspectedColumn.getRemarks())
                .append("\")");
        System.out.println(sb1.toString());
        field.addJavaDocLine(sb1.toString());
    }

    @Override
    public void addGeneralMethodComment(Method method, IntrospectedTable introspectedTable)
    {
        if (suppressAllComments)
        {
            return;
        }
        //      method.addJavaDocLine("/**");
        //      addJavadocTag(method, false);
        //      method.addJavaDocLine(" */");
    }

    @Override
    public void addGetterComment(Method method, IntrospectedTable introspectedTable, IntrospectedColumn introspectedColumn)
    {
        if (suppressAllComments)
        {
            return;
        }

        method.addJavaDocLine("/**");

        StringBuilder sb = new StringBuilder();
        sb.append(" * ");
        sb.append(introspectedColumn.getRemarks());
        method.addJavaDocLine(sb.toString());

        sb.setLength(0);
        sb.append(" * @return ");
        sb.append(introspectedColumn.getActualColumnName());
        sb.append(" ");
        sb.append(introspectedColumn.getRemarks());
        method.addJavaDocLine(sb.toString());

        //      addJavadocTag(method, false);

        method.addJavaDocLine(" */");
    }

    @Override
    public void addSetterComment(Method method, IntrospectedTable introspectedTable, IntrospectedColumn introspectedColumn)
    {
        if (suppressAllComments)
        {
            return;
        }


        method.addJavaDocLine("/**");
        StringBuilder sb = new StringBuilder();
        sb.append(" * ");
        sb.append(introspectedColumn.getRemarks());
        method.addJavaDocLine(sb.toString());

        Parameter parm = method.getParameters().get(0);
        sb.setLength(0);
        sb.append(" * @param ");
        sb.append(parm.getName());
        sb.append(" ");
        sb.append(introspectedColumn.getRemarks());
        method.addJavaDocLine(sb.toString());

        //      addJavadocTag(method, false);

        method.addJavaDocLine(" */");
    }

    /**
     * 內部類的註釋
     *
     * @param innerClass
     * @param introspectedTable
     * @param markAsDoNotDelete
     * @return
     * @throws
     * @auther 
     * @since 11:59 2019/1/9
     */

    @Override
    public void addClassComment(InnerClass innerClass, IntrospectedTable introspectedTable, boolean markAsDoNotDelete)
    {
        if (suppressAllComments)
        {
            return;
        }

        StringBuilder sb = new StringBuilder();

        innerClass.addJavaDocLine("/**");
        sb.append(" * ");
        sb.append(introspectedTable.getFullyQualifiedTable());
        innerClass.addJavaDocLine(sb.toString());

        sb.setLength(0);
        sb.append(" * @author ");
        sb.append(systemPro.getProperty("user.name"));
        sb.append(" ");
        sb.append(currentDateStr);

        //      addJavadocTag(innerClass, markAsDoNotDelete);

        innerClass.addJavaDocLine(" */");
    }

    /**
     * 獲取表註釋，設置到Bean註釋
     *
     * @param topLevelClass
     * @param introspectedTable
     * @return
     * @throws
     * @auther 
     * @since 11:57 2019/1/9
     */
    @Override
    public void addModelClassComment(TopLevelClass topLevelClass, IntrospectedTable introspectedTable)
    {

        topLevelClass.addJavaDocLine("/**");

        String remarks = introspectedTable.getRemarks();
        if (StringUtility.stringHasValue(remarks))
        {
            String[] remarkLines = remarks.split(System.getProperty("line.separator"));
            for (String remarkLine : remarkLines)
            {
                topLevelClass.addJavaDocLine(" * " + remarkLine);
            }
        }

        //        topLevelClass.addJavaDocLine(" * ");
        StringBuilder sb = new StringBuilder();
        sb.append(" * ");
        sb.append(introspectedTable.getFullyQualifiedTable());
        topLevelClass.addJavaDocLine(sb.toString());
//        topLevelClass.addJavaDocLine(" *");
//        addJavadocTag(topLevelClass, false);
        topLevelClass.addJavaDocLine(" */");

    }

}

OverIsMergeablePlugin

該插件用於解決屢次執行generate，生成的xml只能追加沒法覆蓋問題。通常狀況下不須要屢次執行generate操做。

package com.zqq.plugins;

import org.mybatis.generator.api.GeneratedXmlFile;
import org.mybatis.generator.api.IntrospectedTable;
import org.mybatis.generator.api.PluginAdapter;

import java.lang.reflect.Field;
import java.util.List;

/**
 * 解決生成xml沒法覆蓋只能追加的問題
 *
 * @author 
 * @version v1.0
 * @since 13:42 2019/1/9
 */
public class OverIsMergeablePlugin extends PluginAdapter
{
    @Override
    public boolean validate(List<String> warnings)
    {
        return true;
    }

    @Override
    public boolean sqlMapGenerated(GeneratedXmlFile sqlMap, IntrospectedTable introspectedTable)
    {
        try
        {
            Field field = sqlMap.getClass().getDeclaredField("isMergeable");
            field.setAccessible(true);
            field.setBoolean(sqlMap, false);
        } catch (Exception e)
        {
            e.printStackTrace();
        }
        return true;
    }
}

生成

MBG啓動能夠直接經過mybatis-generator:generate命令執行，也能夠直接經過main方法執行。下面給出main方法執行的方式。

package com.zqq;

import org.mybatis.generator.api.MyBatisGenerator;
import org.mybatis.generator.config.Configuration;
import org.mybatis.generator.config.xml.ConfigurationParser;
import org.mybatis.generator.exception.InvalidConfigurationException;
import org.mybatis.generator.exception.XMLParserException;
import org.mybatis.generator.internal.DefaultShellCallback;

import java.io.File;
import java.io.IOException;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

public class App
{


    public static void main(String[] args)
    {
        List<String> warnings = new ArrayList<String>();
        try
        {
            // true:生成的文件覆蓋以前的
            boolean overwrite = true;
            // 讀取配置,構造 Configuration 對象.
            // 若是不想使用配置文件的話,也能夠直接來 new Configuration(),而後給相應屬性賦值.
            File configFile = new File("./src/main/resources/generatorConfig.xml");
            ConfigurationParser cp = new ConfigurationParser(warnings);
            // Configuration config = cp.parseConfiguration(App.class.getClassLoader().getResourceAsStream("generatorConfig.xml"));
            Configuration config = cp.parseConfiguration(configFile);
            DefaultShellCallback callback = new DefaultShellCallback(overwrite);
            MyBatisGenerator myBatisGenerator = new MyBatisGenerator(config, callback, warnings);
            myBatisGenerator.generate(null);
        } catch (SQLException e)
        {
            e.printStackTrace();
        } catch (IOException e)
        {
            e.printStackTrace();
        } catch (InterruptedException e)
        {
            e.printStackTrace();
        } catch (InvalidConfigurationException e)
        {
            e.printStackTrace();
        } catch (XMLParserException e)
        {
            e.printStackTrace();
        }
    }

}

項目工程文件

MyBatisGeneratorDemo

參考資料
Mybatis Generator的model生成中文註釋,支持oracle和mysql

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