MyBatis逆向工程生成配置 generator (生成pojo、mapper.xml、mapper.java)

MyBatis逆向工程生成

mybatis需要程序员自己编写sql语句，mybatis官方提供逆向工程，可以针对单表自动生成mybatis执行所需要的代码（mapper.java、mapper.xml、pojo…），可以让程序员将更多的精力放在繁杂的业务逻辑上。

企业实际开发中，常用的逆向工程方式：由数据库的表生成java代码。

​ 之所以强调单表两个字，是因为Mybatis逆向工程生成的Mapper所进行的操作都是针对单表的，也许你可能会觉得那这就有点鸡肋了，但是在大型项目中，很少有复杂的多表关联查询，所以作用还是很大的。

介绍

MyBatis生成器（MBG）是MyBatis MyBatis 和iBATIS的代码生成器。它将为MyBatis的所有版本以及版本2.2.0之后的iBATIS生成代码。它将内省一个数据库表（或多个表），并将生成可用于访问表的工件。这减轻了设置对象和配置文件以与数据库表进行交互的麻烦。MBG试图对简单CRUD（创建，检索，更新，删除）的大部分数据库操作产生重大影响。您仍将需要手工编写SQL和对象代码以进行联接查询或存储过程。

官方仓库 官方文档

开始上代码

目录总体结构：

主要文件

pom依赖

 		<!--mybatis依赖-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.2</version>
        </dependency>

        <!--逆向工程生成-->
        <dependency>
            <groupId>org.mybatis.generator</groupId>
            <artifactId>mybatis-generator-maven-plugin</artifactId>
            <version>1.3.5</version>
        </dependency>

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

分页配置类

MySQLLimitPlugin.java

package com.meng.device.util;

import org.mybatis.generator.api.GeneratedJavaFile;
import org.mybatis.generator.api.GeneratedXmlFile;
import org.mybatis.generator.api.IntrospectedTable;
import org.mybatis.generator.api.PluginAdapter;
import org.mybatis.generator.api.dom.java.*;
import org.mybatis.generator.api.dom.xml.Attribute;
import org.mybatis.generator.api.dom.xml.Document;
import org.mybatis.generator.api.dom.xml.TextElement;
import org.mybatis.generator.api.dom.xml.XmlElement;
import org.mybatis.generator.codegen.XmlConstants;
import org.mybatis.generator.config.PropertyRegistry;

import java.io.File;
import java.util.ArrayList;
import java.util.List;
import java.util.StringTokenizer;

/**
 * Created by meng
 */
public class MySQLLimitPlugin extends PluginAdapter {

    private static String XMLFILE_POSTFIX = "Ext";

    private static String JAVAFILE_POTFIX = "Ext";

    private static String ANNOTATION_RESOURCE = "javax.annotation.Resource";

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

    /**
     * 为每个Example类添加limit和offset属性已经set、get方法
     */
    @Override
    public boolean modelExampleClassGenerated(TopLevelClass topLevelClass, IntrospectedTable introspectedTable) {

        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;
    }

    // 添删改Document的sql语句及属性
    @Override
    public boolean sqlMapDocumentGenerated(Document document,
                                           IntrospectedTable introspectedTable) {

        XmlElement parentElement = document.getRootElement();

//        updateDocumentNameSpace(introspectedTable, parentElement);

//        moveDocumentInsertSql(parentElement);
//
//        updateDocumentInsertSelective(parentElement);
//
//        moveDocumentUpdateByPrimaryKeySql(parentElement);
//
//        generateMysqlPageSql(parentElement, introspectedTable);
//
//        generateDataAccessSql(parentElement);

        return super.sqlMapDocumentGenerated(document, introspectedTable);
    }

    private void updateDocumentNameSpace(IntrospectedTable introspectedTable,
                                         XmlElement parentElement) {
        Attribute namespaceAttribute = null;
        for (Attribute attribute : parentElement.getAttributes()) {
            if (attribute.getName().equals("namespace")) {
                namespaceAttribute = attribute;
            }
        }
        parentElement.getAttributes().remove(namespaceAttribute);
        parentElement.getAttributes().add(
                new Attribute("namespace", introspectedTable
                        .getMyBatis3JavaMapperType() + JAVAFILE_POTFIX));
    }

    /**
     * 为Mapper.xml的selectByExample添加limit
     */
    @Override
    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 TextElement("limit ${offset}, ${limit}"));
        ifLimitNotNullElement.addElement(ifOffsetNotNullElement);

        XmlElement ifOffsetNullElement = new XmlElement("if");
        ifOffsetNullElement.addAttribute(new Attribute("test", "offset == null"));
        ifOffsetNullElement.addElement(new TextElement("limit ${limit}"));
        ifLimitNotNullElement.addElement(ifOffsetNullElement);

        element.addElement(ifLimitNotNullElement);

        return true;
    }

    // 生成XXExt.xml
    @Override
    public List<GeneratedXmlFile> contextGenerateAdditionalXmlFiles(
            IntrospectedTable introspectedTable) {

        String[] splitFile = introspectedTable.getMyBatis3XmlMapperFileName()
                .split("\\.");
        String fileNameExt = null;
        if (splitFile[0] != null) {
            fileNameExt = splitFile[0] + XMLFILE_POSTFIX + ".xml";
        }

        if (isExistExtFile(context.getSqlMapGeneratorConfiguration()
                        .getTargetProject(),
                introspectedTable.getMyBatis3XmlMapperPackage(), fileNameExt)) {
            return super.contextGenerateAdditionalXmlFiles(introspectedTable);
        }

        Document document = new Document(
                XmlConstants.MYBATIS3_MAPPER_PUBLIC_ID,
                XmlConstants.MYBATIS3_MAPPER_SYSTEM_ID);

        XmlElement root = new XmlElement("mapper");
        document.setRootElement(root);
        String namespace = introspectedTable.getMyBatis3SqlMapNamespace()
                + XMLFILE_POSTFIX;
        root.addAttribute(new Attribute("namespace", namespace));

        GeneratedXmlFile gxf = new GeneratedXmlFile(document, fileNameExt,
                introspectedTable.getMyBatis3XmlMapperPackage(), context
                .getSqlMapGeneratorConfiguration().getTargetProject(),
                false, context.getXmlFormatter());

        List<GeneratedXmlFile> answer = new ArrayList<GeneratedXmlFile>(1);
        answer.add(gxf);

        return answer;
    }

    // 生成XXExt.java
    @Override
    public List<GeneratedJavaFile> contextGenerateAdditionalJavaFiles(
            IntrospectedTable introspectedTable) {

        FullyQualifiedJavaType type = new FullyQualifiedJavaType(
                introspectedTable.getMyBatis3JavaMapperType() + JAVAFILE_POTFIX);
        Interface interfaze = new Interface(type);
        interfaze.setVisibility(JavaVisibility.PUBLIC);
        context.getCommentGenerator().addJavaFileComment(interfaze);

        FullyQualifiedJavaType baseInterfaze = new FullyQualifiedJavaType(
                introspectedTable.getMyBatis3JavaMapperType());
        interfaze.addSuperInterface(baseInterfaze);

        FullyQualifiedJavaType annotation = new FullyQualifiedJavaType(
                ANNOTATION_RESOURCE);
        interfaze.addAnnotation("@Resource");
        interfaze.addImportedType(annotation);

        CompilationUnit compilationUnits = interfaze;
        GeneratedJavaFile generatedJavaFile = new GeneratedJavaFile(
                compilationUnits,
                context.getJavaModelGeneratorConfiguration().getTargetProject(),
                context.getProperty(PropertyRegistry.CONTEXT_JAVA_FILE_ENCODING),
                context.getJavaFormatter());

        if (isExistExtFile(generatedJavaFile.getTargetProject(),
                generatedJavaFile.getTargetPackage(),
                generatedJavaFile.getFileName())) {
            return super.contextGenerateAdditionalJavaFiles(introspectedTable);
        }
        List<GeneratedJavaFile> generatedJavaFiles = new ArrayList<GeneratedJavaFile>(
                1);
        generatedJavaFile.getFileName();
        generatedJavaFiles.add(generatedJavaFile);
        return generatedJavaFiles;
    }

    private boolean isExistExtFile(String targetProject, String targetPackage,
                                   String fileName) {

        File project = new File(targetProject);
        if (!project.isDirectory()) {
            return true;
        }

        StringBuilder sb = new StringBuilder();
        StringTokenizer st = new StringTokenizer(targetPackage, ".");
        while (st.hasMoreTokens()) {
            sb.append(st.nextToken());
            sb.append(File.separatorChar);
        }

        File directory = new File(project, sb.toString());
        if (!directory.isDirectory()) {
            boolean rc = directory.mkdirs();
            if (!rc) {
                return true;
            }
        }

        File testFile = new File(directory, fileName);
        if (testFile.exists()) {
            return true;
        } else {
            return false;
        }
    }
}

主要配置 映射哪些表也是在这个里面配置（每次只需要修改这个）

generatorConfig_local.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>
    <!--<classPathEntry location="C:/Project/DB/mysql-connector-java-5.1.40-bin.jar"/>-->
    <context id="base_resource" targetRuntime="MyBatis3">

        <property name="useActualColumnNames" value="false"/>

        <plugin type="com.meng.device.util.MySQLLimitPlugin"/>

        <commentGenerator>
            <property name="suppressDate" value="true"/>
        </commentGenerator>

        <jdbcConnection driverClass="com.mysql.jdbc.Driver"
                        connectionURL="jdbc:mysql://127.0.0.1:3306/springboot?useUnicode=true&amp;characterEncoding=UTF-8"
                        userId="root"
                        password="root">
        </jdbcConnection>

        <!-- targetProject:生成PO类的位置  根据自己项目位置更改 -->
        <javaModelGenerator targetPackage="com.meng.device.dao"
                            targetProject="E:\project\IdeaProjects\device\src\main\java">
            <!-- enableSubPackages:是否让schema作为包的后缀 -->
            <property name="enableSubPackages" value="true"/>
            <!-- 从数据库返回的值被清理前后的空格 -->
            <property name="trimStrings" value="true"/>
        </javaModelGenerator>

        <!-- targetProject:mapper映射文件生成的位置  根据自己项目位置更改-->
        <sqlMapGenerator targetPackage="com.meng.device.mapper"
                         targetProject="E:\project\IdeaProjects\device\src\main\resources">
            <!-- enableSubPackages:是否让schema作为包的后缀 -->
            <property name="enableSubPackages" value="true"/>
        </sqlMapGenerator>

        <!-- targetPackage：mapper接口生成的位置 根据自己项目位置更改-->
        <javaClientGenerator type="XMLMAPPER" targetPackage="com.meng.device.mapper"
                             targetProject="E:\project\IdeaProjects\device\src\main\java">
            <!-- enableSubPackages:是否让schema作为包的后缀 -->
            <property name="enableSubPackages" value="true"/>
        </javaClientGenerator>

        <!-- 指定数据库表 -->
        <!--映射表名  多个表可以写多个-->
        <!--<table tableName="表名" domainObjectName="实体名">
            <property name="useActualColumnNames" value="false"/>
            <generatedKey column="id" sqlStatement="MySql" identity="true"/>
        </table>-->

        <!-- 有些表的字段需要指定java类型

         <table schema=""tableName="">

            <columnOverridecolumn="" javaType="" />

        </table> -->

    </context>
</generatorConfiguration>

启动类

Generator.java

package com.meng.device.generator;

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

import java.util.ArrayList;
import java.util.List;

/**
 * @description: mybatis逆向工程    自动生成mybatis-Mapper工具
 * @author: meng
 * @create: 2019-09-11 08:58
 **/
public class Generator {

    /**
     * 目前在系统中本地环境使用local来配置mapper生成规则
     */
    //指定逆向工程配置文件
    private static final String config_url = "generatorConfig_local.xml";

    public void generator() throws Exception {
        List<String> warnings = new ArrayList<String>();
        ConfigurationParser cp = new ConfigurationParser(warnings);

        Configuration config = cp.parseConfiguration(Generator.class.getClassLoader().getResourceAsStream(config_url));

        DefaultShellCallback callback = new DefaultShellCallback(true);
        MyBatisGenerator myBatisGenerator = new MyBatisGenerator(config, callback, warnings);
        myBatisGenerator.generate(null);
    }

    /**
     * 主函数
     */
    public static void main(String[] args) throws Exception {
        try {
            Generator generatorSqlmap = new Generator();
            generatorSqlmap.generator();
        } catch (Exception e) {
            e.printStackTrace();
        }
        System.out.println("generator 执行成功!");
    }

}

配置完成后执行Generator类中主函数