用 mybatis-generator 通过 main 方法 自动生成代码 并 在字段上加注释

mybatis-generator 是我们常用的生成代码的工具,一般都是在开发工具上配置启动生成，这种方法比较麻烦；而今天我们通过一个工具类自动生成，方便、快捷，不会因为开发环境差异，而影响使用。

1、generatorConfig.xml 配置文件处理

<?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>

    <context id="generatorTables" targetRuntime="MyBatis3">

        <!-- commentGenerator 自动生成注释 这里是一个工具类注意目录！！！  -->
        <commentGenerator type="com.jy.utils.MyCommentGenerator">
        </commentGenerator>

        <jdbcConnection driverClass="com.mysql.jdbc.Driver"
                        connectionURL="jdbc:mysql://180.176.76.118:3306/nandao" userId="root"
                        password="root">
        </jdbcConnection>

        <!-- 默认false，把JDBC DECIMAL 和 NUMERIC 类型解析为 Integer true， 把 JDBC DECIMAL 和 NUMERIC 类型解析为java.math.BigDecimal -->
        <javaTypeResolver>
            <property name="forceBigDecimals" value="false" />
        </javaTypeResolver>

        <!-- javaModelGenerator是模型的生成信息，这里将指定这些Java model类的生成路径； -->
        <javaModelGenerator targetPackage="com.jy.po"
                            targetProject="src/main/java">
            <property name="enableSubPackages" value="true" />
            <property name="trimStrings" value="true" />
        </javaModelGenerator>

        <!-- sqlMapGenerator是mybatis 的sqlMapper XML文件的生成信息，包括生成路径等； 先生成xml，在生成java -->
        <sqlMapGenerator targetPackage="com.jy.mapper"
                         targetProject="src/main/java">
            <property name="enableSubPackages" value="true" />
        </sqlMapGenerator>

        <!-- javaClientGenerator是应用接口的生成信息； -->
        <javaClientGenerator type="XMLMAPPER"
                             targetPackage="com.jy.dao" targetProject="src/main/java">
            <property name="enableSubPackages" value="true" />
        </javaClientGenerator>

        <!-- table 是用户指定的被生成相关信息的表，它必须在指定的jdbc连接中已经被建立。是否可以多个 -->
        <table tableName="student_test" domainObjectName="StudentTest"
               enableCountByExample="false" enableUpdateByExample="false"
               enableDeleteByExample="false" enableSelectByExample="false"
               selectByExampleQueryId="true"></table>

    </context>
</generatorConfiguration>

2、MyCommentGenerator 工具类内容

package com.jy.utils;

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;

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

/**
* @Title: 自定义comment生成器.
* @author jxx
* @date  2018/3/20
* @time 16:10
*/
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());
    }

    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.
     */
    public void addComment(XmlElement xmlElement) {
        return;
    }

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

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

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

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

 
    protected String getDateString() {
        String result = null;
        if (!suppressDate) {
            result = currentDateStr;
        }
        return result;
    }

    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(" */");
    }

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

        StringBuilder sb = new StringBuilder();

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

    public void addFieldComment(Field field, IntrospectedTable introspectedTable,
                                IntrospectedColumn introspectedColumn) {
        if (suppressAllComments) {
            return;
        }

        StringBuilder sb = new StringBuilder();

        if(!StringUtils.isEmpty(introspectedColumn.getRemarks())){
            field.addJavaDocLine("/**");
            sb.append(" * ");
            sb.append(introspectedColumn.getRemarks());
            field.addJavaDocLine(sb.toString());
            field.addJavaDocLine(" */");
        }
    }

    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(" */");
    }

   
    public void addGeneralMethodComment(Method method, IntrospectedTable introspectedTable) {
        if (suppressAllComments) {
            return;
        }
     
    }

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

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

    }

    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);

        innerClass.addJavaDocLine(" */");
    }
}

3、重要的工具类：

package com.jy.utils;

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.IOException;
import java.io.InputStream;
import java.net.URISyntaxException;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

/**
 * @Title:
 * main方法启动后自动生成数据库表对应的实体和mapper文件,
 * 使用该工具类的前将数据库的表字段注释加上，这样才能生成对应的注释
 * @date  2020/4/20
 */
public class GenerateDataTableFile {
    public static void main(String[] args) throws URISyntaxException {
        try {
            List<String> warnings = new ArrayList<>();
            boolean overwrite = true;
            //从配置文件中获取数据库连接,以及生成的类路径
            ClassLoader classloader = Thread.currentThread().getContextClassLoader();
            InputStream is = classloader.getResourceAsStream("config/mybatis/generatorConfig.xml");
            ConfigurationParser cp = new ConfigurationParser(warnings);
            Configuration config = cp.parseConfiguration(is);
            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();
        }
    }
}

到这来就结束了，使用不明白的地方可以留言！！！