Mybatis-Generator 可自动生成Model、Dao、Mapper代码,但其自带生成的代码存在以下问题：
生成的注释不是我们想要的,我们期望的是根据数据库表、字段生成不同的注释；
分页代码生成缺失，每个公司的分页方式不同，尤其是老久项目或已发布API，不能随意变动，那么如何自适应分页代码生成；
Mapper.xml没有group by相关代码生成；
重复生成代码时，Mapper.xml并不是覆盖原代码，而是对内容进行了追加；
序列化，mybatis-generator内置了SerializablePlugin，但仅对Model，并没有对 Example序列化，在一些开发中是不够的；
对Service Layer代码没有生成。
实际上，mybatis-generator提供了PluginAdapter供我们来继承，进行个性化的一些扩展(Plugin的相关内容是阅读本文的前置条件）如果不熟悉的同学，请自行补充，本文不对其进行相关介绍)。同时，本文不可能涵盖所有业务所需的扩展点，但是基本样板已有，可参考本文代码继续进行扩展。
一、注释的自定义生成根据数据库表或字段的COMMENT生成注释。@Date 生成的时间可根据需要自己定义格式。
package run.override; import java.util.Date; import java.util.Properties; import org.mybatis.generator.api.IntrospectedColumn; import org.mybatis.generator.api.IntrospectedTable; import org.mybatis.generator.api.dom.java.CompilationUnit; import org.mybatis.generator.api.dom.java.Field; import org.mybatis.generator.api.dom.java.InnerClass; import org.mybatis.generator.api.dom.java.InnerEnum; import org.mybatis.generator.api.dom.java.JavaElement; import org.mybatis.generator.api.dom.java.Method; import org.mybatis.generator.api.dom.java.Parameter; import org.mybatis.generator.api.dom.xml.XmlElement; import org.mybatis.generator.internal.DefaultCommentGenerator; import org.mybatis.generator.internal.util.StringUtility; /** * Comment Generator * @ClassName CommentGenerator * @Description * @author Marvis */ public class CommentGenerator extends DefaultCommentGenerator { private Properties properties; private boolean suppressDate; private boolean suppressAllComments; public CommentGenerator() { this.properties = new Properties(); this.suppressDate = false; this.suppressAllComments = false; } public void addJavaFileComment(CompilationUnit compilationUnit) { compilationUnit.addFileCommentLine("/*** copyright (c) 2019 Marvis ***/"); } /** * XML file Comment */ public void addComment(XmlElement xmlElement) { if (this.suppressAllComments) { return; } } public void addRootComment(XmlElement rootElement) { } public void addConfigurationProperties(Properties properties) { this.properties.putAll(properties); this.suppressDate = StringUtility.isTrue(properties.getProperty("suppressDate")); this.suppressAllComments = StringUtility.isTrue(properties.getProperty("suppressAllComments")); } protected void addJavadocTag(JavaElement javaElement, boolean markAsDoNotDelete) { StringBuilder sb = new StringBuilder(); sb.append(" * "); sb.append("@date"); String s = getDateString(); if (s != null) { sb.append(' '); sb.append(s); } javaElement.addJavaDocLine(sb.toString()); } protected String getDateString() { if (this.suppressDate) { return null; } return new Date().toString(); } /** * Comment of Example inner class(GeneratedCriteria ,Criterion) */ public void addClassComment(InnerClass innerClass, IntrospectedTable introspectedTable) { if (this.suppressAllComments) { return; } innerClass.addJavaDocLine("/**"); innerClass.addJavaDocLine(" * " + introspectedTable.getFullyQualifiedTable().getDomainObjectName()+ "<p/>"); innerClass.addJavaDocLine(" * " + introspectedTable.getFullyQualifiedTable().toString()); addJavadocTag(innerClass, false); innerClass.addJavaDocLine(" */"); } public void addEnumComment(InnerEnum innerEnum, IntrospectedTable introspectedTable) { if (this.suppressAllComments) { return; } StringBuilder sb = new StringBuilder(); innerEnum.addJavaDocLine("/**"); innerEnum.addJavaDocLine(" * " + introspectedTable.getFullyQualifiedTable().getAlias()+ "<p/>"); innerEnum.addJavaDocLine(" * " + introspectedTable.getFullyQualifiedTable()); innerEnum.addJavaDocLine(sb.toString()); addJavadocTag(innerEnum, false); innerEnum.addJavaDocLine(" */"); } /** * entity filed Comment */ public void addFieldComment(Field field, IntrospectedTable introspectedTable, IntrospectedColumn introspectedColumn) { if (this.suppressAllComments) { return; } // if(introspectedColumn.getRemarks() != null && !introspectedColumn.getRemarks().trim().equals("")) field.addJavaDocLine("/**"); field.addJavaDocLine(" * " + introspectedColumn.getRemarks()); field.addJavaDocLine(" * @author " ); field.addJavaDocLine(" * @date " + getDateString() ); field.addJavaDocLine(" * @return"); field.addJavaDocLine(" */"); } /** * Comment of EXample filed */ public void addFieldComment(Field field, IntrospectedTable introspectedTable) { if (this.suppressAllComments) { return; } field.addJavaDocLine("/**"); addJavadocTag(field, false); field.addJavaDocLine(" */"); } /** * Comment of Example method */ public void addGeneralMethodComment(Method method, IntrospectedTable introspectedTable) { if (this.suppressAllComments) { return; } } /** * * entity Getter Comment */ public void addGetterComment(Method method, IntrospectedTable introspectedTable, IntrospectedColumn introspectedColumn) { if (this.suppressAllComments) { return; } method.addJavaDocLine("/**"); method.addJavaDocLine(" * @return " + introspectedTable.getFullyQualifiedTable().getAlias() + " : " + introspectedColumn.getRemarks()); method.addJavaDocLine(" */"); } public void addSetterComment(Method method, IntrospectedTable introspectedTable, IntrospectedColumn introspectedColumn) { if (this.suppressAllComments) { return; } StringBuilder sb = new StringBuilder(); method.addJavaDocLine("/**"); Parameter parm = (Parameter) method.getParameters().get(0); sb.append(" * @param "); sb.append(parm.getName()); sb.append(" : "); sb.append(introspectedColumn.getRemarks()); method.addJavaDocLine(sb.toString()); method.addJavaDocLine(" */"); } /** * Comment of Example inner class(Criteria) */ public void addClassComment(InnerClass innerClass, IntrospectedTable introspectedTable, boolean markAsDoNotDelete) { if (this.suppressAllComments) { return; } innerClass.addJavaDocLine("/**"); innerClass.addJavaDocLine(" * " + introspectedTable.getFullyQualifiedTable().getAlias()+ "<p/>"); innerClass.addJavaDocLine(" * " + introspectedTable.getFullyQualifiedTable().toString()); addJavadocTag(innerClass, markAsDoNotDelete); innerClass.addJavaDocLine(" */"); }