02.25 代码演示Mybatis-Generator 扩展自定义生成（上）

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：

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，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。

<code>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()+ "

"); 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()+ "

"); 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()+ "

"); innerClass.addJavaDocLine(" * " + introspectedTable.getFullyQualifiedTable().toString()); addJavadocTag(innerClass, markAsDoNotDelete); innerClass.addJavaDocLine(" */"); }/<code>

Model 类注释(表的描述): MySQL。

1）EntityCommentPlugin

<code>package run.override.model;import java.sql.Connection;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;import java.util.Date;import java.util.List;import org.mybatis.generator.api.FullyQualifiedTable;import org.mybatis.generator.api.IntrospectedTable;import org.mybatis.generator.api.PluginAdapter;import org.mybatis.generator.api.dom.java.TopLevelClass;import org.mybatis.generator.internal.JDBCConnectionFactory;import org.mybatis.generator.internal.util.StringUtility;/** * Comment of Entity,only support MySQL * @ClassName CommentPlugin * @Description * @author Marvis */public class EntityCommentPlugin extends PluginAdapter { @Override public boolean modelBaseRecordClassGenerated(TopLevelClass topLevelClass, IntrospectedTable introspectedTable) { addModelClassComment(topLevelClass, introspectedTable); return super.modelBaseRecordClassGenerated(topLevelClass, introspectedTable); } @Override public boolean modelRecordWithBLOBsClassGenerated(TopLevelClass topLevelClass, IntrospectedTable introspectedTable) { addModelClassComment(topLevelClass, introspectedTable); return super.modelRecordWithBLOBsClassGenerated(topLevelClass, introspectedTable); } protected void addModelClassComment(TopLevelClass topLevelClass, IntrospectedTable introspectedTable) { FullyQualifiedTable table = introspectedTable.getFullyQualifiedTable(); String tableComment = getTableComment(table); topLevelClass.addJavaDocLine("/**"); if(StringUtility.stringHasValue(tableComment)) topLevelClass.addJavaDocLine(" * " + tableComment + "

"); topLevelClass.addJavaDocLine(" * " + table.toString() + "

"); topLevelClass.addJavaDocLine(" * @date " + new Date().toString()); topLevelClass.addJavaDocLine(" *"); topLevelClass.addJavaDocLine(" */"); } /** * @author Marvis * @date Jul 13, 2017 4:39:52 PM * @param table */ private String getTableComment(FullyQualifiedTable table) { String tableComment = ""; Connection connection = null; Statement statement = null; ResultSet rs = null; try { JDBCConnectionFactory jdbc = new JDBCConnectionFactory(context.getJdbcConnectionConfiguration()); connection = jdbc.getConnection(); statement = connection.createStatement(); rs = statement.executeQuery("SHOW CREATE TABLE " + table.getIntrospectedTableName()); if (rs != null && rs.next()) { String createDDL = rs.getString(2); int index = createDDL.indexOf("COMMENT='"); if (index < 0) { tableComment = ""; } else { tableComment = createDDL.substring(index + 9); tableComment = tableComment.substring(0, tableComment.length() - 1); } } } catch (SQLException e) { } finally { closeConnection(connection, statement, rs); } return tableComment; } /** * * @author Marvis * @date Jul 13, 2017 4:45:26 PM * @param connection * @param statement * @param rs */ private void closeConnection(Connection connection, Statement statement, ResultSet rs) { try { if (null != rs) rs.close(); } catch (SQLException e) { e.printStackTrace(); } finally { try { if (statement != null) statement.close(); } catch (Exception e) { e.printStackTrace(); } finally { try { if (connection != null) connection.close(); } catch (SQLException e) { e.printStackTrace(); } } } } /** * This plugin is always valid - no properties are required */ @Override public boolean validate(List<string> warnings) { return true; }}/<string>/<code>

二、分页和分组代码生成

这里，我对Dao Model进行了通用方法的抽取，建立通用基类。同时，对其进行了一些扩展，增加分页和分组。

先对基类进行介绍。

1）BaseMapper

<code>package cn.xxx.core.base.dao;import java.util.List;import org.apache.ibatis.annotations.Param;public interface BaseMapper { long countByExample(Example example); int deleteByExample(Example example); int deleteByPrimaryKey(ID id); int insert(T record); int insertSelective(T record); List selectByExample(Example example); T selectByPrimaryKey(ID id); int updateByExampleSelective(@Param("record") T record, @Param("example") Example example); int updateByExample(@Param("record") T record, @Param("example") Example example); int updateByPrimaryKeySelective(T record); int updateByPrimaryKey(T record);}/<code>

2）BaseExample

<code>package cn.xxx.core.base.model;/** * BaseExample 基类 * @ClassName BaseExample * @Description 增加分页参数 * @author Marvis * @date Jul 31, 2017 11:26:53 AM */public abstract class BaseExample { protected PageInfo pageInfo; protected String groupByClause; public PageInfo getPageInfo() { return pageInfo; } public void setPageInfo(PageInfo pageInfo) { this.pageInfo = pageInfo; } public String getGroupByClause() { return groupByClause; } public void setGroupByClause(String groupByClause) { this.groupByClause = groupByClause; } }/<code>

3）PageInfo

<code>package cn.xxx.core.base.model;import com.fasterxml.jackson.annotation.JsonIgnore;/** * 分页查询参数类 * * @author * */public class PageInfo { public static final int Default_PageSize = 20; // 当前页码 protected int currentPage = 1; // 总页数 protected int totalPage; // 总记录数 protected int totalCount; // 每页条数 protected int pageSize = Default_PageSize; // 开始 protected int pageBegin = 0; // 结束 protected int pageEnd = 20; /** * bean起始坐标(不包含) */ private Integer pageBeginId = null; public static final String PageQuery_classname = "pageInfo"; /** * 将分布参数传入处理，最终计算出当前页码PageQuery_currPage，开始坐标PageQuery_star， * 结束坐标PageQuery_end，总页数PageQuery_Psize *

* 页数从1开始计数 * * @param totalCount * 记录总数 * @param pageSize * 每页显示个数 * @param currentPage * 当前页码 */ public void setPageParams(int totalCount, int pageSize, int currentPage) { this.totalPage = pageSize == 0 ? 1 : (int) Math.ceil((double) totalCount / (double) pageSize); this.totalCount = totalCount; this.pageSize = pageSize; this.currentPage = currentPage; float Psize_l = totalCount / (float) (this.pageSize); if (currentPage < 2) { currentPage = 1; pageBegin = 0; } else if (currentPage > Psize_l) { if (Psize_l == 0) { currentPage = 1; } else { currentPage = (int) Math.ceil(Psize_l); } pageBegin = (currentPage - 1) * this.pageSize; } else { pageBegin = (currentPage - 1) * this.pageSize; } pageSize = (int) Math.ceil(Psize_l); this.pageEnd = currentPage * this.pageSize; if (this.currentPage <= 0 || this.currentPage > this.totalPage) this.pageSize = 0; } /** * 将分布参数传入处理，最终计算出当前页码PageQuery_currPage，开始坐标PageQuery_star， * 结束坐标PageQuery_end，总页数PageQuery_Psize * * @param infoCount * 记录总数 */ public void setPageParams(int totalCount) { this.setPageParams(totalCount, this.pageSize, this.currentPage); } @Override public String toString() { return "PageInfo [currentPage=" + currentPage + ", totalPage=" + totalPage + ", totalCount=" + totalCount + ", pageSize=" + pageSize + ", pageBegin=" + pageBegin + ", pageEnd=" + pageEnd + ", pageBeginId=" + pageBeginId + "]"; } public int getCurrentPage() { return currentPage; } public int getTotalPage() { return totalPage; } public int getTotalCount() { return totalCount; } /** * 每页显示个数 */ public int getPageSize() { return pageSize; } @JsonIgnore public int getPageBegin() { return pageBegin; } @JsonIgnore public int getPageEnd() { return pageEnd; } /** * bean起始id(不包含) */ @JsonIgnore public Integer getPageBeginId() { return pageBeginId; } /** * 请求页 */ public void setCurrentPage(int currentPage) { this.currentPage = currentPage; } /** * 每页显示个数 */ public void setPageSize(int pageSize) { this.pageSize = pageSize; }}/<code>

4）PaginationPlugin

分页扩展。并且Example继承BaseExample。

<code>package run.override.pagination;import org.mybatis.generator.api.IntrospectedTable;import org.mybatis.generator.api.dom.java.FullyQualifiedJavaType;import org.mybatis.generator.api.dom.java.TopLevelClass;import org.mybatis.generator.api.dom.xml.Attribute;import org.mybatis.generator.api.dom.xml.TextElement;import org.mybatis.generator.api.dom.xml.XmlElement;import run.override.mapper.SqlMapIsMergeablePlugin;import run.override.proxyFactory.FullyQualifiedJavaTypeProxyFactory;public class PaginationPlugin extends SqlMapIsMergeablePlugin { @Override public boolean modelExampleClassGenerated(TopLevelClass topLevelClass, IntrospectedTable introspectedTable) { FullyQualifiedJavaType baseExampleType = FullyQualifiedJavaTypeProxyFactory.getBaseExampleInstance(); topLevelClass.setSuperClass(baseExampleType); topLevelClass.addImportedType(baseExampleType); return super.modelExampleClassGenerated(topLevelClass, introspectedTable); } @Override public boolean sqlMapSelectByExampleWithBLOBsElementGenerated(XmlElement element, IntrospectedTable introspectedTable) { XmlElement isNotNullElement1 = new XmlElement("if"); isNotNullElement1.addAttribute(new Attribute("test", "groupByClause != null")); isNotNullElement1.addElement(new TextElement("group by ${groupByClause}")); element.addElement(5, isNotNullElement1); XmlElement isNotNullElement = new XmlElement("if"); isNotNullElement.addAttribute(new Attribute("test", "pageInfo != null")); isNotNullElement.addElement(new TextElement("limit #{pageInfo.pageBegin} , #{pageInfo.pageSize}")); element.addElement(isNotNullElement); return super.sqlMapUpdateByExampleWithBLOBsElementGenerated(element, introspectedTable); } @Override public boolean sqlMapSelectByExampleWithoutBLOBsElementGenerated(XmlElement element, IntrospectedTable introspectedTable) { XmlElement isNotNullElement1 = new XmlElement("if"); isNotNullElement1.addAttribute(new Attribute("test", "groupByClause != null")); isNotNullElement1.addElement(new TextElement("group by ${groupByClause}")); element.addElement(5, isNotNullElement1); XmlElement isNotNullElement = new XmlElement("if"); isNotNullElement.addAttribute(new Attribute("test", "pageInfo != null")); isNotNullElement.addElement(new TextElement("limit #{pageInfo.pageBegin} , #{pageInfo.pageSize}")); element.addElement(isNotNullElement); return super.sqlMapUpdateByExampleWithoutBLOBsElementGenerated(element, introspectedTable); } @Override public boolean sqlMapCountByExampleElementGenerated(XmlElement element, IntrospectedTable introspectedTable) { XmlElement answer = new XmlElement("select"); String fqjt = introspectedTable.getExampleType(); answer.addAttribute(new Attribute("id", introspectedTable.getCountByExampleStatementId())); answer.addAttribute(new Attribute("parameterType", fqjt)); answer.addAttribute(new Attribute("resultType", "java.lang.Integer")); this.context.getCommentGenerator().addComment(answer); StringBuilder sb = new StringBuilder(); sb.append("select count(1) from "); sb.append(introspectedTable.getAliasedFullyQualifiedTableNameAtRuntime()); XmlElement ifElement = new XmlElement("if"); ifElement.addAttribute(new Attribute("test", "_parameter != null")); XmlElement includeElement = new XmlElement("include"); includeElement.addAttribute(new Attribute("refid", introspectedTable.getExampleWhereClauseId())); ifElement.addElement(includeElement); element.getElements().clear(); element.getElements().add(new TextElement(sb.toString())); element.getElements().add(ifElement); return super.sqlMapUpdateByExampleWithoutBLOBsElementGenerated(element, introspectedTable); }}/<code>

<code>package run.override.proxyFactory;import org.mybatis.generator.api.dom.java.FullyQualifiedJavaType;public class FullyQualifiedJavaTypeProxyFactory extends FullyQualifiedJavaType{ private static FullyQualifiedJavaType pageInfoInstance = new FullyQualifiedJavaType("cn.xxx.core.base.model.PageInfo"); private static FullyQualifiedJavaType baseExampleInstance = new FullyQualifiedJavaType("cn.xxx.core.base.model.BaseExample"); private static FullyQualifiedJavaType baseMapperInstance = new FullyQualifiedJavaType("cn.xxx.core.base.dao.BaseMapper"); private static FullyQualifiedJavaType baseServiceInstance = new FullyQualifiedJavaType("cn.xxx.core.base.service.BaseService"); private static FullyQualifiedJavaType baseServiceImplInstance = new FullyQualifiedJavaType("cn.xxx.core.base.service.impl.BaseServiceImpl"); public FullyQualifiedJavaTypeProxyFactory(String fullTypeSpecification) { super(fullTypeSpecification); } public static final FullyQualifiedJavaType getPageInfoInstanceInstance() { return pageInfoInstance; } public static final FullyQualifiedJavaType getBaseExampleInstance() { return baseExampleInstance; } public static final FullyQualifiedJavaType getBaseMapperInstance() { return baseMapperInstance; } public static final FullyQualifiedJavaType getBaseServiceInstance() { return baseServiceInstance; } public static final FullyQualifiedJavaType getBaseServiceImplInstance() { return baseServiceImplInstance; }}/<code>

三、Dao生成代码简化

1）ClientDaoPlugin

<code>package run.override.dao;import java.util.Arrays;import java.util.List;import java.util.stream.Collectors;import org.mybatis.generator.api.IntrospectedTable;import org.mybatis.generator.api.JavaTypeResolver;import org.mybatis.generator.api.dom.java.FullyQualifiedJavaType;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 org.mybatis.generator.internal.types.JavaTypeResolverDefaultImpl;import run.override.model.EntityCommentPlugin;import run.override.proxyFactory.FullyQualifiedJavaTypeProxyFactory;/** * javaClient("XMLMAPPER") extended * * @ClassName ClientDaoPlugin * @Description Mapper.java * @author Marvis */public class ClientDaoPlugin extends EntityCommentPlugin { @Override public boolean clientGenerated(Interface interfaze, TopLevelClass topLevelClass, IntrospectedTable introspectedTable) { JavaTypeResolver javaTypeResolver = new JavaTypeResolverDefaultImpl(); FullyQualifiedJavaType calculateJavaType = javaTypeResolver .calculateJavaType(introspectedTable.getPrimaryKeyColumns().get(0)); FullyQualifiedJavaType superInterfaceType = new FullyQualifiedJavaType( new StringBuilder("BaseMapper") .toString() ); FullyQualifiedJavaType baseMapperInstance = FullyQualifiedJavaTypeProxyFactory.getBaseMapperInstance(); interfaze.addSuperInterface(superInterfaceType); interfaze.addImportedType(baseMapperInstance); List<method> changeMethods = interfaze.getMethods().stream() .filter(method -> method.getName().endsWith("WithBLOBs") || method.getReturnType().toString().endsWith("WithBLOBs") || Arrays.toString(method.getParameters().toArray()).contains("WithBLOBs")) .collect(Collectors.toList()); interfaze.getMethods().retainAll(changeMethods); if (changeMethods.isEmpty()) interfaze.getImportedTypes().removeIf(javaType -> javaType.getFullyQualifiedName().equals("java.util.List") || javaType.getFullyQualifiedName().equals("org.apache.ibatis.annotations.Param")); return super.clientGenerated(interfaze, topLevelClass, introspectedTable); }}/<method>/<code>

四、修正

重复生成时Mapper.xml不是覆盖原代码，而是对内容进行了追加。

1）SqlMapIsMergeablePlugin

<code>package run.override.mapper;import org.mybatis.generator.api.GeneratedXmlFile;import org.mybatis.generator.api.IntrospectedTable;import run.override.dao.ClientDaoPlugin;public class SqlMapIsMergeablePlugin extends ClientDaoPlugin { @Override public boolean sqlMapGenerated(GeneratedXmlFile sqlMap, IntrospectedTable introspectedTable) { //重新生成代码,xml内容覆盖 sqlMap.setMergeable(false); return super.sqlMapGenerated(sqlMap, introspectedTable); }}/<code>

五、序列化自定义扩展

增加Example的序列化，并增加@SuppressWarnings("serial")注解。

1）SerializablePlugin

<code>package run.override;import java.util.List;import java.util.Properties;import org.mybatis.generator.api.IntrospectedTable;import org.mybatis.generator.api.PluginAdapter;import org.mybatis.generator.api.dom.java.FullyQualifiedJavaType;import org.mybatis.generator.api.dom.java.TopLevelClass;public class SerializablePlugin extends PluginAdapter { private FullyQualifiedJavaType serializable; private FullyQualifiedJavaType gwtSerializable; private boolean addGWTInterface; private boolean suppressJavaInterface; public SerializablePlugin() { this.serializable = new FullyQualifiedJavaType("java.io.Serializable"); this.gwtSerializable = new FullyQualifiedJavaType("com.google.gwt.user.client.rpc.IsSerializable"); } @Override public void setProperties(Properties properties) { super.setProperties(properties); this.addGWTInterface = Boolean.valueOf(properties.getProperty("addGWTInterface")).booleanValue(); this.suppressJavaInterface = Boolean.valueOf(properties.getProperty("suppressJavaInterface")).booleanValue(); } @Override public boolean modelBaseRecordClassGenerated(TopLevelClass topLevelClass, IntrospectedTable introspectedTable) { makeSerializable(topLevelClass, introspectedTable); return true; } @Override public boolean modelPrimaryKeyClassGenerated(TopLevelClass topLevelClass, IntrospectedTable introspectedTable) { makeSerializable(topLevelClass, introspectedTable); return true; } @Override public boolean modelRecordWithBLOBsClassGenerated(TopLevelClass topLevelClass, IntrospectedTable introspectedTable) { makeSerializable(topLevelClass, introspectedTable); return true; } @Override public boolean modelExampleClassGenerated(TopLevelClass topLevelClass,IntrospectedTable introspectedTable){ makeSerializable(topLevelClass, introspectedTable); return true; } protected void makeSerializable(TopLevelClass topLevelClass, IntrospectedTable introspectedTable) { if (this.addGWTInterface) { topLevelClass.addImportedType(this.gwtSerializable); topLevelClass.addSuperInterface(this.gwtSerializable); } if (!(this.suppressJavaInterface)) { topLevelClass.addImportedType(this.serializable); topLevelClass.addSuperInterface(this.serializable); topLevelClass.addAnnotation("@SuppressWarnings(\"serial\")"); } } /** * This plugin is always valid - no properties are required */ @Override public boolean validate(List<string> warnings) { return true; }}/<string>/<code>