首先获得源码

在任一项目中引入jar包，使用maven download sources获取源码，最新版本1.3.7

<dependency>
    <groupId>org.mybatis.generator</groupId>
    <artifactId>mybatis-generator-core</artifactId>
    <version>1.3.7</version>
</dependency>

构建项目

新建一个maven项目，设置groupId和artifactId

<groupId>com.mine.generator</groupId>
<artifactId>mybatis-generator-core</artifactId>
<version>1.0-SNAPSHOT</version>

把解压后的源码复制到目录

在pom.xml中添加项目依赖

<dependencies>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <scope>provided</scope>
            <version>1.2.17</version>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <scope>provided</scope>
            <version>1.7.25</version>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-api</artifactId>
            <scope>provided</scope>
            <version>2.11.0</version>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>commons-logging</groupId>
            <artifactId>commons-logging</artifactId>
            <scope>provided</scope>
            <version>1.2</version>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.apache.ant</groupId>
            <artifactId>ant</artifactId>
            <scope>provided</scope>
            <version>1.10.4</version>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.junit.vintage</groupId>
            <artifactId>junit-vintage-engine</artifactId>
            <version>5.2.0</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.hsqldb</groupId>
            <artifactId>hsqldb</artifactId>
            <version>2.4.1</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>com.github.javaparser</groupId>
            <version>3.6.12</version>
            <artifactId>javaparser-core</artifactId>
        </dependency>
</dependencies>

View Code

功能拓展

model中文注释、精简其他注释

修改生成注释默认用的DefaultCommentGenerator

package org.mybatis.generator.internal;
import org.mybatis.generator.api.CommentGenerator;
import org.mybatis.generator.api.IntrospectedColumn;
import org.mybatis.generator.api.IntrospectedTable;
import org.mybatis.generator.api.MyBatisGenerator;
import org.mybatis.generator.api.dom.java.*;
import org.mybatis.generator.api.dom.xml.XmlElement;
import org.mybatis.generator.internal.util.StringUtility;
import java.text.SimpleDateFormat;
import java.time.ZonedDateTime;
import java.time.format.DateTimeFormatter;
import java.util.Date;
import java.util.Properties;
import java.util.Set;
/**
 * @author Jeff Butler
 */
public class DefaultCommentGenerator implements CommentGenerator {
    private SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    public DefaultCommentGenerator() {
        super();
    }
    @Override
    public void addJavaFileComment(CompilationUnit compilationUnit) {
    }
    @Override
    public void addComment(XmlElement xmlElement) {
    }
    @Override
    public void addRootComment(XmlElement rootElement) {
    }
    @Override
    public void addConfigurationProperties(Properties properties) {
    }
    protected String getDateString() {
        return dateFormat.format(new Date());
    }
    @Override
    public void addClassComment(InnerClass innerClass,
                                IntrospectedTable introspectedTable) {
    }
    @Override
    public void addClassComment(InnerClass innerClass,
                                IntrospectedTable introspectedTable, boolean markAsDoNotDelete) {
    }
    @Override
    public void addModelClassComment(TopLevelClass topLevelClass,
                                     IntrospectedTable introspectedTable) {
        topLevelClass.addJavaDocLine("/**");
        topLevelClass.addJavaDocLine(" * 生成日期:" + getDateString());
        topLevelClass.addJavaDocLine(" * 表名: " + introspectedTable.getFullyQualifiedTable().toString());
        topLevelClass.addJavaDocLine(" */");
    }
    @Override
    public void addEnumComment(InnerEnum innerEnum,
                               IntrospectedTable introspectedTable) {
    }
    @Override
    public void addFieldComment(Field field,
                                IntrospectedTable introspectedTable,
                                IntrospectedColumn introspectedColumn) {
        field.addJavaDocLine("/**");
        field.addJavaDocLine(" * " + introspectedColumn.getRemarks());
        field.addJavaDocLine(" */");
    }
    @Override
    public void addFieldComment(Field field, IntrospectedTable introspectedTable) {
    }
    @Override
    public void addGeneralMethodComment(Method method,
                                        IntrospectedTable introspectedTable) {
    }
    @Override
    public void addGetterComment(Method method,
                                 IntrospectedTable introspectedTable,
                                 IntrospectedColumn introspectedColumn) {
    }
    @Override
    public void addSetterComment(Method method,
                                 IntrospectedTable introspectedTable,
                                 IntrospectedColumn introspectedColumn) {
    }
    @Override
    public void addGeneralMethodAnnotation(Method method, IntrospectedTable introspectedTable,
                                           Set<FullyQualifiedJavaType> imports) {
        imports.add(new FullyQualifiedJavaType("javax.annotation.Generated"));
        String comment = "Source Table: " + introspectedTable.getFullyQualifiedTable().toString();
        method.addAnnotation(getGeneratedAnnotation(comment));
    }
    @Override
    public void addGeneralMethodAnnotation(Method method, IntrospectedTable introspectedTable,
                                           IntrospectedColumn introspectedColumn, Set<FullyQualifiedJavaType> imports) {
        imports.add(new FullyQualifiedJavaType("javax.annotation.Generated"));
        String comment = "Source field: "
                + introspectedTable.getFullyQualifiedTable().toString()
                + "."
                + introspectedColumn.getActualColumnName();
        method.addAnnotation(getGeneratedAnnotation(comment));
    }
    @Override
    public void addFieldAnnotation(Field field, IntrospectedTable introspectedTable,
                                   Set<FullyQualifiedJavaType> imports) {
        imports.add(new FullyQualifiedJavaType("javax.annotation.Generated"));
        String comment = "Source Table: " + introspectedTable.getFullyQualifiedTable().toString();
        field.addAnnotation(getGeneratedAnnotation(comment));
    }
    @Override
    public void addFieldAnnotation(Field field, IntrospectedTable introspectedTable,
                                   IntrospectedColumn introspectedColumn, Set<FullyQualifiedJavaType> imports) {
        imports.add(new FullyQualifiedJavaType("javax.annotation.Generated"));
        String comment = "Source field: "
                + introspectedTable.getFullyQualifiedTable().toString()
                + "."
                + introspectedColumn.getActualColumnName();
        field.addAnnotation(getGeneratedAnnotation(comment));
        String remarks = introspectedColumn.getRemarks();
        if (StringUtility.stringHasValue(remarks)) {
            field.addJavaDocLine("/**");
            field.addJavaDocLine(" * Database Column Remarks:");
            String[] remarkLines = remarks.split(System.getProperty("line.separator"));
            for (String remarkLine : remarkLines) {
                field.addJavaDocLine(" *   " + remarkLine);
            }
            field.addJavaDocLine(" */");
        }
    }
    @Override
    public void addClassAnnotation(InnerClass innerClass, IntrospectedTable introspectedTable,
                                   Set<FullyQualifiedJavaType> imports) {
        imports.add(new FullyQualifiedJavaType("javax.annotation.Generated"));
        String comment = "Source Table: " + introspectedTable.getFullyQualifiedTable().toString();
        innerClass.addAnnotation(getGeneratedAnnotation(comment));
    }
    private String getGeneratedAnnotation(String comment) {
        StringBuilder buffer = new StringBuilder();
        buffer.append("@Generated(");
        buffer.append("value=\"");
        buffer.append(MyBatisGenerator.class.getName());
        buffer.append('\"');
        buffer.append(", date=\"");
        buffer.append(DateTimeFormatter.ISO_OFFSET_DATE_TIME.format(ZonedDateTime.now()));
        buffer.append('\"');
        buffer.append(", comments=\"");
        buffer.append(comment);
        buffer.append('\"');
        buffer.append(')');
        return buffer.toString();
    }
}

View Code

Model类使用lombok简化

修改BaseRecordGenerator的getCompilationUnits的方法即可

　　public List<CompilationUnit> getCompilationUnits() {
        FullyQualifiedTable table = introspectedTable.getFullyQualifiedTable();
        progressCallback.startTask(getString(
                "Progress.8", table.toString())); //$NON-NLS-1$
        Plugin plugins = context.getPlugins();
        CommentGenerator commentGenerator = context.getCommentGenerator();
        FullyQualifiedJavaType type = new FullyQualifiedJavaType(
                introspectedTable.getBaseRecordType());
        TopLevelClass topLevelClass = new TopLevelClass(type);
        topLevelClass.addImportedType("lombok.Getter");// 导入lombok类
        topLevelClass.addImportedType("lombok.Setter");
        topLevelClass.setVisibility(JavaVisibility.PUBLIC);
        commentGenerator.addJavaFileComment(topLevelClass);
        FullyQualifiedJavaType superClass = getSuperClass();
        if (superClass != null) {
            topLevelClass.setSuperClass(superClass);
            topLevelClass.addImportedType(superClass);
        }
        commentGenerator.addModelClassComment(topLevelClass, introspectedTable);
        topLevelClass.addAnnotation("@Getter");// 增加lombok注解
        topLevelClass.addAnnotation("@Setter");
        List<IntrospectedColumn> introspectedColumns = getColumnsInThisClass();
        if (introspectedTable.isConstructorBased()) {
            addParameterizedConstructor(topLevelClass, introspectedTable.getNonBLOBColumns());
            if (includeBLOBColumns()) {
                addParameterizedConstructor(topLevelClass, introspectedTable.getAllColumns());
            }
            if (!introspectedTable.isImmutable()) {
                addDefaultConstructor(topLevelClass);
            }
        }
        String rootClass = getRootClass();
        for (IntrospectedColumn introspectedColumn : introspectedColumns) {
            if (RootClassInfo.getInstance(rootClass, warnings)
                    .containsProperty(introspectedColumn)) {
                continue;
            }
            Field field = getJavaBeansField(introspectedColumn, context, introspectedTable);
            if (plugins.modelFieldGenerated(field, topLevelClass,
                    introspectedColumn, introspectedTable,
                    Plugin.ModelClassType.BASE_RECORD)) {
                topLevelClass.addField(field);
                topLevelClass.addImportedType(field.getType());
            }
        }
        List<CompilationUnit> answer = new ArrayList<>();
        if (context.getPlugins().modelBaseRecordClassGenerated(
                topLevelClass, introspectedTable)) {
            answer.add(topLevelClass);
        }
        return answer;
　　}

增加selectOneByExample

首先查看类似的方法selectByExample是怎么生成的，然后参考增加这个方法。

在IntrospectedTable中增加方法

　　public String getSelectOneByExampleStatementId() {
        return "selectOneByExample";//可以跟其他源码一样设置成常量，这里简单处理
　　}

增加一个SelectOneByExampleMethodGenerator

/**
 *    Copyright 2006-2016 the original author or authors.
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */
package org.mybatis.generator.codegen.mybatis3.javamapper.elements;
import org.mybatis.generator.api.dom.java.*;
import java.util.Set;
import java.util.TreeSet;
/**
 *
 * @author Jeff Butler
 *
 */
public class SelectOneByExampleMethodGenerator extends
        AbstractJavaMapperMethodGenerator {
    public SelectOneByExampleMethodGenerator() {
        super();
    }
    @Override
    public void addInterfaceElements(Interface interfaze) {
        Set<FullyQualifiedJavaType> importedTypes = new TreeSet<>();
        FullyQualifiedJavaType type = new FullyQualifiedJavaType(
                introspectedTable.getExampleType());
        importedTypes.add(type);
        importedTypes.add(FullyQualifiedJavaType.getNewListInstance());
        Method method = new Method();
        method.setVisibility(JavaVisibility.PUBLIC);
        FullyQualifiedJavaType returnType = introspectedTable.getRules()
                .calculateAllFieldsClass();
        method.setReturnType(returnType);
        method.setName(introspectedTable.getSelectOneByExampleStatementId());
        method.addParameter(new Parameter(type, "example")); //$NON-NLS-1$
        context.getCommentGenerator().addGeneralMethodComment(method,
                introspectedTable);
        addMapperAnnotations(interfaze, method);
        if (context.getPlugins()
                .clientSelectByExampleWithBLOBsMethodGenerated(method, interfaze,
                        introspectedTable)) {
            addExtraImports(interfaze);
            interfaze.addImportedTypes(importedTypes);
            interfaze.addMethod(method);
        }
    }
    public void addMapperAnnotations(Interface interfaze, Method method) {
    }
    public void addExtraImports(Interface interfaze) {
    }
}

View Code

增加一个SelectOneByExampleElementGenerator

/**
 *    Copyright 2006-2016 the original author or authors.
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */
package org.mybatis.generator.codegen.mybatis3.xmlmapper.elements;
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 static org.mybatis.generator.internal.util.StringUtility.stringHasValue;
/**
 *
 * @author Jeff Butler
 *
 */
public class SelectOneByExampleElementGenerator extends
        AbstractXmlElementGenerator {
    public SelectOneByExampleElementGenerator() {
        super();
    }
    @Override
    public void addElements(XmlElement parentElement) {
        String fqjt = introspectedTable.getExampleType();
        XmlElement answer = new XmlElement("select"); //$NON-NLS-1$
        answer.addAttribute(new Attribute("id", //$NON-NLS-1$
                introspectedTable.getSelectOneByExampleStatementId()));
        answer.addAttribute(new Attribute(
                "resultMap", introspectedTable.getBaseResultMapId())); //$NON-NLS-1$
        answer.addAttribute(new Attribute("parameterType", fqjt)); //$NON-NLS-1$
        context.getCommentGenerator().addComment(answer);
        answer.addElement(new TextElement("select")); //$NON-NLS-1$
        XmlElement ifElement = new XmlElement("if"); //$NON-NLS-1$
        ifElement.addAttribute(new Attribute("test", "distinct")); //$NON-NLS-1$ //$NON-NLS-2$
        ifElement.addElement(new TextElement("distinct")); //$NON-NLS-1$
        answer.addElement(ifElement);
        StringBuilder sb = new StringBuilder();
        if (stringHasValue(introspectedTable
                .getSelectByExampleQueryId())) {
            sb.append('\'');
            sb.append(introspectedTable.getSelectByExampleQueryId());
            sb.append("' as QUERYID,"); //$NON-NLS-1$
            answer.addElement(new TextElement(sb.toString()));
        }
        answer.addElement(getBaseColumnListElement());
        sb.setLength(0);
        sb.append("from "); //$NON-NLS-1$
        sb.append(introspectedTable
                .getAliasedFullyQualifiedTableNameAtRuntime());
        answer.addElement(new TextElement(sb.toString()));
        answer.addElement(getExampleIncludeElement());
        ifElement = new XmlElement("if"); //$NON-NLS-1$
        ifElement.addAttribute(new Attribute("test", "orderByClause != null")); //$NON-NLS-1$ //$NON-NLS-2$
        ifElement.addElement(new TextElement("order by ${orderByClause}")); //$NON-NLS-1$
        answer.addElement(ifElement);
        if (context.getPlugins()
                .sqlMapSelectByExampleWithoutBLOBsElementGenerated(answer,
                        introspectedTable)) {
            parentElement.addElement(answer);
        }
        answer.addElement(new TextElement("limit 1"));
    }
}

View Code

修改JavaMapperGenerator，在getCompilationUnits方法中增加addSelectOneByExampleMethod(interfaze)，这里顺带把生成的代码排了个序，并且把不常用的几个方法给注释掉了。

@Override
public List<CompilationUnit> getCompilationUnits() {
    progressCallback.startTask(getString("Progress.17", //$NON-NLS-1$
            introspectedTable.getFullyQualifiedTable().toString()));
    CommentGenerator commentGenerator = context.getCommentGenerator();

    FullyQualifiedJavaType type = new FullyQualifiedJavaType(
            introspectedTable.getMyBatis3JavaMapperType());
    Interface interfaze = new Interface(type);
    interfaze.setVisibility(JavaVisibility.PUBLIC);
    commentGenerator.addJavaFileComment(interfaze);

    String rootInterface = introspectedTable
            .getTableConfigurationProperty(PropertyRegistry.ANY_ROOT_INTERFACE);
    if (!stringHasValue(rootInterface)) {
        rootInterface = context.getJavaClientGeneratorConfiguration()
                .getProperty(PropertyRegistry.ANY_ROOT_INTERFACE);
    }

    if (stringHasValue(rootInterface)) {
        FullyQualifiedJavaType fqjt = new FullyQualifiedJavaType(
                rootInterface);
        interfaze.addSuperInterface(fqjt);
        interfaze.addImportedType(fqjt);
    }

    addInsertSelectiveMethod(interfaze);
    addDeleteByPrimaryKeyMethod(interfaze);
    addDeleteByExampleMethod(interfaze);
    addUpdateByPrimaryKeySelectiveMethod(interfaze);
    addUpdateByExampleSelectiveMethod(interfaze);
    addSelectByPrimaryKeyMethod(interfaze);
    addSelectOneByExampleMethod(interfaze);  //由addSelectByExampleWithoutBLOBsMethod改造而来
    addSelectByExampleWithoutBLOBsMethod(interfaze);    
    addSelectByExampleWithBLOBsMethod(interfaze);
    addCountByExampleMethod(interfaze);
    //addInsertMethod(interfaze);
    //addUpdateByExampleWithBLOBsMethod(interfaze);
    //addUpdateByExampleWithoutBLOBsMethod(interfaze);
    //addUpdateByPrimaryKeyWithBLOBsMethod(interfaze);
    //addUpdateByPrimaryKeyWithoutBLOBsMethod(interfaze);

    List<CompilationUnit> answer = new ArrayList<>();
    if (context.getPlugins().clientGenerated(interfaze, null,
            introspectedTable)) {
        answer.add(interfaze);
    }

    List<CompilationUnit> extraCompilationUnits = getExtraCompilationUnits();
    if (extraCompilationUnits != null) {
        answer.addAll(extraCompilationUnits);
    }

    return answer;
}

//增加方法
protected void addSelectOneByExampleMethod(Interface interfaze) {
　　AbstractJavaMapperMethodGenerator methodGenerator = new SelectOneByExampleMethodGenerator();
　　initializeAndExecuteGenerator(methodGenerator, interfaze);
}

同样地，修改XMLMapperGenerator

protected XmlElement getSqlMapElement() {
        FullyQualifiedTable table = introspectedTable.getFullyQualifiedTable();
        progressCallback.startTask(getString(
                "Progress.12", table.toString())); //$NON-NLS-1$
        XmlElement answer = new XmlElement("mapper"); //$NON-NLS-1$
        String namespace = introspectedTable.getMyBatis3SqlMapNamespace();
        answer.addAttribute(new Attribute("namespace", //$NON-NLS-1$
                namespace));
        context.getCommentGenerator().addRootComment(answer);
        addResultMapWithoutBLOBsElement(answer);
        addResultMapWithBLOBsElement(answer);
        addExampleWhereClauseElement(answer);
        addMyBatis3UpdateByExampleWhereClauseElement(answer);
        addBaseColumnListElement(answer);
        addBlobColumnListElement(answer);
        addInsertSelectiveElement(answer);
        addDeleteByPrimaryKeyElement(answer);
        addDeleteByExampleElement(answer);
        addUpdateByPrimaryKeySelectiveElement(answer);
        addUpdateByExampleSelectiveElement(answer);
        addSelectByPrimaryKeyElement(answer);
        addSelectOneByExampleElement(answer);
        addSelectByExampleWithoutBLOBsElement(answer);
        addSelectByExampleWithBLOBsElement(answer);
        addCountByExampleElement(answer);
        //addSelectByExampleWithBLOBsElement(answer);
        //addInsertElement(answer);
        //addUpdateByExampleWithBLOBsElement(answer);
        //addUpdateByExampleWithoutBLOBsElement(answer);
        //addUpdateByPrimaryKeyWithBLOBsElement(answer);
        //addUpdateByPrimaryKeyWithoutBLOBsElement(answer);
 
        return answer;
}

//增加方法
protected void addSelectOneByExampleElement(XmlElement parentElement) {
 　　if (introspectedTable.getRules().generateSelectByExampleWithoutBLOBs()) {
　　　　AbstractXmlElementGenerator elementGenerator = new SelectOneByExampleElementGenerator();
　　　　initializeAndExecuteGenerator(elementGenerator, parentElement);
　　}
}

投入使用

deploy项目打包，然后在需要使用的项目中，修改pom.xml引入，再使用generator的generate命令即可

　　　　　　　<plugin>
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-maven-plugin</artifactId>
                <version>1.3.7</version>
                <dependencies>
                    <dependency>
                        <groupId>com.mine.generator</groupId>
                        <artifactId>mybatis-generator-core</artifactId>
                        <version>1.0-SNAPSHOT</version>
                    </dependency>
                </dependencies>
            </plugin>