mybatis-generator扩展

在新公司的新项目想用mybatis-generator来生成dao层，有同事提出一些改进意见，遂获得源码后进行小幅改造。

目标：

• 中文注释，精简注释
• model类使用lombok简化
• 增加selectonebyexample方法（较多的使用唯一索引查询场景）

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>