• MyBatis Generator 代码生成工具

     本文完整代码已上传Github仓库：https://github.com/ouyangyewei/mybatis-codegen

    1、MBG 的简介

     MyBatis Generator官网：MyBatis Generator Core – Introduction to MyBatis Generator

    借助MyBatis Generator（MBG）工具，可以基于数据库表结构自动生成Bean/Mapper/Mapper XML代码，简化了大量重复繁琐的开发步骤，相关信息如下：

    2、MGB 自定义插件

    MGB支持自定义插件，比如：自动生成代码时带上表/表字段注释、分页、Lombok

    2.1、注释插件

    1. package com.github.codegen;
    2.  
    3. import org.apache.logging.log4j.util.Strings;
    4. import org.mybatis.generator.api.IntrospectedColumn;
    5. import org.mybatis.generator.api.IntrospectedTable;
    6. import org.mybatis.generator.api.dom.java.Field;
    7. import org.mybatis.generator.api.dom.java.TopLevelClass;
    8. import org.mybatis.generator.internal.DefaultCommentGenerator;
    9. import org.mybatis.generator.internal.util.StringUtility;
    10.  
    11. import java.text.SimpleDateFormat;
    12. import java.util.Date;
    13. import java.util.Properties;
    14.  
    15. /**
    16.  * 注释生成器
    17.  * 
    18.  *     根据元数据表的字段注释给JavaBean字段添加注释
    19.  * 
    20.  * @author ouyangyewei
    21.  * @date 2021-09-01
    22.  **/
    23. public class CommentGenerator extends DefaultCommentGenerator {
    24.     private boolean addRemarkComments = false;
    25.  
    26.     /**
    27.      * 设置用户配置的参数
    28.      * @param properties
    29.      */
    30.     @Override
    31.     public void addConfigurationProperties(Properties properties) {
    32.         super.addConfigurationProperties(properties);
    33.         this.addRemarkComments = StringUtility.isTrue(properties.getProperty("addRemarkComments"));
    34.     }
    35.  
    36.     /**
    37.      * 根据表注释设置类文件注释
    38.      * @param topLevelClass
    39.      * @param introspectedTable
    40.      */
    41.     private static final SimpleDateFormat DATE_FORMAT = new SimpleDateFormat("yyyy-MM-dd");
    42.     public void addModelClassComment(TopLevelClass topLevelClass, IntrospectedTable introspectedTable) {
    43.         if (this.addRemarkComments) {
    44.             topLevelClass.addJavaDocLine("/**");
    45.             topLevelClass.addJavaDocLine(" * " + introspectedTable.getRemarks());
    46.             topLevelClass.addJavaDocLine(" * @author MyBatis Generator");
    47.             topLevelClass.addJavaDocLine(" * @date " + DATE_FORMAT.format(new Date()));
    48.             topLevelClass.addJavaDocLine(" */");
    49.         }
    50.     }
    51.  
    52.     /**
    53.      * 给字段添加注释
    54.      * @param field
    55.      * @param introspectedTable
    56.      * @param introspectedColumn
    57.      */
    58.     @Override
    59.     public void addFieldComment(Field field, IntrospectedTable introspectedTable, IntrospectedColumn introspectedColumn) {
    60.         String remarks = introspectedColumn.getRemarks();
    61.         // 根据参数和备注信息判断是否添加备注信息
    62.         if (this.addRemarkComments && StringUtility.stringHasValue(remarks)) {
    63.             // 数据库中特殊字符需要转义
    64.             if (remarks.contains("\"")) {
    65.                 remarks = remarks.replace("\"","'");
    66.             }
    67.             // model的字段添加注解
    68.             field.addJavaDocLine("/**" + Strings.LINE_SEPARATOR + "     * " + remarks + Strings.LINE_SEPARATOR + "     */");
    69.         }
    70.     }
    71. }

    2.2、分页插件

    1. package com.github.codegen;
    2.  
    3. import org.mybatis.generator.api.IntrospectedTable;
    4. import org.mybatis.generator.api.PluginAdapter;
    5. import org.mybatis.generator.api.dom.java.*;
    6. import org.mybatis.generator.api.dom.xml.Attribute;
    7. import org.mybatis.generator.api.dom.xml.TextElement;
    8. import org.mybatis.generator.api.dom.xml.XmlElement;
    9.  
    10. import java.util.List;
    11.  
    12. /**
    13.  * Mybatis Page Limit Plugin
    14.  * 
    15.  *     用于为每个Example类添加offset和limit属性方法
    16.  * 
    17.  * @author ouyangyewei
    18.  * @date 2021-08-31
    19.  **/
    20. public class LimitPlugin extends PluginAdapter {
    21.  
    22.     @Override
    23.     public boolean validate(List list) {
    24.         return true;
    25.     }
    26.  
    27.     /**
    28.      * 为每个Example类添加offset和rows属性已经set、get方法
    29.      * @param topLevelClass
    30.      * @param introspectedTable
    31.      * @return
    32.      */
    33.     @Override
    34.     public boolean modelExampleClassGenerated(TopLevelClass topLevelClass, IntrospectedTable introspectedTable) {
    35.         PrimitiveTypeWrapper integerWrapper = FullyQualifiedJavaType.getIntInstance().getPrimitiveTypeWrapper();
    36.  
    37.         Field limit = new Field("limit", integerWrapper);
    38.         limit.setVisibility(JavaVisibility.PRIVATE);
    39.         topLevelClass.addField(limit);
    40.  
    41.         Method setLimit = new Method("setLimit");
    42.         setLimit.setVisibility(JavaVisibility.PUBLIC);
    43.         setLimit.addParameter(new Parameter(integerWrapper, "limit"));
    44.         setLimit.addBodyLine("this.limit = limit;");
    45.         topLevelClass.addMethod(setLimit);
    46.  
    47.         Method getLimit = new Method("getLimit");
    48.         getLimit.setVisibility(JavaVisibility.PUBLIC);
    49.         getLimit.setReturnType(integerWrapper);
    50.         getLimit.addBodyLine("return limit;");
    51.         topLevelClass.addMethod(getLimit);
    52.  
    53.         Field offset = new Field("offset", integerWrapper);
    54.         offset.setVisibility(JavaVisibility.PRIVATE);
    55.         topLevelClass.addField(offset);
    56.  
    57.         Method setOffset = new Method("setOffset");
    58.         setOffset.setVisibility(JavaVisibility.PUBLIC);
    59.         setOffset.addParameter(new Parameter(integerWrapper, "offset"));
    60.         setOffset.addBodyLine("this.offset = offset;");
    61.         topLevelClass.addMethod(setOffset);
    62.  
    63.         Method getOffset = new Method("getOffset");
    64.         getOffset.setVisibility(JavaVisibility.PUBLIC);
    65.         getOffset.setReturnType(integerWrapper);
    66.         getOffset.addBodyLine("return offset;");
    67.         topLevelClass.addMethod(getOffset);
    68.         return true;
    69.     }
    70.  
    71.     /**
    72.      * 为Mapper.xml的selectByExample添加limit
    73.      * @param element
    74.      * @param introspectedTable
    75.      * @return
    76.      */
    77.     @Override
    78.     public boolean sqlMapSelectByExampleWithoutBLOBsElementGenerated(XmlElement element, IntrospectedTable introspectedTable) {
    79.         XmlElement ifLimitNotNullElement = new XmlElement("if");
    80.         ifLimitNotNullElement.addAttribute(new Attribute("test", "limit != null"));
    81.  
    82.         XmlElement ifOffsetNotNullElement = new XmlElement("if");
    83.         ifOffsetNotNullElement.addAttribute(new Attribute("test", "offset != null"));
    84.         ifOffsetNotNullElement.addElement(new TextElement("limit ${offset}, ${limit}"));
    85.         ifLimitNotNullElement.addElement(ifOffsetNotNullElement);
    86.  
    87.         XmlElement ifOffsetNullElement = new XmlElement("if");
    88.         ifOffsetNullElement.addAttribute(new Attribute("test", "offset == null"));
    89.         ifOffsetNullElement.addElement(new TextElement("limit ${limit}"));
    90.         ifLimitNotNullElement.addElement(ifOffsetNullElement);
    91.  
    92.         element.addElement(ifLimitNotNullElement);
    93.         return true;
    94.     }
    95. }

    2.3、Lombok插件

    1. package com.github.codegen;
    2.  
    3. import org.mybatis.generator.api.IntrospectedColumn;
    4. import org.mybatis.generator.api.IntrospectedTable;
    5. import org.mybatis.generator.api.PluginAdapter;
    6. import org.mybatis.generator.api.dom.java.FullyQualifiedJavaType;
    7. import org.mybatis.generator.api.dom.java.Interface;
    8. import org.mybatis.generator.api.dom.java.Method;
    9. import org.mybatis.generator.api.dom.java.TopLevelClass;
    10.  
    11. import java.util.*;
    12.  
    13. /**
    14.  * A MyBatis Generator plugin to use Lombok's annotations.
    15.  * For example, use @Data annotation instead of getter ands setter.
    16.  *
    17.  * @See https://github.com/softwareloop/mybatis-generator-lombok-plugin
    18.  * @author Paolo Predonzani (http://softwareloop.com/)
    19.  */
    20. public class LombokPlugin extends PluginAdapter {
    21.  
    22.     private final Collection annotations;
    23.  
    24.     /**
    25.      * LombokPlugin constructor
    26.      */
    27.     public LombokPlugin() {
    28.         this.annotations = new LinkedHashSet<>(Annotations.values().length);
    29.     }
    30.  
    31.     /**
    32.      * @param warnings list of warnings
    33.      * @return always true
    34.      */
    35.     @Override
    36.     public boolean validate(List warnings) {
    37.         return true;
    38.     }
    39.  
    40.     /**
    41.      * Intercepts base record class generation
    42.      *
    43.      * @param topLevelClass     the generated base record class
    44.      * @param introspectedTable The class containing information about the table as
    45.      *                          introspected from the database
    46.      * @return always true
    47.      */
    48.     @Override
    49.     public boolean modelBaseRecordClassGenerated(
    50.             TopLevelClass topLevelClass,
    51.             IntrospectedTable introspectedTable) {
    52.         this.addAnnotations(topLevelClass);
    53.         return true;
    54.     }
    55.  
    56.     /**
    57.      * Intercepts primary key class generation
    58.      *
    59.      * @param topLevelClass     the generated primary key class
    60.      * @param introspectedTable The class containing information about the table as
    61.      *                          introspected from the database
    62.      * @return always true
    63.      */
    64.     @Override
    65.     public boolean modelPrimaryKeyClassGenerated(
    66.             TopLevelClass topLevelClass,
    67.             IntrospectedTable introspectedTable) {
    68.         this.addAnnotations(topLevelClass);
    69.         return true;
    70.     }
    71.  
    72.     /**
    73.      * Intercepts "record with blob" class generation
    74.      *
    75.      * @param topLevelClass     the generated record with BLOBs class
    76.      * @param introspectedTable The class containing information about the table as
    77.      *                          introspected from the database
    78.      * @return always true
    79.      */
    80.     @Override
    81.     public boolean modelRecordWithBLOBsClassGenerated(
    82.             TopLevelClass topLevelClass,
    83.             IntrospectedTable introspectedTable) {
    84.         this.addAnnotations(topLevelClass);
    85.         return true;
    86.     }
    87.  
    88.     /**
    89.      * Prevents all getters from being generated.
    90.      * See SimpleModelGenerator
    91.      *
    92.      * @param method             the getter, or accessor, method generated for the specified
    93.      *                           column
    94.      * @param topLevelClass      the partially implemented model class
    95.      * @param introspectedColumn The class containing information about the column related
    96.      *                           to this field as introspected from the database
    97.      * @param introspectedTable  The class containing information about the table as
    98.      *                           introspected from the database
    99.      * @param modelClassType     the type of class that the field is generated for
    100.      */
    101.     @Override
    102.     public boolean modelGetterMethodGenerated(
    103.             Method method,
    104.             TopLevelClass topLevelClass,
    105.             IntrospectedColumn introspectedColumn,
    106.             IntrospectedTable introspectedTable,
    107.             ModelClassType modelClassType) {
    108.         return false;
    109.     }
    110.  
    111.     /**
    112.      * Prevents all setters from being generated
    113.      * See SimpleModelGenerator
    114.      *
    115.      * @param method             the setter, or mutator, method generated for the specified
    116.      *                           column
    117.      * @param topLevelClass      the partially implemented model class
    118.      * @param introspectedColumn The class containing information about the column related
    119.      *                           to this field as introspected from the database
    120.      * @param introspectedTable  The class containing information about the table as
    121.      *                           introspected from the database
    122.      * @param modelClassType     the type of class that the field is generated for
    123.      * @return always false
    124.      */
    125.     @Override
    126.     public boolean modelSetterMethodGenerated(
    127.             Method method,
    128.             TopLevelClass topLevelClass,
    129.             IntrospectedColumn introspectedColumn,
    130.             IntrospectedTable introspectedTable,
    131.             ModelClassType modelClassType) {
    132.         return false;
    133.     }
    134.  
    135.     /**
    136.      * Adds the lombok annotations' imports and annotations to the class
    137.      *
    138.      * @param topLevelClass the partially implemented model class
    139.      */
    140.     private void addAnnotations(TopLevelClass topLevelClass) {
    141.         for (Annotations annotation : this.annotations) {
    142.             topLevelClass.addImportedType(annotation.javaType);
    143.             topLevelClass.addAnnotation(annotation.asAnnotation());
    144.         }
    145.     }
    146.  
    147.     @Override
    148.     public void setProperties(Properties properties) {
    149.         super.setProperties(properties);
    150.  
    151.         // @Data is default annotation
    152.         this.annotations.add(Annotations.DATA);
    153.  
    154.         for (String annotationName : properties.stringPropertyNames()) {
    155.             if (annotationName.contains(".")) {
    156.                 // Not an annotation name
    157.                 continue;
    158.             }
    159.             String value = properties.getProperty(annotationName);
    160.             if (!Boolean.parseBoolean(value)) {
    161.                 // The annotation is disabled, skip it
    162.                 continue;
    163.             }
    164.             Annotations annotation = Annotations.getValueOf(annotationName);
    165.             if (annotation == null) {
    166.                 continue;
    167.             }
    168.             String optionsPrefix = annotationName + ".";
    169.             for (String propertyName : properties.stringPropertyNames()) {
    170.                 if (!propertyName.startsWith(optionsPrefix)) {
    171.                     // A property not related to this annotation
    172.                     continue;
    173.                 }
    174.                 String propertyValue = properties.getProperty(propertyName);
    175.                 annotation.appendOptions(propertyName, propertyValue);
    176.                 this.annotations.add(annotation);
    177.                 this.annotations.addAll(Annotations.getDependencies(annotation));
    178.             }
    179.         }
    180.     }
    181.  
    182.     @Override
    183.     public boolean clientGenerated(Interface interfaze, IntrospectedTable introspectedTable) {
    184.         interfaze.addImportedType(new FullyQualifiedJavaType("org.springframework.stereotype.Service"));
    185.         interfaze.addAnnotation("@Service");
    186.         return true;
    187.     }
    188.  
    189.     private enum Annotations {
    190.         /**
    191.          * Data
    192.          */
    193.         DATA("data", "@Data", "lombok.Data"),
    194.         /**
    195.          * Builder
    196.          */
    197.         BUILDER("builder", "@Builder", "lombok.Builder"),
    198.         /**
    199.          * AllArgsConstructor
    200.          */
    201.         ALL_ARGS_CONSTRUCTOR("allArgsConstructor", "@AllArgsConstructor", "lombok.AllArgsConstructor"),
    202.         /**
    203.          * NoArgsConstructor
    204.          */
    205.         NO_ARGS_CONSTRUCTOR("noArgsConstructor", "@NoArgsConstructor", "lombok.NoArgsConstructor"),
    206.         /**
    207.          * ToString
    208.          */
    209.         TO_STRING("toString", "@ToString", "lombok.ToString");
    210.  
    211.         private final String paramName;
    212.         private final String name;
    213.         private final FullyQualifiedJavaType javaType;
    214.         private final List options;
    215.  
    216.         Annotations(String paramName, String name, String className) {
    217.             this.paramName = paramName;
    218.             this.name = name;
    219.             this.javaType = new FullyQualifiedJavaType(className);
    220.             this.options = new ArrayList<>();
    221.         }
    222.  
    223.         private static Annotations getValueOf(String paramName) {
    224.             for (Annotations annotation : Annotations.values()) {
    225.                 if (String.CASE_INSENSITIVE_ORDER.compare(paramName, annotation.paramName) == 0) {
    226.                     return annotation;
    227.                 }
    228.             }
    229.  
    230.             return null;
    231.         }
    232.  
    233.         private static Collection getDependencies(Annotations annotation) {
    234.             if (annotation == ALL_ARGS_CONSTRUCTOR) {
    235.                 return Collections.singleton(NO_ARGS_CONSTRUCTOR);
    236.             } else {
    237.                 return Collections.emptyList();
    238.             }
    239.         }
    240.  
    241.         /**
    242.          * A trivial quoting.
    243.          * Because Lombok annotation options type is almost String or boolean.
    244.          * @param value
    245.          * @return
    246.          */
    247.         private static String quote(String value) {
    248.             if (Boolean.TRUE.toString().equals(value) || Boolean.FALSE.toString().equals(value)) {
    249.                 // case of boolean, not passed as an array.
    250.                 return value;
    251.             }
    252.             return value.replaceAll("[\\w]+", "\"$0\"");
    253.         }
    254.  
    255.         private void appendOptions(String key, String value) {
    256.             String keyPart = key.substring(key.indexOf(".") + 1);
    257.             String valuePart = value.contains(",") ? String.format("{%s}", value) : value;
    258.             this.options.add(String.format("%s=%s", keyPart, quote(valuePart)));
    259.         }
    260.  
    261.         private String asAnnotation() {
    262.             if (this.options.isEmpty()) {
    263.                 return this.name;
    264.             }
    265.             StringBuilder sb = new StringBuilder();
    266.             sb.append(this.name);
    267.             sb.append("(");
    268.             boolean first = true;
    269.             for (String option : this.options) {
    270.                 if (first) {
    271.                     first = false;
    272.                 } else {
    273.                     sb.append(", ");
    274.                 }
    275.                 sb.append(option);
    276.             }
    277.             sb.append(")");
    278.             return sb.toString();
    279.         }
    280.     }
    281. }

    3、MBG 如何使用

    完整代码：https://github.com/ouyangyewei/mybatis-codegen

    Git地址：git clone https://github.com/ouyangyewei/mybatis-codegen

    步骤一：MySQL建表

    1. -- ----------------------------
    2. -- Table structure for t_project
    3. -- ----------------------------
    4. DROP TABLE IF EXISTS `t_project`;
    5. CREATE TABLE IF NOT EXISTS `t_project` (
    6.     `id`          int      NOT NULL AUTO_INCREMENT COMMENT '项目Id',
    7.     `name`        varchar(100) DEFAULT NULL COMMENT '项目名称',
    8.     `code`        bigint   NOT NULL COMMENT '项目编号',
    9.     `description` varchar(200) DEFAULT NULL COMMENT '描述',
    10.     `user_id`     int          DEFAULT NULL COMMENT '创建者ID',
    11.     `flag`        tinyint      DEFAULT '1' COMMENT '0:不可用，1:可用',
    12.     `create_time` datetime NOT NULL COMMENT '创建时间',
    13.     `update_time` datetime     DEFAULT NULL COMMENT '更新时间',
    14.     PRIMARY KEY (`id`)
    15. ) ENGINE = InnoDB AUTO_INCREMENT = 1 DEFAULT CHARSET = utf8 COMMENT ='项目表';

    步骤二：运行MyBatisGenerator，自动生成代码

    ​

    生成的Java Bean对象自动添加@author、@date、表/字段注释、lombok注解

    ​

    生成的Java Mapper对象支持分页操作

    ​

    CURD的使用样例

    1. package com.github.codegen;
    2.  
    3. import com.github.dao.domain.Project;
    4. import com.github.dao.domain.ProjectExample;
    5. import com.github.dao.mapper.ProjectMapper;
    6. import org.junit.jupiter.api.MethodOrderer;
    7. import org.junit.jupiter.api.Order;
    8. import org.junit.jupiter.api.Test;
    9. import org.junit.jupiter.api.TestMethodOrder;
    10. import org.springframework.beans.factory.annotation.Autowired;
    11. import org.springframework.boot.test.context.SpringBootTest;
    12. import org.springframework.util.Assert;
    13.  
    14. import java.util.Date;
    15. import java.util.List;
    16.  
    17. @SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
    18. @TestMethodOrder(MethodOrderer.OrderAnnotation.class)
    19. public class MBGTester {
    20.  
    21.     @Autowired
    22.     private ProjectMapper projectMapper;
    23.  
    24.     private static int projectId;
    25.  
    26.     @Test
    27.     @Order(1)
    28.     public void testInsert() {
    29.         // insert：插入完整记录，要求字段完整
    30.         // insertSelective：插入记录，允许插入部分字段
    31.  
    32.         Project project = new Project();
    33.         project.setCode(1L);
    34.         project.setName("PROJ-1");
    35.         project.setDescription("testing desc");
    36.         project.setFlag((byte) 1);
    37.         project.setCreateTime(new Date());
    38.         project.setUpdateTime(new Date());
    39.         int nEffectRows = this.projectMapper.insert(project);
    40.  
    41.         // 获取刚插入的记录的自增主键ID
    42.         projectId = project.getId();
    43.         Assert.isTrue(nEffectRows == 1);
    44.     }
    45.  
    46.     /**
    47.      * 条件查询
    48.      */
    49.     @Test
    50.     @Order(2)
    51.     public void testConditionQuery() {
    52.         // selectByPrimaryKey：根据主键查询
    53.         // selectByExample：根据条件查询
    54.  
    55.         ProjectExample example = new ProjectExample();
    56.         example.createCriteria().andCodeIsNotNull();
    57.         List projects = this.projectMapper.selectByExample(example);
    58.         Assert.notEmpty(projects);
    59.     }
    60.  
    61.     /**
    62.      * 分页查询
    63.      */
    64.     @Test
    65.     @Order(3)
    66.     public void testPagingQuery() {
    67.         ProjectExample example = new ProjectExample();
    68.         example.createCriteria().andCodeIsNotNull();
    69.         example.setOffset(0);
    70.         example.setLimit(100);
    71.         List projects = this.projectMapper.selectByExample(example);
    72.         Assert.notEmpty(projects);
    73.     }
    74.  
    75.     @Test
    76.     @Order(4)
    77.     public void testUpdate() {
    78.         // updateByPrimaryKey：根据主键更新
    79.         // updateByPrimaryKeySelective：根据主键更新部分字段
    80.         // updateByExample：根据条件更新
    81.         // updateByExampleSelective：根据条件更新部分字段
    82.  
    83.         Project project = new Project();
    84.         project.setId(projectId);
    85.         project.setCode(100L);
    86.         project.setName("PROJ-1");
    87.         project.setCreateTime(new Date());
    88.         project.setUpdateTime(new Date());
    89.  
    90.         int nEffectRows = this.projectMapper.updateByPrimaryKey(project);
    91.         Assert.isTrue(nEffectRows == 1);
    92.     }
    93.  
    94.     @Test
    95.     @Order(5)
    96.     public void testDelete() {
    97.         // deleteByPrimaryKey：根据主键删除
    98.         // deleteByExample：根据条件删除
    99.  
    100.         int nEffectRows = this.projectMapper.deleteByPrimaryKey(projectId);
    101.         Assert.isTrue(nEffectRows == 1);
    102.     }
    103. }

     

     

     

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  • 原文地址：https://blog.csdn.net/yeweiouyang/article/details/126321829