Spring Data JPA--根据表生成代码--方法

旧城等待， 2022-09-14 11:17 217阅读 0赞

原文网址：[Spring Data JPA--根据表生成代码--方法-\_IT利刃出鞘的博客-CSDN博客][Spring Data JPA--_--_-_IT_-CSDN]

# 简介 #

**说明**

我们可以根据已有的表来生成代码（Entity、DAO、Service、Controller），省去手写的时间。MybatisPlus的自动生成代码的工程见：[Mybatis-Plus--根据表生成代码\_IT利刃出鞘的博客-CSDN博客][Mybatis-Plus--_IT_-CSDN]。

本文参考Mybatis-Plus的这种方案，来生成我们JPA相关类。本方案优点如下：

1.  不依赖于工具。只要有文本编辑器，有JDK，就可以运行。
2.  可以自定义任意想要的格式。
3.  每个字段都会把表中的注释给带过来。

**其他人的方案**

我搜了很多JPA通过表生成代码的文章，但感觉都不好，不如本文这种方式。其他的方案不外乎这三种：

1.  使用Idea工具（依赖于工具）
2.  使用Eclipse（依赖于工具）
3.  使用Maven插件。（不依赖于工具）
    
    1.  插件：hibernate-tools-maven-plugin

# 实例 #

项目结构

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBASVTliKnliIPlh7rpnpg_size_11_color_FFFFFF_t_70_g_se_x_16][]

## 创建表 ##

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBASVTliKnliIPlh7rpnpg_size_20_color_FFFFFF_t_70_g_se_x_16][]

## pom.xml ##

<?xml version="1.0" encoding="UTF-8"?>
    <project xmlns="http://maven.apache.org/POM/4.0.0"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
    
        <groupId>org.example</groupId>
        <artifactId>GenerateCode</artifactId>
        <version>1.0-SNAPSHOT</version>
    
        <dependencies>
            <dependency>
                <groupId>com.baomidou</groupId>
                <artifactId>mybatis-plus-generator</artifactId>
                <version>3.4.0</version>
            </dependency>
            <dependency>
                <groupId>org.freemarker</groupId>
                <artifactId>freemarker</artifactId>
                <version>2.3.30</version>
            </dependency>
    
            <dependency>
                <groupId>org.slf4j</groupId>
                <artifactId>slf4j-api</artifactId>
                <version>1.7.30</version>
            </dependency>
    
            <dependency>
                <groupId>org.slf4j</groupId>
                <artifactId>slf4j-simple</artifactId>
                <version>1.7.30</version>
            </dependency>
    
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>8.0.21</version>
            </dependency>
        </dependencies>
    
    </project>

## 自定义格式 ##

### Controller ###

MyController.java.ftl

import org.springframework.web.bind.annotation.RequestMapping;
    <#if restControllerStyle>
    import org.springframework.web.bind.annotation.RestController;
    <#else>
    import org.springframework.stereotype.Controller;
    </#if>
    <#if superControllerClassPackage??>
    import ${superControllerClassPackage};
    </#if>
    
    <#if restControllerStyle>
    @RestController
    <#else>
    @Controller
    </#if>
    @RequestMapping("<#if package.ModuleName?? && package.ModuleName != "">/${package.ModuleName}</#if>/<#if controllerMappingHyphenStyle??>${controllerMappingHyphen}<#else>${table.entityPath}</#if>")
    <#if kotlin>
    class ${table.controllerName}<#if superControllerClass??> : ${superControllerClass}()</#if>
    <#else>
        <#if superControllerClass??>
    public class ${table.controllerName} extends ${superControllerClass} {
        <#else>
    public class ${table.controllerName} {
        </#if>
    
    }
    </#if>

### Service ###

MyService.java.ftl

<#if kotlin>
    interface ${table.serviceName} : ${superServiceClass}<${entity}>
    <#else>
    public interface ${table.serviceName} {
    
    }
    </#if>

### Repository ###

MyRepository.java.ftl

import ${cfg.jpaSuperRepositoryClassPackage};
    
    @Repository
    <#if kotlin>
    interface ${table.mapperName} : ${superMapperClass}<${entity}>
    <#else>
    public interface ${table.mapperName} extends ${superMapperClass}<${entity}, Long>, JpaSpecificationExecutor<${entity}> {
        // 接口的第二个泛型是主键的类型。要按实际修改
    }
    </#if>

### Entity ###

MyEntity.java.ftl

<#if swagger2>
    import io.swagger.annotations.ApiModel;
    import io.swagger.annotations.ApiModelProperty;
    </#if>
    <#if entityLombokModel>
    import lombok.Data;
    import lombok.NoArgsConstructor;
    
    import javax.persistence.Entity;
    import javax.persistence.GeneratedValue;
    import javax.persistence.GenerationType;
    import javax.persistence.Id;
        <#if chainModel>
    import lombok.experimental.Accessors;
        </#if>
    </#if>
    
    <#if entityLombokModel>
    @Data
    @NoArgsConstructor
        <#if chainModel>
    @Accessors(chain = true)
        </#if>
    </#if>
    <#if table.convert>
    @Entity(name = "${table.name}")
    </#if>
    <#if swagger2>
    @ApiModel(value="${entity}对象", description="${table.comment!}")
    </#if>
    <#if superEntityClass??>
    public class ${entity} extends ${superEntityClass}<#if activeRecord><${entity}></#if> {
    <#elseif activeRecord>
    public class ${entity} extends Model<${entity}> {
    <#else>
    public class ${entity} {
    </#if>
    <#-- ----------  BEGIN 字段循环遍历  ---------->
    <#list table.fields as field>
        <#if field.keyFlag>
            <#assign keyPropertyName="${field.propertyName}"/>
        </#if>
        <#if field.comment!?length gt 0>
            <#if swagger2>
        @ApiModelProperty(value = "${field.comment}")
            <#else>
        // ${field.comment}
            </#if>
        </#if>
        <#if field.keyFlag>
        <#-- 主键 -->
            <#if field.keyIdentityFlag>
        @Id
        @GeneratedValue(strategy = GenerationType.AUTO)
            <#elseif idType??>
        @Id
        @GeneratedValue(strategy = GenerationType.AUTO)
            <#elseif field.convert>
        @Id
        @GeneratedValue(strategy = GenerationType.AUTO)
            </#if>
        <#-- 普通字段 -->
        <#elseif field.fill??>
        <#-- -----   存在字段填充设置   ----->
            <#if field.convert>
        @TableField(value = "${field.annotationColumnName}", fill = FieldFill.${field.fill})
            <#else>
        @TableField(fill = FieldFill.${field.fill})
            </#if>
        <#elseif field.convert>
        @TableField("${field.annotationColumnName}")
        </#if>
    <#-- 乐观锁注解 -->
        <#if (versionFieldName!"") == field.name>
        @Version
        </#if>
    <#-- 逻辑删除注解 -->
        <#if (logicDeleteFieldName!"") == field.name>
        @TableLogic
        </#if>
        private ${field.propertyType} ${field.propertyName};
    
    </#list>
    <#------------  END 字段循环遍历  ---------->
    <#if !entityLombokModel>
        <#list table.fields as field>
            <#if field.propertyType == "boolean">
                <#assign getprefix="is"/>
            <#else>
                <#assign getprefix="get"/>
            </#if>
        public ${field.propertyType} ${getprefix}${field.capitalName}() {
            return ${field.propertyName};
        }
            <#if chainModel>
        public ${entity} set${field.capitalName}(${field.propertyType} ${field.propertyName}) {
            <#else>
        public void set${field.capitalName}(${field.propertyType} ${field.propertyName}) {
            </#if>
            this.${field.propertyName} = ${field.propertyName};
            <#if chainModel>
                return this;
            </#if>
        }
        </#list>
    </#if>
    <#if entityColumnConstant>
        <#list table.fields as field>
         public static final String ${field.name?upper_case} = "${field.name}";
    
        </#list>
    </#if>
    <#if activeRecord>
        @Override
        protected Serializable pkVal() {
        <#if keyPropertyName??>
            return this.${keyPropertyName};
        <#else>
            return null;
        </#if>
        }
    </#if>
    <#if !entityLombokModel>
        @Override
        public String toString() {
        return "${entity}{" +
        <#list table.fields as field>
            <#if field_index==0>
                "${field.propertyName}=" + ${field.propertyName} +
            <#else>
                ", ${field.propertyName}=" + ${field.propertyName} +
            </#if>
        </#list>
        "}";
        }
    </#if>
    }

## 提供主类 ##

package com.example.generate;
    
    import com.baomidou.mybatisplus.generator.AutoGenerator;
    import com.baomidou.mybatisplus.generator.InjectionConfig;
    import com.baomidou.mybatisplus.generator.config.*;
    import com.baomidou.mybatisplus.generator.config.rules.NamingStrategy;
    import com.baomidou.mybatisplus.generator.engine.FreemarkerTemplateEngine;
    
    import java.util.HashMap;
    import java.util.Map;
    
    public class Generate {
        private static final String url = "jdbc:mysql://127.0.0.1:3306/blog" +
                "?useUnicode=true&characterEncoding=utf8" +
                "&allowPublicKeyRetrieval=True&useSSL=false" +
                "&serverTimezone=Asia/Shanghai";
        private static final String userName    = "root";
        private static final String password    = "222333";
        private static final String tableName   = "t_blog";
        private static final String tablePrefix = "t_";
    
        // 演示例子
        public static void main(String[] args) {
            // 代码生成器
            AutoGenerator autoGenerator = new AutoGenerator();
    
            // 全局配置
            GlobalConfig globalConfig = new GlobalConfig();
            String projectPath = System.getProperty("user.dir");
            globalConfig.setOutputDir(projectPath + "/src/main/java");
            globalConfig.setAuthor("xxx");
            globalConfig.setFileOverride(false);  //默认就是false
            globalConfig.setOpen(false);
            // gc.setBaseResultMap(true); // mapper.xml 生成 ResultMap
            // gc.setBaseColumnList(true); // mapper.xml 生成 ColumnList
    
            // 自定义文件命名，注意 %s 会自动填充表实体属性！
            globalConfig.setMapperName("%sRepository");
            // gc.setXmlName("%sDao");
            globalConfig.setServiceName("%sService");
            globalConfig.setServiceImplName("%sServiceImpl");
            globalConfig.setControllerName("%sController");
            // gc.setSwagger2(true); 实体属性 Swagger2 注解
            autoGenerator.setGlobalConfig(globalConfig);
    
            // 数据源配置
            DataSourceConfig dataSourceConfig = new DataSourceConfig();
    
            dataSourceConfig.setUrl(url);
            // dsc.setSchemaName("public");
            dataSourceConfig.setDriverName("com.mysql.cj.jdbc.Driver");
            dataSourceConfig.setUsername(userName);
            dataSourceConfig.setPassword(password);
            autoGenerator.setDataSource(dataSourceConfig);
    
            // 包配置
            PackageConfig packageConfig = new PackageConfig();
            // pc.setParent("com.example.generate.out");
            // pc.setModuleName("xxx");
            packageConfig.setMapper("repository");
            packageConfig.setParent("com.example.generate." + tableName.substring(tablePrefix.length()));
            autoGenerator.setPackageInfo(packageConfig);
    
            //自定义配置
            InjectionConfig customConfig = new InjectionConfig() {
                @Override
                public void initMap() {
                    Map<String, Object> map = new HashMap<>();
                    map.put("jpaSuperRepositoryClassPackage",
                            "org.springframework.data.jpa.repository.JpaRepository");
                    this.setMap(map);
                }
            };
            autoGenerator.setCfg(customConfig);
    
            // 配置自定义输出模板
            TemplateConfig templateConfig = new TemplateConfig();
            //指定自定义模板路径，注意不要带上.ftl/.vm, 会根据使用的模板引擎自动识别
            templateConfig.setController("templates_mp/MyController.java");
            templateConfig.setService("templates_mp/MyService.java");
            templateConfig.setServiceImpl("templates_mp/MyServiceImpl.java");
            templateConfig.setMapper("templates_mp/MyRepository.java");
            templateConfig.setEntity("templates_mp/MyEntity.java");
            templateConfig.setXml(null);
            autoGenerator.setTemplate(templateConfig);
    
            // 策略配置
            StrategyConfig strategyConfig = new StrategyConfig();
            strategyConfig.setNaming(NamingStrategy.underline_to_camel);
            strategyConfig.setColumnNaming(NamingStrategy.underline_to_camel);
            strategyConfig.setSuperMapperClass("JpaRepository");
            //strategy.setSuperEntityClass("你自己的父类实体,没有就不用设置!");
            strategyConfig.setEntityLombokModel(true);
            strategyConfig.setRestControllerStyle(true);
    
            // 公共父类
            // strategy.setSuperControllerClass("你自己的父类控制器,没有就不用设置!");
            // 写于父类中的公共字段
            // strategy.setSuperEntityColumns("id");
    
            // 表名
            strategyConfig.setInclude(tableName);
            strategyConfig.setTablePrefix(tablePrefix);
            strategyConfig.setControllerMappingHyphenStyle(true);
    
            autoGenerator.setStrategy(strategyConfig);
            autoGenerator.setTemplateEngine(new FreemarkerTemplateEngine());
            autoGenerator.execute();
        }
    }

## 运行主类 ##

运行之前

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBASVTliKnliIPlh7rpnpg_size_11_color_FFFFFF_t_70_g_se_x_16 1][]

运行之后（红框中是新生成的文件）

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBASVTliKnliIPlh7rpnpg_size_11_color_FFFFFF_t_70_g_se_x_16 2][]

# 其他网址 #

[Mybatis-Plus--代码生成器\_IT利刃出鞘的博客-CSDN博客][Mybatis-Plus--_IT_-CSDN]

[Spring Boot JPA生成实体类的3种方法][Spring Boot JPA_3]  
[SpringBoot学习录（2）- SpringBoot、JPA之生成实体类 - 简书][SpringBoot_2_- SpringBoot_JPA_ -]  
[springboot-jpa: 根据实体类自动生成controller service 实现类以及Dao][springboot-jpa_ _controller service _Dao]

[Spring Data JPA--_--_-_IT_-CSDN]: https://knife.blog.csdn.net/article/details/120643968
[Mybatis-Plus--_IT_-CSDN]: https://knife.blog.csdn.net/article/details/108233196
[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBASVTliKnliIPlh7rpnpg_size_11_color_FFFFFF_t_70_g_se_x_16]: /images/20220828/36504b2ca1c94b16aaa09ff0297cc3cd.png
[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBASVTliKnliIPlh7rpnpg_size_20_color_FFFFFF_t_70_g_se_x_16]: /images/20220828/ef07a1f80dee4947a828426ba9179583.png
[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBASVTliKnliIPlh7rpnpg_size_11_color_FFFFFF_t_70_g_se_x_16 1]: /images/20220828/0f2735617d9349bc9b13248cf4fb205a.png
[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBASVTliKnliIPlh7rpnpg_size_11_color_FFFFFF_t_70_g_se_x_16 2]: /images/20220828/3d5ea9231b43413bb8bf05285f8958bd.png
[Spring Boot JPA_3]: https://juejin.cn/post/6844903877095997453
[SpringBoot_2_- SpringBoot_JPA_ -]: https://www.jianshu.com/p/31fa94724ccc
[springboot-jpa_ _controller service _Dao]: https://gitee.com/mao_jiafeng/springboot-jpa