SpringBoot从入门到精通教程（二十五）- Mybatis-Plus快速开发框架用法

蔚落 2021-10-15 03:18 446阅读 0赞

# 需求背景 #

> Springboot集成：Mybatis-Plus快速开发框架用法

# 框架介绍 #

> MyBatis-Plus 荣获【2018年度开源中国最受欢迎的中国软件】 TOP5，为简化开发而生
> 
> 框架有以下三个特点：
> 
> **1. 润物无声**  
> 只做增强不做改变，引入它不会对现有工程产生影响，如丝般顺滑。
> 
> **2. 效率至上**  
> 只需简单配置，即可快速进行 CRUD 操作，从而节省大量时间。
> 
> **3. 丰富功能**  
> 热加载、代码生成、分页、性能分析等功能一应俱全。

# 当前最新版本 #

<dependency>
        <groupId>com.baomidou</groupId>
        <artifactId>mybatis-plus</artifactId>
        <version>3.2.0</version>
    </dependency>

# 准备工作 #

1. 提前准备好一个mysql连接库，导入[db.sql文件内容][db.sql]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9oZW1pbi5ibG9nLmNzZG4ubmV0_size_16_color_FFFFFF_t_70][]

# 代码演示 #

**1. 项目目录结构**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9oZW1pbi5ibG9nLmNzZG4ubmV0_size_16_color_FFFFFF_t_70 1][]

**2. pom.xml依赖组件**

<?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>
    
    	<parent>
    		<groupId>com.md</groupId>
    		<artifactId>spring-boot2-parent</artifactId>
    		<version>0.0.1-SNAPSHOT</version>
    		<relativePath>../pom.xml</relativePath>
    	</parent>
    
    	<artifactId>spring-boot2-mybatis-plus</artifactId>
    	<packaging>jar</packaging>
    
    	<name>spring-boot2-mybatis-plus</name>
    	<description>Spring Boot, MVC, Rest API for App</description>
    
    	<properties>
    		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    		<java.version>1.8</java.version>
    		<swagger.version>2.9.2</swagger.version>
    		<mybatisplus.version>3.2.0</mybatisplus.version>
    	</properties>
    
    	<dependencies>
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter</artifactId>
    		</dependency>
    		
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-web</artifactId>
    		</dependency>
    		<dependency>
    			<groupId>net.sf.json-lib</groupId>
    			<artifactId>json-lib-ext-spring</artifactId>
    		</dependency>
    		<dependency>
    			<groupId>mysql</groupId>
    			<artifactId>mysql-connector-java</artifactId>
    		</dependency>
    		<dependency>
    			<groupId>org.projectlombok</groupId>
    			<artifactId>lombok</artifactId>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-test</artifactId>
    			<scope>test</scope>
    		</dependency>
    		<dependency>
    			<groupId>junit</groupId>
    			<artifactId>junit</artifactId>
    		</dependency>
    		
    		<dependency>
    			<groupId>io.springfox</groupId>
    			<artifactId>springfox-swagger2</artifactId>
    			<version>${swagger.version}</version>
    		</dependency>
    		
    		<dependency>
    			<groupId>io.springfox</groupId>
    			<artifactId>springfox-swagger-ui</artifactId>
    			<version>${swagger.version}</version>
    		</dependency>
    		
    		<dependency>
    			<groupId>com.github.xiaoymin</groupId>
    			<artifactId>swagger-bootstrap-ui</artifactId>
    			<version>1.9.3</version>
    		</dependency>
    		
    		<dependency>
    			<groupId>com.baomidou</groupId>
    			<artifactId>mybatis-plus-generator</artifactId>
    			<version>${mybatisplus.version}</version>
    		</dependency>
    		<dependency>
    			<groupId>com.baomidou</groupId>
    			<artifactId>mybatis-plus-boot-starter</artifactId>
    			<version>${mybatisplus.version}</version>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-freemarker</artifactId>
    		</dependency>
    	</dependencies>
    
    	<build>
    		<plugins>
    			<plugin>
    				<groupId>org.springframework.boot</groupId>
    				<artifactId>spring-boot-maven-plugin</artifactId>
    			</plugin>
    		</plugins>
    	</build>
    
    </project>

**3. 自动生成代码类**

CodeGenerator.java，相关注释说明已有

package com.md.demo.auto;
    
    import java.util.ArrayList;
    import java.util.List;
    import java.util.Scanner;
    
    import com.baomidou.mybatisplus.core.exceptions.MybatisPlusException;
    import com.baomidou.mybatisplus.core.toolkit.StringPool;
    import com.baomidou.mybatisplus.core.toolkit.StringUtils;
    import com.baomidou.mybatisplus.generator.AutoGenerator;
    import com.baomidou.mybatisplus.generator.InjectionConfig;
    import com.baomidou.mybatisplus.generator.config.DataSourceConfig;
    import com.baomidou.mybatisplus.generator.config.FileOutConfig;
    import com.baomidou.mybatisplus.generator.config.GlobalConfig;
    import com.baomidou.mybatisplus.generator.config.PackageConfig;
    import com.baomidou.mybatisplus.generator.config.StrategyConfig;
    import com.baomidou.mybatisplus.generator.config.TemplateConfig;
    import com.baomidou.mybatisplus.generator.config.po.TableInfo;
    import com.baomidou.mybatisplus.generator.config.rules.NamingStrategy;
    import com.baomidou.mybatisplus.generator.engine.FreemarkerTemplateEngine;
    
    /**
     * 代码生成器
     * 
     * @author Minbo
     *
     */
    public class CodeGenerator {
    
    	/**
    	 * RUN THIS
    	 */
    	public static void main(String[] args) {
    		AutoGenerator mpg = new AutoGenerator();
    
    		// 全局配置
    		GlobalConfig gc = new GlobalConfig();
    		String projectPath = System.getProperty("user.dir");
    		gc.setOutputDir(projectPath + "/src/main/java");
    		gc.setAuthor(scanner("开发者"));
    		gc.setOpen(false);
    		// 是否启动Swagger2
    		gc.setSwagger2(true);
    		// 默认不覆盖，如果文件存在，将不会再生成，配置true就是覆盖
    		gc.setFileOverride(true);
    		mpg.setGlobalConfig(gc);
    
    		// 数据源配置
    		DataSourceConfig dsc = new DataSourceConfig();
    		dsc.setUrl("jdbc:mysql://localhost:33061/test?useUnicode=true&useSSL=false&characterEncoding=utf8");
    		dsc.setDriverName("com.mysql.jdbc.Driver");
    		dsc.setUsername("root");
    		dsc.setPassword("hs2019");
    		mpg.setDataSource(dsc);
    
    		// 包配置
    		PackageConfig pc = new PackageConfig();
    		pc.setModuleName(scanner("模块名"));
    		pc.setParent("com.md.demo").setEntity("entity.vo").setMapper("dao");
    		mpg.setPackageInfo(pc);
    
    		// 自定义配置
    		InjectionConfig cfg = new InjectionConfig() {
    			@Override
    			public void initMap() {
    				// to do nothing
    			}
    		};
    
    		// 如果模板引擎是 freemarker
    		String templatePath = "/templates/mapper.xml.ftl";
    
    		// 自定义输出配置
    		List<FileOutConfig> focList = new ArrayList<>();
    		// 自定义配置会被优先输出
    		focList.add(new FileOutConfig(templatePath) {
    			@Override
    			public String outputFile(TableInfo tableInfo) {
    				// 自定义输出文件名 ， 如果你 Entity 设置了前后缀、此处注意 xml 的名称会跟着发生变化！！
    				return projectPath + "/src/main/resources/mapper/" + pc.getModuleName() + "/"
    						+ tableInfo.getEntityName() + "Mapper" + StringPool.DOT_XML;
    			}
    		});
    
    		cfg.setFileOutConfigList(focList);
    		mpg.setCfg(cfg);
    
    		// 配置模板
    		TemplateConfig templateConfig = new TemplateConfig();
    		templateConfig.setXml(null);
    		mpg.setTemplate(templateConfig);
    
    		// 策略配置
    		StrategyConfig strategy = new StrategyConfig();
    		strategy.setNaming(NamingStrategy.underline_to_camel);
    		strategy.setColumnNaming(NamingStrategy.underline_to_camel);
    
    		strategy.setEntityLombokModel(true);
    		strategy.setRestControllerStyle(true);
    
    		strategy.setInclude(scanner("表名"));
    		strategy.setControllerMappingHyphenStyle(true);
    		strategy.setTablePrefix(pc.getModuleName() + "_");
    
    		mpg.setStrategy(strategy);
    		// 选择 freemarker 引擎需要指定如下加，注意 pom 依赖必须有！
    		mpg.setTemplateEngine(new FreemarkerTemplateEngine());
    
    		mpg.execute();
    	}
    
    	/**
    	 * <p>
    	 * 读取控制台内容
    	 * </p>
    	 */
    	@SuppressWarnings("resource")
    	public static String scanner(String tip) {
    		Scanner scanner = new Scanner(System.in);
    		StringBuilder help = new StringBuilder();
    		help.append("请输入" + tip + "：");
    		System.out.println(help.toString());
    		if (scanner.hasNext()) {
    			String ipt = scanner.next();
    			if (StringUtils.isNotEmpty(ipt)) {
    				return ipt;
    			}
    		}
    		throw new MybatisPlusException("请输入正确的" + tip + "！");
    	}
    }

**4. 运行上面的类**

控制台会提示你输入开发者名，模块名，表名，此框架会自动给你生成相应的类

控制台输出：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9oZW1pbi5ibG9nLmNzZG4ubmV0_size_16_color_FFFFFF_t_70 2][]

项目最终图：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9oZW1pbi5ibG9nLmNzZG4ubmV0_size_16_color_FFFFFF_t_70 3][]

通过此框架，能节省大量类似重复的操作事项等

**5. 相关类代码展示**

比如：实体类Myuser.java（这里用到了lombok组件，不再需要写getter/setter方法）

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9oZW1pbi5ibG9nLmNzZG4ubmV0_size_16_color_FFFFFF_t_70 4][]

**6. 新增访问接口**

MyuserController.java

package com.md.demo.test.controller;
    
    import java.util.List;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    import com.md.demo.test.entity.vo.Myuser;
    import com.md.demo.test.service.IMyuserService;
    import com.md.demo.util.JsonResult;
    import com.md.demo.util.ResultCode;
    
    import io.swagger.annotations.ApiImplicitParam;
    import io.swagger.annotations.ApiOperation;
    
    /**
     * <p>
     * 前端控制器
     * </p>
     *
     * @author MMinbo
     * @since 2019-10-25
     */
    @RestController
    @RequestMapping("/test/myuser")
    public class MyuserController {
    
    	@Autowired
    	private IMyuserService myuserService;
    
    	@ApiOperation(value = "获得用户列表", notes = "", httpMethod = "GET")
    	@RequestMapping(value = "/listUser")
    	public JsonResult listUser() {
    		// 框架自带的方法
    		List<Myuser> list = this.myuserService.list(null);
    		return new JsonResult(ResultCode.SUCCESS, list);
    	}
    
    	@ApiOperation(value = "根据用户名获得用户记录", notes = "名称不能为空", httpMethod = "GET")
    	@ApiImplicitParam(dataType = "string", name = "name", value = "用户名", required = true)
    	@RequestMapping(value = "/getUserByName")
    	public JsonResult getUserByName(String name) {
    		// 自定义的方法
    		Myuser myuser = this.myuserService.getUserByName(name);
    		return new JsonResult(ResultCode.SUCCESS, myuser);
    	}
    }

**7. 在线接口测试**

启动项目，访问swagger2地址（[Swagger2集成教程用法][Swagger2]）：

[http://localhost:9090/doc.html][http_localhost_9090_doc.html]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9oZW1pbi5ibG9nLmNzZG4ubmV0_size_16_color_FFFFFF_t_70 5][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9oZW1pbi5ibG9nLmNzZG4ubmV0_size_16_color_FFFFFF_t_70 6][]

# 完整源码下载 #

我的[Github源码地址：][Github]

[https://github.com/hemin1003/spring-boot-study/tree/master/spring-boot2-study/spring-boot2-parent/spring-boot2-mybatis-plus][https_github.com_hemin1003_spring-boot-study_tree_master_spring-boot2-study_spring-boot2-parent_spring-boot2-mybatis-plus]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9oZW1pbi5ibG9nLmNzZG4ubmV0_size_16_color_FFFFFF_t_70 7][]

# 注意事项 #

1. Application.java启动类中，需要配置@MapperScan注解，扫描mapper定义的类，否则报错

2019-10-25 01:22:02,702 [main] [org.springframework.boot.SpringApplication] [ERROR] (SpringApplication.java:837)- Application run failed
    org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'myuserController': Unsatisfied dependency expressed through field 'myuserService'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'myuserServiceImpl': Unsatisfied dependency expressed through field 'baseMapper'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.md.demo.test.dao.MyuserMapper' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
    	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:584)
    	at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:90)
    	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:370)
    	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1336)
    	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:572)
    	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:495)
    	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317)
    	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
    	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315)
    	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199)

2. 之所以能有框架很多自带的方法，是因为继承了IService和BaseMapper两个接口，可见源码

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9oZW1pbi5ibG9nLmNzZG4ubmV0_size_16_color_FFFFFF_t_70 8][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9oZW1pbi5ibG9nLmNzZG4ubmV0_size_16_color_FFFFFF_t_70 9][]

3. 虽然框架支持jpa方法定义sql（如下图所示），但这里还是建议使用xml sql的方式，因为对于后续扩展和查障相对来说，会方便很多，所以不建议使用jpa这种方式

![20191025012806687.png][]

# 其他资料 #

[Mybatis-Plus官方][Mybatis-Plus]

[Swagger2集成教程用法][Swagger2]

# 下一章教程 #

[SpringBoot从入门到精通教程（二十六）- 全局header/body接口请求参数+Swagger2集成/接口规范用法][SpringBoot_- _header_body_Swagger2]

# 该系列教程 #

[SpringBoot从入门到精通教程][SpringBoot]

至此，全部介绍就结束了

\------------------------------------------------------

[关于我][Link 1]（个人域名）

[我的开源项目集Github][Github 1]

期望和大家***一起学习，一起成长***，共勉，O(∩\_∩)O谢谢

欢迎交流问题，可加个人QQ 469580884，

或者，加我的群号 **751925591**，一起探讨交流问题

不讲虚的，只做实干家

Talk is cheap，show me the code

![20180411181545874][]

[db.sql]: https://github.com/hemin1003/spring-boot-study/blob/master/spring-boot2-study/spring-boot2-parent/spring-boot2-mybatis-plus/db.sql
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9oZW1pbi5ibG9nLmNzZG4ubmV0_size_16_color_FFFFFF_t_70]: /images/20211015/8a5d8c896cf74225b6a226fb9db767b3.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9oZW1pbi5ibG9nLmNzZG4ubmV0_size_16_color_FFFFFF_t_70 1]: /images/20211015/eed835a2d3c7471e9983391b53009d76.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9oZW1pbi5ibG9nLmNzZG4ubmV0_size_16_color_FFFFFF_t_70 2]: /images/20211015/32b1a030189a4a0a9effbf3714d0be1f.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9oZW1pbi5ibG9nLmNzZG4ubmV0_size_16_color_FFFFFF_t_70 3]: /images/20211015/d8746efe248547f88596dd7e2ed5902c.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9oZW1pbi5ibG9nLmNzZG4ubmV0_size_16_color_FFFFFF_t_70 4]: /images/20211015/7f4a491f510b4dce88f9aaf591bbdb50.png
[Swagger2]: https://hemin.blog.csdn.net/article/details/99637936
[http_localhost_9090_doc.html]: http://localhost:9090/doc.html
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9oZW1pbi5ibG9nLmNzZG4ubmV0_size_16_color_FFFFFF_t_70 5]: /images/20211015/a0984569027349f589a8d1e7b6522425.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9oZW1pbi5ibG9nLmNzZG4ubmV0_size_16_color_FFFFFF_t_70 6]: /images/20211015/821e6c3498ab47eaadaff6f6a0f64342.png
[Github]: https://github.com/hemin1003/spring-boot-study/tree/master/spring-boot2-study/spring-boot2-parent
[https_github.com_hemin1003_spring-boot-study_tree_master_spring-boot2-study_spring-boot2-parent_spring-boot2-mybatis-plus]: https://github.com/hemin1003/spring-boot-study/tree/master/spring-boot2-study/spring-boot2-parent/spring-boot2-mybatis-plus
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9oZW1pbi5ibG9nLmNzZG4ubmV0_size_16_color_FFFFFF_t_70 7]: /images/20211015/f945ac91499f41478a8995334269d02f.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9oZW1pbi5ibG9nLmNzZG4ubmV0_size_16_color_FFFFFF_t_70 8]: /images/20211015/7ac8d2d66835434d87fde6a0d95e280c.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9oZW1pbi5ibG9nLmNzZG4ubmV0_size_16_color_FFFFFF_t_70 9]: /images/20211015/05e6fcb62c1a4bcea7a4c2840412350b.png
[20191025012806687.png]: /images/20211015/d0402b4b60034b4886942f046a53da7f.png
[Mybatis-Plus]: https://mybatis.plus/
[SpringBoot_- _header_body_Swagger2]: https://blog.csdn.net/hemin1003/article/details/99638102
[SpringBoot]: https://hemin.blog.csdn.net/column/info/40170
[Link 1]: http://heminit.com/about/
[Github 1]: https://github.com/hemin1003
[20180411181545874]: /images/20211015/ade64e3b3cb84424826bb6f36c7dd787.png