=============
后端_创建项目
=============

1 新建项目

IDEA
    新建项目
        Spring Initializr
            名称：barblog
            位置：~\Projects\BarBlog\code\barblog
            语言：Java
            类型：Maven
            组：com.weihome
            工件：barblog
            软件包名称：com.weihome.barblog
            项目SDK：1.8
            Java：8
            打包：Jar
        依赖项
            Developer Tools
                Spring Boot DevTools
                Lombok
            Web
                Spring Web
            SQL
                MySQL Driver

/pom.xml：

...
<parent>
    ...
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.2.6.RELEASE</version>
    ...
</parent>
...

删除/.mvn、/.gitignore、/mvnw和/mvnw.cmd。

2 添加依赖

/pom.xml：

...
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-freemarker</artifactId>
</dependency>
<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>3.2.0</version>
</dependency>
<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-generator</artifactId>
    <version>3.2.0</version>
</dependency>
...

3 添加配置

/src/main/resources/application.yml：

spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/barblogdb?useUnicode=true&useSSL=false&characterEncoding=utf8&serverTimezone=Asia/Shanghai
    username: root
    password: 123456
mybatis-plus:
  mapper-locations: classpath*:/mapper/**Mapper.xml
server:
  port: 8081

4 建库建表

Navicat
    localhost_3306右键
        新建数据库...
            数据库名：barblogdb
            字符集：utf8

用户表：

DROP TABLE IF EXISTS `t_user`;

CREATE TABLE `t_user` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `username` varchar(64) DEFAULT NULL,
  `avatar` varchar(255) DEFAULT NULL,
  `email` varchar(64) DEFAULT NULL,
  `password` varchar(64) DEFAULT NULL,
  `status` int(5) NOT NULL,
  `created` datetime DEFAULT NULL,
  `last_login` datetime DEFAULT NULL,
  PRIMARY KEY (`id`),
  KEY `UK_USERNAME` (`username`) USING BTREE
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

INSERT INTO `t_user` VALUES ('1', 'bear', 'bear.png', 'johnmin74@hotmail.com', '96e79218965eb72c92a549dd5a330112', '0', '2022-03-22 12:00:00', null);
INSERT INTO `t_user` VALUES ('2', 'rabbit', 'rabbit.png', 'weiyang8779@163.com', '96e79218965eb72c92a549dd5a330112', '0', '2022-03-22 12:00:00', null);

博客表：

DROP TABLE IF EXISTS `t_blog`;

CREATE TABLE `t_blog` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `user_id` bigint(20) NOT NULL,
  `title` varchar(255) NOT NULL,
  `description` varchar(255) NOT NULL,
  `content` longtext,
  `created` datetime NOT NULL ON UPDATE CURRENT_TIMESTAMP,
  `status` tinyint(4) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

INSERT INTO `t_blog` VALUES ('1', '1', '小熊', '小熊的自我介绍', '我是小熊。', '2022-03-22 13:00:00', '0');
INSERT INTO `t_blog` VALUES ('2', '2', '小兔', '小兔的自我介绍', '我是小兔。', '2022-03-22 14:00:00', '0');

SET FOREIGN_KEY_CHECKS=0;

5 添加MyBatis-Plus配置类

/src/main/java/com/weihome/barblog/config/MybatisPlusConfig.java：

/**
 * MyBatis-Plus配置类
 */
@Configuration
@EnableTransactionManagement
@MapperScan("com.weihome.barblog.mapper")
public class MybatisPlusConfig {
    @Bean
    public PaginationInterceptor paginationInterceptor() {
        PaginationInterceptor paginationInterceptor = new PaginationInterceptor();
        return paginationInterceptor;
    }
}

- 通过MapperScan注解指定要变成实现类的接口所在的包
- 创建并返回PaginationInterceptor类型的分页插件

6 添加代码生成器类

/src/main/java/com/weihome/barblog/CodeGenerator.java：

/**
 * 代码生成器类
 */
public class CodeGenerator {
    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 + "！");
    }

    public static void main(String[] args) {
        AutoGenerator mpg = new AutoGenerator();

        GlobalConfig gc = new GlobalConfig();
        String projectPath = System.getProperty("user.dir");
        gc.setOutputDir(projectPath + "/src/main/java");
        gc.setAuthor("BarBlog");
        gc.setOpen(false);
        gc.setServiceName("%sService");
        mpg.setGlobalConfig(gc);

        DataSourceConfig dsc = new DataSourceConfig();
        dsc.setUrl("jdbc:mysql://localhost:3306/barblogdb?useUnicode=true&useSSL=false&characterEncoding=utf8&serverTimezone=UTC");
        dsc.setDriverName("com.mysql.cj.jdbc.Driver");
        dsc.setUsername("root");
        dsc.setPassword("123456");
        mpg.setDataSource(dsc);

        PackageConfig pc = new PackageConfig();
        pc.setModuleName(null);
        pc.setParent("com.weihome.barblog");
        mpg.setPackageInfo(pc);

        InjectionConfig cfg = new InjectionConfig() {
            @Override
            public void initMap() {
            }
        };

        String templatePath = "/templates/mapper.xml.ftl";

        List<FileOutConfig> focList = new ArrayList<>();
        focList.add(new FileOutConfig(templatePath) {
            @Override
            public String outputFile(TableInfo tableInfo) {
                return projectPath + "/src/main/resources/mapper/"
                    + "/" + tableInfo.getEntityName() + "Mapper" + StringPool.DOT_XML;
            }
        });

        cfg.setFileOutConfigList(focList);
        mpg.setCfg(cfg);

        TemplateConfig templateConfig = new TemplateConfig();

        templateConfig.setXml(null);
        mpg.setTemplate(templateConfig);

        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，多个英文逗号分割").split(","));
        strategy.setControllerMappingHyphenStyle(true);
        strategy.setTablePrefix("t_");
        mpg.setStrategy(strategy);
        mpg.setTemplateEngine(new FreemarkerTemplateEngine());
        mpg.execute();
    }
}

7 生成代码

执行CodeGenerator.main()...

请输入表名，多个英文逗号分割：
t_user,t_blog

回车生成如下代码文件：

/src/
└─main/
  ├─java/
  │ └─com/
  │   └─weihome/
  │     └─barblog/
  │       │
  │       ├─controller/              - 控制器 <- Servlet
  │       │ ├─BlogController.java
  │       │ └─UserController.java
  │       │
  │       ├─entity/                  - 实体类
  │       │ ├─Blog.java
  │       │ └─User.java
  │       │
  │       ├─mapper/                  - 数据访问接口 <---
  │       │ ├─BlogMapper.java                          |
  │       │ └─UserMapper.java                          |
  │       │                                            |
  │       └─service/                 - 服务接口 <-     |
  │         ├─BlogService.java                   |     |
  │         ├─UserService.java                Service  |
  │         │                                    |    DAO
  │         └─impl/                  - 服务实现 <-     |
  │           ├─BlogServiceImpl.java                   |
  │           └─UserServiceImpl.java                   |
  │                                                    |
  └─resources/                                         |
    │                                                  |
    └─mapper/                        - 数据访问对象 <---
      ├─BlogMapper.xml
      └─UserMapper.xml

控制器->服务接口                         \
           |多态                         |
        服务实现->数据访问接口 \         |
                       |多态   | MyBatis | MyBatis-Plus
                  数据访问对象 /         |
                       |JDBC             |
                     数据库              /

8 为控制器添加测试方法

/src/main/java/com/weihome/barblog/controller/UserController.java：

@RestController
@RequestMapping("/user")
public class UserController {
    @Autowired
    private UserService userService;

    @GetMapping("/index")
    public Object index() {
        return userService.getById(1L);
    }
}

9 运行测试

执行BarblogApplication.main()...

http://localhost:8081/user/index

{
    "id": 1,
    "username": "bear",
    "avatar": "bear.png",
    "email": "johnmin74@hotmail.com",
    "password": "96e79218965eb72c92a549dd5a330112",
    "status": 0,
    "created": "2022-03-22T12:00:00",
    "lastLogin": null
}