选择 Spring Initializer

父项目无需选择任何一个 Dependencies ，因为它不会作为一个具体项目去使用，而是供具体的子模块来继承。然后在父项目的 pom.xml 中添加：

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<packaging>pom</packaging>

若不添加该节点，则打包子模块时会报错

子模块记得让 Maven 来 Enable Auto-Import

此时，需要修改子项目中的继承方式：

修改后，继承关系为：spring_initializer ——> springboot_parent ——> spring-boot-starter-parent

继承后的好处：

修改SpringBoot 版本号，只需更改 parent 的 pom.xml 即可。

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<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.3.6.RELEASE</version> <!--更改此处的版本号即可-->
</parent>

image-20210305212623163

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package top.joydee.controllers;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/hello")
public class HelloController {
    @RequestMapping("/sayhello")
    public String sayHello(){
        return "Hello, SpringBoot!";
    }
}
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 .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::                (v2.4.3)

2021-03-05 16:39:25.956  INFO 15928 --- [           main] t.j.SpringInitializerDemoApplication     : Starting SpringInitializerDemoApplication using Java 15 on DESKTOP-TUSDBAD with PID 15928 (E:\springboot_parent\spring_initializer_demo\target\classes started by luffy in E:\springboot_parent)
2021-03-05 16:39:25.959  INFO 15928 --- [           main] t.j.SpringInitializerDemoApplication     : No active profile set, falling back to default profiles: default
2021-03-05 16:39:26.763  INFO 15928 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2021-03-05 16:39:26.781  INFO 15928 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2021-03-05 16:39:26.782  INFO 15928 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.43]
2021-03-05 16:39:26.829  INFO 15928 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2021-03-05 16:39:26.830  INFO 15928 --- [           main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 825 ms
2021-03-05 16:39:26.931  INFO 15928 --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Initializing ExecutorService 'applicationTaskExecutor'
2021-03-05 16:39:27.060  INFO 15928 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2021-03-05 16:39:27.068  INFO 15928 --- [           main] t.j.SpringInitializerDemoApplication     : Started SpringInitializerDemoApplication in 1.561 seconds (JVM running for 2.483)
2021-03-05 16:40:47.192  INFO 15928 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring DispatcherServlet 'dispatcherServlet'
2021-03-05 16:40:47.192  INFO 15928 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
2021-03-05 16:40:47.193  INFO 15928 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Completed initialization in 1 ms

image-20210305222504587

在相应的模块中加这个依赖

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<!--生成META-INF元数据，用于提供IDEA自动提示配置文件-->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-configuration-processor</artifactId>
    <!--依赖不会传播（继承关系上）-->
    <optional>true</optional>
</dependency>

image-20210305222236595

image-20210305223956396

要先启动一次，让 classes 目录生成 META-INF ，IDEA才能自动提示

yml 写法演示

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user:
  username: 张三
  age: ${random.int[100,200]} #逗号别加空格
  birthday: 2001/01/07
  hobbies: [睡觉, 学习]
#    - 睡觉
#    - 学习
  score: {Math : 94.0, Chinese : 100.0, English : 94.0}
  address:
    id: 1
    desc: ${user.username}的家在广州
# 它不支持 SPEL，只支持属性占位符

# score:
#    高等数学: 94.0
#    线性代数: 100.0
#    概率论与数理统计: 94.0

热部署

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<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-devtools</artifactId>
    <optional>true</optional>
</dependency>

IDEA 配置：

image-20210305235115522

ctrl + shift + alt + / ,选择Registry,勾上 Compiler autoMake allow when app running

指定 webapp 作为编译的位置？