四、SpringBoot的最佳实践

# 16、最佳实践-SpringBoot应用如何编写

引入场景依赖
- 官方文档 (opens new window)

查看自动配置了哪些（选做）

自己分析，引入场景对应的自动配置一般都生效了

配置文件中debug=true开启自动配置报告。会打印下列信息

Positive matches:
-----------------

   AopAutoConfiguration matched:
      - @ConditionalOnProperty (spring.aop.auto=true) matched (OnPropertyCondition)

   AopAutoConfiguration.ClassProxyingConfiguration matched:
      - @ConditionalOnMissingClass did not find unwanted class 'org.aspectj.weaver.Advice' (OnClassCondition)
      - @ConditionalOnProperty (spring.aop.proxy-target-class=true) matched (OnPropertyCondition)

   DispatcherServletAutoConfiguration matched:
      - @ConditionalOnClass found required class 'org.springframework.web.servlet.DispatcherServlet' (OnClassCondition)
      - found 'session' scope (OnWebApplicationCondition)

   DispatcherServletAutoConfiguration.DispatcherServletConfiguration matched:
      - @ConditionalOnClass found required class 'javax.servlet.ServletRegistration' (OnClassCondition)
      - Default DispatcherServlet did not find dispatcher servlet beans (DispatcherServletAutoConfiguration.DefaultDispatcherServletCondition)
.......

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Negative（不生效）
Positive（生效）

是否需要修改
- 参照文档修改配置项
  - 官方文档 (opens new window)
  - 自己分析。xxxxProperties绑定了配置文件的哪些。
- 自定义加入或者替换组件
  - @Bean、@Component...
- 自定义器 XXXXXCustomizer；
- ......

# 17、最佳实践-Lombok简化开发

Lombok用标签方式代替构造器、getter/setter、toString()等鸡肋代码。

spring boot已经管理Lombok。引入依赖：

 <dependency>
     <groupId>org.projectlombok</groupId>
     <artifactId>lombok</artifactId>
</dependency>

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IDEA中File->Settings->Plugins，搜索安装Lombok插件。

@NoArgsConstructor // 无参构造器
// @AllArgsConstructor // 全参构造器
@Data
@ToString
@EqualsAndHashCode
public class User {

    private String name;
    private Integer age;

    private Pet pet;

    public User(String name,Integer age){
        this.name = name;
        this.age = age;
    }
}

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简化日志开发

@Slf4j
@RestController
public class HelloController {
    @RequestMapping("/hello")
    public String handle01(@RequestParam("name") String name){
        log.info("请求进来了....");
        return "Hello, Spring Boot 2!"+"你好："+name;
    }
}

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# 18、最佳实践-dev-tools

Spring Boot includes an additional set of tools that can make the application development experience a little more pleasant. The spring-boot-devtools module can be included in any project to provide additional development-time features.——link (opens new window)

Applications that use spring-boot-devtools automatically restart whenever files on the classpath change. This can be a useful feature when working in an IDE, as it gives a very fast feedback loop for code changes. By default, any entry on the classpath that points to a directory is monitored for changes. Note that certain resources, such as static assets and view templates, do not need to restart the application (opens new window).——link (opens new window)

Triggering a restart

As DevTools monitors classpath resources, the only way to trigger a restart is to update the classpath. The way in which you cause the classpath to be updated depends on the IDE that you are using:

In Eclipse, saving a modified file causes the classpath to be updated and triggers a restart.

In IntelliJ IDEA, building the project (Build -> Build Project)(shortcut: Ctrl+F9) has the same effect.

令代码修改快速生效，其实只是重启项目，并不是热更新，若只是更新了静态页面也不用重启

添加依赖：

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