SpringBoot框架(1)--入门篇

蔚落 2021-12-07 11:23 309阅读 0赞

** 什么是SpringBoot?**

Spring Boot是由Pivotal团队提供的全新框架，其设计目的是用来简化新Spring应用的初始搭建以及开发过程。

特征

*  创建独立的Spring应用程序
 *  直接嵌入Tomcat，Jetty或Undertow（无需部署WAR文件）
 *  提供固定的“入门”依赖项以简化构建配置
 *  尽可能自动配置Spring和第三方库
 *  提供生产就绪功能，例如指标，运行状况检查和外部化配置
 *  绝对没有代码生成，也不需要XML配置

** 快速入门**

（1）新建空项目New Project

![455969-20190520101302406-1826830750.png][]

==》命名项目名称，并选择要保存的目录

![455969-20190520101229847-900450059.png][]

剩余步骤默认不用更改，直接ok即可。到此空白项目创建完成。

接下来在空白项目上建立模块（module）

（2）创建模块

![455969-20190520102940215-526618683.png][]

==》创建modules --> Maven --> 选择SDK --> Create from archetype --> org.apache.maven.archetypes

![455969-20190520103122816-1386662540.png][]

==>命名GroupId,ArtifactId

![455969-20190520103717671-119798830.png][]

==》配置仓库

![455969-20190520103938609-1756435701.png][]

==》命名模块名字，最终完成模块的创建

![455969-20190520104044567-785920660.png][]

注：创建时，屏幕右下角提示如下，选择Enable Auto-Import即可

![455969-20190520104223938-1569582813.png][]

到此。模块创建完成

（3）配置项目配置文件(pom.xml)

1 <parent>
    2     <groupId>org.springframework.boot</groupId>
    3     <artifactId>spring-boot-starter-parent</artifactId>
    4     <version>2.1.5.RELEASE</version>
    5 </parent>

1 <dependency>
    2     <groupId>org.springframework.boot</groupId>
    3     <artifactId>spring-boot-starter-web</artifactId>
    4 </dependency>

![455969-20190520105626107-648277193.png][]

（4）提供应用程序入口

1 package com.demo.boot;
     2 
     3 import org.springframework.boot.SpringApplication;
     4 import org.springframework.boot.autoconfigure.SpringBootApplication;
     5 import org.springframework.context.ConfigurableApplicationContext;
     6 
     7 /**
     8  * Hello world!
     9  */
    10 @SpringBootApplication
    11 public class App {
    12     public static void main(String[] args) {
    13         ConfigurableApplicationContext context = SpringApplication.run(App.class, args);
    14     }
    15 }

(5)类的管理调用

==》pom.xml文件 添加类的依赖 spring-context

1    <dependencies>
     2         <dependency>
     3             <groupId>org.springframework</groupId>
     4             <artifactId>spring-context</artifactId>
     5             <version>5.1.7.RELEASE</version>
     6         </dependency>
     7 
     8         <dependency>
     9             <groupId>org.springframework.boot</groupId>
    10             <artifactId>spring-boot-starter-web</artifactId>
    11         </dependency>
    12     </dependencies>

==》创建类User.java

1 package com.demo.boot;
     2 
     3 import org.springframework.stereotype.Component;
     4 
     5 /**
     6  * 使用@Component管理类
     7  */
     8 @Component//别名 -->默认为类名首字母小写
     9 public class User {
    10 
    11     @Override
    12     public String toString() {
    13         return "com.demo.boot.User:" + super.toString();
    14     }
    15 }

==>创建UserConfig类

1 package com.demo.boot;
     2 
     3 import org.springframework.boot.SpringBootConfiguration;
     4 import org.springframework.context.annotation.Bean;
     5 
     6 /**
     7  * 通过@Configuration注解把User类交给Spring容器管理
     8  */
     9 @SpringBootConfiguration
    10 public class UserConfig {
    11     @Bean//@Bean("createUser")默认别名，是方法名称
    12     public User createUser() {
    13         return new User();
    14     }
    15 }

==》应用程序入口

1 package com.demo.boot;
     2 
     3 import org.springframework.boot.autoconfigure.SpringBootApplication;
     4 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
     5 
     6 /**
     7  * Hello world!
     8  */
     9 @SpringBootApplication//@SpringBootApplication=@Configuration+@ComponentScan+@EnableAutoConfiguration
    10 public class App {
    11     public static void main(String[] args) {
    12         //ConfigurableApplicationContext context = SpringApplication.run(App.class, args);
    13         AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext("com.demo.boot");
    14         User user = context.getBean("user", User.class);//别名为类名首字母小写
    15         User user1 = context.getBean("createUser", User.class);//类别名为方法名
    16         UserConfig userConfig = context.getBean(UserConfig.class);//类别名为方法名
    17         System.out.print(user + "," + user1 + "," + userConfig);//实际通过springCGLIB代理类动态调用自定义方法（createUser）创建类实例
    18         //输出：com.demo.boot.User:com.demo.boot.User@4c15e7fd,com.demo.boot.User:com.demo.boot.User@23986957,com.demo.boot.UserConfig$$EnhancerBySpringCGLIB$$72899f9e@23f7d05d
    19         //context.close();
    20     }
    21 }

转载于:https://www.cnblogs.com/lfhappy/p/10882465.html

[455969-20190520101302406-1826830750.png]: /images/20211207/592a4662373d4cae98f6897517331520.png
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[455969-20190520105626107-648277193.png]: /images/20211207/3d5ce59b699f4f979efd9179712cc028.png