Hello! I am Xiaoxiao, today is the fifth part of this week, and the fifth part of this week will focus on the Hello World of Spring Boot

Preface

Reasons for Spring Boot

The emergence of Spring Boot is mainly used to solve some problems of Spring in the past. It puts forward the idea of convention over configuration. By default, many methods are set so that developers can quickly build projects and integrate third-party content. Makes development efficiency greatly improved.

basic concept

Spring Boot is not only a set of frameworks, but also a set of systems. The purpose is to simplify Spring development.

Features

Spring-based development provides a faster entry point to get started directly, redundant code does not have an embedded container to simplify Spring

core function

Extremely dependent on build tools for automated configuration

Hello World

Maven create

Create a new empty project and create modules respectively, as shown in the figure below

Create Maven Module

Create a Module, select the Maven project, check the previously used web skeleton and fill in the GroupID. After the ArtifactID is selected, press Enter to complete the creation of a basic maven project

Add start-up dependency

According to the requirements of Spring Boot, perform simple tests and add corresponding start-up dependencies. You need to inherit the start-up dependency of Spring Boot. Spring boot starter parent In order to integrate Spring MVC for Controller development, you need to import Spring boot starter web

<?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>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.7.RELEASE</version>
    </parent>

    <groupId>cn.ideal</groupId>
    <artifactId>springboot_01_start</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    </dependencies>
</project>

Write Spring Boot startup class

Write Spring Boot startup class here

package cn.ideal;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class MySpringBootApplication {
    public static void main(String[] args) {
        SpringApplication.run(MySpringBootApplication.class);
    }
}

Create a control layer

package cn.ideal.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
public class QuickStartController {
    @RequestMapping("/test")
    @ResponseBody
    public String test(){
        return "springboot 访问测试，起飞，飞飞飞飞 ~ ~ ~";
    }
}

Test Spring Boot

The project starts, the console will output the following

 .   ____          _            __ _ _
 /\ / ___'_ __ _ _(_)_ __  __ _    
( ( )___ | '_ | '_| | '_ / _` |    
 \/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |___, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.2.7.RELEASE)

2020-05-10 22:11:34.973  INFO 30580 --- [           main] cn.ideal.MySpringBootApplication         : Starting MySpringBootApplication on LAPTOP-5T03DV1G with PID 30580 (F:developIdeaProjectsframework-codespringboot_01_demospringboot_01_starttargetclasses started by abc in F:developIdeaProjectsframework-codespringboot_01_demo)
2020-05-10 22:11:34.976  INFO 30580 --- [           main] cn.ideal.MySpringBootApplication         : No active profile set, falling back to default profiles: default
2020-05-10 22:11:35.686  INFO 30580 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2020-05-10 22:11:35.693  INFO 30580 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2020-05-10 22:11:35.693  INFO 30580 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.34]
2020-05-10 22:11:35.765  INFO 30580 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2020-05-10 22:11:35.766  INFO 30580 --- [           main] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 747 ms
2020-05-10 22:11:35.884  INFO 30580 --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Initializing ExecutorService 'applicationTaskExecutor'
2020-05-10 22:11:35.990  INFO 30580 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2020-05-10 22:11:35.993  INFO 30580 --- [           main] cn.ideal.MySpringBootApplication         : Started MySpringBootApplication in 1.318 seconds (JVM running for 2.665)

The picture shows the following input and the created controller project is directly printed out

The project is packaged into a jar package

Add dependency

<plugin>
	<!-- 打包插件 -->
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-maven-plugin</artifactId>
</plugin>

Click on the right, package for packaging, select the package option

You can see that a new jar package is generated under target, which is run directly in cmd

About the author

I am a little, a little programmer. bye~bye!

Xiaoming Vegetable Market

Spring Boot | The first Spring Boot application of a post-90s girl