Spring Boot HelloWorld程序

1、idea创建一个maven工程
2、xml下添加springboot父工程管理依赖配置、添加springboot框架启动器
3、主启动类
4、hello controller类
5、直接run主启动类，访问http://localhost:8080/hello?name=Catalina

<?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>

    <groupId>com.example</groupId>
    <artifactId>springboot01</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

    <!--所有springboot项目都需要继承springboot父工程
    父工程管理所有依赖配置。
    -->
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.2.RELEASE</version>
    </parent>

    <!--增加springboot框架启动器，就是所依赖的jar包
    web启动器：增加和web开发相关所有jar包
    -->
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    </dependencies>
</project>

Application

package com.example.springboot;

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

/**
 * 每一个springboot项目都需要一个主启动类
 */
@SpringBootApplication //声明当前应用是一个springboot应用
public class Application {
    public static void main(String[] args) {
        //启动tomcat，运行springboot应用
        SpringApplication.run(Application.class,args);
    }
}

controller

package com.example.springboot.controller;

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

//所有组件类，都应该存放在主启动类application那个类所在的包，或子包下。
@RestController
public class HelloController {

    @RequestMapping("/hello")
    public String hello(String name){
        return "Hello, Spring Boot!!!!" + name;
    }
}

查看默认的自定义配置文件命名格式

<artifactId>spring-boot-starter-parent</artifactId>

	  <resource>
        <filtering>true</filtering>
        <directory>${basedir}/src/main/resources</directory>
        <includes>
          <include>**/application*.yml</include>
          <include>**/application*.yaml</include>
          <include>**/application*.properties</include>
        </includes>
      </resource>

查看默认端口号

    {
      "name": "server.port",
      "defaultValue": 8080
    },

修改端口号 application.properties

server.port-8899

运行显示端口号修改为8899

INFO 89131 --- [main] o.s.b.w.embedded.tomcat.TomcatWebServer  
: Tomcat started on port(s): 8899 (http) with context path ''

开发 生产环境配置

# 激活开发环境配置文件
spring:
  profiles:
    active: pro


#开发环境
spring:
  jdbc:
    datasource:
      driverClassName: com.mysql.jdbc.Driver
      url: jdbc:mysql:///springboot
      username: root
      password: root


#生成/产品环境
spring:
  jdbc:
    datasource:
      driverClassName: com.mysql.jdbc.Driver
      url: jdbc:mysql:///business
      username: business
      password: business