SpringBoot快速入门

1 打印hello world

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导入依赖

<?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>org.example</groupId>
    <artifactId>springboot-test</artifactId>
    <version>1.0-SNAPSHOT</version>

    <!--springboot工程需要继承的父工程-->
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.6.5</version>
    </parent>

    <dependencies>
        <!--web开发的起步依赖-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

    </dependencies>
</project>

创建controller

package com.controller;

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

/**
 * @Yanx
 * @Create 2022-03-30-14:25
 */
@RestController
public class HelloController {
    @RequestMapping("/hello")
    public String hello(){
        return "hello Spring boot";
    }
}

创建springboot引导类

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

/**
 * 引导类springBoot项目的入口
 * @Yanx
 * @Create 2022-03-30-14:27
 */
@SpringBootApplication
public class HelloApplication {
    public static void main(String[] args) {
        SpringApplication.run(HelloApplication.class,args);
    }
}

访问8080 启动成功
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同一级目录文件下优先级：properties > yml >yaml

一 Spring Boot 配置

1 YAML 数据格式

1 对象（map)键值对的集合

person:
	name: zhangsan 
#行内写法 注意空格
person:	{name: zhangsan}

2 数组：一组按次序排列的值

address:  #注意横杠空格
	- beijing
	- shanghai
#行内写法
address: [beijing,shanghai]

3 纯量：单个的，不可再分的值

#\n 表示换行
msg1: 'hello \n world' #单引号忽略转义字符
msg2: "hello \n world" #双引号识别转移字符

4 参数引用

name: lisi 
person: 
	name: ${name}#引用上面定义的name值

2 读取配置内容

yaml 文件内容

server:
  port: 8010

name: lisi

person:
  name: ${name} #引用上面定义的name值
  age: 20

address:
  - beijing
  - shanghai

msg1: 'hello \n world'
msg2: "hello \n world"

1 @Value

 /*===========获取对象============*/
    @Value("${name}")
    private String name;

    @Value("${person.age}")
    private int age;

    /*===========获取数组============*/
    @Value("${address[0]}")
    private String address;

    /*===========获取纯量============*/
    @Value("${msg1}")
    private String msg1;

    @Value("${msg2}")
    private String msg2;

    @RequestMapping("/hello2")
    public String hello2(){
        System.out.println(name);
        System.out.println(age);
        System.out.println(address);
        System.out.println(msg1);
        System.out.println(msg2);
        return "hello world";
    }

控制台打印

lisi
20
beijing
hello \n world
hello 
 world

2 Envrionment

    @Autowired
    private Environment env;

    @RequestMapping("/hello")
    public String hello(){
        System.out.println(env.getProperty("person.name"));
        System.out.println(env.getProperty("address[0]"));
        System.out.println(env.getProperty("msg1"));
        return "hello world";
    }

控制台输出

lisi
beijing
hello \n world

3 @ConfigurationPropertis

name: lisi
person:
  name: ${name} #引用上面定义的name值
  age: 20
  address:
    - beijing
    - shanghai

@Component
@ConfigurationProperties(prefix = "person")
public class Person {
    private String name;
    private int age;
    private String[] address;

    .............
     省略 get and set toString
    .............
}

    @Autowired
    private Person person;

    @RequestMapping("/hello")
    public String hello(){
        System.out.println(person);
        String[] address = person.getAddress();
        for(String s :address){
            System.out.println(s);
        }
        return "hello world";
    }

Person{name='lisi', age=20}
beijing
shanghai

3 profile

1 profile配置方式

多profile文件方式：提供多个配置文件，每个代表一种环境。
application-dev.properties/yml 开发环境
application-test.properties/yml 测试环境
application-pro.properties/yml 生产环境
yml多文档方式：
在yml中使用—分隔不同配置

2 profile激活方式

配置文件：再配置文件中配置：spring.profiles.active=dev
虚拟机参数：在VM options 指定：-Dspring.profiles.active=dev
命令行参数：java –jar xxx.jar --spring.profiles.active=dev

动态配置切换

激活配置
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spring.profiles.active=dev

**yaml多文档 **

---
server:
  port: 8081
spring:
  profiles: dev
---
server:
  port: 8082
spring:
  profiles: test
---
server:
  port: 8083
spring:
  profiles: pro
---
spring:
  profiles:
    active: pro

命令行参数

java -jar .\springboot-profiles-0.0.1-SNAPSHOT.jar --spring.profiles.active=pro

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4 配置加载顺序

1 内部加载顺序

Springboot程序启动时，会从以下位置加载配置文件：

file:./config/：当前项目下的/config目录下
file:./ ：当前项目的根目录
classpath:/config/：classpath的/config目录
classpath:/ ：classpath的根目录

加载顺序为上文的排列顺序，高优先级配置的属性会生效
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在这里插入图片描述
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2 外部配置

java -jar .\springboot-profiles-0.0.1-SNAPSHOT.jar --server.port=8010

二 Spring Boot 整合框架

1 Spring Boot整合Junit

@RunWith(SpringRunner.class)
@SpringBootTest(classes = SpringbootJunitApplication.class)
public class UserServiceTest {
    @Autowired
    private UserService userService;

    @Test
    public void testAdd(){
        userService.add();
    }
}

2 Spring Boot整合Redis

1 查看redis是否启动

ps -ef |grep redis

2 开放6379端口号

firewall-cmd --add-port=6379/tcp --permanent
#重启防火墙
firewall-cmd --reload

3 配置yml

spring:
    redis:
        host: 4*.**.1*0.**
        port: 6379
        password: ********

4 导入redis依赖

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-redis</artifactId>
        </dependency>

5 创建测试类测试

@SpringBootTest
class SpringbootRedisApplicationTests {

    @Autowired
    private RedisTemplate redisTemplate;

    @Test
    public void testSet() {
        //存入数据
        redisTemplate.boundValueOps("name").set("zhangsan");
    }

    @Test
    public void testGet() {
        //存入数据
        Object name = redisTemplate.boundValueOps("name").get();
        System.out.println(name);
    }
}

3 Spring Boot 整合MyBatis

1 导入依赖

        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.2.2</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>

2 创建实体类user
3 创建mapper

@Mapper
public interface UserMapper {
    @Select("select * from user")
    public List<User> findAll();
}

4 配置mysql连接

#DataSource
spring:
  datasource:
    url: jdbc:mysql://localhost:3306/t_user
    username: root
    password: *********
    driver-class-name: com.mysql.cj.jdbc.Driver

配置文件方式

mybatis:
  mapper-locations: classpath:mapper/*Mapper.xml #mapper映射路径
  type-aliases-package: domain # 别名
  # config-location # 指定mybatis的核心配置文件

@Mapper
@Repository
public interface UserXmlMapper {

    public List<User> findAll();
}

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.example.springbootmybatis.mapper.UserXmlMapper">
    <select id="findAll" resultType="user">
        select * from user
    </select>
</mapper>

原文链接：https://blog.csdn.net/weixin_45914119/article/details/123861082