springBoot快速入门

github详情：https://github.com/wangbowen1024/springboot-learning-quick

一、配置文件

首先使用IDEA创建spring项目，勾选Web和Mybatis以及XXX等所需要的组件，然后开始编写代码。

• pom.xml

xml

<?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>

    <!-- 1.所有springboot工程都必须要继承spring-boot-starter-parent -->
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.1.RELEASE</version>
    </parent>

    <groupId>com.springboot</groupId>
    <artifactId>springboot-learning</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <!-- 2.web功能的起步依赖 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!--热部署配置-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
        </dependency>
    </dependencies>
</project>

• application.yml

yml

# 数据库连接信息(MySql5.7)
spring:
  datasource:
    driverClassName: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT
    username: root
    password: Bow1024

在SpringbootApplication类同目录下都可以扫包读到注解，所以mybatis、controller等可以直接写。

二、编写类

2.1 启动类

SpringbootApplication.java

java

package com.springboot;

import org.eclipse.paho.client.mqttv3.MqttException;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

/**
 * 基于注解的mybatis-boot整合
 */
@SpringBootApplication
@MapperScan(basePackages = "com.springboot.mapper") // mapper注解扫包
public class SpringbootApplication {

    public static void main(String[] args) throws MqttException {
        SpringApplication.run(SpringbootApplication.class, args);
    }
}

2.2 Controller

UserController.java

java

package com.springboot.controller;

import com.springboot.domain.User;
import com.springboot.mapper.UserMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import java.util.List;

@Controller
public class UserController {
    @Autowired
    private UserMapper userMapper;

    @RequestMapping("/queryUser")
    @ResponseBody
    public List<User> queryUser(){
        List<User> users = userMapper.getAllUsers();
        return users;
    }
}

2.3 JavaBean

User.java

java

package com.springboot.domain;

public class User {
    private Integer id;
    private String username;
    private String password;
    private String name;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                ", name='" + name + '\'' +
                '}';
    }
}

2.4 Mapper接口

UserMapper.java

java

package com.springboot.mapper;

import com.springboot.domain.User;
import org.apache.ibatis.annotations.Select;

import java.util.List;

public interface UserMapper {

    @Select("select * from user")
    List<User> getAllUsers();
}

三、获取.yml文件中的键值对

application.yml

Code

# 普通数据的配置
name: zhangsan

# 对象的配置
person:
  name: zhangsan
  age: 18
  addr: beijing

# 行内对象配置(类json)
server: {port: 8082}

# 配置数组、集合(普通字符串)
city:
  - beijing
  - tianjin

# 或city: [beijing,tianjin]

# 配置数组、集合(对象数据)
student:
  - name: tom
    age: 18
    addr: beijing
  - name: lucy
    age: 17
    addr: tianjin

# 或student: [{name: tom,age: 18,addr: beijing},{name: lucy,age: 17,addr: tianjin}]

# Map配置
map:
  key1: value1
  key2: value2

3.1 获取方式1

java

// 取配置文件信息
@Value("${name}")
private String name;

@Value("${person.addr}")
private String addr;

3.2 获取方式2

java

@Controller
@ConfigurationProperties(prefix = "person") // 从配置文件中，前缀
public class Quick3Controller {

    private String name;
    private String addr;
    private Integer age;

    @RequestMapping("/quick3")
    @ResponseBody
    public String quick2() {
        // 获得配置文件的信息
        return "name: " + name + ",addr: " + addr;
    }

    // 需要get/set方法
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getAddr() {
        return addr;
    }

    public void setAddr(String addr) {
        this.addr = addr;
    }
}