Java springboot最简可运行项目

一、最基础的配置只需两个文件

1.pom.xml有两种配置方式

a.使用spring-boot-starter-web来引入相关包,启动项目

b.需要关联包:spring-boot-dependencies

一种是parent方式，这在引用的文章里已有

另一种是dependencyManagement方式

<?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>net.highersoft</groupId>
    <artifactId>springboot</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
        <spring.cloud-version>Hoxton.SR9</spring.cloud-version>
        <spring.boot-version>2.3.6.RELEASE</spring.boot-version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <mybatis-spring-version>2.1.4</mybatis-spring-version>
    </properties>
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>${spring.boot-version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
           
        </dependencies>
    </dependencyManagement>
    <dependencies>
        <!-- spring boot实现Java Web服务 -->

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

       
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>



    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

2.springboot启动类

net.highersoft.springboot.Application.java

package net.highersoft.springboot;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@Configuration
@ComponentScan
@EnableAutoConfiguration
public class Application {
    public static void main(String[] args) {
        ConfigurableApplicationContext context=SpringApplication.run(Application.class);
        System.out.println("in");
    }
}

添加application.yml,这里只配置端口号.

小知识:

对于springboot项目 application.properties > application.yml ，前者的配置的优先级高于后者，前者更管用，后者更先加载。

springboot不识别而springcloud识别的文件bootstrap.yml ,这个

server:
  port: 8082
spring:
  application:
    name: springboot

三、添加Controller类

返回Json数据

package net.highersoft.springboot;

import net.highersoft.springboot.entity.InfoEntry;
import net.highersoft.springboot.mapper.ItemMapper;
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.HashMap;
import java.util.List;
import java.util.Map;

@Controller
public class TestController {

  
    @RequestMapping("/")
    @ResponseBody
    public Map<String,String> home(){
        Map<String,String> rst=new HashMap<>();
        rst.put("key","val");
        return rst;
    }

 

}

添加pom.xml依赖

<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>${mybatis-spring-version}</version>
</dependency>
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>8.0.18</version>
</dependency>

server:
  port: 8082
spring:
  application:
    name: springboot
  datasource:
    driver-class-name: com.mysql.jdbc.Driver
    password: 'xx'
    url: jdbc:mysql://localhost/test?useUnicode=true&characterEncoding=UTF8&rewriteBatchedStatements=true
    username: root
mybatis:
  mapperLocations: classpath:mapper/*.xml

import org.apache.ibatis.annotations.Mapper;

@Mapper

最后Controller里添加一个接口，来显示数据库里的数据：

@Autowired
private ItemMapper itemMapper;


@RequestMapping("/list")
@ResponseBody
public List<InfoEntry> list() {
    return itemMapper.selectLastInfo();

}

本文内容基于http://www.highersoft.net/html/notice/notice_572.html，再添加spring cloude部分。

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