SpringBoot学习笔记：Getting Started构建第一个Spring Boot工程

本文参考 Spring Boot官方文档 Part II. Getting Started部分
特定版本如1.5.10.RELEASE版本官方文档地址：
https://docs.spring.io/spring...
注：本文基于Spring Boot 1.5.10.RELEASE构建

The Spring Boot repository has also a bunch of samples you can run.（话说spring-boot在github上已经有23000多颗星了，足见spring-boot火爆程度）

Spring Boot简介

以下介绍引自 https://projects.spring.io/sp...

Spring Boot makes it easy to create stand-alone, production-grade Spring based Applications that you can "just run". We take an opinionated view of the Spring platform and third-party libraries so you can get started with minimum fuss. Most Spring Boot applications need very little Spring configuration.

Features

• Create stand-alone Spring applications
  创建独立的Spring应用程序
• Embed Tomcat, Jetty or Undertow directly (no need to deploy WAR files)
  直接嵌入Tomcat，Jetty或Undertow（无需部署WAR文件）
• Provide opinionated 'starter' POMs to simplify your Maven
  configuration
  提供自己的'入门'POM来简化你的Maven配置
• Automatically configure Spring whenever possible
  尽可能自动配置Spring
• Provide production-ready features such as metrics, health checks and
  externalized configuration
  提供生产就绪功能，如指标，运行状况检查和外部配置
• Absolutely no code generation and no requirement for XML
  configuration
  绝对不会生成代码，并且不需要XML配置

系统要求

Spring Boot 1.5.10.RELEASE版本需要

Java 7 and Spring Framework 4.3.14.RELEASE or above 最好java8及以上
构建工具：Maven (3.2+), and Gradle 2 (2.9 or later) and 3.

Servlet容器：

构建工程

这里笔者采用构建Empty Project作为Spring Boot学习过程的总工程，以添加Module的方式构建不同学习过程如springboot-first-app、springboot-redis等

步骤演示

在Idea欢迎页点击Create New Project或File --> New Project，弹出以下界面并选择Empty Project

点击Next，填写Project name如SpringBootLearning

点击Finish完成创建，进入工程Idea会弹出Project Structure窗口，可以点击绿色的+按钮来New Module

也可以通过File --> New --> Module

使用Maven构建第一个Spring Boot应用

以上构建空工程的步骤只是笔者为了自身的系统学习，读者可以直接创建一个Spring Boot工程
方法一：在 Spring Boot官方Initializer页面 在线构建工程再导入到Ide中

方法二：直接在Idea中Create New Project --> Spring Initializr --> 填写group、artifact -->钩上web --> 点下一步就行了，具体步骤参照笔者New Module步骤即可

工程目录结构

pom.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>

    <groupId>cn.fulgens.springbootlearning</groupId>
    <artifactId>springboot-first-app-maven</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>springboot-first-app-maven</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.10.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

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

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

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

</project>

编写HelloController

package cn.fulgens.springbootlearning.springbootfirstappmaven.web;

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

@RestController
public class HelloController {

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

}

启动第一个Spring Boot应用

方法一：直接运行SpringbootFirstAppMavenApplication中的main方法

package cn.fulgens.springbootlearning.springbootfirstappmaven;

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

@SpringBootApplication
public class SpringbootFirstAppMavenApplication {

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

启动后在浏览器输入localhost:8080

方法二：maven命令启动
cd到项目主目录后执行（其中-Dtest.skip=true表示跳过单元测试）

mvn clean package 
mvn spring-boot:run -Dtest.skip=true

如果是Gradle构建可执行
gradle build
gradle bootRun

方法三：以java -jar的方式启动
maven打包完成后cd到target目录下执行，jar包名称视自己情况而定

java -jar springboot-first-app-maven-0.0.1-SNAPSHOT.jar

单元测试

package cn.fulgens.springbootlearning.springbootfirstappmaven;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.http.HttpMethod;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
import org.springframework.test.web.servlet.result.MockMvcResultMatchers;

@RunWith(SpringRunner.class)
@SpringBootTest
@AutoConfigureMockMvc
public class HelloControllerTest {

    @Autowired
    private MockMvc mockMvc;

    @Test
    public void helloControllerTest() throws Exception {
        mockMvc.perform(MockMvcRequestBuilders.request(HttpMethod.GET, "/"))
                .andExpect(MockMvcResultMatchers.status().isOk())
                .andExpect(MockMvcResultMatchers.content().string("Hello Spring Boot!"));
    }

}

spring boot 1.4.0 版本之前使用以下三个注解，参考Spring Boot 系列（二）单元测试&网络请求
@RunWith(SpringJUnit4ClassRunner.class)
@SpringApplicationConfiguration(classes = DemoApplication.class) //在spring boot 1.4.0 版本之后取消了 //classes需要指定spring boot 的启动类如：DemoApplication.class 不然WebApplicationContext不被实例化
@WebAppConfiguration