SpringBoot入门系列：第一篇 Hello World

跟随SpringBoot的文档（http://docs.spring.io/spring-boot/docs/current-SNAPSHOT/reference/htmlsingle/#boot-documentation）学习，前后几章关联才调通代码，煞是痛苦，在这里记录结果，过程隐忍。

一、准备工作

1、根据Maven工程特点，建立文档结果

myFirstProject

  +-src

    +-main

      +-java

      +-resources

    +-test

      +-java

      +-resources

2、再在src/main/java下依次建立文件夹com，example，myFirstProject，可以构成Maven工程包(package)-->com.example.myFirstProject,最后文档结构如图1

                           图1

3、编制pom.xml,存于myFirstProject文件夹下，与src同级

<?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>myFirstproject</artifactId>
    <version>0.0.1-SNAPSHOT</version>

    <!-- Inherit defaults from Spring Boot -->
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.4.0.BUILD-SNAPSHOT</version>
    </parent>

    <!-- Add typical dependencies for a web application -->
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    </dependencies>

    <!-- Package as an executable jar -->
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

    <!-- Add Spring repositories -->
    <!-- (you don't need this if you are using a .RELEASE version) -->
    <repositories>
        <repository>
            <id>spring-snapshots</id>
            <url>http://repo.spring.io/snapshot</url>
            <snapshots><enabled>true</enabled></snapshots>
        </repository>
        <repository>
            <id>spring-milestones</id>
            <url>http://repo.spring.io/milestone</url>
        </repository>
    </repositories>
    <pluginRepositories>
        <pluginRepository>
            <id>spring-snapshots</id>
            <url>http://repo.spring.io/snapshot</url>
        </pluginRepository>
        <pluginRepository>
            <id>spring-milestones</id>
            <url>http://repo.spring.io/milestone</url>
        </pluginRepository>
    </pluginRepositories>
</project>

文档内容从SpringBoot的文档拷贝

4、编制Application.java存于myFirstProjectsrcmainjavacomexamplemyFirstProject下

package com.example.myFirstProject;

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


@SpringBootApplication
public class Application {

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

5、编制Example.java，存于myFirstProjectsrcmainjavacomexamplemyFirstProject下

package com.example.myFirstProject;

import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@EnableAutoConfiguration
public class Example {

    @RequestMapping("/")
    String home() {
        return "Hello World!";
    }

    @RequestMapping("/hello/{myName}")
    String index(@PathVariable String myName) {
        return "Hello "+myName+"!!!";
    }
}

二、Maven工程导入

1、启动eclipse

    1.1、java-->jdk1.7.0_80x64

    1.2、maven-->Apache Maven 3.3.3

    1.3、Eclipse Java EE IDE for Web Developers. Version: Mars Release (4.5.0)

    1.4、为本练习，新建一个workgroup

2、在eclipse中，依次点击file-->import-->Maven-->Existing Maven Projects-->Next-->Browse-->定位到myFirstProject文件夹-->确定--Finish

3、导入结果如图2

图2

三、运行

1、在eclipse的工程myFirstProject上右击鼠标，选择Run as-->Java Application，如图3

2、在select Java Aplication中选择“Application -com.example.myFirstProject”，如图4

图4

3、再次点击“OK”按钮,在Eclipse的Console中开始打印如图5

图5

4、打开浏览器，输入http://localhost:8080，显示如图6

5、在浏览器中,输入http://localhost:8080/hello/SpringBoot

四、后记

痛则不通，通则不痛。这个例子非常之简单，为了这个简单，费事不少。为了这个例子能够成功，最好做以下准备

1、构建本地的Maven伺服，否则速度痛苦

2、Sonatype Nexus尽量和jdk相对应的版本，不要最求最新，否则可能启动不起来。

3、Sonatype Nexus搭建，参考