為基於spring-boot的應用新增根據執行時作業系統環境來提示使用者選擇active profile的功能

spring-boot有一個根據JVM變數-Dspring.profiles.active來設定執行時的active profile的功能，但是有些時候我們也許會不小心忘記設定這個變數，這樣在生產環境中會帶來一定的困擾，所以我想了一個辦法，來給忘記設定-Dspring.profiles.active的程式設計師一次“secend chance”。

先來講一下思路：

• step0 約定好profiles的命名，“development”代表開發環境(也可以將預設的profile設為開發環境)，“production”代表生產環境
• step1 判斷是否設定了-Dspring.profiles.active，如果已經設定，直接跳轉step3
• step2 判斷當前作業系統環境，如果不是Linux環境則認定為開發環境，自動倒數計時啟用開發的profile；如果是Linux環境則認定為生產環境，輸出選擇profile的控制檯資訊，並等待使用者控制檯輸入進行選擇，並依據使用者選擇來啟用profile
• step3 SpringApplication.run()

程式碼如下：

spring-boot配置檔案(使用了預設profile作為開發環境)：

spring:
  application:
    name: comchangyoueurekaserver #注意命名要符合RFC 2396，否則會影響服務發現 詳見https://stackoverflow.com/questions/37062828/spring-cloud-brixton-rc2-eureka-feign-or-rest-template-configuration-not-wor

server:
  port: 8001

eureka:
  instance:
    hostname: localhost
  client:
    registerWithEureka: false
    fetchRegistry: false
    serviceUrl:
      defaultZone: http://${eureka.instance.hostname}:${server.port}

---
spring:
  profiles: production
  application:
    name: comchangyoueurekaserver

server:
  port: 8001

eureka:
  instance:
    hostname: localhost
  client:
    registerWithEureka: false
    fetchRegistry: false
    serviceUrl:
      defaultZone: http://${eureka.instance.hostname}:${server.port}
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BootStarter封裝了step1-step3的邏輯：

import org.apache.commons.lang3.StringUtils;

import java.util.Scanner;
import java.util.Timer;
import java.util.TimerTask;
import java.util.regex.Pattern;

public class BootStarter {

    //用於後續Spring Boot操作的回撥
    public interface Callback {
        void bootRun();
    }

    private boolean enableAutomaticallyStart = true;
    private int automaticallyStartDelay = 10;

    public boolean isEnableAutomaticallyStart() {
        return enableAutomaticallyStart;
    }

    public void setEnableAutomaticallyStart(boolean enableAutomaticallyStart) {
        this.enableAutomaticallyStart = enableAutomaticallyStart;
    }

    public int getAutomaticallyStartDelay() {
        return automaticallyStartDelay;
    }

    public void setAutomaticallyStartDelay(int automaticallyStartDelay) {
        this.automaticallyStartDelay = automaticallyStartDelay;
    }

    public void startup(boolean enableAutomaticallyStart, int automaticallyStartDelay, Callback callback) {
        if (StringUtils.isBlank(System.getProperty("spring.profiles.active"))) { //如果沒有通過引數spring.profiles.active設定active profile則讓使用者在控制檯自己選擇
            System.out.println("***Please choose active profile:***\n\tp: production\n\td: development");

            final boolean[] started = {false};
            Timer timer = new Timer();
            if (enableAutomaticallyStart && System.getProperty("os.name").lastIndexOf("Linux") == -1) { //如果當前作業系統環境為非Linux環境(一般為開發環境)則automaticallyStartDelay秒後自動設定為開發環境
                System.out.printf("\nSystem will automatically select 'd' in %d seconds.\n", automaticallyStartDelay);
                final int[] count = {automaticallyStartDelay};
                timer.scheduleAtFixedRate(new TimerTask() {
                    @Override
                    public void run() {
                        if (count[0]-- == 0) {
                            timer.cancel();
                            started[0] = true;

                            System.setProperty("spring.profiles.active", "development");
                            callback.bootRun();
                        }
                    }
                }, 0, 1000);
            }

            Scanner scanner = new Scanner(System.in);
            Pattern pattern = Pattern.compile("^p|d$");
            //如果是Linux系統(一般為生產環境)則強制等待使用者輸入(一般是忘記設定spring.profiles.active了，這等於給了設定active profile的"second chance")
            while (scanner.hasNextLine()) {
                if (started[0]) {
                    break;
                }
                String line = scanner.nextLine();
                if (!pattern.matcher(line).find()) {
                    System.out.println("INVALID INPUT!");
                } else {
                    timer.cancel();
                    System.setProperty("spring.profiles.active", line.equals("d") ? "development" : "production");
                    callback.bootRun();
                    break;
                }
            }
        } else { //如果已經通過引數spring.profiles.active設定了active profile直接啟動
            callback.bootRun();
        }
    }

    public void startup(Callback callback) {
        startup(this.enableAutomaticallyStart, this.automaticallyStartDelay, callback);
    }
}

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main()：

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
import org.springframework.context.ApplicationContext;

@EnableEurekaServer
@SpringBootApplication
public class App {

    private static final Logger LOGGER = LoggerFactory.getLogger(App.class);

    public static void main(String[] args) {
        new BootStarter().startup(() -> {
            ApplicationContext applicationContext = SpringApplication.run(App.class, args);
            for (String activeProfile : applicationContext.getEnvironment().getActiveProfiles()) {
                LOGGER.warn("***Running with profile: {}***", activeProfile);
            }
        });
    }
}
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執行效果(開發環境Mac OS)：

擴充套件： 其實在這裡我們還可以發散一下思維，基於spring-boot的應用比起傳統spring應用的一大優勢是自己可以掌控main()方法，有了這一點，我們是能玩出很多花樣來的，思路不要被侷限在tomcat時代了。

main法在手，天下我有。

---

2017-1-22更新：增加了執行緒安全的處理

import org.apache.commons.lang3.StringUtils;

import java.util.Scanner;
import java.util.Timer;
import java.util.TimerTask;
import java.util.regex.Pattern;

public class BootStarter {

    private volatile boolean started;

    //用於後續Spring Boot操作的回撥
    public interface Callback {
        void bootRun();
    }

    private boolean enableAutomaticallyStart = true;
    private int automaticallyStartDelay = 3;

    public boolean isEnableAutomaticallyStart() {
        return enableAutomaticallyStart;
    }

    public void setEnableAutomaticallyStart(boolean enableAutomaticallyStart) {
        this.enableAutomaticallyStart = enableAutomaticallyStart;
    }

    public int getAutomaticallyStartDelay() {
        return automaticallyStartDelay;
    }

    public void setAutomaticallyStartDelay(int automaticallyStartDelay) {
        this.automaticallyStartDelay = automaticallyStartDelay;
    }

    public void startup(boolean enableAutomaticallyStart, int automaticallyStartDelay, Callback callback) {
        if (StringUtils.isBlank(System.getProperty("spring.profiles.active"))) { //如果沒有通過引數spring.profiles.active設定active profile則讓使用者在控制檯自己選擇
            System.out.println("***Please choose active profile:***\n\tp: production\n\td: development");

            Timer timer = new Timer();
            if (enableAutomaticallyStart && System.getProperty("os.name").lastIndexOf("Linux") == -1) { //如果當前作業系統環境為非Linux環境(一般為開發環境)則automaticallyStartDelay秒後自動設定為開發環境
                System.out.printf("\nSystem will automatically select 'd' in %d seconds.\n", automaticallyStartDelay);
                timer.scheduleAtFixedRate(new TimerTask() {

                    private ThreadLocal<Integer> countDown = ThreadLocal.withInitial(() -> automaticallyStartDelay);

                    @Override
                    public void run() {
                        if (countDown.get() == 0) {
                            timer.cancel();
                            started = true;

                            System.setProperty("spring.profiles.active", "development");
                            callback.bootRun();
                        }
                        countDown.set(countDown.get() - 1);
                    }
                }, 0, 1000);
            }

            Scanner scanner = new Scanner(System.in);
            Pattern pattern = Pattern.compile("^p|d$");
            //如果是Linux系統(一般為生產環境)則強制等待使用者輸入(一般是忘記設定spring.profiles.active了，這等於給了設定active profile的"second chance")
            while (scanner.hasNextLine()) {
                if (started) {
                    break;
                }
                String line = scanner.nextLine();
                if (!pattern.matcher(line).find()) {
                    System.out.println("INVALID INPUT!");
                } else {
                    timer.cancel();
                    System.setProperty("spring.profiles.active", line.equals("d") ? "development" : "production");
                    callback.bootRun();
                    break;
                }
            }
        } else { //如果已經通過引數spring.profiles.active設定了active profile直接啟動
            callback.bootRun();
        }
    }

    public void startup(Callback callback) {
        startup(this.enableAutomaticallyStart, this.automaticallyStartDelay, callback);
    }
}

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---

2017-01-25更新：

補上了 try-with-resource

import org.apache.commons.lang3.StringUtils;

import java.util.Scanner;
import java.util.Timer;
import java.util.TimerTask;
import java.util.regex.Pattern;

public class BootStarter {

    private volatile boolean started;

    //用於後續Spring Boot操作的回撥
    public interface Callback {
        void bootRun();
    }

    private boolean enableAutomaticallyStart = true;
    private int automaticallyStartDelay = 3;

    public boolean isEnableAutomaticallyStart() {
        return enableAutomaticallyStart;
    }

    public void setEnableAutomaticallyStart(boolean enableAutomaticallyStart) {
        this.enableAutomaticallyStart = enableAutomaticallyStart;
    }

    public int getAutomaticallyStartDelay() {
        return automaticallyStartDelay;
    }

    public void setAutomaticallyStartDelay(int automaticallyStartDelay) {
        this.automaticallyStartDelay = automaticallyStartDelay;
    }

    public void startup(boolean enableAutomaticallyStart, int automaticallyStartDelay, Callback callback) {
        if (StringUtils.isBlank(System.getProperty("spring.profiles.active"))) { //如果沒有通過引數spring.profiles.active設定active profile則讓使用者在控制檯自己選擇
            System.out.println("***Please choose active profile:***\n\tp: production\n\td: development");

            Timer timer = new Timer();
            if (enableAutomaticallyStart && System.getProperty("os.name").lastIndexOf("Linux") == -1) { //如果當前作業系統環境為非Linux環境(一般為開發環境)則automaticallyStartDelay秒後自動設定為開發環境
                System.out.printf("\nSystem will automatically select 'd' in %d seconds.\n", automaticallyStartDelay);
                timer.scheduleAtFixedRate(new TimerTask() {

                    private ThreadLocal<Integer> countDown = ThreadLocal.withInitial(() -> automaticallyStartDelay);

                    @Override
                    public void run() {
                        if (countDown.get() == 0) {
                            timer.cancel();
                            started = true;

                            System.setProperty("spring.profiles.active", "development");
                            callback.bootRun();
                        }
                        countDown.set(countDown.get() - 1);
                    }
                }, 0, 1000);
            }

            try (Scanner scanner = new Scanner(System.in)) {
                Pattern pattern = Pattern.compile("^p|d$");
                //如果是Linux系統(一般為生產環境)則強制等待使用者輸入(一般是忘記設定spring.profiles.active了，這等於給了設定active profile的"second chance")
                while (scanner.hasNextLine()) {
                    if (started) {
                        break;
                    }
                    String line = scanner.nextLine();
                    if (!pattern.matcher(line).find()) {
                        System.out.println("INVALID INPUT!");
                    } else {
                        timer.cancel();
                        System.setProperty("spring.profiles.active", line.equals("d") ? "development" : "production");
                        callback.bootRun();
                        break;
                    }
                }
            }
        } else { //如果已經通過引數spring.profiles.active設定了active profile直接啟動
            callback.bootRun();
        }
    }

    public void startup(Callback callback) {
        startup(this.enableAutomaticallyStart, this.automaticallyStartDelay, callback);
    }
}

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