server.port=${random.int(2000,8000)}

@Slf4j
public class NetUtils {
  
  /**
   * 測(cè)試本機(jī)端口是否被使用
   * @param port
   * @return
   */
  public static boolean isLocalPortUsing(int port){
    boolean flag = true;
    try {
      //如果該端口還在使用則返回true,否則返回false,127.0.0.1代表本機(jī)
      flag = isPortUsing("127.0.0.1", port);
    } catch (Exception e) {
    }
    return flag;
  }
  /***
   * 測(cè)試主機(jī)Host的port端口是否被使用
   * @param host
   * @param port
   * @throws UnknownHostException
   */
  public static boolean isPortUsing(String host,int port) {
    boolean flag = false;
    try {
      InetAddress Address = InetAddress.getByName(host);
      Socket socket = new Socket(Address,port); //建立一個(gè)Socket連接
      flag = true;
    } catch (IOException e) {
      //log.info(e.getMessage(),e);
    }
    return flag;
  }

  //start--end是所要檢測(cè)的端口范圍
  static int start=0;
  static int end=1024;
  
  /**
   * 由于本機(jī)上安裝了mysql，采用3306端口去驗(yàn)證
   * @param args
   */
  public static void main(String args[]){
      int testPost =3306;
      if(isLocalPortUsing(testPost)){
        System.out.println("端口 "+testPost+" 已被使用");
      }else{
        System.out.println("端口 "+testPost+"未使用");
      }
  }
}

 public class ServerPortUtils {

  /**
   * 獲取可用端口
   * @return
   */
  public static int getAvailablePort(){
     int max = 65535;
     int min = 2000;

     Random random = new Random();
     int port = random.nextInt(max)%(max-min +1) + min;
     boolean using = NetUtils.isLocalPortUsing(port);
     if(using){
       return getAvailablePort();
     }else{
       return port;
     }
  }

}

/**
 * 開始命令
 */
@Slf4j
public class StartCommand {

  public StartCommand(String[] args){
     Boolean isServerPort = false;
     String serverPort = "";
     if(args != null){
       for (String arg:args){
          if(StringUtils.hasText(arg) &&
              arg.startsWith("--server.port")
          ){
            isServerPort = true;
            serverPort = arg;
            break;
          }
       }
     }

     //沒有指定端口，則隨機(jī)生成一個(gè)可用的端口
    if(!isServerPort){
       int port = ServerPortUtils.getAvailablePort();
       log.info("current server.port=" + port);
       System.setProperty("server.port",String.valueOf(port));
    }else{//指定了端口，則以指定的端口為準(zhǔn)
      log.info("current server.port=" + serverPort.split("=")[1]);
      System.setProperty("server.port",serverPort.split("=")[1]);
    }
  }

}

@SpringBootApplication
@EnableUserClient
@RestController
public class DemoApplication {
  @Autowired
  Environment environment;

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

public class MyEnvironmentPostProcessor implements EnvironmentPostProcessor {

  @Override
  public void postProcessEnvironment(ConfigurableEnvironment environment, SpringApplication application) {
    //MapPropertySource
    Properties properties = new Properties();
    properties.put("server.port", ServerPortUtils.getAvailablePort());
    System.out.println(properties.get("server.port"));
    PropertiesPropertySource source = new PropertiesPropertySource("myCustom", properties);
    environment.getPropertySources().addLast(source);
    //environment.getPropertySources().addAfter();
  }
}

org.springframework.boot.env.EnvironmentPostProcessor=com.laowan.demo.command.MyEnvironmentPostProcessor