Java:为什么我的主人和职位在其他班级中返回null

Question

import javax.swing.JOptionPane; 
public class connectFenetre {
  private String host ;
  private Integer port ;
  public connectFenetre(){
   }
  public void run()
  { 
     String input = JOptionPane.showInputDialog("What's the port? and host?
    String[] token = input.split(":");
     if(token.length != 2){
         JOptionPane.showMessageDialog(null, "need host and port!");
     }

     this.host = token[0];
    this.port = Integer.parseInt(token[1]);
    System.out.println(getPort());
    System.out.println(getHost());
     CommBase c = new CommBase();
     c.start();
     FenetrePrincipale fenetre = new FenetrePrincipale(c);
     c.setPropertyChangeListener(fenetre);
 }
 public String getHost(){
    return host;
 }
 public Integer getPort(){
        return port;
  }
 }

为什么我的端口和主机在其他班级中返回null？

在其他类中我声明

connectFenetre c = new connectFenetre();
println("c.getPort()");
println("c.getHost()");
Output: NULL NULL

Answer 1

为设置要执行的主机和端口的代码创建c之后，您需要调用c.Run()。尝试以下操作：

connectFenetre c = new connectFenetre();
c.run();
println("c.getPort()");
println("c.getHost()");

您可能还需要将主机和端口字段初始化为connectFenetre构造函数中的某些默认值。即使从未执行run()，这也将避免NULL值。