为什么我用JFrame获得变量声明错误？

Question

我的最终目标是让用户输入三名选手的名字以及他们完成比赛的时间。它将根据无暇的时间组织选手，并且我想将结果打印到一张表格中，但是当我最后编译时出现以下错误;

error: variable declaration not allowed here 
     JFrame frame = new JFrame(); 

当我单独运行的JFrame代码，它工作得很好，但后来当我编译所有的代码放在一起我收到上述错误的。

import java.awt.BorderLayout; 
import javax.swing.*; 

public class JTableCreatingDemo { 
    public static void main(String args[]) { 

    String runner1, runner2, runner3; 
    double runTime1, runTime2, runTime3; 

    //Get the names and run time of each runner 
    runner1 = JOptionPane.showInputDialog("Enter name of runner 1"); //runner1 
    runTime1 = Double.parseDouble(JOptionPane.showInputDialog("Enter runtime of runner 1 in minutes")); //runTime1 
    while (runTime1<0) 
     { 
      JOptionPane.showMessageDialog(null, "Invalid Entry"); 
      runtTime1 = Double.parseDouble(JOptionPane.showInputDialog("Enter runtime of runner 1 in minutes \nEntery format should be MM.SS")); 
     } 

    runner2 = JOptionPane.showInputDialog("Enter name of runner 2"); //runner2 
    runTime2 = Double.parseDouble(JOptionPane.showInputDialog("Enter runtime of runner 2 in minutes")); //runTime2 
    while (runTime2<0) 
     { 
      JOptionPane.showMessageDialog(null, "Invalid Entry"); 
      runtTime2 = Double.parseDouble(JOptionPane.showInputDialog("Enter runtime of runner 2 in minutes \nEntery format should be MM.SS")); 
     } 

    runner3 = JOptionPane.showInputDialog("Enter name of runner 3"); //runner3 
    runtime3 = Double.parseDouble(JOptionPane.showInputDialog("Enter runtime of runner 3 in minutes")); //runTime3 
    while (runTime3<0) 
     { 
      JOptionPane.showMessageDialog(null, "Invalid Entry"); 
      runtTime3 = Double.parseDouble(JOptionPane.showInputDialog("Enter runtime of runner 3 in minutes \nEntery format should be MM.SS")); 
     } 

    //Sort the runners by their respective run times 
    if(runtime1<=runtime2 && runtime1<=runtime3) //runner1 is the fastest 
    { 
     if(runtime2<=runtime3) 
      JFrame frame = new JFrame(); 
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 

      Object rowData[][] = { { runner1, runtime1 + " minutes", "-" }, 
       { runner2, runtime2 + " minutes", (runtime2-runtime1) }, 
       {runner3, runtime3 + " minutes", (runtime3-runTime1)} }; 
      Object columnNames[] = { "Runners Name", "Finish Time", "Differnce" }; 
      JTable table = new JTable(rowData, columnNames); 

      JScrollPane scrollPane = new JScrollPane(table); 
      frame.add(scrollPane, BorderLayout.CENTER); 
      frame.setSize(300, 150); 
      frame.setVisible(true); 
    } 

    } 
} 

Answer 1

试试这个代码，它应该工作。我刚刚修复了括号内的错误:)

import java.awt.BorderLayout; 
import javax.swing.*; 

public class JTableCreatingDemo { 
    public static void main(String args[]) { 

    String runner1, runner2, runner3; 
    double runTime1, runTime2, runTime3; 

    //Get the names and run time of each runner 
    runner1 = JOptionPane.showInputDialog("Enter name of runner 1"); //runner1 
    runTime1 = Double.parseDouble(JOptionPane.showInputDialog("Enter runtime of runner 1 in minutes")); //runTime1 
    while (runTime1<0) 
     { 
      JOptionPane.showMessageDialog(null, "Invalid Entry"); 
      runtTime1 = Double.parseDouble(JOptionPane.showInputDialog("Enter runtime of runner 1 in minutes \nEntery format should be MM.SS")); 
     } 

    runner2 = JOptionPane.showInputDialog("Enter name of runner 2"); //runner2 
    runTime2 = Double.parseDouble(JOptionPane.showInputDialog("Enter runtime of runner 2 in minutes")); //runTime2 
    while (runTime2<0) 
     { 
      JOptionPane.showMessageDialog(null, "Invalid Entry"); 
      runtTime2 = Double.parseDouble(JOptionPane.showInputDialog("Enter runtime of runner 2 in minutes \nEntery format should be MM.SS")); 
     } 

    runner3 = JOptionPane.showInputDialog("Enter name of runner 3"); //runner3 
    runtime3 = Double.parseDouble(JOptionPane.showInputDialog("Enter runtime of runner 3 in minutes")); //runTime3 
    while (runTime3<0) 
     { 
      JOptionPane.showMessageDialog(null, "Invalid Entry"); 
      runtTime3 = Double.parseDouble(JOptionPane.showInputDialog("Enter runtime of runner 3 in minutes \nEntery format should be MM.SS")); 
     } 

    //Sort the runners by their respective run times 
    if(runtime1<=runtime2 && runtime1<=runtime3) //runner1 is the fastest 
    { 
     if(runtime2<=runtime3) 
      { 
      JFrame frame = new JFrame(); 
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 

      Object rowData[][] = { { runner1, runtime1 + " minutes", "-" }, 
       { runner2, runtime2 + " minutes", (runtime2-runtime1) }, 
       {runner3, runtime3 + " minutes", (runtime3-runTime1)} }; 
      Object columnNames[] = { "Runners Name", "Finish Time", "Differnce" 
      } 
}; 
      JTable table = new JTable(rowData, columnNames); 

      JScrollPane scrollPane = new JScrollPane(table); 
      frame.add(scrollPane, BorderLayout.CENTER); 
      frame.setSize(300, 150); 
      frame.setVisible(true); 
    } 

    } 
    }