当我试图关闭它时，循环程序。我如何修复这个无限循环？

Question

这个程序应该接受用户的输入，将其放入一个文本文件中，然后能够在以后需要时提取信息(尚未实现)。程序打开并接受值并保存它们，但当我关闭程序时，会出现一个新窗口，并且重复此过程。有什么关于如何阻止这种情况的帮助吗？它可能只是在某个地方丢失了一个突破口，但我终生无法修复它。

public class FirstTr {

final private static int MAX_RECORD_NUMBER = 71;
final private static int MAX_PLAYER_NUMBER = 99;
final private static char PLAYER_NAME = 26;
final private static char TEAM_NAME = 26;
final private static int SKILL_LEVEL = 5;
final private static int DRAFT_DATE = 9;
final private static int RECORD_LENGTH = 16;
final private static int PLAYER_ID = 20;
final private static int ID_Length = 5;


public static void main(String[] args) throws FileNotFoundException, IOException {


    File loc = new File("C:\\Users\\Desktop\\Exc2.1.txt");
    RandomAccessFile store = new RandomAccessFile(loc, "rw");
    String id1 = "";
    String id2 = "";
    String id3 = "";
    String id4 = "";
    String id = "";
    String Description = "";
    int recLocation = 0;
    String cmd = "Start";
    String where = "0";




    cmd= JOptionPane.showInputDialog(null, " Please type in a command : new, old or exit");

    if (cmd.compareToIgnoreCase("end")== 0){
        store.close();
        System.exit(0);

    }

    while (cmd.compareToIgnoreCase("end")!= 0){

        if (cmd.compareToIgnoreCase("new") == 0){
            //Ask user for ID 1-20, read ID
            try{
                id1 = JOptionPane.showInputDialog(null,"Enter ID(1-20):");
                recLocation= Integer.parseInt(id1);
                assert Integer.MAX_VALUE == PLAYER_ID;

                JOptionPane.showInputDialog(null, "The ID IS "+ id1);
            }
            catch (Exception e){
                JOptionPane.showInputDialog(null, "SORRY THIS IS NOT AN INTEGER PLEASE PRESS ENTER TO CONTINUE");

            }
            try{
                //Ask user for player name, read name
                id2 = JOptionPane.showInputDialog(null, "Enter a players name");
                assert id.length()== PLAYER_NAME;
                JOptionPane.showInputDialog("The players name is " + id2 + " press enter to continue");
                store.writeUTF(id2); 
            }
            catch (Exception e){
                JOptionPane.showInputDialog(null, "SORRY SOMETHING WENT WRONG PLEASE PRESS ENTER TO CONTINUE");

            }
            try{
                //ask for player team name, read team name
                id3 = JOptionPane.showInputDialog(null, "Enter a players team name");
                JOptionPane.showInputDialog("The players team name is " + id3 + ", press enter to continue");
                assert id.length()== TEAM_NAME;
                store.writeUTF(id3);
            }
            catch (Exception e){
                JOptionPane.showInputDialog(null, "SOMETHING WENT WRONG PLEASE PRESS ENTER TO CONTINUE");

            }

            //enter player skill level, read skill level(0-99)
            try{    
                id4 = JOptionPane.showInputDialog(null,"Enter a players skill level (0-99)");
                recLocation = Integer.parseInt(id4);
                JOptionPane.showInputDialog("The players skill level " + id4 + " press enter to continue");
            }
            catch (Exception e){
                JOptionPane.showInputDialog(null, "SORRY THIS IS NOT AN INTEGER PLEASE PRESS ENTER TO CONTINUE");

            }
            //enter player skill level, read skill level
            try{    
                id = JOptionPane.showInputDialog(null, "Enter todays Date");
                JOptionPane.showInputDialog("Today is " + id + " press enter to continue");
                assert id.length()== DRAFT_DATE;
                store.writeUTF(id);
            }
            catch (Exception e){
                JOptionPane.showInputDialog(null, "SORRY THIS IS NOT AN INTEGER PLEASE PRESS ENTER TO CONTINUE");
                continue;
            }
            //convert ID and skill level to string(char-5)


        }



        //if command is old, ask for ID and read Id, then use ID to retrieve record, display the record formatted for readability


        if (cmd.compareToIgnoreCase("old") == 0) {
            try{
                where = JOptionPane.showInputDialog(null, "Enter player:");
                recLocation = Integer.parseInt(where);
                store.seek((PLAYER_ID) * (recLocation-1));
                Description = store.readUTF();

                JOptionPane.showMessageDialog(null, Description);
            }
            catch(Exception e){
                JOptionPane.showInputDialog("Sorry there is no player try again");
                continue;
            }
        }
    }
}

Answer 1

您只读取cmd的输入一次，然后它永远不会被重新分配。因此，如果第一个while循环的条件(cmd.compareToIgnoreCase("end")!= 0)一开始就为真，那么它将永远循环。

Answer 2

你的while loop是罪魁祸首。从字面上讲，循环一直在进行，因为没有任何东西在改变条件。

如果你想在你的脚本中把这个条件(cmd.compareToIgnoreCase("end")!= 0)改成true，你的脚本就会按照你想要的方式终止！

注意：您没有将单词"exit"分配给命令！也许为它做一个命令会让脚本做你想做的事情！

EDIT:在这里尝试将这些代码片段中的"end"更改为"exit"！

if (cmd.compareToIgnoreCase("end")== 0){
        store.close();
        System.exit(0);

while (cmd.compareToIgnoreCase("end")!= 0)

EDIT2：通过将上面的if语句添加到while循环的底部，它应该退出！

while (cmd.compareToIgnoreCase("exit")!= 0){

    if (cmd.compareToIgnoreCase("new") == 0){
        //Ask user for ID 1-20, read ID
        try{
            id1 = JOptionPane.showInputDialog(null,"Enter ID(1-20):");
            recLocation= Integer.parseInt(id1);
            assert Integer.MAX_VALUE == PLAYER_ID;

            JOptionPane.showInputDialog(null, "The ID IS "+ id1);
        }
        catch (Exception e){
            JOptionPane.showInputDialog(null, "SORRY THIS IS NOT AN INTEGER PLEASE PRESS ENTER TO CONTINUE");

        }
        try{
            //Ask user for player name, read name
            id2 = JOptionPane.showInputDialog(null, "Enter a players name");
            assert id.length()== PLAYER_NAME;
            JOptionPane.showInputDialog("The players name is " + id2 + " press enter to continue");
            store.writeUTF(id2); 
        }
        catch (Exception e){
            JOptionPane.showInputDialog(null, "SORRY SOMETHING WENT WRONG PLEASE PRESS ENTER TO CONTINUE");

        }
        try{
            //ask for player team name, read team name
            id3 = JOptionPane.showInputDialog(null, "Enter a players team name");
            JOptionPane.showInputDialog("The players team name is " + id3 + ", press enter to continue");
            assert id.length()== TEAM_NAME;
            store.writeUTF(id3);
        }
        catch (Exception e){
            JOptionPane.showInputDialog(null, "SOMETHING WENT WRONG PLEASE PRESS ENTER TO CONTINUE");

        }

        //enter player skill level, read skill level(0-99)
        try{    
            id4 = JOptionPane.showInputDialog(null,"Enter a players skill level (0-99)");
            recLocation = Integer.parseInt(id4);
            JOptionPane.showInputDialog("The players skill level " + id4 + " press enter to continue");
        }
        catch (Exception e){
            JOptionPane.showInputDialog(null, "SORRY THIS IS NOT AN INTEGER PLEASE PRESS ENTER TO CONTINUE");

        }
        //enter player skill level, read skill level
        try{    
            id = JOptionPane.showInputDialog(null, "Enter todays Date");
            JOptionPane.showInputDialog("Today is " + id + " press enter to continue");
            assert id.length()== DRAFT_DATE;
            store.writeUTF(id);
        }
        catch (Exception e){
            JOptionPane.showInputDialog(null, "SORRY THIS IS NOT AN INTEGER PLEASE PRESS ENTER TO CONTINUE");
            continue;
        }
        //convert ID and skill level to string(char-5)


    }



    //if command is old, ask for ID and read Id, then use ID to retrieve record, display the record formatted for readability


    if (cmd.compareToIgnoreCase("old") == 0) {
        try{
            where = JOptionPane.showInputDialog(null, "Enter player:");
            recLocation = Integer.parseInt(where);
            store.seek((PLAYER_ID) * (recLocation-1));
            Description = store.readUTF();

            JOptionPane.showMessageDialog(null, Description);
        }
        catch(Exception e){
            JOptionPane.showInputDialog("Sorry there is no player try again");
            continue;
        }

    if (cmd.compareToIgnoreCase("exit")== 0){
            store.close();
            System.exit(0);
            }
        }
    }
}

希望这能有所帮助！