“线程中的异常”；“主要”；java.lang.IllegalStateException:扫描程序在文件I/O时关闭

我目前正在创建一个类，允许用户根据用户输入的ID编辑行。但是，我有以下错误：

线程“main”java.lang.IllegalStateException中的异常：扫描程序已关闭”

即使我在

int phone input

下面放了一个

scanner.close（）

。 为什么会发生这种情况，有什么解释吗

package com.company;

import javax.sound.midi.SysexMessage;
import java.io.*;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Scanner;

public class Edit {
    static Scanner x;

    public static void editRecord() throws ParseException {
        Scanner scanner = new Scanner(System.in);
        System.out.println("ENter your ID");
        String ID = scanner.nextLine();
        System.out.println("ENter your new name");
        String name = scanner.nextLine();
        System.out.println("ENter your new EMail");
        String email = scanner.nextLine();
        System.out.println("ENter your new Address");
        String address = scanner.nextLine();
        System.out.println("ENter your new Date");
        String date = scanner.nextLine();
        SimpleDateFormat format = new SimpleDateFormat("dd-MM-yyyy");
        Date userDate = format.parse(date);
        System.out.println("ENter your Gender");
        String gender = scanner.nextLine();
        boolean Gender = Boolean.parseBoolean(gender);
        System.out.println("ENter your new phone number");
        int phone = scanner.nextInt();


        String filepath = "leads.csv";
    String tempfile = "temp.csv";
    File oldFile = new File(filepath);
    File newFile = new File(tempfile);
    String ID1 = ""; String name1 = "";String email1="";String address1 = ""; String userdate1 = "";
    String Gender1 = ""; String phone1 = "";
    scanner.close();
    try{
        FileWriter fw = new FileWriter(tempfile,true);
        BufferedWriter bw = new BufferedWriter(fw);
        PrintWriter pw = new PrintWriter(bw);
        x = new Scanner(new File(filepath));
        x.useDelimiter("[,\n]");

        while (x.hasNext()){
            ID1 = x.next();
            name1 = x.next();
            phone1 = x.next();
            email1 = x.next();
            address1 = x.next();
            userdate1 = x.next();
            Gender1 = x.next();
            if(ID1.equals(ID)){
                pw.println(name+","+phone+","+email+","+address+","+userDate+","+Gender);
            }
            else {
                pw.println(name1+","+phone1+","+email1+","+address1+","+userdate1+","+Gender1);
            }
            x.close();
            pw.flush();
            pw.close();
            oldFile.delete();
            File dump = new File(filepath);
            newFile.renameTo(dump);
        }


    } catch (IOException e) {
        e.printStackTrace();
        System.out.println("Error Occured");
    }


    }
}

---

扫描仪在系统上初始化。在中读取用户输入即可。 IllegalStateException从在try块中初始化的扫描仪中抛出

在while循环中关闭扫描仪时引发异常。 为了避免它，将x.close（）和pw.close（）语句移动到finally块中，如下所示

PrintWriter pw = null;
try {
    FileWriter fw = new FileWriter(tempfile,true);
    BufferedWriter bw = new BufferedWriter(fw);
    pw = new PrintWriter(bw);
    x = new Scanner(new File(filepath));
    x.useDelimiter("[,\n]");

    while (x.hasNext()){
        ...
        pw.flush();
    }

} catch (IOException e) {
    e.printStackTrace();
    System.out.println("Error Occured");
} finally {
    x.close();
    if (pw != null) {
        pw.close();
    }  
}

---

请看这篇文章，希望它能解决您的问题@Seralathan嘿，我确实试着按照您的指示做了，但不幸的是，除非我加入尝试，否则pw.close（）无法识别bracket@PhạmQuốcMinhĐăng您需要try、catch和finally块。x.close（）和pw.close（）需要放在finally块。将pw.close（）移动到finally块后，您能否分享您面临的结果/错误。@PhạmQuốcMinhĐăng有关关闭PrintWriter的建议方法，请参阅文档。pw.close（）无法识别变量（无法解析符号“pw”）@PhạmQuốcMinhĐăng pw变量的作用域当前仅在try块的作用域中。在try块之前声明它，以便在块结束后可用。

PrintWriter pw=null

在尝试关闭PrintWriter之前，还要检查finally块中的null值。

finally{

如果（pw！=null）{

pw.close（）；

}

}