我有我的代码在这里:替换文本文件中的Java一句话
public void Edit()throws IOException{
FileWriter writeFile=new FileWriter("voters.txt", true);
BufferedWriter outFile=new BufferedWriter(writeFile);
File readFile=new File("voters.txt");
BufferedReader read=new BufferedReader(new FileReader(readFile));
vNumForEdit=JOptionPane.showInputDialog("Enter voters number: ");
String line=null;
while((line=read.readLine())!=null){
String [] info=line.split("/");
if(info[0].matches(vNumForEdit)){
String [] forEditMenu={"Name", "Age", "Gender", "Date of Birth", "Place of Birth", "Address", "Civil Status", "Citizenship", "Profession/Occupation", "Father's Name", "Mother's Name"};
forEdit=(String)JOptionPane.showInputDialog(null, line+"\n\nPlease select what you want to edit", "National Election 2765", 1, null, forEditMenu, forEditMenu[0]);
switch(forEdit){
case "Name":
newName=JOptionPane.showInputDialog("Enter new name: ");
if(info[1].matches(oldName)){
outFile.append(info[1]=newName);
outFile.close();
}
read.close();
break;
}
}
}
}
文本文件看起来像这样
1/d/19/Male/e//s/Single/v/e/e/f
2/c/98/Male//d/c/Single/r/w/q/d
,你可以看到我发的信息/线阵列,它可以读取作为投票号码的索引0中的值。任务是用户将输入选民号码,然后如果发现,用户将再次输入他想要编辑的内容。我使用数组以及确定的姓名,年龄,性别等数组是这样的:
info[0] = voters number
info[1]= name
info[2] = age
info[3] = date of birth
info[4]= place of birth
info[5] = status
info[6] = citizenship
info[7] = profession
info[8] = father's name
info[9] = mother's name
,但我的代码总是错误java.lang.NullPointerException
结束。我大部分的变量有全局声明
编辑:这里的错误/堆栈跟踪
Exception in thread "main" java.lang.NullPointerException
at java.util.regex.Pattern.<init>(Unknown Source)
at java.util.regex.Pattern.compile(Unknown Source)
at java.util.regex.Pattern.matches(Unknown Source)
at java.lang.String.matches(Unknown Source)
at lozada.My_Voting_System_Official.Edit(My_Voting_System_Official.java:135)
at lozada.My_Voting_System_Official.Menu(My_Voting_System_Official.java:43)
at lozada.My_Voting_System_Official.main(My_Voting_System_Official.java:15)
请包括堆栈跟踪。 – Veluria
代码中的哪一行会得到NPE? – Sachin
此外,如果检查其常规字符串是否使用“equals”或“equalsIgnoreCase”而不是“matches”。 – Sachin