java.lang.NullPointerException的问题

Question

public void readfile()
     {
         
         String[] record = new String[50];
         String str_relation=new String();
         int i=0;         try
         {
             FileReader read=new FileReader("Family Info.txt");
             Scanner scanner=new Scanner(read);
             while(scanner.hasNextLine())
             {
                 i++;
                 record[i]=scanner.nextLine();
                 System.out.println(record[i]);
             }
             System.out.println(i);
             for(int a=0;a<i;a++)
             {
                 if(record[a].equals("Relation:Key Person"))
                 {
                     System.out.println("ok");
                 }
                 else
                 {
                     System.out.println("not ok");
                 }             }                       read.close();
             }catch(Exception e){
                 System.out.println(e);         }     }
 if(record[a].equals("Relation:Key Person"))出现java.lang.NullPointerException的问题
把a换成数字就没问题了，怎样解决？

Answer 1

数组里面有null呗。没别的可能了。

Answer 2

debug,看当a运行到几的时候抛异常

Answer 3

LZ，你i初始化是0，然后while马上就++，那么我问，数组下标为0的不是null吗？？

Answer 4

可能是数组里有空指针你把
while(scanner.hasNextLine())
             {
                 i++;
                 record[i]=scanner.nextLine();
                 System.out.println(record[i]);
             }改成
while(scanner.hasNextLine())
             {
               record[i]=scanner.nextLine();
               i++;                 System.out.println(record[i]);
             }再试试

Answer 5

record[0]是空的把。。楼主你的数据是从1开始的