Java 继续获取空指针异常错误？我的逻辑几乎是准确的

为什么当我输入1或2激活开关时，情况1或2我有一个空指针异常错误？？我真的需要有人能解释我的问题。我相信我的开关箱没有问题。我错过了什么

   package dakilangtaoako;
   import java.io.BufferedReader;
   import java.io.IOException;
   import java.io.InputStreamReader;
    import java.util.logging.Level;
   import java.util.logging.Logger;


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

    BufferedReader dataIn = new BufferedReader(new InputStreamReader( System.in) );
    String mydata[][] = new String[5][3] ;
    String inttoword [] = new String [5];
    int wordtoint[] = new int [5]; 
    int mychoice = 0;
    String toreturn = "";

    for (int outside = 0; outside < 5; outside++){
        System.out.println("Entry no." + (outside + 1));
        for (int inside = 0; inside < 3; inside++){
        if(inside == 0){
            try {
                System.out.print("Name: ");
                mydata[outside][inside]= dataIn.readLine();
            } catch (IOException ex) {
                Logger.getLogger(DakilangTaoAko.class.getName()).log(Level.parse("OK"), null, ex);
            }
 }
        else if(inside == 1){
            try {
                System.out.print("ID: ");
                mydata[outside][inside]= dataIn.readLine();
            } catch (IOException ex) {
                Logger.getLogger(DakilangTaoAko.class.getName()).log(Level.parse("OK"), null, ex);
            }
  }
        else if(inside ==2){
            try {
                System.out.print("Subject: ");
                mydata[outside][inside]= dataIn.readLine();
            } catch (IOException ex) {
                Logger.getLogger(DakilangTaoAko.class.getName()).log(Level.parse("OK"), null, ex);
            }


 }
}
    }
 for(int outside= 0; outside <5; outside++){
            for(int inside = 1; inside <= 3; inside++){
                if(inside ==0)
                    inttoword[outside]=(mydata[outside][inside])+";"+(mydata[outside][inside]);
            }
       }
 for(int outside = 0; outside < 5; outside++){
            for(int inside = 1; inside <= 3; inside++){
                if(inside ==0)
                    wordtoint[outside]=Integer.parseInt(mydata[outside][inside]);
            }
       }


 for(int i=0;i<5;i++){
 wordtoint[i]=Integer.parseInt(mydata[i][1]);
 }

       while(mychoice != 5){
       System.out.println("-------- DISPLAY OPTIONS --------");
       System.out.println("\t [1] Display Entries Alphabetically ");
       System.out.println("\t [2] Display Entries by Ascending ID number ");
       System.out.println("\t [3] Display Students Enrolled in Prog2 ");
       System.out.println("\t [4] Display Students Enrolled in CSO ");
       System.out.println("\t [5] Exit ");
       System.out.println();
       System.out.print("\t Choice:");
            try {
                mychoice = Integer.parseInt(dataIn.readLine());
            } catch (IOException ex) {
                Logger.getLogger(DakilangTaoAko.class.getName()).log(Level.SEVERE, null, ex);
            }

            switch (mychoice){



                case 1:
                  System.out.println("----Entries In Alphabetical Order----");
                  alphabetSorter(inttoword);
                        for(int limiter = 0; limiter < 5; limiter++)
               System.out.println(inttoword[limiter]);


                  System.out.print("Press [r] to Return to Main Menu...");
        try {
           toreturn = dataIn.readLine();
       } catch (IOException ex) {
           Logger.getLogger(DakilangTaoAko.class.getName()).log(Level.SEVERE, null, ex);
       }
                     if("r".equals(toreturn)) 
                    break;
                case 2:

                  System.out.println(" ---- Entries by Ascending ID Number ----");  
                        for(int outside = 0; outside < 5; outside++){
                        numSorter(wordtoint);
                        for(int inside = 0; inside < 5; inside++){
                        if(Integer.parseInt(mydata[inside][1])== wordtoint[outside])
                  System.out.println(wordtoint[outside] + ";" + mydata[inside][0]);
               }                
           } 
                   System.out.print("Press [r] to return to main Menu...");
        try {
           toreturn = dataIn.readLine();
       } catch (IOException ex) {
           Logger.getLogger(DakilangTaoAko.class.getName()).log(Level.SEVERE, null, ex);
       }            
                 if("r".equals(toreturn))
                         break;

                case 3:
                    System.out.println(" ---- Students Enrolled in Prog2 ----");
                    String mustfind1 = "PROG2";     
                    for(int outside = 0; outside < 5; outside++){
                    if(mydata[outside][2].equalsIgnoreCase(mustfind1)){
                    System.out.println(mydata[outside][0]+";"+mydata[outside][1]);
                                        }
                        }System.out.print("Press [r] to Return to Main Menu...");
        try {
           toreturn = dataIn.readLine();
       } catch (IOException ex) {
           Logger.getLogger(DakilangTaoAko.class.getName()).log(Level.SEVERE, null, ex);
       }
                  if("r".equals(toreturn))   
                    break;

                case 4:
                    System.out.println(" ---- Students Enrolled in CSO ---- ");
                    String mustfind2 = "CSO";
                    for(int outside = 0; outside < 5; outside++){
                        if(mydata[outside][2].equalsIgnoreCase(mustfind2))
                            System.out.println(mydata[outside][0]+";"+mydata[outside][1]);
                                        }
                        System.out.print("Press [r] to Return to Main Menu...");
       try {
           toreturn = dataIn.readLine();
       } catch (IOException ex) {
           Logger.getLogger(DakilangTaoAko.class.getName()).log(Level.SEVERE, null, ex);
       }
                  if("r".equals(toreturn))
                    break;

                case 5:
                    mychoice = 5;

                    break;  

                default:
                    System.out.println("Sorry the Number is Not in the Choices!!");
                    System.out.print("Press [r] to Return to Main Menu...");
        try {
           toreturn = dataIn.readLine();
             } catch (IOException ex) {
           Logger.getLogger(DakilangTaoAko.class.getName()).log(Level.SEVERE, null, ex);
          }
                 if("r".equals(toreturn))
                     break;
            }     }   
   }
       public static void numSorter(int given[]){

  int temp;
  for(int outside = 0; outside < given.length-1; outside++)
    {
        for(int inside = outside+1 ; inside < given.length; inside++)
        {  
            if(given[outside] > given[inside])
            {                                         
            temp = given[outside];
            given[outside]= given[inside];  
            given[inside]=temp;                                    
            } 
        } 
    } 
    }
    public static void alphabetSorter(String given[]){

String temp;
for(int outside = 0; outside < given.length -1; outside++)
    {
        for(int inside = outside +1; inside < given.length; inside++)
        {  
            if(given[outside].compareToIgnoreCase(given[inside])>0)
            {                                         
            temp= given[outside];
            given[outside]= given[inside];  
            given[inside]=temp;                                    
            } 
        } 
      } 
 }




  }

大吉朗塔瓦科包装；
导入java.io.BufferedReader；
导入java.io.IOException；
导入java.io.InputStreamReader；
导入java.util.logging.Level；
导入java.util.logging.Logger；
公务舱大吉朗塔阿科{
公共静态void main（字符串[]args）{
BufferedReader dataIn=新的BufferedReader（新的InputStreamReader（System.in））；
字符串mydata[][]=新字符串[5][3]；
字符串inttoword[]=新字符串[5]；
int wordtoint[]=新的int[5]；
int mychoice=0；
字符串toreturn=“”；
for（int-outside=0；outside<5；outside++）{
系统输出打印项次（“条目号”+（外部+1））；
用于（内部int=0；内部<3；内部++）{
如果（内部==0）{
试一试{
系统输出打印（“名称：”）；
mydata[外部][内部]=dataIn.readLine（）；
}捕获（IOEX异常）{
Logger.getLogger（DakilangTaoAko.class.getName（））.log（Level.parse（“OK”），null，ex）；
}
}
else if（内部==1）{
试一试{
系统输出打印（“ID:”）；
mydata[外部][内部]=dataIn.readLine（）；
}捕获（IOEX异常）{
Logger.getLogger（DakilangTaoAko.class.getName（））.log（Level.parse（“OK”），null，ex）；
}
}
else if（内部==2）{
试一试{
系统输出打印（“主题：”）；
mydata[外部][内部]=dataIn.readLine（）；
}捕获（IOEX异常）{
Logger.getLogger（DakilangTaoAko.class.getName（））.log（Level.parse（“OK”），null，ex）；
}
}
}
}
对于（int-outside=0；outside来说，这是因为您没有初始化数组inttoword。它的所有条目都为null，这将阻塞此语句：

if（给定[外部]）.compareTignoreCase（给定[内部]）>0）

您要求jdk执行以下操作：
if（null.compareToIgnoreCase（null）>0）
查看日志文件，因为您正在使用Logger或只是在开发时使用
ex.printStackTrace（）
。这是大量代码；请尝试缩小问题的范围。您可能对我编写的日志文件感兴趣。如果您没有缩小问题范围，人们往往不会提供很大帮助。“几乎准确”和“准确”的意思是相反的。线程“main”中的异常java.lang.NullPointerException位于dakilangtaoako.dakilangtaoako.alphabetSorter（dakilangtaoako.java:195）位于dakilangtaoako.dakilangtaoako.main（dakilangtaoako.java:91）Java结果：1当我输入1或2时，当代码要求显示选项时..我已经编辑了我的答案。这对你有帮助吗？我如何解决问题？我仍然有点困惑。。