引起：java.util.NoSuchElementException

Question

大家好，我正在使用以下代码 代码在下面的字符串工作正常 StringTokenizer st = new StringTokenizer("abc,koch, Ranchi, zalkhand, NY, 10001, India");

但当我删除字符串中的任何元素时= =“abc” 它显示

 Caused by: java.util.NoSuchElementException" exception..
 StringTokenizer st = new StringTokenizer("koch, Ranchi, zalkhand, NY, 10001, India"); 

代码：

package com.test;


import java.util.StringTokenizer;

import android.app.Activity;
import android.os.Bundle;

public class Test extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        StringTokenizer st = new StringTokenizer("koch, Ranchi, zalkhand, NY, 10001, India"); 
        System.out.println("Tokens are seperated");
        int i=0;
        String address[] = new String[7];

         String contlocation="";
         String contfirst_street="";
         String contsecond_street="";
         String contcity="";
         String contstate="";
         String contzipcode="";
         String contcountry="";


      /*  while(st.hasMoreTokens())
        {

          */      
              for(i=0;i<7;i++)
              {
                    address[i] = st.nextToken(",");
                   System.out.println("address "+i+": "+address[i]);
              }

              if(address.length==7)
              {

                  System.out.println("\n-------------address.length==7--------------------");

                  contlocation=address[0];
                  System.out.println("contlocation :"+contlocation);

                  contfirst_street=address[1];
                  System.out.println("contfirst_street :"+contfirst_street);

                  contsecond_street=address[2];
                  System.out.println("contsecond_street :"+contsecond_street);

                  contcity=address[3];
                  System.out.println("contcity :"+contcity);

                  contstate=address[4];
                  System.out.println("contstate :"+contstate);

                  contzipcode=address[5];
                  System.out.println("contzipcode :"+contzipcode);

                  contcountry=address[6];
                  System.out.println("contcountry :"+contcountry);

                  System.out.println("\n-------------address.length==7--------------------");
              }
              else if(address.length==6)
              {
                  System.out.println("\n-------------address.length==6--------------------");

                  contlocation="";
                  System.out.println("contlocation :"+contlocation);

                  contfirst_street=address[0];
                  System.out.println("contfirst_street :"+contfirst_street);

                  contsecond_street=address[1];
                  System.out.println("contsecond_street :"+contsecond_street);

                  contcity=address[2];
                  System.out.println("contcity :"+contcity);

                  contstate=address[3];
                  System.out.println("contstate :"+contstate);

                  contzipcode=address[4];
                  System.out.println("contzipcode :"+contzipcode);

                  contcountry=address[5];
                  System.out.println("contcountry :"+contcountry);

                  System.out.println("\n-------------address.length==6--------------------");
              }
              else if(address.length==5)
              {
                  System.out.println("\n-------------address.length==5--------------------");

                  contlocation="";
                  System.out.println("contlocation :"+contlocation);

                  contfirst_street=address[0];
                  System.out.println("contfirst_street :"+contfirst_street);

                  contsecond_street="";
                  System.out.println("contsecond_street :"+contsecond_street);

                  contcity=address[1];
                  System.out.println("contcity :"+contcity);

                  contstate=address[2];
                  System.out.println("contstate :"+contstate);

                  contzipcode=address[3];
                  System.out.println("contzipcode :"+contzipcode);

                  contcountry=address[4];
                  System.out.println("contcountry :"+contcountry);

                  System.out.println("\n-------------address.length==5--------------------");
              }

              else if(address.length==4)
              {
                  System.out.println("\n-------------address.length==4--------------------");

                  contlocation="";
                  System.out.println("contlocation :"+contlocation);

                  contfirst_street=address[0];
                  System.out.println("contfirst_street :"+contfirst_street);

                  contsecond_street="";
                  System.out.println("contsecond_street :"+contsecond_street);

                  contcity=address[1];
                  System.out.println("contcity :"+contcity);

                  contstate=address[2];
                  System.out.println("contstate :"+contstate);

                  contzipcode="";
                  System.out.println("contzipcode :"+contzipcode);

                  contcountry=address[3];
                  System.out.println("contcountry :"+contcountry);

                  System.out.println("\n-------------address.length==4--------------------");
              }

              else if(address.length==3)
              {
                  System.out.println("\n-------------address.length==3--------------------");

                  contlocation="";
                  System.out.println("contlocation :"+contlocation);

                  contfirst_street=address[0];
                  System.out.println("contfirst_street :"+contfirst_street);

                  contsecond_street="";
                  System.out.println("contsecond_street :"+contsecond_street);

                  contcity=address[1];
                  System.out.println("contcity :"+contcity);

                  contstate="";
                  System.out.println("contstate :"+contstate);

                  contzipcode="";
                  System.out.println("contzipcode :"+contzipcode);

                  contcountry=address[2];
                  System.out.println("contcountry :"+contcountry);

                  System.out.println("\n-------------address.length==3--------------------");
              }

                         // System.out.println(st.nextToken(""));
        //}  


    }
    }

这是错误： -

> 06-23 11:12:59.931:
> ERROR/AndroidRuntime(794): FATAL
> EXCEPTION: main 06-23 11:12:59.931:
> ERROR/AndroidRuntime(794):
> java.lang.RuntimeException: Unable to
> start activity
> ComponentInfo{com.test/com.test.Test}:
> java.util.NoSuchElementException 06-23
> 11:12:59.931:
> ERROR/AndroidRuntime(794):     at
> android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
> 06-23 11:12:59.931:
> ERROR/AndroidRuntime(794):     at
> android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
> 06-23 11:12:59.931:
> ERROR/AndroidRuntime(794):     at
> android.app.ActivityThread.access$2300(ActivityThread.java:125)
> 06-23 11:12:59.931:
> ERROR/AndroidRuntime(794):     at
> android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
> 06-23 11:12:59.931:
> ERROR/AndroidRuntime(794):     at
> android.os.Handler.dispatchMessage(Handler.java:99)
> 06-23 11:12:59.931:
> ERROR/AndroidRuntime(794):     at
> android.os.Looper.loop(Looper.java:123)
> 06-23 11:12:59.931:
> ERROR/AndroidRuntime(794):     at
> android.app.ActivityThread.main(ActivityThread.java:4627)
> 06-23 11:12:59.931:
> ERROR/AndroidRuntime(794):     at
> java.lang.reflect.Method.invokeNative(Native
> Method) 06-23 11:12:59.931:
> ERROR/AndroidRuntime(794):     at
> java.lang.reflect.Method.invoke(Method.java:521)
> 06-23 11:12:59.931:
> ERROR/AndroidRuntime(794):     at
> com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
> 06-23 11:12:59.931:
> ERROR/AndroidRuntime(794):     at
> com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
> 06-23 11:12:59.931:
> ERROR/AndroidRuntime(794):     at
> dalvik.system.NativeStart.main(Native
> Method) 06-23 11:12:59.931:
> ERROR/AndroidRuntime(794): Caused by:
> java.util.NoSuchElementException 06-23
> 11:12:59.931:
> ERROR/AndroidRuntime(794):     at
> java.util.StringTokenizer.nextToken(StringTokenizer.java:272)
> 06-23 11:12:59.931:
> ERROR/AndroidRuntime(794):     at
> java.util.StringTokenizer.nextToken(StringTokenizer.java:287)
> 06-23 11:12:59.931:
> ERROR/AndroidRuntime(794):     at
> com.test.Test.onCreate(Test.java:34)
> 06-23 11:12:59.931:
> ERROR/AndroidRuntime(794):     at
> android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
> 06-23 11:12:59.931:
> ERROR/AndroidRuntime(794):     at
> android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)

Answer 1

我不确定您期望发生什么：如果有六个令牌，您只能拨打nextToken()六次。这就是StringTokenizer的工作原理。您可以使用countTokens()查看有多少令牌，也可以使用hasMoreTokens()检查下一次调用nextToken()是否会引发异常。

Answer 2

for循环中的语句正在执行7次，但StringTokenizer只包含6个字符串。尝试用以下代码替换for循环：

int i=0;
while(st.hasMoreTokens()) {
address[i] = st.nextToken(",");
System.out.println("address "+i+": "+address[i]);   
i++; 
}

Answer 3

使用StringTokenizer st = new StringTokenizer("koch, Ranchi, zalkhand, NY, 10001, India", ",");创建字符串标记生成器。 我现在修改了你的代码它的工作正常。

使用以下代码

import java.util.StringTokenizer;

import android.app.Activity;
import android.os.Bundle;

    public class Test extends Activity {
        /** Called when the activity is first created. */
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.main);


    StringTokenizer st = new StringTokenizer("koch, Ranchi, zalkhand, NY, 10001, India", ","); 
            int numberOfToken = st.countTokens();
            System.out.println("Tokens are seperated");
            int i=0;
            String address[] = new String[numberOfToken];

             String contlocation="";
             String contfirst_street="";
             String contsecond_street="";
             String contcity="";
             String contstate="";
             String contzipcode="";
             String contcountry="";


          /*  while(st.hasMoreTokens())
            {

              */      

                  for(i=0;i<numberOfToken;i++)
                  {
                        address[i] = st.nextToken();
                       System.out.println("address "+i+": "+address[i]);
                  }

                  if(numberOfToken==7)
                  {

                      System.out.println("\n-------------address.length==7--------------------");

                      contlocation=address[0];
                      System.out.println("contlocation :"+contlocation);

                      contfirst_street=address[1];
                      System.out.println("contfirst_street :"+contfirst_street);

                      contsecond_street=address[2];
                      System.out.println("contsecond_street :"+contsecond_street);

                      contcity=address[3];
                      System.out.println("contcity :"+contcity);

                      contstate=address[4];
                      System.out.println("contstate :"+contstate);

                      contzipcode=address[5];
                      System.out.println("contzipcode :"+contzipcode);

                      contcountry=address[6];
                      System.out.println("contcountry :"+contcountry);

                      System.out.println("\n-------------address.length==7--------------------");
                  }
                  else if(numberOfToken==6)
                  {
                      System.out.println("\n-------------address.length==6--------------------");

                      contlocation="";
                      System.out.println("contlocation :"+contlocation);

                      contfirst_street=address[0];
                      System.out.println("contfirst_street :"+contfirst_street);

                      contsecond_street=address[1];
                      System.out.println("contsecond_street :"+contsecond_street);

                      contcity=address[2];
                      System.out.println("contcity :"+contcity);

                      contstate=address[3];
                      System.out.println("contstate :"+contstate);

                      contzipcode=address[4];
                      System.out.println("contzipcode :"+contzipcode);

                      contcountry=address[5];
                      System.out.println("contcountry :"+contcountry);

                      System.out.println("\n-------------address.length==6--------------------");
                  }
                  else if(numberOfToken==5)
                  {
                      System.out.println("\n-------------address.length==5--------------------");

                      contlocation="";
                      System.out.println("contlocation :"+contlocation);

                      contfirst_street=address[0];
                      System.out.println("contfirst_street :"+contfirst_street);

                      contsecond_street="";
                      System.out.println("contsecond_street :"+contsecond_street);

                      contcity=address[1];
                      System.out.println("contcity :"+contcity);

                      contstate=address[2];
                      System.out.println("contstate :"+contstate);

                      contzipcode=address[3];
                      System.out.println("contzipcode :"+contzipcode);

                      contcountry=address[4];
                      System.out.println("contcountry :"+contcountry);

                      System.out.println("\n-------------address.length==5--------------------");
                  }

                  else if(numberOfToken==4)
                  {
                      System.out.println("\n-------------address.length==4--------------------");

                      contlocation="";
                      System.out.println("contlocation :"+contlocation);

                      contfirst_street=address[0];
                      System.out.println("contfirst_street :"+contfirst_street);

                      contsecond_street="";
                      System.out.println("contsecond_street :"+contsecond_street);

                      contcity=address[1];
                      System.out.println("contcity :"+contcity);

                      contstate=address[2];
                      System.out.println("contstate :"+contstate);

                      contzipcode="";
                      System.out.println("contzipcode :"+contzipcode);

                      contcountry=address[3];
                      System.out.println("contcountry :"+contcountry);

                      System.out.println("\n-------------address.length==4--------------------");
                  }

                  else if(numberOfToken==3)
                  {
                      System.out.println("\n-------------address.length==3--------------------");

                      contlocation="";
                      System.out.println("contlocation :"+contlocation);

                      contfirst_street=address[0];
                      System.out.println("contfirst_street :"+contfirst_street);

                      contsecond_street="";
                      System.out.println("contsecond_street :"+contsecond_street);

                      contcity=address[1];
                      System.out.println("contcity :"+contcity);

                      contstate="";
                      System.out.println("contstate :"+contstate);

                      contzipcode="";
                      System.out.println("contzipcode :"+contzipcode);

                      contcountry=address[2];
                      System.out.println("contcountry :"+contcountry);

                      System.out.println("\n-------------address.length==3--------------------");
                  }
    }
        }