java - NumberformatException JFreeChart

Question

输入文件(内容):

8dict, 3
9GAG, 2
RT, 7
The, 2
awkward, 2
co, 14
http, 11
https, 3
irrfan_k, 2
is, 2
my, 3
rainymornings, 3
t, 14
the, 2
this, 2
you, 3

我的代码是:

package pck;

import java.io.*; 
import java.util.StringTokenizer; 
import org.jfree.chart.ChartUtilities; 
import org.jfree.chart.ChartFactory; 
import org.jfree.chart.JFreeChart; 
import org.jfree.data.general.DefaultPieDataset;

public class PieChart_File 
{
   public static void main( String[ ] args )throws Exception
   {
      String mobilebrands[ ] = {    
        "8dict" ,   
        "9GAGs" ,   
        "RT" ,    
        "The" ,
        "awkward",
        "co",
        "http",
        "https",
        "irrfan_k",
        "is",
        "my",
        "rainymornings",
        "t",
        "the",
        "this",
        "you"
      };

      InputStream in = new FileInputStream( new File( "C:/temp/test.txt" ) );          
      BufferedReader reader = new BufferedReader(new InputStreamReader(in ) );          
      StringBuilder out = new StringBuilder();          
      String line;          
      DefaultPieDataset dataset = new DefaultPieDataset();          

      while (( line = reader.readLine() ) != null ) 
      {
         out.append( line );
      }
      StringTokenizer s = new StringTokenizer( out.toString(), "," );
      int i=0;      
      while( s.hasMoreTokens( ) && ( mobilebrands [i] != null ) )
      {

          dataset.setValue(mobilebrands[i], Double.parseDouble( s.nextToken( ) ));
         i++;
      }
      JFreeChart chart = ChartFactory.createPieChart( 
         "Repeated words",  // chart title           
         dataset,         // data           
         true,            // include legend           
         true,           
         false);

      int width = 560; /* Width of the image */          
      int height = 370; /* Height of the image */                          
      File pieChart = new File( "pie_Chart.jpeg" );                        
      ChartUtilities.saveChartAsJPEG( pieChart, chart, width, height); 
   }
}

当我尝试运行该文件时出现以下错误:

Exception in thread "main" java.lang.NumberFormatException: For input string: "8dict"
    at sun.misc.FloatingDecimal.readJavaFormatString(Unknown Source)
    at sun.misc.FloatingDecimal.parseDouble(Unknown Source)
    at java.lang.Double.parseDouble(Unknown Source)
    at pck.PieChart_File.main(PieChart_File.java:48)

所有文件均已正确导入，仅出现此错误。输入文件路径也正确。 请帮忙。

Answer 1

你试图将一个字符串解析为一个数值，但字符串当然无法解析，如果你解析它，“8dict”的值是多少？

您应该尝试仅解析每个字符串的第一个数值。

<小时/>

使用正则表达式的解决方案

替换

dataset.setValue(mobilebrands[i], Double.parseDouble( s.nextToken( ) ));

与

Pattern p = Pattern.compile("\\d*"); // Finds the digits in a given String
Matcher m = p.matcher(s.nextToken());
m.find();
dataset.setValue(mobilebrands[i], Double.parseDouble(m.group(0)));