該程序包含：樣條插值法、讀取文件，寫入文件，字符型轉double型方法等；

適合初學Java的人學習；

在cmd中執行，

在Linux中執行

完整代碼如下：

樣條插值法:

  1 import java.io.BufferedReader;
  2 import java.io.File;
  3 import java.io.FileInputStream;
  4 import java.io.FileNotFoundException;
  5 import java.io.FileWriter;
  6 import java.io.IOException;
  7 import
 
 java.io.InputStreamReader;
  8 import java.io.UnsupportedEncodingException;
  9 import java.util.ArrayList;
 10 import java.util.List;
 11 
 12 import org.apache.commons.lang3.StringUtils;
 13 import org.apache.commons.math3.analysis.interpolation.SplineInterpolator;
 14 import org.apache.commons.math3.analysis.polynomials.PolynomialSplineFunction;
 
 15 
 16 
 17 /**
 18  * 樣條插值法
 19  * @author 91911
 20  */
 21 public class SplineInterpolatorImpl {
 22     public static void main(String[] args){
 23 //        String[] source = new String[]{
 24 //                "0,1,2,3    0,1,1,0    2.5",
 25 //                "0,1,2,3    0,1,1,0    1.5"
 26 //        };
 27
 
         // 判斷傳入參數的長度，必須輸入兩個參數（輸入文件和輸出文件），否則報錯
 28         if (args.length != 2) {
 29             System.out.println("請輸入原文件和輸出文件的路徑！！");
 30             System.exit(0);
 31         }
 32         SplineInterpolatorImpl splineInterpolatorImpl = new SplineInterpolatorImpl();
 33         List<String> source = splineInterpolatorImpl.getFileContent(args[0]);
 34         File file = new File(args[1]);
 35 //        List<String> source = splineInterpolatorImpl.getFileContent("C:/Users/91911/Desktop/test.txt");
 36 //        File file = new File("C:/Users/91911/Desktop/result.txt");
 37         for(String s1:source) {
 38             String splited[] = s1.split("\t");
 39             double[] x = splineInterpolatorImpl.String2Double(splited[0]);
 40             double[] y = splineInterpolatorImpl.String2Double(splited[1]);
 41             double z = Double.parseDouble(splited[2]);
 42             double result = splineInterpolatorImpl.caculate(x, y, z);
 43             exportFile(s1+"\t"+result,file);
 44 //            System.out.println(splineInterpolatorImpl.caculate(x, y, z));
 45         }
 46     }
 47 
 48     // 讀取配置文檔
 49     public static List<String> getFileContent(String filepath) {
 50         List<String> list = new ArrayList<>();
 51         BufferedReader br;
 52         String rec;
 53         try {
 54             br = new BufferedReader(new InputStreamReader(new FileInputStream(new File(filepath)), "GBK"));
 55             while ((rec = br.readLine()) != null) {
 56                 if (StringUtils.isNotEmpty(rec.trim())) {
 57                     list.add(rec);
 58                 }
 59             }
 60             br.close();
 61         } catch (UnsupportedEncodingException e) {
 62             // TODO Auto-generated catch block
 63             System.out.println("轉碼出錯！");
 64             e.printStackTrace();
 65             return null;
 66         } catch (FileNotFoundException e) {
 67             // TODO Auto-generated catch block
 68             System.out.println("未找到配置文件 " + filepath + " ，請檢查該路徑是否正確！");
 69             e.printStackTrace();
 70             return null;
 71         } catch (IOException e) {
 72             // TODO Auto-generated catch block
 73             e.printStackTrace();
 74             return null;
 75         }
 76         return list;
 77     }
 78     
 79     //寫文件    
 80     public static void exportFile(String content,File file){                
 81         try {
 82             FileWriter out = new FileWriter(file,true);    
 83             out.write(content + "\r\n");
 84             out.flush();
 85             out.close();
 86         }catch (IOException e){
 87             System.out.println("！IO異常，寫文件異常");
 88         }    
 89     }
 90     //樣條計算法
 91     public double caculate(double[] x,double[] y, double z){
 92         SplineInterpolator sp = new SplineInterpolator();
 93         PolynomialSplineFunction f = sp.interpolate(x, y);
 94         return f.value(z);
 95     }
 96     
 97     //將字符型轉換為double型
 98     public static double[] String2Double(String str) {
 99         double[] d = { 1 };
100         if (str.contains(",")) {
101             String[] arr = str.split(",");
102             d = new double[arr.length];
103             for (int i = 0; i < arr.length; i++) {
104                 // System.out.println(arr[i]);
105                 d[i] = Double.valueOf(arr[i].trim());
106             }
107         }
108         return d;
109     }
110 }

樣條插值法（Java）