Question

我正在寻找一些从excel文件中读取内容的帮助。这是代码，我希望它从.csv文件中读取生成相同的结果。

我的错误显示

java.lang.NumberFormatException: For input string: "companycode"
    at sun.misc.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:2043)
    at sun.misc.FloatingDecimal.parseDouble(FloatingDecimal.java:110)
    at java.lang.Double.parseDouble(Double.java:538)
    at java.lang.Double.valueOf(Double.java:502)
    at testgbt.TestGBT.main(TestGBT.java:40)

请提前帮助和谢谢!!

package testgbt;

import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileWriter;
import java.io.InputStreamReader;
import java.util.Vector;
import java.io.FileOutputStream;

import testgbt.BoostingTree;
import testgbt.BoostingTree.ResultFunction;

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

                String data_name = "C:\\Mihir\\NetBeans\\TestGBT\\data.csv"; 

        Vector<Vector<Double>> x = new Vector<Vector<Double>>();
        Vector<Double>         y = new Vector<Double>();

        try {

                        FileInputStream fis = new FileInputStream("C:\\Mihir\\NetBeans\\TestGBT\\data.csv");

            // -------- load data from the file -------------
            // get object of data input stream
            BufferedReader  b_reader = new BufferedReader(new 
                                InputStreamReader(new FileInputStream(data_name))); // buffer

            String read_line;
            while ((read_line = b_reader.readLine()) != null) {

                String[] str_list = read_line.trim().split(",");

                Vector<Double> buffer_x = new Vector<Double>();
                buffer_x.add(Double.valueOf(str_list[0]));
                x.add(buffer_x);                
                y.add(Double.valueOf(str_list[1]));
            }
            b_reader.close();

            // --------- learn a function of y=f(x) -------
            BoostingTree gbt_ranker = new BoostingTree();
            ResultFunction res_fun = gbt_ranker.gradient_boosting_tree(x, y);

            // --------- save the curve fitting result y=f(x) ------
            FileWriter file_writer = new FileWriter("C:\\Mihir\\NetBeans\\TestGBT\\result.txt");
                        FileOutputStream fos=new FileOutputStream("C:\\Mihir\\NetBeans\\TestGBT\\result.csv");

            for (int i = 0; i < x.size(); i ++) {
                file_writer.append(String.format("%f,%f,%f\n",
                        x.get(i).get(0),
                        res_fun.get_value(x.get(i)),
                        y.get(i)));
            }

            file_writer.close();

        } catch (Exception err) {
            err.printStackTrace();
            System.exit(0);
        }

    }
}

Answer 1

您的输入CSV是否有标题行？从输入数据中删除标题行或更改代码以跳过第一行。

您可以通过更改此行轻松跳过第一行：

String read_line;

到此：

String read_line = b_reader.readLine();

Answer 2

看起来str_list [1]不是您要查找的数据。事实上，您似乎正在尝试将一个列标题转换为双精度。您可能只需要跳过标题。

读取excel文件的内容

2 个答案: