java - 在if语句中解析日期并仅显示规定时间范围内的结果

Question

目前我正在编写一个 java 程序来找出在哪一天 Hammer或其他Candlestick pattern形成。

用户在执行程序时必须输入 2 个日期作为参数，例如java ReadingTest 2016-09-03 2016-10-31，程序会在 2016-09-03 到 2016-10-31 期间寻找 Hammer 模式。

代码如下:

import java.io.*;
import java.util.*;
import java.text.*;

public class ReadingTest
{
    public static void main(String[] args) throws IOException,ParseException
    {
    //Import file to java
    File file = new file("table.csv");

    //Read the file
    Scanner infile = new Scanner(file);

    //Skip the first line in table.csv
    infile.nextLine();

    //Define format of date
    SImpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");

    //Name the variables user enters
    Date start = sdf.parse(args[0]);
    Date end = sdf.parse(args[1]);

    //Create ArrayList for each column of data
    ArrayList<String> date = new ArrayList<String>();
    ArrayList<Double> open = new ArrayList<Double>();
    ArrayList<Double> high = new ArrayList<Double>();
    ArrayList<Double> low = new ArrayList<Double>();
    ArrayList<Double> close = new ArrayList<Double>();

    while (infile.hasNext())
    {
        //Tokenize columns by comma
        String[] data = infile.nextLine().split(",");
        //Organize each column of data to one index of data array
        date.add(data[0]);
        open.add(Double.parseDouble(data[1]));
        high.add(Double.parseDouble(data[2]));
        low.add(Double.parseDouble(data[3]));
        close.add(Double.parseDouble(data[4]));
    }
    //Show options and ask user to choose
    System.out.println("1. Hammer");
    System.out.println("2. Three white soldiers");
    System.out.println("3. Bullish kicker");

    //Record user input and execute corresponding code
    Scanner input = new Scanner(System.in);
    int choice = input.nextInt();

    if (choice == 1)
        for (int i = 0; i < date.size(); i++)
            if (close.get(i) > open.get(i) &&
                close.get(i) > ((high.get(i)) + (low.get(i)))/2 &&
                ((close.get(i) - low.get(i))/2 > (high.get(i) - close.get(i)))
            System.out.println("Pattern found: " + date.get(i));
}
}

代码到这里为止都可以正常工作。但是，最后一行代码的输出是 dd/MM/yyyy 格式，我尝试使用 sdf.parse(date.get(i)) 而不是 date.get(i) 以 yyyy-MM 显示结果-dd 格式。使用 sdf.parse(date.get(i)) 运行代码会返回以下错误:

Exception in thread "main" java.text.ParseException: Unparseable date: 
"25/10/2016" at 
java.text.DateFormat.parse(Unknown source) at ReadingTest.main(ReadingTest.java:59)

我还尝试只显示显示 Hammer 的日期使用:

(date.get(i).after(start) && date.get(i).before(end))

结果是

error: cannot find symbol
symbol: method before(Date)
location: class String

CSV 文件如下所示:

Date       Open  High  Low  Close  
31/10/2016 58.25 58.65 58.2 58.35
28/10/2016 58.95 59    58.3 58.35
.
.
.
1/8/2016   50.8  51.1 50.75  50.8

应该如何修改代码以使其工作？

Answer 1

我猜你想要的是这个

SimpleDateFormat hammerFormat = new SimpleDateFormat("yyyy-MM-dd");
SimpleDateFormat slashFormat = new SimpleDateFormat("dd/MM/yyyy");

因此您可以像这样将日期解析为 yyyy-MM-dd 表示形式

hammerFormat.format(slashFormat.parse(date.get(i))));

完整代码

import java.io.File;
import java.io.IOException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.Scanner;

public class ReadingTest {
    public static void main(String[] args) throws IOException, ParseException {
        // Import file to java
        File file = new File("table.csv");

        // Read the file
        Scanner infile = new Scanner(file);

        // Skip the first line in table.csv
        infile.nextLine();

        // Define format of date
        SimpleDateFormat hammerFormat = new SimpleDateFormat("yyyy-MM-dd");
        SimpleDateFormat slashFormat = new SimpleDateFormat("dd/MM/yyyy");

        // Name the variables user enters
        Date start = hammerFormat.parse(args[0]);
        Date end = hammerFormat.parse(args[1]);

        // Create ArrayList for each column of data
        ArrayList < String > date = new ArrayList < String > ();
        ArrayList < Double > open = new ArrayList < Double > ();
        ArrayList < Double > high = new ArrayList < Double > ();
        ArrayList < Double > low = new ArrayList < Double > ();
        ArrayList < Double > close = new ArrayList < Double > ();

        while (infile.hasNext()) {
            // Tokenize columns by comma
            String[] data = infile.nextLine().split(",");
            // Organize each column of data to one index of data array
            date.add(data[0]);
            open.add(Double.parseDouble(data[1]));
            high.add(Double.parseDouble(data[2]));
            low.add(Double.parseDouble(data[3]));
            close.add(Double.parseDouble(data[4]));
        }
        // Show options and ask user to choose
        System.out.println("1. Hammer");
        System.out.println("2. Three white soldiers");
        System.out.println("3. Bullish kicker");

        // Record user input and execute corresponding code
        Scanner input = new Scanner(System.in);
        int choice = input.nextInt();

        if (choice == 1)
            for (int i = 0; i < date.size(); i++)
                if (close.get(i) > open.get(i) && close.get(i) > ((high.get(i)) + (low.get(i))) / 2 && ((close.get(i) - low.get(i)) / 2 > (high.get(i) - close.get(i))))
                    System.out.println("Pattern found: " + hammerFormat.format(slashFormat.parse(date.get(i))));
    }
}

编辑:

像这样的 .csv 文件格式(因为在代码中它说 .split(","))

31/10/2016, 58.25, 58.65, 58.20, 58.35
28/10/2016, 58.95, 59.00, 58.30, 58.35
01/08/2016, 50.80, 51.10, 50.75, 50.80

它对我来说很好用。我在执行程序时传递了两个参数2016-09-03 2016-10-31。