在Java中向服务器请求表

2019年7月22日 279次阅读

我想问这个服务器的表,但我不知道该怎么做.基本上我试图让
Eclipse程序在运行程序时打印出类似的内容：

<tr><td>
 <pre>

                       <b>2011 Phases of the Moon</b>
                            Universal Time

        New Moon   First Quarter       Full Moon    Last Quarter   

         d  h  m         d  h  m         d  h  m         d  h  m

    Jan  4  9 03    Jan 12 11 31    Jan 19 21 21    Jan 26 12 57
    Feb  3  2 31    Feb 11  7 18    Feb 18  8 36    Feb 24 23 26
    Mar  4 20 46    Mar 12 23 45    Mar 19 18 10    Mar 26 12 07
    Apr  3 14 32    Apr 11 12 05    Apr 18  2 44    Apr 25  2 47
    May  3  6 51    May 10 20 33    May 17 11 09    May 24 18 52
    Jun  1 21 03    Jun  9  2 11    Jun 15 20 14    Jun 23 11 48
    Jul  1  8 54    Jul  8  6 29    Jul 15  6 40    Jul 23  5 02
    Jul 30 18 40    Aug  6 11 08    Aug 13 18 57    Aug 21 21 54
    Aug 29  3 04    Sep  4 17 39    Sep 12  9 27    Sep 20 13 39
    Sep 27 11 09    Oct  4  3 15    Oct 12  2 06    Oct 20  3 30
    Oct 26 19 56    Nov  2 16 38    Nov 10 20 16    Nov 18 15 09
    Nov 25  6 10    Dec  2  9 52    Dec 10 14 36    Dec 18  0 48
    Dec 24 18 06                                               
 </pre>
 </td></tr>

这是我到目前为止：

import java.util.Scanner;
import java.io.*;
import java.net.*;
/**
   This program shows the moon phase table for the given year
*/
public class MoonPhaseTable
{  
    public static void main(String[] args) throws IOException
    {  
        Scanner in = new Scanner(System.in); //read year number from user
        System.out.print("Please enter the year (e.g. 1977): ");
        int year = in.nextInt();

        // Build the URL string and open a URLConnection
        // Be sure to set the year on the URL string!!!
        URL moonphase = new URL("http://aa.usno.navy.mil/cgi-bin/aa_moonphases.pl?year=2015/");
        URLConnection mp = moonphase.openConnection();      

        // Get the connection's input stream, and make a Scanner for it
        BufferedReader r = new BufferedReader(new InputStreamReader(mp.getInputStream()));

        Scanner s = new Scanner(moonphase.openStream());

        String inputLine;

        boolean printingTable = false;
        while ((inputLine = r.readLine()) !=null) {
                 // Read input lines from the scanner into the String named line.

             if (printingTable) {     
                 // Check if the line contains the </table> end tag -- if seen, turn off printing
                 System.out.print("CONTAINS </table>");
                 s.close(); 
             }
             if (printingTable) {
                 // If inside the Table, print the line.
                 // Optionally clean up any unwanted tags, such as
                 // <pre>, <tr>, <td>, <b> before printing.
                 System.out.print(inputLine);

             }
             if (!printingTable) {
                 // Check if the line contains the <table ...> start tag -- if seen, turn on printing
                 System.out.print(inputLine);
             }
           }
        }

    }

现在,它打印整个源代码..我只想要如上所示的代码.我知道我没有检查该行是否正确表格块,但我不知道该怎么做.如果有人有任何建议,将不胜感激.我想我必须向aa.usno.navy.mil服务器询问月球表,但又一次……我迷路了.

最佳答案 在循环内部,您需要根据您收集的输入中的匹配来计算printingTable.

这样的东西可能有助于计算printingTable：

printingTable = inputLine.contains("table");

这非常粗糙,但对于这种情况可能会运作良好.

现在,如果printingTable为true或false,则代码为打印行,并且不会从其初始值false更新printingTable.

或者,有一些非常好的HTML HTML5解析库,如Validator.nu HTML Parser：
https://about.validator.nu/htmlparser/

它提供SAX,DOM和其他解析模式. DOM可能是最好的,因为您可以轻松地获取表格的整个子树,并逐个选择元素.

我已经用它来在工作中对相当混乱的数据源进行Web挖掘,这使得它更易于管理.我会请求允许发布我在2011年写回的网络指南.

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