Question

我需要从网站中提取一些数据，然后在变量中保存一些值。

您已获得代码：

public class Principal {

 public static void main(String[] args) throws IOException {

    URL url = new URL("http://www.numbeo.com/cost-of-living/country_result.jsp?country=Turkey");
    URLConnection yc = url.openConnection();
    BufferedReader in = new BufferedReader(new InputStreamReader(yc.getInputStream()));
    String inputLine;
            String valor;
            String str = null;

    while ((inputLine = in.readLine()) != null) {
                    if(inputLine.contains("Milk"))
                    {
                         System.out.println("Encontrei! " + inputLine );
                         valor=inputLine.substring(inputLine.lastIndexOf("\"priceValue\">") + 14);
                         System.out.println("valor:" +valor);

                    }

            }
    in.close();
    }

  }

第一个输入行打印：<tr class="tr_standard"><td>Milk (regular), (1 liter) </td> <td style="text-align: right" class="priceValue"> 2.45 TL</td>

现在我必须提取"2.45"我该怎么做？我已经尝试了一些正则表达式，但无法使其正常工作。对不起我的英语不好。提前谢谢。

Answer 1

您可以尝试以下正则表达式：

(?:class="priceValue">\s*)(\d*\.\d+)

它会查找class="priceValue"字符串后跟价格

以下是DEMO和explanation

Answer 2

我知道你要求正则表达式，但是考虑通过解析HTML来使你的生活更轻松，好像它是一个结构化的XML文档，而不是一个普通的字符串。有些库可以为您处理此问题，并且可以避免担心文本格式，法律换行和其他内容：

<dependency>
    <groupId>org.jsoup</groupId>
    <artifactId>jsoup</artifactId>
    <version>1.7.1</version>
</dependency>

import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;

import java.io.IOException;

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

        Document doc;
        try {
            doc = Jsoup.connect("http://www.numbeo.com/cost-of-living/country_result.jsp?country=Turkey").get();
            Elements rows = doc.select("table.data_wide_table tr.tr_standard"); // CSS selector to find all table rows
            for (Element row : rows) {
                System.out.println("Item name: " + row.child(0).text()); // Milk will be here somewhere
                System.out.println("  Item price by column number: " + row.child(1).text());
                System.out.println("  Item price by column class:  " + row.getElementsByAttributeValue("class", "priceValue").get(0).text());
            }

        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

/**
 Output:
 Item name: Meal, Inexpensive Restaurant
   Item price by column number: 15.00 TL
   Item price by column class: 15.00 TL
 Item name: McMeal at McDonalds (or Equivalent Combo Meal)
  Item price by column number: 15.00 TL
  Item price by column class: 15.00 TL
...
*/

Java - 拆分字符串以获取十进制数

2 个答案: