The application scenario of the HTMLPARSER framework in the development of Java
The HTMLPARSER framework is a powerful tool for Java development that can analyze and process HTML documents.It provides a series of APIs and features that can easily extract the required data from HTML and further process and analyze it.Here are some common application scenarios and examples of the HTMLPARSER framework in Java development.
1. Internet crawler
HTMLPARSER can be used to build network crawlers and grab the required data from the webpage.For example, suppose we need to obtain the company name and recruitment position from a recruitment website. You can use HTMLPARSER to resolve the HTML code of the webpage and extract the required information.
import org.htmlparser.Parser;
import org.htmlparser.filters.HasAttributeFilter;
import org.htmlparser.util.NodeList;
import org.htmlparser.util.ParserException;
import org.htmlparser.util.Translate;
public class WebCrawler {
public static void main(String[] args) {
try {
String url = "https://example.com";
Parser parser = new Parser(url);
HasAttributeFilter filter = new HasAttributeFilter("class", "job-title");
NodeList nodeList = parser.extractAllNodesThatMatch(filter);
for (int i = 0; i < nodeList.size(); i++) {
String companyName = Translate.decode(nodeList.elementAt(i).toPlainTextString());
System.out.println("Company: " + companyName);
}
} catch (ParserException e) {
e.printStackTrace();
}
}
}
2. Data extraction and conversion
HTMLPARSER can be used to extract data from the HTML document and convert it into other formats.For example, suppose we have a HTML file containing table data. We can use HTMLPARSER to analyze the file and convert the table data to CSV format.
import org.htmlparser.Parser;
import org.htmlparser.filters.TagNameFilter;
import org.htmlparser.util.NodeList;
import org.htmlparser.util.ParserException;
import java.io.FileWriter;
import java.io.IOException;
public class HtmlToCsvConverter {
public static void main(String[] args) {
try {
String html = "<table><tr><th>Name</th><th>Age</th></tr><tr><td>John</td><td>25</td></tr><tr><td>Emily</td><td>30</td></tr></table>";
Parser parser = new Parser(html);
TagNameFilter tableFilter = new TagNameFilter("table");
NodeList tableNodes = parser.extractAllNodesThatMatch(tableFilter);
NodeList rowNodes = tableNodes.elementAt(0).getChildren().extractAllNodesThatMatch(new TagNameFilter("tr"), true);
FileWriter csvWriter = new FileWriter("output.csv");
for (int i = 0; i < rowNodes.size(); i++) {
NodeList cellNodes = rowNodes.elementAt(i).getChildren().extractAllNodesThatMatch(new TagNameFilter("td"));
StringBuilder line = new StringBuilder();
for (int j = 0; j < cellNodes.size(); j++) {
line.append(cellNodes.elementAt(j).toPlainTextString());
if (j < cellNodes.size() - 1) {
line.append(",");
}
}
csvWriter.write(line.toString());
csvWriter.write("
");
}
csvWriter.close();
} catch (ParserException | IOException e) {
e.printStackTrace();
}
}
}
3. Data analysis and processing
HTMLPARSER can be used to capture data from the webpage and further analyze and process it.For example, suppose we need to capture the title and summary of the news articles from the news website and perform emotional analysis. You can use HTMLPARSER to analyze the webpage and extract the relevant information of the article.
import org.htmlparser.Parser;
import org.htmlparser.filters.HasAttributeFilter;
import org.htmlparser.util.NodeList;
import org.htmlparser.util.ParserException;
import org.htmlparser.util.Translate;
import com.google.cloud.language.v1.Document;
import com.google.cloud.language.v1.Document.Type;
import com.google.cloud.language.v1.LanguageServiceClient;
import com.google.cloud.language.v1.Sentiment;
import com.google.cloud.language.v1.SentimentResult;
public class NewsAnalyzer {
public static void main(String[] args) {
try {
String url = "https://example.com/news";
Parser parser = new Parser(url);
HasAttributeFilter titleFilter = new HasAttributeFilter("class", "article-title");
NodeList titleNodeList = parser.extractAllNodesThatMatch(titleFilter);
HasAttributeFilter summaryFilter = new HasAttributeFilter("class", "article-summary");
NodeList summaryNodeList = parser.extractAllNodesThatMatch(summaryFilter);
for (int i = 0; i < titleNodeList.size(); i++) {
String title = Translate.decode(titleNodeList.elementAt(i).toPlainTextString());
String summary = Translate.decode(summaryNodeList.elementAt(i).toPlainTextString());
System.out.println("Title: " + title);
System.out.println("Summary: " + summary);
// Perform sentiment analysis
try (LanguageServiceClient language = LanguageServiceClient.create()) {
Document document = Document.newBuilder()
.setContent(summary)
.setType(Type.PLAIN_TEXT)
.build();
Sentiment sentiment = language.analyzeSentiment(document).getDocumentSentiment();
SentimentResult sentimentResult = language.analyzeSentiment(document);
System.out.printf("Sentiment: %s, Score: %s%n", sentimentResult.getSentences(0).getSentiment().getScore(), sentimentResult.getSentences(0).getSentiment().getMagnitude());
}
}
} catch (ParserException | IOException e) {
e.printStackTrace();
}
}
}
The above are some common application scenarios and examples of the HTMLPARSER framework in Java development.The HTMLPARSER framework provides powerful functions, which can easily process and analyze HTML documents, and extract the required information from it so that developers can process and analyze web data more efficiently.
