common programming operations

- convert html to txt (java)

content/Programming/Common Programming Operations.md

@@ -7,8 +7,9 @@ tags:
   - java
   - cpp
   - python
+  - programming
 Creation Date: 2024-12-14, 20:31
-Last Date: 2024-12-16T22:14:18+08:00
+Last Date: 2024-12-18T23:05:46+08:00
 References: 
 draft: 
 description: 
@@ -120,4 +121,40 @@ minHeap.push(5);
 minHeap.pop();
 // Return the smallest element from the heap
 minHeap.top().val;
-```
+```
+
+
+## Convert HTML to TXT
+---
+>[!important]
+> We don’t want to extract the content as a single string because this would result in losing all the formatting information provided by the HTML tags. Reformatting the content based on the document structure afterward is tedious, error-prone, and not scalable. 
+> 
+> Instead, the idea is to retain the formatting information we need before removing all the HTML tags. Then, we can use this retained formatting information to generate a text file with the desired formatting.
+
+
+```java title="Java"
+// Generate a placeholder string using UUID to avoid conflicts with the HTML content
+String uniquePlaceholder = UUID.randomUUID().toString();
+
+// This step retains line break information, which we will later replace with actual line breaks (\n)
+String htmlContent = rawHtml.replace("<br />", "<span>" + uniquePlaceholder + "</span>");
+
+// Parse the modified HTML content using Jsoup to extract plain text
+// Replace the placeholder with actual line breaks (\n) to simulate the original formatting
+String txtContent = Jsoup.parse(htmlContent).text().replace(uniquePlaceholder, "\n");
+
+// Create a FileWriter to write the plain text content to a file
+FileWriter writer = new FileWriter("output.txt");
+
+// Write the plain text content into the file
+writer.write(txtContent);
+
+writer.close();
+
+```
+
+>[!code]
+> This above code example assumes that `<br />` is the only tag used to denote line breaks in the given HTML string. If other tags or methods are used for formatting, additional handling may be required.
+> 
+>  Also note that, The `FileWriter writer` formats and writes the content into a text file, ensuring that line breaks are correctly represented using `\n`.
+