waluty - wersja DOM

src/main/java/p20_xml/Waluty1_Dom.java

+package p20_xml;
+
+import org.w3c.dom.Document;
+import org.w3c.dom.Element;
+import org.w3c.dom.Node;
+import org.w3c.dom.NodeList;
+
+import javax.xml.parsers.DocumentBuilder;
+import javax.xml.parsers.DocumentBuilderFactory;
+import java.io.File;
+
+public class Waluty1_Dom {
+    public static void main(String[] args) {
+        File plik = new File("pliki/waluty2023.xml");
+        String waluta = "EUR";
+
+        System.out.println("Startujemy");
+        long t1 = System.nanoTime();
+        try {
+            DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
+            DocumentBuilder builder = dbf.newDocumentBuilder();
+            Document doc = builder.parse(plik);
+            long t2 = System.nanoTime();
+
+            double min = Double.MAX_VALUE, max = 0, sum = 0;
+            int count = 0;
+
+            NodeList tables = doc.getElementsByTagName("ExchangeRatesTable");
+            final int n = tables.getLength();
+            for(int i = 0; i < n; i++) {
+                Element table = (Element) tables.item(i);
+                // ryzyko NPE, gdyby plik był niepoprawny:
+                String effectiveDate = table.getElementsByTagName("EffectiveDate").item(0).getTextContent();
+                // System.out.println(effectiveDate);
+                NodeList rates = table.getElementsByTagName("Rate");
+                final int m = rates.getLength();
+                for(int j = 0; j < m; j++) {
+                    Element rate = (Element) rates.item(j);
+                    String code = rate.getElementsByTagName("Code").item(0).getTextContent();
+                    if(code.equals(waluta)) {
+                        double mid = Double.parseDouble(rate.getElementsByTagName("Mid").item(0).getTextContent());
+                        count++;
+                        sum += mid;
+                        if(mid < min) min = mid;
+                        if(mid > max) max = mid;
+                    }
+                }
+            }
+            long t3 = System.nanoTime();
+            Runtime runtime = Runtime.getRuntime();
+            long pamiec = runtime.totalMemory() - runtime.freeMemory();
+
+            System.out.printf("Czas czytania pliku: %.6f s%n", (t2-t1) * 1e-9);
+            System.out.printf("Czas liczenia      : %.6f s%n", (t3-t2) * 1e-9);
+            System.out.printf("Czas łączny        : %.6f s%n", (t3-t1) * 1e-9);
+            System.out.printf("Zajęta pamięć      : %,d B%n", pamiec);
+            System.out.println("Count: " + count);
+            if(count > 0) {
+                System.out.println("Avg: " + (sum / count));
+                System.out.println("Min: " + min);
+                System.out.println("Max: " + max);
+            }
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+}