W7

W7/ScoreAverage.java

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+import java.io.BufferedReader;
+import java.io.FileReader;
+import java.io.IOException;
+
+public class ScoreAverage {
+    public static void main(String[] args) {
+        String fileName = "scores.txt";
+        int sum = 0;
+        int count = 0;
+
+        // 1. 使用 try-with-resources 自动关闭流，确保资源释放
+        try (BufferedReader br = new BufferedReader(new FileReader(fileName))) {
+            String line;
+
+            // 2. 逐行读取文件
+            while ((line = br.readLine()) != null) {
+                // 跳过空行，避免 NumberFormatException
+                line = line.trim();
+                if (line.isEmpty()) {
+                    continue;
+                }
+
+                try {
+                    // 3. 转换为整数并累加
+                    int score = Integer.parseInt(line);
+                    sum += score;
+                    count++;
+                } catch (NumberFormatException e) {
+                    // 处理数字格式错误
+                    System.err.println("警告：无法将内容 '" + line + "' 转换为整数，已跳过。");
+                }
+            }
+
+            // 4. 计算并输出平均分
+            if (count > 0) {
+                double average = (double) sum / count;
+                System.out.println("成绩文件读取完成。");
+                System.out.println("总分：" + sum);
+                System.out.println("人数：" + count);
+                System.out.printf("平均分：%.2f%n", average);
+            } else {
+                System.out.println("文件中没有有效的成绩数据。");
+            }
+
+        } catch (IOException e) {
+            // 处理文件不存在、读取错误等IO异常
+            System.err.println("读取文件时发生错误：" + e.getMessage());
+            e.printStackTrace();
+        }
+    }
+}