重构“裸奔”代码

w7/ScoreAvg.java

@@ -0,0 +1,58 @@
+import java.io.BufferedReader;
+import java.io.FileReader;
+import java.io.IOException;
+
+public class ScoreAvg {
+    public static void main(String[] args) {
+        String fileName = "scores.txt";
+        BufferedReader br = null;
+        int sum = 0;
+        int count = 0;
+
+        // ========================
+        // 题目要求：try catch finally
+        // ========================
+        try {
+            // 1. 打开文件
+            br = new BufferedReader(new FileReader(fileName));
+
+            // 2. 读取每一行
+            String line;
+            while ((line = br.readLine()) != null) {
+                line = line.trim();
+                if (line.isEmpty()) continue;
+
+                try {
+                    int score = Integer.parseInt(line);
+                    sum += score;
+                    count++;
+                } catch (NumberFormatException e) {
+                    System.out.println("格式错误：" + line);
+                }
+            }
+
+            // 3. 输出结果
+            System.out.println("总分：" + sum);
+            System.out.println("平均分：" + (double) sum / count);
+
+        } catch (IOException e) {
+            // 异常处理
+            System.out.println("文件操作失败！");
+            e.printStackTrace();
+
+        } finally {
+            // ========================
+            // finally：必须执行，关闭流！
+            // 题目要求必须写这里！
+            // ========================
+            try {
+                if (br != null) {
+                    br.close();
+                    System.out.println("流已关闭！");
+                }
+            } catch (IOException e) {
+                System.out.println("关闭失败！");
+            }
+        }
+    }
+}

w7/scores

@@ -0,0 +1,4 @@
+90
+85
+95
+88