Update ModifyUtils.java

src/util/ModifyUtils.java

@@ -1,76 +1,77 @@
-package util;
-
-import java.io.*;
-import java.util.ArrayList;
-import java.util.List;
-
-/**
- * Utility class to modify specific fields in user.txt.
- * 替换了 ModifyClass.java 和 ModifyPassword.java。
- */
-public class ModifyUtils {
-
-    private static List<String> readAllLines(String filePath, List<String> lines) throws IOException {
-        try (BufferedReader reader = new BufferedReader(new FileReader(filePath))) {
-            String line;
-            while ((line = reader.readLine()) != null) {
-                lines.add(line);
-            }
-        }
-        return lines;
-    }
-
-    private static void writeAllLines(String filePath, List<String> lines) throws IOException {
-        try (BufferedWriter writer = new BufferedWriter(new FileWriter(filePath))) {
-            for (String l : lines) {
-                writer.write(l + System.lineSeparator());
-            }
-        }
-    }
-
-    private static int findTargetLine(List<String> lines, String targetName) {
-        for (int i = 0; i < lines.size(); i++) {
-            String line = lines.get(i).trim();
-            if (line.isEmpty()) continue;
-
-            String[] parts = line.split("\\s+");
-            if (parts.length > 0 && parts[0].equals(targetName)) {
-                return i; // 0-based index
-            }
-        }
-        return -1;
-    }
-
-    // 核心逻辑：修改文件中特定用户的某个字段 (0-based)
-    public static int modifyFileField(String filePath, String targetName,
-                                      int fieldIndex, String newValue) {
-        List<String> lines = new ArrayList<>();
-        try {
-            readAllLines(filePath, lines);
-        } catch (IOException e) {
-            System.err.println("读取文件错误: " + e.getMessage());
-            return -1;
-        }
-
-        int idx = findTargetLine(lines, targetName);
-        if (idx == -1) {
-            return -1;
-        }
-
-        String[] parts = lines.get(idx).trim().split("\\s+");
-        if (parts.length > fieldIndex) {
-            parts[fieldIndex] = newValue;
-            lines.set(idx, String.join(" ", parts));
-            try {
-                writeAllLines(filePath, lines);
-                return idx + 1; // 返回 1-based 行号
-            } catch (IOException e) {
-                System.err.println("写入文件错误: " + e.getMessage());
-                return -1;
-            }
-        } else {
-            System.out.println("目标行元素不足。");
-            return -1;
-        }
-    }
+package util;
+
+import java.io.*;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Utility class to modify specific fields in user.txt.
+ * 替换了 ModifyClass.java 和 ModifyPassword.java。
+ */
+public class ModifyUtils {
+
+    private static List<String> readAllLines(String filePath, List<String> lines) throws IOException {
+        try (BufferedReader reader = new BufferedReader(new FileReader(filePath))) {
+            String line;
+            while ((line = reader.readLine()) != null) {
+                lines.add(line);
+            }
+        }
+        return lines;
+    }
+
+    private static void writeAllLines(String filePath, List<String> lines) throws IOException {
+        try (BufferedWriter writer = new BufferedWriter(new FileWriter(filePath))) {
+            for (String l : lines) {
+                writer.write(l + System.lineSeparator());
+            }
+        }
+    }
+
+    private static int findTargetLine(List<String> lines, String targetName) {
+        for (int i = 0; i < lines.size(); i++) {
+            String line = lines.get(i).trim();
+            if (line.isEmpty()) {
+              continue;
+            }
+            String[] parts = line.split("\\s+");
+            if (parts.length > 0 && parts[0].equals(targetName)) {
+                return i; // 0-based index
+            }
+        }
+        return -1;
+    }
+
+    // 核心逻辑：修改文件中特定用户的某个字段 (0-based)
+    public static int modifyFileField(String filePath, String targetName,
+                                      int fieldIndex, String newValue) {
+        List<String> lines = new ArrayList<>();
+        try {
+            readAllLines(filePath, lines);
+        } catch (IOException e) {
+            System.err.println("读取文件错误: " + e.getMessage());
+            return -1;
+        }
+
+        int idx = findTargetLine(lines, targetName);
+        if (idx == -1) {
+            return -1;
+        }
+
+        String[] parts = lines.get(idx).trim().split("\\s+");
+        if (parts.length > fieldIndex) {
+            parts[fieldIndex] = newValue;
+            lines.set(idx, String.join(" ", parts));
+            try {
+                writeAllLines(filePath, lines);
+                return idx + 1; // 返回 1-based 行号
+            } catch (IOException e) {
+                System.err.println("写入文件错误: " + e.getMessage());
+                return -1;
+            }
+        } else {
+            System.out.println("目标行元素不足。");
+            return -1;
+        }
+    }
 }