Java文件操作：读写文件的实战案例

原创谁践踏了优雅 2024-09-11 06:54 71阅读 0赞

在Java中，文件操作主要涉及`File`类和相关的API。以下是一些实战案例：

1. **创建新文件**：
   ```java
   // 创建一个名为"example.txt"的新文件
   File file = new File("example.txt");
   if (!file.createNewFile()) {
       System.out.println("Failed to create file.");
       return;
   }
   System.out.println("Successfully created file.");
   ```

2. **读取文件内容**：
   ```java
   // 读取"example.txt"的内容
   try (BufferedReader reader = new BufferedReader(new FileReader(file)))) {
       String line;
       while ((line = reader.readLine()) != null) {
           System.out.println(line);
       }
   } catch (IOException e) {
       System.err.println("Failed to read file: " + e.getMessage());
       e.printStackTrace();
   }

// 读取文件的所有行到ArrayList中
   List<String> fileContentList = new ArrayList<>();
   try (BufferedReader reader = new BufferedReader(new FileReader(file)))) {
       String line;
       while ((line = reader.readLine()) != null) {
           fileContentList.add(line);
       }
   } catch (IOException e) {
       System.err.println("Failed to read file into list: " + e.getMessage());
       e.printStackTrace();
   }

```

3. **写入文件内容**：
   ```java
   // 向"example.txt"追加内容
   try (PrintWriter writer = new PrintWriter(new FileWriter(file, true)))) {
       writer.println("This is appended content.");
   } catch (IOException e) {
       System.err.println("Failed to append to file: " + e.getMessage());
       e.printStackTrace();
   }

// 将List内容写入文件
   try (BufferedWriter writer = new BufferedWriter(new FileWriter(file, false)))) {
       for (String line : fileContentList) {
           writer.write(line);
           writer.newLine(); // 添加换行符
       }
   } catch (IOException e) {
       System.err.println("Failed to write list to file: " + e.getMessage());
       e.printStackTrace();
   }

```

注意：在实际操作中，需要处理好文件可能存在的异常情况。