无法获取PrintWriter来替换文件中的文本

import java.io.*;

public class FileTextReplacement {
    public static void main(String[] args) {
        String filePath = "path/to/file.txt"; // 文件路径
        String searchText = "old text"; // 需要替换的文本
        String replaceText = "new text"; // 替换后的文本

        try {
            // 读取文件内容
            BufferedReader reader = new BufferedReader(new FileReader(filePath));
            StringBuilder content = new StringBuilder();
            String line;
            while ((line = reader.readLine()) != null) {
                content.append(line).append(System.lineSeparator());
            }
            reader.close();

            // 在内存中替换文本
            String replacedContent = content.toString().replace(searchText, replaceText);

            // 将替换后的文本写入新文件或覆盖原文件
            PrintWriter writer = new PrintWriter(new FileWriter(filePath));
            writer.write(replacedContent);
            writer.close();

            System.out.println("文本替换成功！");
        } catch (IOException e) {
            System.out.println("发生错误：" + e.getMessage());
        }
    }
}