如何在不覆盖 Java 中的当前内容的情况下写入外部文本文件

Question

我正在尝试将错过的响应写入外部文本文件。以下方法将无法识别的响应存储到外部文本文件中，但会覆盖以前的内容。如何阻止它被覆盖？

//写一个列表方法

       public void writeAList(ArrayList<String> list, String filename)
        {
            if(list != null) {
                try (FileWriter writer = new FileWriter(filename)) {
                    for(String item : list) {
                        writer.write(item.trim());
                        writer.write('\n');
                    }                    
                }
                catch(IOException e) {
                    System.out.println("Problem writing file: " + filename +
                                       " in writeAList");
                }
            }
            else {
                System.out.println("Null list passed to writeAList.");
            }
        }

//我在这个方法中调用它

public String generateResponse(ArrayList<String> words)
{
    Iterator<String> it = words.iterator();
    while(it.hasNext()) {
        String word = it.next();
        String response = responseMap.get(word);
        if(response != null) {
            return response;
        }
    }
    //If we get here, none of the words from the input line was recognized
    //In this case, a default response is returned
    //The words not recognised are stored in "missed.txt"
    helper.writeAList(words,"missed.txt");
    return pickDefaultResponse();

}

Answer 1

而不是 new FileWriter(filename)

试试

new FileWriter(filename, true)

在追加模式下创建文件写入器，请参阅文档here

Answer 2

在你的代码中，你需要替换：

FileWriter writer = new FileWriter(filename)

与：

FileWriter writer = new FileWriter(filename, true)

这里的额外参数true是启用追加模式。