Java 如何使用Gson将文件中存储为字符串的点的ArrayList转换为ArrayList对象？

我将点对象的Arraylist作为字符串存储在文件中。我使用gson库将其转换为字符串

for (final VisionDetRet ret : results) {
    ArrayList<Point> landmarks = ret.getFaceLandmarks();
    Gson gson = new Gson();
    FileWriter writer = new FileWriter(Environment.getExternalStorageDirectory()+"fileName.txt", true);
    gson.toJson(landmarks, writer);
    writer.close();
}

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我想从该文件中读取字符串并想转换回ArrayList。

您只需要为

ArrayList

创建一个定义了特定泛型类型的TypeToken

FileReader reader = new FileReader(Environment.getExternalStorageDirectory()+"fileName.txt");

Type listType = new TypeToken<ArrayList<Point>>() { }.getType();

ArrayList<Point> landmarks = new Gson().fromJson(reader, listType);

FileReader=newfilereader（Environment.getExternalStorageDirectory（）+“fileName.txt”）；
类型listType=newTypeToken（）{}.getType（）；
ArrayList landmarks=new Gson（）.fromJson（reader，listType）；

FileReader reader = new FileReader(Environment.getExternalStorageDirectory()+"fileName.txt");

Type listType = new TypeToken<ArrayList<Point>>() { }.getType();

ArrayList<Point> landmarks = new Gson().fromJson(reader, listType);