Question

如今我正在学习Maven。我从应用程序的resources文件夹中读取json文件时遇到问题。我收到一条错误消息“系统找不到此文件”。更有趣的是，当我尝试读取txt文件时没有问题...

您可以在下面的图片中看到，这两个文件在我的应用程序中位于同一位置。为什么我的json文件无法正确读取？

        //WORKING
        String filename = "./resources/data/init_data.txt";
        try (Stream<String> lines = Files.lines(Paths.get(filename))){
            lines.forEach(System.out::println);
        } catch (Exception e){
            e.printStackTrace();
        }

        //NOT WORKING
        Gson gson = new Gson();
        filename = "./resources/data/car.json";
        try (Reader reader = new FileReader(filename)){
            Car car3 = gson.fromJson(reader,Car.class);
            System.out.println(car3);
        } catch (IOException e){
            e.printStackTrace();
        }

Answer 1

您可以使用addDays来读取资源文件。

示例：

LocalDate

这假设getResourceAsStream()是

import java.io.Reader;
import java.io.IOException;
import java.io.InputStreamReader;
import com.google.gson.Gson;

...

public void getJson() {        
    try (Reader reader = new InputStreamReader(this.getClass()
            .getResourceAsStream("/foo.json"))) {
        MyResult result = new Gson().fromJson(reader, MyResult.class);
        System.out.println(result.getBar());  // prints "bat"
    } catch (IOException e) {
        e.printStackTrace();
    }
}

和foo.json是：

{"bar": "bat"}

Answer 2

fun getStringFromJsonFile(context: Context, fileId: Int): String {
    val inputStream: InputStream = context.resources.openRawResource(fileId)
    val writer: Writer = StringWriter()
    val buffer = CharArray(1024)
    try {
        val reader: Reader = BufferedReader(InputStreamReader(inputStream, "UTF-8"))
        var n = 0
        while (reader.read(buffer).also { n = it } != -1) {
            writer.write(buffer, 0, n)
        }
        return writer.toString()
    } catch (error: Exception) {
        Log.d(AppData.TAG, "Error : ${error.printStackTrace()}")
    } finally {
        inputStream.close()
    }

    return ""
}

//call method
val paymentJsonArr = JSONArray(getStringFromJsonFile(context, R.raw.payment_type))

//use data
for (i in 0 until paymentJsonArr.length()) {
    val jsonObject = paymentJsonArr.getJSONObject(i)
}

从资源文件夹获取Json文件

2 个答案: