Question

使用这段代码，我想要一个.jar文件来读取位于jar文件夹数据中的文本文件“file.txt”。这是一个使用Processing编程的应用程序，因此我想要读取的所有文件都在数据文件夹中。任何人都可以解释为什么我得到NullPointerException？该文件存在并包含文本。

import java.io.*;

void setup() {
  size(500, 500);
  try {
    // HERE I TRY TO READ THE FILE WHICH IS LOCATED IN THE JAR FILE IN THE FOLDER "DATA"
    InputStream is = getClass().getResourceAsStream("/data/file.txt");

    // HERE I GET A NULL-POINTER-EXCEPTION BECAUSE THE FILE CANNOT BE READ (IS = NULL, WHY IS THE INPUT STREAM NULL?)
    BufferedReader br = new BufferedReader(new InputStreamReader(is));

    // THE FIRST LINE OF THE DOCUMENT IS READ AND PRINTED IN THE CONSOLE
    String read = br.readLine();
    br.close();
    println(read);
  } 
  catch (IOException e) {
    // IF THE FILE DOESN'T EXIST AN IO-EXCEPTION WILL BE CAUGHT
    println("Error reading file");
  }
}

Answer 1

getClass().getResourceAsStream("/data/file.txt");返回null，因为它使用了该类＆＃39;系统装载机，看不到你的罐子。改为使用

YourClassName.class.getResourceAsStream("/data/file.txt");

在.jar-application中读取文本文件

1 个答案: