读取. jar应用程序中的文本文件[重复]

Question

有了这个代码，我想要一个. jar文件来读取文本文件“file.txt”，它位于文件夹数据的jar中。这是一个应用程序编程与处理，所以我想读的所有文件都在数据文件夹中。有人能解释为什么我得到一个NullPointerExcema吗？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，因为它使用的类的系统加载器无法看到您的jar。改用

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