在Spring项目中尝试以下代码

ClassPathResource resource = new ClassPathResource("fileName");
InputStream inputStream = resource.getInputStream();

或者在非弹簧项目上

 ClassLoader classLoader = getClass().getClassLoader();
 File file = new File(classLoader.getResource("fileName").getFile());
 InputStream inputStream = new FileInputStream(file);

下面的类可用于从类路径加载资源，并在给定的filePath出现问题时接收适当的错误消息。

import java.io.InputStream;
import java.nio.file.NoSuchFileException;

public class ResourceLoader
{
    private String filePath;

    public ResourceLoader(String filePath)
    {
        this.filePath = filePath;

        if(filePath.startsWith("/"))
        {
            throw new IllegalArgumentException("Relative paths may not have a leading slash!");
        }
    }

    public InputStream getResource() throws NoSuchFileException
    {
        ClassLoader classLoader = this.getClass().getClassLoader();

        InputStream inputStream = classLoader.getResourceAsStream(filePath);

        if(inputStream == null)
        {
            throw new NoSuchFileException("Resource file not found. Note that the current directory is the source folder!");
        }

        return inputStream;
    }
}

导入以下文件:

import java.io.IOException;
import java.io.FileNotFoundException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.InputStream;
import java.util.ArrayList;

下面的方法返回一个字符串数组列表中的文件:

public ArrayList<String> loadFile(String filename){

  ArrayList<String> lines = new ArrayList<String>();

  try{

    ClassLoader classloader = Thread.currentThread().getContextClassLoader();
    InputStream inputStream = classloader.getResourceAsStream(filename);
    InputStreamReader streamReader = new InputStreamReader(inputStream, StandardCharsets.UTF_8);
    BufferedReader reader = new BufferedReader(streamReader);
    for (String line; (line = reader.readLine()) != null;) {
      lines.add(line);
    }

  }catch(FileNotFoundException fnfe){
    // process errors
  }catch(IOException ioe){
    // process errors
  }
  return lines;
}

试试下一个:

ClassLoader classloader = Thread.currentThread().getContextClassLoader();
InputStream is = classloader.getResourceAsStream("test.csv");

如果上面没有工作，各种项目已经添加了以下类:ClassLoaderUtil1(代码在这里).2

下面是一些如何使用该类的示例:

src\main\java\com\company\test\YourCallingClass.java
src\main\java\com\opensymphony\xwork2\util\ClassLoaderUtil.java
src\main\resources\test.csv

// java.net.URL
URL url = ClassLoaderUtil.getResource("test.csv", YourCallingClass.class);
Path path = Paths.get(url.toURI());
List<String> lines = Files.readAllLines(path, StandardCharsets.UTF_8);

// java.io.InputStream
InputStream inputStream = ClassLoaderUtil.getResourceAsStream("test.csv", YourCallingClass.class);
InputStreamReader streamReader = new InputStreamReader(inputStream, StandardCharsets.UTF_8);
BufferedReader reader = new BufferedReader(streamReader);
for (String line; (line = reader.readLine()) != null;) {
    // Process line
}

笔记

在《时光倒流机》中可以看到。 也在GitHub。

对于1.7之后的java

 List<String> lines = Files.readAllLines(Paths.get(getClass().getResource("test.csv").toURI()));

或者，如果你在Spring回声系统中，你可以使用Spring utils

final val file = ResourceUtils.getFile("classpath:json/abcd.json");

想了解更多幕后消息，请查看下面的博客

https://todzhang.com/blogs/tech/en/save_resources_to_files

getResource()只能在src/main/resources中使用资源文件。要获取src/main/resources路径之外的文件，比如src/test/java，你需要明确地创建它。

下面的例子可能会帮助你

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.net.URISyntaxException;
import java.net.URL;

public class Main {
    public static void main(String[] args) throws URISyntaxException, IOException {
        URL location = Main.class.getProtectionDomain().getCodeSource().getLocation();
        BufferedReader br = new BufferedReader(new FileReader(location.getPath().toString().replace("/target/classes/", "/src/test/java/youfilename.txt")));
    }
}