工具类ClassPathResourceReader

import java.io.*;
import java.util.stream.Collectors;

import org.springframework.core.io.ClassPathResource;

public final class ClassPathResourceReader {

    private final String path;

    private String content;

    public ClassPathResourceReader(String path) {
        this.path = path;
    }

    public String getContent() {
        if (content == null) {
            BufferedReader reader = null;
            try {
                ClassPathResource resource = new ClassPathResource(path);
                reader = new BufferedReader(new InputStreamReader(resource.getInputStream()));
                content = reader.lines().collect(Collectors.joining("\n"));
            } catch (IOException ex) {
                throw new RuntimeException(ex);
            } finally {
                try {
                    if (reader != null) {
                        reader.close();
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return content;
    }
}

• 测试

String content = new ClassPathResourceReader("token.txt").getContent();
System.out.println(content);