SpringBoot中读取jar包中的resources目录下的文件的三种方式

public static void printFileContent(Object obj) throws IOException {
    if (null == obj) {
        throw new RuntimeException("参数为空");
    }
    BufferedReader reader = null;
    // 如果是文件路径
    if (obj instanceof String) {
        reader = new BufferedReader(new FileReader(new File((String) obj)));
    // 如果是文件输入流
    } else if (obj instanceof InputStream) {
        reader = new BufferedReader(new InputStreamReader((InputStream) obj));
    }
    String line = null;
    while ((line = reader.readLine()) != null) {
        System.out.println(line);
    }
    reader.close();
}

public class ResourceUtil {
    public void getResource(String fileName) throws IOException{
        InputStream in = this.getClass().getClassLoader().getResourceAsStream(fileName);
        printFileContent(in);
    }
    public static void main(String[] args) throws IOException {
        new ResourceUtil().getResource("config/test.properties");
    }
}

public void getResource2(String fileName) throws IOException{
    InputStream in = this.getClass().getResourceAsStream("/" + fileName);
    printFileContent(in);
}
public static void main(String[] args) throws IOException {
    new ResourceUtil().getResource2("config/test.properties");
}

public void getResource3(String fileName) throws IOException{
    ClassPathResource classPathResource = new ClassPathResource(fileName);
    printFileContent(classPathResource.getInputStream());
}
public static void main(String[] args) throws IOException {
    new ResourceUtil().getResource3("config/test.properties");
}