Spring Boot：无法从资源加载文件

Question

I have few files with SQL queries in my Spring Boot project. These queries are located by path

spring-boot-sql-in-files/src/main/resources/sql/query.sql

When I run my application I execute loading of these queries to static variables.

private static final String PATH_PREFIX = "src/main/resources/sql/";

public static String loadQueryFromFile(@NonNull String fileName) {
    try {
        return FileUtils.readFileToString(new File(PATH_PREFIX + fileName), Charset.defaultCharset());
    } catch (Exception e) {
        log.error("Error occurred during loading sql file to string, file=" + fileName, e);
        throw new QueryNotLoadedException();
    }
}

It works fine when I run it using IDE but it doesn't work when I run name.jar file, I get the following error:

java.io.FileNotFoundException: File 'src/main/resources/sql/query.sql' does not exist

How can I fix this path?

Answer 1

src/main/resources like src/main/java becomes the root of your classpath and as such won't work. It won't work with only sql as well as it isn't a file when packaged as a jar . Instead use the Spring Resource abstraction to load the file and the StreamUtils to load it into a String .

public static String loadQueryFromFile(@NonNull String fileName) {
    try {
        Resource resource = new ClassPathResource("sql/" + fileName);
        return StreamUtils.copyToString(resource.getInputStream(), Charset.defaultCharset());
    } catch (Exception e) {
        log.error("Error occurred during loading sql file to string, file=" + fileName, e);
        throw new QueryNotLoadedException();
    }
}

Something like that should do the trick.