Spring-boot: Thymeleaf templates preceded by a slash are found when running in an IDE but not when running from a jar

[wilkinsona]

See http://stackoverflow.com/questions/26493831/spring-boot-thymeleaf-not-resolving-fragments-after-packaging. I'm not sure that there's anything we can do but I'd like to investigate.

[wilkinsona]

It seems to be a basic limitation of the JDK. This small class:

public class TestResourceLoading {
    public static void main(String[] args) throws IOException {
        System.out.println(Application.class.getClassLoader().getResourceAsStream("foo/bar"));
        System.out.println(Application.class.getClassLoader().getResourceAsStream("foo//bar"));
    }
}

Run in an IDE:

java.io.BufferedInputStream@74e22632
java.io.BufferedInputStream@2b39d891

Run with java -jar:

sun.net.www.protocol.jar.JarURLConnection$JarURLInputStream@61bbe9ba
null

[wilkinsona]

We could possibly do something in LanchedURLClassLoader to turn more than one consecutive slash into a single slash but I'm not sure it's worth it.

[philwebb]

Seems like this might be a common mistake, it's been raised again in #2057. Striping double slashes might be an option but we need to check that this won't break existing code.

[transentia]

Following on from #2507...with more (poss. important?) details.

I originally didn't have preceding '/' characters on my view names. The problem came when I introduced spring security:

   @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
                .csrf().disable();
        http
                .authorizeRequests()
                .antMatchers("/").permitAll()
                .anyRequest().authenticated();
        http
                .formLogin()
                .loginPage("/login")
                .defaultSuccessUrl("/home")
                .failureUrl("/login?error")
                .permitAll()
                .and()
                .logout()
                .invalidateHttpSession(true)
                .logoutSuccessUrl("/login?logout")
                .permitAll();
    }

I found that I could not use simply 'login' instead of '/login', etc. (maybe SS is dong something different to Thymeleaf?) So I needed to find a solution that preserved the slash at the beginning of view names, while stripping the duplicate away. Thus I adopted the classpath configuration:

    spring:
      thymeleaf:
        cache: false
        prefix: classpath:/templates

[philwebb]

Having review the behavior of the standard URLClassLoader I don't think double slash detection is something that we should do.

Given the following code:

InputStream url = Thing.class.getClassLoader().getResourceAsStream("sample//test.txt");
System.out.println(url != null);

Running the application from an IDE will print return true. Package into a jar and running using java -cp ./target/test-0.0.1-SNAPSHOT.jar sample.Test will return false.

This shows that our fat jar support is working in the same way as the standard JDK and I think it's best to keep consistency rather than introduce a difference and potentially break things in other ways.

[izeye]

If it's a common mistake, I think giving a warning message would be helpful.

[opensource21]

Just as an extra information. I have a similar issue and there it works in the IDE and Tomcat. So I think the default jdk is inconsistent, would be great to get a warning.

[Dluquem]

Yo tenia el mismo problema, la solución la encontré en este link. https://stackoverflow.com/questions/27249078/spring-boot-gives-templateinputexception-error-resolving-template-when-runnin

Okay, I found where you have to take a close look. In your Controller classes, when you use @RequestMapping on class, no leading slash (e.g. @RequestMapping("property")). On Method you need a leading slash (e.g. @GetMapping("/list")) and the return value no leading slash (e.g. return "property/list";)

An Example Snippet

@Controller
@RequestMapping("property")
public class PropertyController {
    @NonNull PropertyService service;

    @GetMapping("/list")
    public String list() {
        return "property/list";
    }
}

[evertones]

Is this issue resolved?
I've tried with version 1.5.10 and seems to be still happening.

I have the following code:

@Controller
public TestController {
    @RequestMapping(path= "/client/add", method = RequestMethod.GET)
    public String add() {
        return "/client/add";  // STARTS WITH A SLASH
    }
}

It works starting with Spring Boot using Maven: ./mvnw spring-boot:run.
It does not work with the jar: java -jar myapp.jar.

If I change the code above to return the template without the slash in the beginning, it works on both:

@Controller
public TestController {
    @RequestMapping(path= "/client/add", method = RequestMethod.GET)
    public String add() {
        return "client/add";  // DOES NOT START WITH A SLASH
    }
}

Is it the expected behaviour or this issue should've fixed that?

[AleixAlcover]

When you return the URI starting with a slash, you always send a double slash. The difference is that starting with Spring the file system deals with this issue, which doesn't do the JVM, when you run the .jar.

[ghost]

I'm using Spring Boot 2.0.0.RELEASE and I'm experiencing this, I've tried removing slashes on my RequestMapping but I'm still getting HTTP 500. Is there a solution for this?

[AleixAlcover]

Have you checked the links in the .html (Thymeleaf template)? There you could be generating double slashes as well.

[snicoll]

@oratengG4S we don't use the tracker for questions. Please ask on StackOverflow or join us on Gitter.