@RequestMapping("/")
public void home(Device device) {
    if (device.isMobile()) {
        logger.info("Hello mobile user!");
    } else if (device.isTablet()) {
        logger.info("Hello tablet user!");
    } else {
        logger.info("Hello desktop user!");         
    }
}

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.mobile.device.view.LiteDeviceDelegatingViewResolver;
import org.springframework.web.servlet.view.tiles3.TilesConfigurer;
import org.springframework.web.servlet.view.tiles3.TilesView;
import org.springframework.web.servlet.view.tiles3.TilesViewResolver;

@Configuration
public class TilesConfig {

    @Bean
    public TilesConfigurer tilesConfigurer() {
        final TilesConfigurer configurer = new TilesConfigurer();
        configurer.setDefinitions(new String[]{"/WEB-INF/tiles/tiles.xml",
             // 모바일 분기 관련 설정 추가부분..
                "WEB-INF/tiles/tiles-mobile.xml"});
        configurer.setCheckRefresh(true);
        return configurer;
    }

    @Bean
    public TilesViewResolver tilesViewResolver() {
        final TilesViewResolver tilesViewResolver = new TilesViewResolver();
        tilesViewResolver.setViewClass(TilesView.class);
        return tilesViewResolver;
    }

    /** 
    * 모바일 분기 관련 설정 추가부분..
    */
    @Bean
    public LiteDeviceDelegatingViewResolver liteDeviceDelegatingViewResolver() {
        LiteDeviceDelegatingViewResolver resolver = new LiteDeviceDelegatingViewResolver(this.tilesViewResolver());
        
        /** 
          tilesViewResolver의 Order 값을 최상위로 높여 주지 않으면  앞서 프로퍼티에서 생성한
          LiteDeviceDelegatingViewResolver에의해 ContentNegotiatingViewResolver 에서 org.springframework.web.servlet.view.JstlView 이 실행되어 Tiles가 동작하지 않게 된다.
        */
        resolver.setOrder(0);
        resolver.setMobilePrefix("mobile/");
        resolver.setEnableFallback(true);
        return resolver;
    }
}

@Controller
@RequestMapping("/")
public class MainController  {

    @GetMapping(value = {"", "index"})
    public ModelAndView index() {

        ModelAndView mv = new ModelAndView();
        
        .....
        로직로직
        ....
        
        mv.setViewName("main/index");
        return mv;
    }
}

public class LiteDeviceDelegatingViewResolver extends AbstractDeviceDelegatingViewResolver {
    private String normalPrefix = "";
    private String mobilePrefix = "";
    private String tabletPrefix = "";
    private String normalSuffix = "";
    private String mobileSuffix = "";
    private String tabletSuffix = "";
 .....
  
   // 1. 앞에 키워드를 붙이는 부분이며 아까 설정에서 mobilePrefix 를 mobile/ 로 설정하였다. 
    protected String getDeviceViewNameInternal(String viewName) {
        RequestAttributes attrs = RequestContextHolder.getRequestAttributes();
        Assert.isInstanceOf(ServletRequestAttributes.class, attrs);
        HttpServletRequest request = ((ServletRequestAttributes)attrs).getRequest();
        Device device = DeviceUtils.getCurrentDevice(request);
        SitePreference sitePreference = SitePreferenceUtils.getCurrentSitePreference(request);
        String resolvedViewName = viewName;
        if (ResolverUtils.isNormal(device, sitePreference)) {
            resolvedViewName = this.getNormalPrefix() + viewName + this.getNormalSuffix();
        } 
        // 2. 모바일 디바이스일 경우 이부분이 조건으로 타게되며 그 경우에 모바일 prefix 인 mobile/ 이 붙에 됨. 
        else if (ResolverUtils.isMobile(device, sitePreference)) {
            resolvedViewName = this.getMobilePrefix() + viewName + this.getMobileSuffix();
        } else if (ResolverUtils.isTablet(device, sitePreference)) {
            resolvedViewName = this.getTabletPrefix() + viewName + this.getTabletSuffix();
        }

        return this.stripTrailingSlash(resolvedViewName);
    }

    private String stripTrailingSlash(String viewName) {
        return viewName.endsWith("//") ? viewName.substring(0, viewName.length() - 1) : viewName;
    }
}

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.view.tiles3.TilesConfigurer;
import org.springframework.web.servlet.view.tiles3.TilesView;
import org.springframework.web.servlet.view.tiles3.TilesViewResolver;

@Configuration
public class TilesConfig {

    @Bean
    public TilesConfigurer tilesConfigurer() {
        final TilesConfigurer configurer = new TilesConfigurer();
        //해당 경로에 tiles.xml 파일을 넣음
        configurer.setDefinitions(new String[]{"/WEB-INF/tiles/tiles.xml"});
        configurer.setCheckRefresh(true);
        return configurer;
    }

    @Bean
    public TilesViewResolver tilesViewResolver() {
        final TilesViewResolver tilesViewResolver = new TilesViewResolver();
        tilesViewResolver.setViewClass(TilesView.class);
        return tilesViewResolver;
    }
}

@Controller
@RequestMapping("/")
public class MainController  {

    @GetMapping(value = {"", "index"})
    public ModelAndView index() {

        ModelAndView mv = new ModelAndView();
        
        .....
        로직로직
        ....
        
        mv.setViewName("main/index");
        return mv;
    }
}