ViewResolver using Java annotation

问题:

Is it possible in Spring 3.1.1 to configure a view resolver using Java annotations?

I am done with all configurations using Java annotations, but I am stuck at view resolver.

Code

package com;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.jdbc.datasource.DriverManagerDataSource;
import javax.sql.DataSource;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import com.*;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
import org.springframework.web.servlet.view.UrlBasedViewResolver;
import org.springframework.web.servlet.view.JstlView;

@Configuration
@ComponentScan("com")
public class AppConfig
{
    {
          //Other bean declarations
    }

    @Bean
    public UrlBasedViewResolver urlBasedViewResolver()
    {
        UrlBasedViewResolver res = new InternalResourceViewResolver();
        res.setViewClass(JstlView.class);
        res.setPrefix("/WEB-INF/");
        res.setSuffix(".jsp");

        return res;
    }
}

I used this code and ran the application, but it's not returning the appropriate view. However, if I configure a viewresolver in the app-servlet.xml file, it works fine.

回答1:

Your class should extend WebMvcConfigurerAdapter class. please have a look at below example

@Configuration
@ComponentScan(basePackages="com")
@EnableWebMvc
public class MvcConfiguration extends WebMvcConfigurerAdapter{

    @Bean
    public ViewResolver getViewResolver(){
        InternalResourceViewResolver resolver = new InternalResourceViewResolver();
        resolver.setPrefix("/WEB-INF/views/");
        resolver.setSuffix(".jsp");
        return resolver;
    }
}

回答2:

I tested your scenario with Spring 4.3.4 and it is working ok. I would suggest double checking packages you scan and that AppConfig is properly provided. I am attaching all files starting from your AppConfig. Yet it is good to extend WebMvcConfigurerAdapter. The source code attached is not ideal, it s simplistic and only to try to reproduce the problem you have reported.

Starting from AppConfig:

package com;

import org.springframework.context.annotation.*;
import org.springframework.web.servlet.view.*;

@Configuration
@ComponentScan("com")
public class AppConfig {
    @Bean
    public UrlBasedViewResolver getViewResovler() {
        UrlBasedViewResolver urlBasedViewResolver = new UrlBasedViewResolver();
        urlBasedViewResolver.setViewClass(JstlView.class);
        urlBasedViewResolver.setPrefix("/WEB-INF/jsp/");
        urlBasedViewResolver.setSuffix(".jsp");
        return urlBasedViewResolver;
    }

}

Then:

package com;

import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

    public class WebInit extends AbstractAnnotationConfigDispatcherServletInitializer {

        @Override
        protected Class<?>[] getRootConfigClasses() {
            return new Class<?>[] { };
        }

        @Override
        protected Class<?>[] getServletConfigClasses() {
            return new Class<?>[] { AppConfig.class };
        }

        @Override
        protected String[] getServletMappings() {
            return new String[] { "/" };
        }
    }

Finally:

package com;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;

@Controller
public class MainController {

    @RequestMapping("/")
    public ModelAndView asdf() {
        return new ModelAndView("ABC");
    }
}

回答3:

The problem with the above is that the DispatcherServlet.initViewResolvers get's called before the bean getViewResolver is defined and it cannot find the bean so it never adds the view resolver.

If you move the bean definition into an xml definition, it get's picked up. For some reason the MvcConfiguration class you have defined does not trigger a DispatcherServlet refresh if there are no ViewResolvers defined in the XML.