配置多个视图解析器(Thymeleaf 和 Json) Spring [英] Configuring Multiple View Resolvers (Thymeleaf and Json) Spring

问题描述

我正在尝试配置一个基于 Spring 的应用程序，我想在其中配置两个视图解析器.从我的控制器中，如果我只返回像login"这样的字符串名称，那么它应该由 Thymeleaf 解析器处理，而如果控制器的方法返回一个对象，则应该使用适当的 json 视图.当我尝试按照下面的配置运行我的应用程序时，出现以下错误

I am trying to configure a Spring based app, where I want to configure two view resolvers. From my controller, if I return just the string name like "login", then it should be handled by the Thymeleaf resolver, whereas if the controller's method returns an object, then appropriate json view should be used. When I try to run my application as configured below, I get the following error

"无法在带有名称的 servlet 中解析名称为登录"的视图'调度员'"

"Could not resolve view with name 'login' in servlet with name 'dispatcher'"

请你们看看下面的 Java 类.第一个是配置类，第二个是我尝试使用的Controller.

Requesting you guys to look at the Java classes below. The first is the configuration class, the second is the Controller I am trying to use.

package com.gojha.web;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.MediaType;
import org.springframework.web.accept.ContentNegotiationManager;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.ContentNegotiationConfigurer;
import org.springframework.web.servlet.config.annotation.DefaultServletHandlerConfigurer;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import org.springframework.web.servlet.view.ContentNegotiatingViewResolver;
import org.thymeleaf.TemplateEngine;
import org.thymeleaf.spring4.SpringTemplateEngine;
import org.thymeleaf.spring4.view.ThymeleafViewResolver;
import org.thymeleaf.templateresolver.ServletContextTemplateResolver;
import org.thymeleaf.templateresolver.TemplateResolver;

@Configuration
@EnableWebMvc
@ComponentScan("com.gojha.web")
public class WebConfig extends WebMvcConfigurerAdapter {

    @Override 
    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) { 
        configurer.enable(); 
    }

    @Bean 
    public ViewResolver viewResolver(ContentNegotiationManager cnm) { 
        ContentNegotiatingViewResolver cnvr = new ContentNegotiatingViewResolver();
        cnvr.setContentNegotiationManager(cnm);
        return cnvr;
    }

    @Override
    public void configureContentNegotiation(ContentNegotiationConfigurer configurer) {
        configurer.defaultContentType(MediaType.APPLICATION_JSON);
    }


    @Bean
    public TemplateResolver templateResolver() {
        TemplateResolver templateResolver = new ServletContextTemplateResolver();
        templateResolver.setPrefix("/WEB-INF/templates/");
        templateResolver.setSuffix(".html");
        templateResolver.setTemplateMode("HTML5");
        return templateResolver;
    }

    @Bean
    public TemplateEngine templateEngine() {
        SpringTemplateEngine templateEngine = new SpringTemplateEngine();
        templateEngine.setTemplateResolver(templateResolver());
        return templateEngine;
    }

    @Bean
    public ViewResolver viewResolver() {
        ThymeleafViewResolver viewResolver = new ThymeleafViewResolver();
        viewResolver.setTemplateEngine((SpringTemplateEngine) templateEngine());
        return viewResolver;
    }

}

控制器

package com.gojha.web;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.client.RestTemplate;

import static org.springframework.web.bind.annotation.RequestMethod.*;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;

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

    private RestTemplate restTemplate;

    private class Test {
        private String a;

        public Test() {
            super();
        }

        public Test(String a) {
            super();
            this.a = a;
        }

        public String getA() {
            return a;
        }

        public void setA(String a) {
            this.a = a;
        }

    }

    @Autowired
    public LoginController(RestTemplate restTemplate) {
        this.restTemplate = restTemplate;
    }

    @RequestMapping(method=GET)
    public String testing(){
        return "login";
    }

    @RequestMapping(method=GET, produces="application/json")
    public Test testing2(){
        return new Test("wow");
    }
}

我希望代码是不言自明的.

I hope the code is self-explanatory.

推荐答案

我通过更改配置文件并分配订单以查看解析器来使其工作.据我了解，它首先尝试使用 ContentNegotiation 解析视图，如果失败，则返回到 Thymeleaf 解析器.我将此标记为答案，如果有人有更好的方法或建议的更正，请告诉我.

I got it working by changing the configuration file and allocating orders to view resolvers. From what I understand, it looks like first it tries to resolve the view using ContentNegotiation, and if it fails, falls back to Thymeleaf resolver. I am marking this as the answer, if someone has a better approach, or a suggested correction, let me know.

package com.gojha.web;

import java.util.ArrayList;
import java.util.List;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.MediaType;
import org.springframework.web.accept.ContentNegotiationManager;
import org.springframework.web.servlet.View;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.ContentNegotiationConfigurer;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import org.springframework.web.servlet.view.ContentNegotiatingViewResolver;
import org.springframework.web.servlet.view.json.MappingJackson2JsonView;
import org.thymeleaf.spring4.SpringTemplateEngine;
import org.thymeleaf.spring4.view.ThymeleafViewResolver;
import org.thymeleaf.templateresolver.ServletContextTemplateResolver;
import org.thymeleaf.templateresolver.TemplateResolver;

@Configuration
@EnableWebMvc
@ComponentScan("com.gojha.web")
public class WebConfig extends WebMvcConfigurerAdapter {


    @Override
    public void configureContentNegotiation(ContentNegotiationConfigurer configurer) {
        configurer.defaultContentType(MediaType.APPLICATION_JSON);
    }

    @Bean
    public ViewResolver viewResolver() {

        TemplateResolver templateResolver = new ServletContextTemplateResolver();
        templateResolver.setPrefix("/WEB-INF/templates/");
        templateResolver.setSuffix(".html");
        templateResolver.setTemplateMode("HTML5");

        SpringTemplateEngine templateEngine = new SpringTemplateEngine();
        templateEngine.setTemplateResolver(templateResolver);

        ThymeleafViewResolver viewResolver = new ThymeleafViewResolver();
        viewResolver.setTemplateEngine(templateEngine);
        viewResolver.setOrder(2);
        return viewResolver;
    }

    @Bean
    public ViewResolver cnViewResolver(ContentNegotiationManager cnm) {
        ContentNegotiatingViewResolver cnvr = new ContentNegotiatingViewResolver();
        cnvr.setContentNegotiationManager(cnm);
        cnvr.setOrder(1);
        List<View> views = new ArrayList<View>();
        views.add(jsonView());
        cnvr.setDefaultViews(views);
        return cnvr;
    }

    @Bean
    public View jsonView() {
        MappingJackson2JsonView view = new MappingJackson2JsonView();
        view.setPrettyPrint(true);
        return view;
    }

}

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