原因：java.lang.IllegalArgumentException：应用程序上下文不能为空

Question

有人可以帮我，那是我的配置类

 package net.king.cofingWeb;

import org.apache.catalina.core.ApplicationContext;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import org.thymeleaf.ITemplateEngine;
import org.thymeleaf.TemplateEngine;
import org.thymeleaf.spring4.SpringTemplateEngine;
import org.thymeleaf.spring4.templateresolver.SpringResourceTemplateResolver;
import org.thymeleaf.spring4.view.ThymeleafViewResolver;
import org.thymeleaf.templatemode.TemplateMode;
import org.thymeleaf.templateresolver.ITemplateResolver;

@Configuration
public class ThymeMvc extends WebMvcConfigurerAdapter {

      @Bean
      public ViewResolver viewResolver() {
            ThymeleafViewResolver resolver = new ThymeleafViewResolver();
            resolver.setTemplateEngine(templateEngine());
            resolver.setCharacterEncoding("UTF-8");
            return resolver;
          }

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

    private ITemplateResolver templateResolver() {
        SpringResourceTemplateResolver resolver = new SpringResourceTemplateResolver();
        resolver.setTemplateMode(TemplateMode.HTML);
        resolver.setCharacterEncoding("UTF-8");
        resolver.setCacheable(false);
        resolver.setPrefix("classpath:/templates/");
        resolver.setSuffix(".html");
        return resolver;
      }









}

我的pom

    <dependency>
        <groupId>org.thymeleaf</groupId>
        <artifactId>thymeleaf</artifactId>
        <version>3.0.9.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.thymeleaf</groupId>
        <artifactId>thymeleaf-spring4</artifactId>
        <version>3.0.9.RELEASE</version>
    </dependency>

我的控制器

    package net.king.web;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;

import net.king.entities.Candidate;

@Controller
@EnableWebMvc
public class HomeController {

    @RequestMapping(value="/")
    public String index() {
        return "index";
    }


}

我的索引文件在模板文件夹中

我的索引文件在template文件夹中，启动服务器后，结果是这里，我花时间解决但仍然没有解决方案

java.lang.IllegalArgumentException: Application Context cannot be null
    at org.thymeleaf.util.Validate.notNull(Validate.java:37) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
    at org.thymeleaf.spring4.templateresource.SpringResourceTemplateResource.<init>(SpringResourceTemplateResource.java:64) ~[thymeleaf-spring4-3.0.9.RELEASE.jar:3.0.9.RELEASE]
    at org.thymeleaf.spring4.templateresolver.SpringResourceTemplateResolver.computeTemplateResource(SpringResourceTemplateResolver.java:69) ~[thymeleaf-spring4-3.0.9.RELEASE.jar:3.0.9.RELEASE]
    at org.thymeleaf.templateresolver.AbstractConfigurableTemplateResolver.computeTemplateResource(AbstractConfigurableTemplateResolver.java:1414) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
    at org.thymeleaf.templateresolver.AbstractTemplateResolver.resolveTemplate(AbstractTemplateResolver.java:356) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
    at org.thymeleaf.engine.TemplateManager.resolveTemplate(TemplateManager.java:845) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
    at org.thymeleaf.engine.TemplateManager.parseAndProcess(TemplateManager.java:607) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
    at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1098) [thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
    at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1072) [thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
    at org.thymeleaf.spring4.view.ThymeleafView.renderFragment(ThymeleafView.java:352) [thymeleaf-spring4-3.0.9.RELEASE.jar:3.0.9.RELEASE]
    at org.thymeleaf.spring4.view.ThymeleafView.render(ThymeleafView.java:190) [thymeleaf-spring4-3.0.9.RELEASE.jar:3.0.9.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1372) [spring-webmvc-5.1.15.RELEASE.jar:5.1.15.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1118) [spring-webmvc-5.1.15.RELEASE.jar:5.1.15.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1057) [spring-webmvc-5.1.15.RELEASE.jar:5.1.15.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) [spring-webmvc-5.1.15.RELEASE.jar:5.1.15.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) [spring-webmvc-5.1.15.RELEASE.jar:5.1.15.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) [spring-webmvc-5.1.15.RELEASE.jar:5.1.15.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:634) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) [spring-webmvc-5.1.15.RELEASE.jar:5.1.15.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) [tomcat-embed-websocket-9.0.34.jar:9.0.34]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) [spring-web-5.1.15.RELEASE.jar:5.1.15.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) [spring-web-5.1.15.RELEASE.jar:5.1.15.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:373) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1590) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) [na:1.8.0_241]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) [na:1.8.0_241]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at java.lang.Thread.run(Unknown Source) [na:1.8.0_241]

2020-06-02 01:31:14.282 ERROR 9236 --- [nio-8080-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.thymeleaf.exceptions.TemplateProcessingException: Exception processing template (template: "index")] with root cause

java.lang.IllegalArgumentException: Application Context cannot be null
    at org.thymeleaf.util.Validate.notNull(Validate.java:37) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
    at org.thymeleaf.spring4.templateresource.SpringResourceTemplateResource.<init>(SpringResourceTemplateResource.java:64) ~[thymeleaf-spring4-3.0.9.RELEASE.jar:3.0.9.RELEASE]
    at org.thymeleaf.spring4.templateresolver.SpringResourceTemplateResolver.computeTemplateResource(SpringResourceTemplateResolver.java:69) ~[thymeleaf-spring4-3.0.9.RELEASE.jar:3.0.9.RELEASE]
    at org.thymeleaf.templateresolver.AbstractConfigurableTemplateResolver.computeTemplateResource(AbstractConfigurableTemplateResolver.java:1414) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
    at org.thymeleaf.templateresolver.AbstractTemplateResolver.resolveTemplate(AbstractTemplateResolver.java:356) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
    at org.thymeleaf.engine.TemplateManager.resolveTemplate(TemplateManager.java:845) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
    at org.thymeleaf.engine.TemplateManager.parseAndProcess(TemplateManager.java:607) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
    at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1098) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
    at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1072) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
    at org.thymeleaf.spring4.view.ThymeleafView.renderFragment(ThymeleafView.java:352) ~[thymeleaf-spring4-3.0.9.RELEASE.jar:3.0.9.RELEASE]
    at org.thymeleaf.spring4.view.ThymeleafView.render(ThymeleafView.java:190) ~[thymeleaf-spring4-3.0.9.RELEASE.jar:3.0.9.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1372) ~[spring-webmvc-5.1.15.RELEASE.jar:5.1.15.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1118) ~[spring-webmvc-5.1.15.RELEASE.jar:5.1.15.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1057) ~[spring-webmvc-5.1.15.RELEASE.jar:5.1.15.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) ~[spring-webmvc-5.1.15.RELEASE.jar:5.1.15.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.1.15.RELEASE.jar:5.1.15.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.1.15.RELEASE.jar:5.1.15.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:634) ~[tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.1.15.RELEASE.jar:5.1.15.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) ~[tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.34.jar:9.0.34]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.1.15.RELEASE.jar:5.1.15.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.1.15.RELEASE.jar:5.1.15.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:373) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1590) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) [na:1.8.0_241]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) [na:1.8.0_241]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.34.jar:9.0.34]
    at java.lang.Thread.run(Unknown Source) [na:1.8.0_241]

Answer 1

这里是Runnig配置的示例，您需要设置ApplicationContext属性并将其设置为resolver：

@Configuration
@ComponentScan(basePackageClasses = { CervejasController.class })
@EnableWebMvc
public class WebConfig extends WebMvcConfigurerAdapter implements ApplicationContextAware {

    private ApplicationContext applicationContext;

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        this.applicationContext = applicationContext;
    }

    @Bean
    public ViewResolver viewResolver() {
        ThymeleafViewResolver resolver = new ThymeleafViewResolver();
        resolver.setTemplateEngine(templateEngine());
        resolver.setCharacterEncoding("UTF-8");
        return resolver;
    }

    @Bean
    public TemplateEngine templateEngine() {
        SpringTemplateEngine engine = new SpringTemplateEngine();
        engine.setEnableSpringELCompiler(true);
        engine.setTemplateResolver(templateResolver());
        engine.addDialect(new LayoutDialect());
        return engine;
    }

    private ITemplateResolver templateResolver() {
        SpringResourceTemplateResolver resolver = new SpringResourceTemplateResolver();
        resolver.setApplicationContext(applicationContext);
        resolver.setPrefix("classpath:/templates/");
        resolver.setSuffix(".html");
        resolver.setTemplateMode(TemplateMode.HTML);
        return resolver;
    }

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/**").addResourceLocations("classpath:/static/");
    }
}

Answer 2

据我所知，这是一个Spring MVC应用程序，我认为问题在于您的@configuration将bean更改为：

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

@Bean
public SpringResourceTemplateResolver templateResolver(){
    // SpringResourceTemplateResolver automatically integrates with Spring's own
    // resource resolution infrastructure, which is highly recommended.
    SpringResourceTemplateResolver templateResolver = new SpringResourceTemplateResolver();
    templateResolver.setApplicationContext(this.applicationContext);
    templateResolver.setPrefix("/WEB-INF/templates/");
    templateResolver.setSuffix(".html");
    // HTML is the default value, added here for the sake of clarity.
    templateResolver.setTemplateMode(TemplateMode.HTML);
    // Template cache is true by default. Set to false if you want
    // templates to be automatically updated when modified.
    templateResolver.setCacheable(true);
    return templateResolver;
}

SpringTemplateEngine类执行所有配置步骤。尝试使用Spring类代替Thymeleaf依赖项进行配置。使用Spring类代替Thymeleaf类进行Thymeleaf的配置，以便在创建bean的过程中注入应用程序上下文。为视图解析器返回ThymeleafViewResolver，但完全可以因为它实现了ViewResolver，但是应该更改其他两个bean。

此外，如果您打算将Spring版本从4升级到5，还可以将配置更改为以下内容：

@Configuration
public WebConfig implements WebMvcConfigurer {
    // ...
}

由于Spring5中已弃用WebMvcConfigurerAdapter。如果您的应用程序是springboot应用程序，而不是您提供的依赖项，请对thymeleaf使用以下依赖项：

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>