关于GenericApplicationContext中getResource的实现(About implementation of getResource in GenericApplicationContext)

 Spring-web，webmvc 4.1.6 Thymeleaf 2.1 
 
 我一直在为SpringBoot中的Thymeleaf配置manualy。 我想在ServletContextTemplateResolver中使用“classpath：”前缀设置路径。 我该怎么做才能解决这个问题？ 
 
@Bean
public ServletContextTemplateResolver templateResolver() {
    ServletContextTemplateResolver templateResolver = new ServletContextTemplateResolver();
    templateResolver.setPrefix("classpath:/templates/");
    templateResolver.setSuffix(".html");
    templateResolver.setTemplateMode("HTML5");        
    templateResolver.setCacheable(false);
    return templateResolver;
 }
 
 但它不起作用。 原因是下面的代码。 在org.springframework.context.support.GenericApplicationContext中 
 
@Override
public Resource getResource(String location) {
    if (this.resourceLoader != null) {
        return this.resourceLoader.getResource(location);    // with setting of template resolver
    }
    return super.getResource(location);    // without setting of template resolver
}
 
 如果没有ServletContextTemplateResolver的任何设置，则调用GenericApplicationContext.getResource。 
 
 设置后，调用StandardRoot.getResourceAsStream。 但是这种方法没有实现支持“class：”前缀。 
 
 
 成功获取资源 
 
 http://docs.spring.io/spring/docs/current/javadoc-api/org/springframework/context/support/GenericApplicationContext.html#getResource-java.lang.String- 
 
 “ClassPathResource已实现” 
 
@Override
public Resource getResource(String location) {
    Assert.notNull(location, "Location must not be null");
    if (location.startsWith("/")) {
        return getResourceByPath(location);
    }
    else if (location.startsWith(CLASSPATH_URL_PREFIX)) {
        return new ClassPathResource(location.substring(CLASSPATH_URL_PREFIX.length()), getClassLoader());
    }
    else {
        try {
            // Try to parse the location as a URL...
            URL url = new URL(location);
            return new UrlResource(url);
        }
        catch (MalformedURLException ex) {
            // No URL -> resolve as resource path.
            return getResourceByPath(location);
        }
    }
}
 
 
 getResource失败 
 
 https://tomcat.apache.org/tomcat-8.0-doc/api/org/apache/catalina/webresources/StandardRoot.html#getResource(java.lang.String） 
 
 在这段代码中，前缀没有实现，所以我意识到我不能使用“class：”前缀作为ServletContextTemplateResolver的属性。 
 
 在org.apache.catalina.webresources.StandardRoot中 
 
@Override
public InputStream getResourceAsStream(String path) {

    if (path == null)
        return (null);

    if (!path.startsWith("/") && GET_RESOURCE_REQUIRE_SLASH)
        return null;

    WebResourceRoot resources = context.getResources();
    if (resources != null) {
         return resources.getResource(path).getInputStream();
    }

    return null;
}

Spring-web,webmvc 4.1.6 Thymeleaf 2.1
 
I have been working for manualy configuration of Thymeleaf in SpringBoot. I want to set path in ServletContextTemplateResolver with "classpath:" prefix. What can I do to deal with this problem?
 
@Bean
public ServletContextTemplateResolver templateResolver() {
    ServletContextTemplateResolver templateResolver = new ServletContextTemplateResolver();
    templateResolver.setPrefix("classpath:/templates/");
    templateResolver.setSuffix(".html");
    templateResolver.setTemplateMode("HTML5");        
    templateResolver.setCacheable(false);
    return templateResolver;
 }
 
But it doesn't work. The reason is the code below. In the org.springframework.context.support.GenericApplicationContext 
 
@Override
public Resource getResource(String location) {
    if (this.resourceLoader != null) {
        return this.resourceLoader.getResource(location);    // with setting of template resolver
    }
    return super.getResource(location);    // without setting of template resolver
}
 
Without any settings of ServletContextTemplateResolver, GenericApplicationContext.getResource is called.
 
With setting of it StandardRoot.getResourceAsStream is called. But this method doesn't have implementation of support "class: " prefix.
 
 
Successfully to getResource
 
http://docs.spring.io/spring/docs/current/javadoc-api/org/springframework/context/support/GenericApplicationContext.html#getResource-java.lang.String-
 
"ClassPathResource is implemented"
 
@Override
public Resource getResource(String location) {
    Assert.notNull(location, "Location must not be null");
    if (location.startsWith("/")) {
        return getResourceByPath(location);
    }
    else if (location.startsWith(CLASSPATH_URL_PREFIX)) {
        return new ClassPathResource(location.substring(CLASSPATH_URL_PREFIX.length()), getClassLoader());
    }
    else {
        try {
            // Try to parse the location as a URL...
            URL url = new URL(location);
            return new UrlResource(url);
        }
        catch (MalformedURLException ex) {
            // No URL -> resolve as resource path.
            return getResourceByPath(location);
        }
    }
}
 
 
Failed getResource
 
https://tomcat.apache.org/tomcat-8.0-doc/api/org/apache/catalina/webresources/StandardRoot.html#getResource(java.lang.String)
 
In this code, the prefix is not implemented so , I realized that I can't use "class:" prefix for the property of ServletContextTemplateResolver.
 
In org.apache.catalina.webresources.StandardRoot
 
@Override
public InputStream getResourceAsStream(String path) {

    if (path == null)
        return (null);

    if (!path.startsWith("/") && GET_RESOURCE_REQUIRE_SLASH)
        return null;

    WebResourceRoot resources = context.getResources();
    if (resources != null) {
         return resources.getResource(path).getInputStream();
    }

    return null;
}

原文：https://stackoverflow.com/questions/32157958