Question

我想写一些像：

    @Autowired
    private SpringTemplateEngine engine;
....
  // Thymeleaf Context
  WebContext thymeleafContext = new WebContext(request, response, request.getServletContext(), locale);

    // cached html of a thymeleaf template file
    String cachedHtml=....

    // process the cached html
  String html=engine.process(cachedHtml, thymeleafContext);

默认情况下，[process]方法无法执行此操作。我可以从文档中了解到我需要一个特殊的模板解析器：

为了执行模板，将使用进程（String，IContext）方法： final String result = templateEngine.process（＆＃34; mytemplate＆＃34;，ctx）; ＆＃34; mytemplate＆＃34; String参数是模板名称，它将以模板解析器配置的方式与模板本身的物理/逻辑位置相关。

有谁知道如何解决我的问题？

目标是将Thymeleaf模板（文件）缓存在字符串中，然后处理这些字符串而不是文件。

Answer 1

我们最终使用的解决方案包含一个新的IResourceResolver，其中包含自定义Context而非自定义TemplateResolver。我们选择这个是因为我们仍然希望在大多数情况下使用类路径扫描，但偶尔会有动态内容。

以下显示我们是如何做到的：

public class StringAndClassLoaderResourceResolver implements IResourceResolver {


    public StringAndClassLoaderResourceResolver() {
        super();
    }


    public String getName() {
        return getClass().getName().toUpperCase();
    }


    public InputStream getResourceAsStream(final TemplateProcessingParameters params, final String resourceName) {
        Validate.notNull(resourceName, "Resource name cannot be null");
        if( StringContext.class.isAssignableFrom( params.getContext().getClass() ) ){
            String content = ((StringContext)params.getContext()).getContent();
            return IOUtils.toInputStream(content);
        }
        return ClassLoaderUtils.getClassLoader(ClassLoaderResourceResolver.class).getResourceAsStream(resourceName);
    }

    public static class StringContext extends Context{

        private final String content;

        public StringContext(String content) {
            this.content = content;
        }

        public StringContext(String content, Locale locale) {
            super(locale);
            this.content = content;
        }

        public StringContext(String content, Locale locale, Map<String, ?> variables) {
            super(locale, variables);
            this.content = content;
        }

        public String getContent() {
            return content;
        }
    }

测试用例

public class StringAndClassLoaderResourceResolverTest {

    private static SpringTemplateEngine templateEngine;

    @BeforeClass
    public static void setup(){
        TemplateResolver resolver = new TemplateResolver();
        resolver.setResourceResolver(new StringAndClassLoaderResourceResolver());
        resolver.setPrefix("mail/"); // src/test/resources/mail
        resolver.setSuffix(".html");
        resolver.setTemplateMode("LEGACYHTML5");
        resolver.setCharacterEncoding(CharEncoding.UTF_8);
        resolver.setOrder(1);

        templateEngine = new SpringTemplateEngine();
        templateEngine.setTemplateResolver(resolver);
    }

    @Test
    public void testStringResolution() {
        String expected = "<div>dave</div>";
        String input = "<div th:text=\"${userName}\">Some Username Here!</div>";
        IContext context = new StringAndClassLoaderResourceResolver.StringContext(input);
        context.getVariables().put("userName", "dave");
        String actual = templateEngine.process("redundant", context);
        assertEquals(expected, actual);
    }

    @Test
    public void testClasspathResolution(){
        IContext context = new Context();
        context.getVariables().put("message", "Hello Thymeleaf!");
        String actual = templateEngine.process("dummy", context);
        String expected = "<h1>Hello Thymeleaf!</h1>";
        assertEquals(expected, actual);
    }
}

src / main / resources / mail / dummy.html中的虚拟模板文件

<h1 th:text="${message}">A message will go here!</h1>

注意：我们使用Apache CommonsIO的 IOUtils 将String转换为InputStream

Answer 2

您可以实施自己的TemplateResolver和IResourceResolver以使用String。

Answer 3

用于简单的单元测试：

static class TestResourceResolver implements IResourceResolver {
    public String content = "";

    @Override
    public String getName() {
        return "TestTemplateResolver";
    }

    @Override
    public InputStream getResourceAsStream(TemplateProcessingParameters templateProcessingParameters,
            String resourceName) {
        return new ByteArrayInputStream(content.getBytes());
    }
}

或仅在Thymeleaf 3中使用org.thymeleaf.templateresolver.StringTemplateResolver

Answer 4

是的，可以使用StringTemplateResolver。

public class ReportTemplateEngine {

    private static TemplateEngine instance;

    private ReportTemplateEngine() {}

    public static TemplateEngine getInstance() {
        if(instance == null){
            synchronized (ReportTemplateEngine.class) {
                if(instance == null) {
                    instance = new TemplateEngine();
                    StringTemplateResolver templateResolver = new StringTemplateResolver();
                    templateResolver.setTemplateMode(TemplateMode.HTML);
                    instance.setTemplateResolver(templateResolver);
                }
            }
        }
        return instance;
    }
}

有没有办法让Spring Thymeleaf进程成为一个字符串模板？

4 个答案: