如何使用 Freemarker 变量解析字符串 HTML

Question

我正在从数据库中检索一个包含 HTML 和 Freemarker 语法混合的字符串值。

像这样：

<p>${fragment.title}</p>
<table id='resultsTable' class='material-table'>
    <tr>
        <th>Instruction</th>
        <th>Action</th>
    </tr>
Test
</table>

以下是我在Freemarker模板中访问上述字符串的方式：

<#include "inc/header.ftl">
<body>
<#include "inc/navigation.ftl">
<div class="container">
    <div class="row">
        <#if fragments??>
            <#list fragments as fragment>
                <div class="col-sm-6">
                    <div class="fragment">
                        ${fragment.design?html}
                    </div>
                </div>              
            </#list>
        </#if>
    </div>
</div>
</body>
<#include "inc/footer.ftl">

但是输出不太正确：

<p>${fragment.title}</p> <table id='resultsTable' class='material-table'> <tr> struction</th> </th> </tr> ddd </table>

如何使用Freemarker同时解析HTML和${fragment.title}的值？

Answer 1

选项一：在java 控制器中处理您的字符串。这样你就不需要改变模板

@RequestMapping("/test2")
public ModelAndView test2() throws IOException, TemplateException {
    Map<String, String> fragment = new HashMap<>();
    fragment.put("title", "Some Title");
    ModelAndView model = new ModelAndView("index", "fragment", fragment);

    //your string should go here instead of this default
    String template = "<div>${fragment.title}</div> <div>some other test</div>";
    fragment.put("design", processTemplate(model.getModel(), template));

    return model;
}

private String processTemplate(Map model, String template)
        throws IOException, TemplateException {
    Template t = new Template("TemplateFromDBName", template,
            Environment.getCurrentEnvironment().getConfiguration());
    Writer out = new StringWriter();
    t.process(model, out);
    return out.toString();
}

模板部分：

<div class="fragment">
    ${fragment.design}
</div>

选项二：创建可在模板中使用的自定义 method expression。

// http://freemarker.org/docs/pgui_datamodel_method.html
public static class ProcessString implements TemplateMethodModelEx {

    public static final String PROCESS_STRING_FUNCTION_NAME = "processString";

    public TemplateModel exec(List args) throws TemplateModelException {
        if (args.size() != 1 ) throw new TemplateModelException("Wrong arguments");

        try {
            Environment env = Environment.getCurrentEnvironment();
            Template t = new Template("TemplateFromDBName", 
                    args.get(0).toString(), env.getConfiguration());

            Writer out = new StringWriter();
            t.process(env.getDataModel(), out);
            return new SimpleScalar(out.toString());
        } catch (IOException | TemplateException e) {
            e.printStackTrace();
        }

        return new SimpleScalar("");

    }
}

在配置中注册

@Configuration
public class FreeMarkerConfig extends WebMvcConfigurerAdapter {
    @Bean
    @Primary
    public FreeMarkerConfigurer freemarkerConfig( ) {
        FreeMarkerConfigurer freeMarkerConfigurer = new FreeMarkerConfigurer();
        // some other config here

        Map properties = new HashMap();
        properties.put(ProcessString.PROCESS_STRING_FUNCTION_NAME,
                new ProcessString());

        freeMarkerConfigurer.setFreemarkerVariables(properties);
        return freeMarkerConfigurer;
    }
}

模板将如下所示：

<div class="fragment">
    ${processString(fragment.design)}
</div>

但是控制器会很干净

@RequestMapping("/test")
public ModelAndView test() throws IOException, TemplateException {
    Map<String, String> fragment = new HashMap<>();
    fragment.put("title", "Some Title");
    fragment.put("design", "<div>${fragment.title}</div><div> other test</div>");
    return new ModelAndView("index", "fragment", fragment);
}

Answer 2

而不是 ${fragment.design?html}，使用 <@fragment.design?interpret />。

如何使用 Freemarker 变量解析字符串 HTML

How to parse String HTML with Freemarker variables

html

java

spring

freemarker

spring-boot