package freemarker;import java.io.IOException;import java.io.Writer;import java.util.Map;import freemarker.core.Environment;import freemarker.template.TemplateDirectiveBody;import freemarker.template.TemplateDirectiveModel;import freemarker.template.TemplateException;import freemarker.template.TemplateModel;import freemarker.template.TemplateNumberModel;public class LabelDirective implements TemplateDirectiveModel {    @Override    public void execute(Environment env, Map params, TemplateModel[] loopVars,            TemplateDirectiveBody body) throws TemplateException, IOException {        Writer out = env.getOut();                //将模版里的数字参数转化成int类型的方法，，其它类型的转换请看freemarker文档        TemplateModel paramValue = (TemplateModel) params.get("num");        int num = ((TemplateNumberModel) paramValue).getAsNumber().intValue();                out.write("Akishimo num=" + params.get("num")+"的类型为:"+paramValue.getClass());        if (body != null) {            body.render(env.getOut());        }else{            throw new RuntimeException("标签内部至少要加一个空格");        }    }}

1 package freemarker; 2  3 import java.io.BufferedWriter; 4 import java.io.File; 5 import java.io.FileOutputStream; 6 import java.io.OutputStreamWriter; 7 import java.io.Writer; 8 import java.util.HashMap; 9 import java.util.Map;10 11 import freemarker.template.Configuration;12 import freemarker.template.DefaultObjectWrapper;13 import freemarker.template.Template;14 15 public class Test {16 17     public static void main(String[] args) throws Exception {18 19         Configuration cfg = new Configuration();20         //将写好的标签加入，起名叫label21         cfg.setSharedVariable("label", new LabelDirective());22         cfg.setDirectoryForTemplateLoading(new File("temp"));23         cfg.setObjectWrapper(new DefaultObjectWrapper());24 25         Template temp = cfg.getTemplate("list.ftl");26 27         Map root = new HashMap();28         root.put("user", "rzy");29 30         /* Writer out = new OutputStreamWriter(System.out); */31 32         File htmlFile = new File("E:/a.html");33         Writer out = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(htmlFile), "UTF-8"));34 35         temp.process(root, out);36         out.flush();37     }38 }

      
${user}自定义标签输出结果
<@label num=12>