freemarker自定义标签的写法和使用

来源:转载

首先是下载freemarker的jar包:下载地址

写标签类(需要继承TemplateDirectiveModel接口重写execute方法)

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"); } }}

写配置和测试的类:

 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 }

模版list.ftl先这么写

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /><title>无标题文档</title></head><body><h1>${user}自定义标签输出结果</h1><br/><@label num=12> </@label></body></html>

运行后打开e盘里面生成的a.html结果为:

 

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