velocity 例子

冷刃寒冰 2010-02-03

展开全文

最简单的hello world 程序。
基础搭建：从网上下载velocity.zip，把lib下的.jar文件导入到工程中。另外还要导入velocity.jar 和velocity-dep.jar.
hellosite.vm 放到工程的目录底下。

Hello $name! Welcome to $site world!

HelloWorld.java

package com;
import java.io.StringWriter;
import org.apache.velocity.Template;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.app.VelocityEngine;
public class HelloWorld {
    public static void main(String[] args) throws Exception {
        /* first, get and initialize an engine */
        VelocityEngine ve = new VelocityEngine();
        ve.init();
        /* next, get the Template */
        Template t = ve.getTemplate("hellosite.vm");
        /* create a context and add data */
        VelocityContext context = new VelocityContext();
        context.put("name", "DingDangXiaoMa");
        context.put("site", "http://www.");
        /* now render the template into a StringWriter */
        StringWriter writer = new StringWriter();
        t.merge(context, writer);
        /* show the World */
        System.out.println(writer.toString());
    }
}

直接运行这个程序，就可以输入模板中的信息。
2。web程序，servlet 调用vm显示信息。
hello.vm 放在webRoot/web/下。

html>
    <body >
     #set($name="Hello ! DingDang")
        Hello, $name
        woowoo
    </body>
</html>

servlet 文件：

public class SampleServlet extends VelocityServlet {
    protected Properties loadConfiguration(ServletConfig config)
            throws IOException, FileNotFoundException {
        Properties p = new Properties();
        String path = config.getServletContext().getRealPath("/");
        if (path == null) {
            System.out
                    .println(" SampleServlet.loadConfiguration() : unable to "
                            + "get the current webapp root.  Using '/'. Please fix.");
            path = "/";
        }
        p.setProperty(Velocity.FILE_RESOURCE_LOADER_PATH, path);
        p.setProperty("runtime.log", path + "velocity.log");
        return p;
    }
    public Template handleRequest(HttpServletRequest request,
            HttpServletResponse response, Context ctx) {
        /**
         * 我的一些测试输出
         */
        System.out.println("Hello  everyone");
        System.out.println("sfdsfsd");
        System.out.println(ctx);
        System.out.println(ctx.toString());
        System.out.println(request.getContextPath());
        Template template = null;

        try {
            /**
             * 主要代码
             */
            Velocity.init();
            /**
             * 注意相对路径
             */
            template = Velocity.getTemplate("/web/hello.vm");
            VelocityContext context = new VelocityContext();
            context.put("name", "wowowowowowo  hello   hello  hello");
            // template = Velocity.getTemplate("/web/sample.html");
        } catch (Exception e) {
            e.printStackTrace();
        }
        return template;
    }
}

以上就是两个最简单的velocity的例子。一个是java application 一个是java web程序。