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 $site world!
HelloWorld.java
package com;
import java.io.StringWriter;
import org.apache.velocity.Template;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.app.VelocityEngine;
public class HelloWorld {
public static void main(String[] args) throws Exception {
/* first, get and initialize an engine */
VelocityEngine ve = new VelocityEngine();
ve.init();
/* next, get the Template */
Template t = ve.getTemplate("hellosite.vm");
/* create a context and add data */
VelocityContext context = new VelocityContext();
context.put("name", "DingDangXiaoMa");
context.put("site", "http://www.sun.com");
/* now render the template into a StringWriter */
StringWriter writer = new StringWriter();
t.merge(context, writer);
/* show the World */
System.out.println(writer.toString());
}
}
直接运行这个程序，就可以输入模板中的信息。
2。web程序，servlet 调用vm显示信息。
hello.vm 放在webRoot/web/下。
<html>
<body >
#set($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。
参考资料：
http://www.javaresearch.org/article/38895.htm