0.开发环境：MyEclipse10.7,jdk1.6,JAVAEE 6.0

1.相关jar包下载：

Engine，velocity-1.7和Tools，velocity-2.0都下载，包很多，我这个例子用到下面的包就可以跑起来：

2.配置，code

新建WebProject-->VelocityTest，创建完成后结构如下：

先在web.xml配置IndexServlet(EncodeFilter是处理字符编码的，我都是UTF-8的)，然后在IndexServlet里用velocity来处理页面。VelocityHelper.java是配置Velocity的。VelocityTest.java是测试的。下面我把代码一一贴出，这里是代码工程：

web.xml:


    
      
     	          
       	
      
       EncodeFilter
        	
      
       com.suchok.filter.EncodeFilter
        
       
       	
      
       EncodeFilter
        	
      
       /*
        
               
          
      
       velocity
           
      
       org.apache.velocity.tools.view.VelocityViewServlet
         
        
          
      
       velocity
           
      
       *.html
         
                     
       	
      
       IndexServlet
          
      
       com.suchok.IndexServlet
        
         
       	
      
       IndexServlet
        	
      
       /*
        
         
         
      
       index.jsp

IndexServlet.java

package com.suchok;import java.io.IOException;import java.io.PrintWriter;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import com.suchok.velocity.VelocityTest;public class IndexServlet extends HttpServlet{	/**	 * 	 */	private static final long serialVersionUID = 1L;	@Override	protected void doGet(HttpServletRequest req, HttpServletResponse resp)			throws ServletException, IOException {		process(req,resp);	}	@Override	protected void doPost(HttpServletRequest req, HttpServletResponse resp)			throws ServletException, IOException {		process(req,resp);	}		private void process(HttpServletRequest req, HttpServletResponse resp){		 PrintWriter out;		try {			resp.setContentType("text/html;charset=UTF-8");			out = resp.getWriter();			out.println(VelocityTest.HelloWorld());		} catch (IOException e) {			e.printStackTrace();		}	}}

EncodeFilter.java

package com.suchok.filter;import java.io.IOException;import javax.servlet.Filter;import javax.servlet.FilterChain;import javax.servlet.FilterConfig;import javax.servlet.ServletException;import javax.servlet.ServletRequest;import javax.servlet.ServletResponse;public class EncodeFilter implements Filter{	@Override	public void destroy() {			}	@Override	public void doFilter(ServletRequest arg0, ServletResponse arg1,			FilterChain arg2) throws IOException, ServletException {		arg0.setCharacterEncoding("utf-8");		arg2.doFilter(arg0, arg1);	}	@Override	public void init(FilterConfig arg0) throws ServletException {			}}

VelocityHelper.java

package com.suchok.velocity;import org.apache.log4j.Logger;import org.apache.velocity.Template;import org.apache.velocity.app.Velocity;public class VelocityHelper {	private static final String TMP_PATH="com/suchok/velocity/tmp";    public static Logger logger = Logger.getLogger(VelocityHelper.class);    static {       	//***find tmp file under class path    	Velocity.setProperty("file.resource.loader.class", "org.apache.velocity.runtime.resource.loader.ClasspathResourceLoader");         try {            Velocity.init();        } catch (Exception e) {            logger.error(e.getMessage(), e);        }    }    public static Template getTemplate(String fileName) throws Exception {        return Velocity.getTemplate(TMP_PATH+"/"+fileName, "UTF-8");    }}

VelocityTest.java

package com.suchok.velocity;import java.io.StringWriter;import org.apache.log4j.Logger;import org.apache.velocity.Template;import org.apache.velocity.VelocityContext;public class VelocityTest {	private static Logger logger = Logger.getLogger(VelocityTest.class);	public static String HelloWorld() {		StringWriter write = null;		try {			Template template = VelocityHelper.getTemplate("hello.html");			VelocityContext vc = new VelocityContext();			vc.put("title", "hello");			write = new StringWriter();			template.merge(vc, write);			write.flush();			write.close();		} catch (Exception e) {			logger.error(e.getMessage(), e);			e.printStackTrace();		}		return write == null ? "null" : write.toString();	}}

hello.html


    内容：$title

3.运行结果

4.感受

才开始学JAVAEE开发，用jsp感觉页面元素比较复杂，有时候要写java code，比较混乱，而velocity页面简单全是html和velocity标签即可，和以前用过php的smarty引擎一样，前端和后端分离了，更好维护了；jsp页面第一次要编译，然后再装载class文件，而velocity直接装载模板，暴露一些细节，但我觉得结构也清晰了。

转载于:https://my.oschina.net/yale8848/blog/167943

你可能感兴趣的文章