Velocity简单用法

example.vm文件编码如下：

##开始

Hello from $name in the $project project.
#set( $this = "TestVelocity")

$this is the best great!

#foreach( $names in $lister )
    $names is very great!
#end

#set( $condition = true)

#if ($condition)
    The condition is true!
#else
    The condition is false!
#end

 

 

velocity.properties文件内容如下：

runtime.log = velocity_example.log

 

 

将上述两个文件放入工程目录下的新建文件夹vm里，然后可以设置路径，在下面的java文件中修改相应的路径就可以了。

 

java文件的编码

 

package app.example;

import org.apache.velocity.app.Velocity;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.Template;

import org.apache.velocity.exception.ParseErrorException;
import org.apache.velocity.exception.ResourceNotFoundException;

import java.io.*;
import java.util.ArrayList;

public class Example
{
    public Example(String templateFile)
    {
        try
        {
            Velocity.init("vm\\example\\velocity.properties ");

            VelocityContext context = new VelocityContext();
            context.put("lister", getNames());
            context.put("name", "Velocity;;;;;;;");
            context.put("project", "Jakarta....");
            StringWriter sw = new StringWriter();
            String s = "$lister";
            Velocity.evaluate( context, sw, "mystring", s );
            System.out.println(sw);

            Template template =  null;

            try
            {
                template = Velocity.getTemplate(templateFile);
            }
            catch( ResourceNotFoundException rnfe )
            {
                System.out.println("Example : error : cannot find template " + templateFile );
            }
            catch( ParseErrorException pee )
            {
                System.out.println("Example : Syntax error in template " + templateFile + ":" + pee );
            }

            BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(System.out));

            if ( template != null)
                template.merge(context, writer);

            writer.flush();         
            writer.close();
           
           
        
        }
        catch( Exception e )
        {
            System.out.println(e);
        }
    }

    public static ArrayList<String> getNames()
    {
        ArrayList<String> list = new ArrayList<String>();

        list.add("ArrayList element 1");
        list.add("ArrayList element 2");
        list.add("ArrayList element 3");
        list.add("ArrayList element 4");

        return list;
    }

    public static void main(String[] args)
    {
         Example t = new Example("vm\\example\\example.vm ");

 

//注释部分为另一种用法，效果类似。

 

    /* Velocity.init();
         
         VelocityContext context = new VelocityContext();
         context.put("name", "Velocity;;;;;;;");
         context.put("project", "Jakarta....");
         context.put("lister", getNames());
         StringWriter sw = new StringWriter();
         Velocity.mergeTemplate("vm\\example\\example.vm", "ISO-8859-1", context, sw );
         String a = sw.toString();
         System.out.println(a);*/
         
    }
}

 

运行结果（控制台输出）如下：

 

[ArrayList element 1, ArrayList element 2, ArrayList element 3, ArrayList element 4]
Hello from Velocity;;;;;;; in the Jakarta.... project.

TestVelocity is the best great!

    ArrayList element 1 is very great!
    ArrayList element 2 is very great!
    ArrayList element 3 is very great!
    ArrayList element 4 is very great!


    The condition is true!