跟学习其它技术一样,首先到官网去下载必要的包,下载地址:http://velocity.apache.org/download.cgi目前使用的是velocity 1.6.3,由于自己的E文水平一般,在使用之前也到网上搜索了相关文章,然后根据前辈们的指导和自己的实践结合.记录下此文,以便以后能快速回忆.
一、在eclipse 中新建一个工程,把包velocity-1.6.3.jar到在WEB-INF/lib下，
二、新建了一个hello.vm的测式模板
Html代码
- <html>
- <head></head>
- <body>
- HELLO! $name,Welcome to velocity!
- </body>
- </html>
三、新建一个java属性文件 velocity.properties，参考了别人的配置示例，详细的说明以后再理解
Java代码
- #Velocity.properties配置示例
- # 如果需要系统从WEB-INF/classes路径加载Velocity的模板文件，取消下面两行的注释
- #resource.loader=class
- #class.resource.loader.class=org.apache.Velocity.runtime.resource.loader.ClasspathResourceLoader
- #如需禁止系统通过文件系统加载模板文件，注释如下两行
- resource.loader=file
- file.resource.loader.path=D:\Workspaces\MyEclipse 8.5\velocity\WebRoot\WEB-INF\velocityTempalte
- #确定从何处加载velocity的模板文件
- file.resource.loader.cache=false
- #设置读取模板文件的解码格式，GB2312是为了支持中文
- input.encoding=gb2312
- #配置输出视图文件的解码格式，GB2312是为了支持中文
- output.encoding=gb2312
四、新建一个测式类VelocityTest.java
Java代码
- package velocity.test;
- import java.io.FileOutputStream;
- import java.io.PrintWriter;
- import java.io.StringWriter;
- import org.apache.velocity.Template;
- import org.apache.velocity.VelocityContext;
- import org.apache.velocity.app.Velocity;
- public class VelocityTest {
- public static void main(String[] args) {
- try {
- // 初始化
- Velocity.init("D:\\Workspaces\\MyEclipse 8.5\\velocity\\WebRoot\\WEB-INF\\velocity.properties");
- //取得velocity上下文
- VelocityContext context = new VelocityContext();
- context.put("name", "sea");
- Template template = Velocity.getTemplate("hello.vm");
- StringWriter writer = new StringWriter();
- template.merge(context, writer);
- PrintWriter filewriter = new PrintWriter(new FileOutputStream("d:\\a.html"),true);
- filewriter.println(writer.toString());
- filewriter.close();
- } catch (Exception e) {
- e.printStackTrace();
- }
- }
- }
最后运行该类时出现如下错误：
Java代码
- Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/collections/ExtendedProperties
发现缺少了集合包，把velicity.1.6.3解压后的lib目录下的commons-collections-3.2.1.jar拷入工程的lib目录下，继续运行，还是出现以后错误：
Java代码
- org.apache.velocity.exception.VelocityException: Failed to initialize an instance of org.apache.velocity.runtime.log.ServletLogChute with the current runtime configuration.
- at org.apache.velocity.runtime.log.LogManager.createLogChute(LogManager.java:206)
- at org.apache.velocity.runtime.log.LogManager.updateLog(LogManager.java:255)
- at org.apache.velocity.runtime.RuntimeInstance.initializeLog(RuntimeInstance.java:795)
- at org.apache.velocity.runtime.RuntimeInstance.init(RuntimeInstance.java:250)
- at org.apache.velocity.runtime.RuntimeInstance.init(RuntimeInstance.java:615)
- at org.apache.velocity.runtime.RuntimeSingleton.init(RuntimeSingleton.java:243)
- at org.apache.velocity.app.Velocity.init(Velocity.java:93)
- at velocity.test.VelocityTest.main(VelocityTest.java:17)
- Caused by: java.lang.UnsupportedOperationException: Could not retrieve ServletContext from application attributes
- at org.apache.velocity.runtime.log.ServletLogChute.init(ServletLogChute.java:73)
- at org.apache.velocity.runtime.log.LogManager.createLogChute(LogManager.java:157)
- ... 7 more
最后分别把 commons-lang-2.4.jar和commons-logging-1.1.jar拷入lib目录才正常
输出d:\a.html下的文件如下
Java代码
- <html>
- <head></head>
- <body>
- HELLO! sea,Welcome to velocity!
- </body>
- </html>
时间： 2024-10-31 19:40:45