velocity自定义标签实现给静态资源添加版本号

使用方法：

$staticFile.src("/css/main.css")

$staticFile.src("/js/common/jquery-1.9.1.min.js")

其中 $staticFile是我自定义的标签，src是其中的一个方法，用来引入静态资源文件，有兴趣的同学可以试试效果。

1、java代码

package com.jd.oms.web.util;

import java.io.File;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import org.apache.commons.lang.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.jd.oms.web.ControllerContext;

/**
*
* @author zhuzi
*
*/
public class VersionlizeStaticFileTag {

private static final long serialVersionUID = -5777586393588508658L;
private static Logger logger = LoggerFactory.getLogger(VersionlizeStaticFileTag.class);
private static Map<String, String> fileElementMap = new HashMap<String, String>();
private static String jsElementHead = "<script type=\"text/javascript\" src=\"";
private static String jsElementTail = "\"></script>\n";
private static String cssElementHead = "<link type=\"text/css\" rel=\"stylesheet\" href=\"";
private static String cssElementTail = "\"/>\n";
public final static int EVAL_BODY_INCLUDE = 1;

public String src(String filePath) {
HttpServletRequest request = ((ServletRequestAttributes)RequestContextHolder.getRequestAttributes()).getRequest();
if (StringUtils.isNotBlank(fileElementMap.get(filePath))) {
return fileElementMap.get(filePath);
}
String contextPath = request.getContextPath();
if (StringUtils.isNotBlank(fileElementMap.get(filePath))) {
return fileElementMap.get(filePath);
}
File file = new File(request.getSession().getServletContext().getRealPath(filePath));
if (!file.exists()) {
logger.info("staticResource filepath: "+filePath+" does not exist");
if (filePath.toLowerCase().endsWith("js")) {
StringBuilder jsElement =new StringBuilder();
jsElement.append(jsElementHead).append(contextPath).append(filePath).append(jsElementTail);
return jsElement.toString();
} else if (filePath.toLowerCase().endsWith("css")) {
StringBuilder cssElement =new StringBuilder();
cssElement.append(cssElementHead).append(contextPath).append(filePath).append(cssElementTail);
return cssElement.toString();
}
}
long lastModified = file.lastModified();
if (filePath.toLowerCase().endsWith("js")) {
StringBuilder jsElement =new StringBuilder();
jsElement.append(jsElementHead).append(contextPath).append(filePath).append("?v=").append(lastModified).append(jsElementTail);
fileElementMap.put(filePath, jsElement.toString());
return jsElement.toString();
} else if (filePath.toLowerCase().endsWith("css")) {
StringBuilder cssElement =new StringBuilder();
cssElement.append(cssElementHead).append(contextPath).append(filePath).append( "?v=").append(lastModified).append(cssElementTail);
fileElementMap.put(filePath, cssElement.toString());
return cssElement.toString();
}
logger.info("staticResource: "+filePath+" is uncorrect,it should be ended with css|js");
return filePath;
}

}

2、需要配置toolbox

<?xml version="1.0" encoding="UTF-8"?>
<!--
=============================================================
静态资源加载，自定义标签，使用方法：
$staticFile.src(arg),arg:js|css文件相对路径
=============================================================
-->

<toolbox>
<tool>
<key>staticFile</key>
<scope>application</scope>
<class>com.**.**.web.util.VersionlizeStaticFileTag</class>
</tool>

</toolbox>

3、velocity中配置视图的属性，这里toolbox.xml放在非/WEB路径下会报nullpoint，找不到文件，暂时没研究出未啥

<bean id="velocityViewResolver" class="org.springframework.web.servlet.view.velocity.VelocityLayoutViewResolver">
......
<property name="toolboxConfigLocation" value="/WEB-INF/vm/toolbox.xml" /><!--toolbox配置文件路径-->
......

</bean>