URL重寫

這幾天蛋疼.看看別人url重寫是怎麼搞的..
1.解釋下什麼事url重寫，以及它的優缺點：

URL重寫，其實就是把帶一大堆參數的url，變成一個看上去很規矩的url。
例：/viewthread.jsp?id=1234
重寫後，能夠用/viewthread/1234.html
1、自定義過濾器示例：

1.配置過濾器通常在web.xml中
<filter>
<filter-name>urlFilter</filter-name>
<filter-class>com.url.filter.URLFilter</filter-class>
</filter>

<filter-mapping>
<filter-name>urlFilter</filter-name>
<url-pattern>*.shtml</url-pattern>
</filter-mapping>
2.新建解析規則配置文件 urlrewrite.xml

<?xml version="1.0" encoding="utf-8"?>
<urlrewrite>
<rule>
<from>^/(\w+)_(\w+)_(\d+)\.shtml$</from> 匹配表達式-正則表達式
<to type="forward">/$1.do?$2=$3</to> 解析後URL
</rule>
</urlrewrite>
3.過濾器處理類 URLFilter.java
public class URLFilter implements Filter {
public void doFilter(ServletRequest servletRequest, ServletResponse
servletResponse, FilterChain filterChain) throws
IOException,ServletException
{
HttpServletRequest request = (HttpServletRequest) servletRequest;
HttpServletResponse response = (HttpServletResponse) servletResponse;
String realPath
=request.getSession().getServletContext().getRealPath("/");

String fileName = realPath + "WEB-INF\\urlrewrite.xml";
String uri = request.getServletPath();
String rewriteUrl = getRewriteUrl(uri, fileName);
if (null != rewriteUrl) {
request.getRequestDispatcher(rewriteUrl).forward(request, response);
return;
}
filterChain.doFilter(servletRequest, servletResponse);

}

private String getRewriteUrl(String url, String fileName) {
DocumentBuilderFactory f = DocumentBuilderFactory.newInstance();
try {
DocumentBuilder builder = f.newDocumentBuilder();
Document document = builder.parse(fileName);
NodeList list = document.getElementsByTagName_r("rule");
for (int i = 0; i < list.getLength(); i++) {
Element elemnt = (Element) list.item(i);
NodeList list2 = elemnt.getElementsByTagName_r("from");
Element element = (Element) list2.item(0);
String formValue = element.getFirstChild().getNodeValue();
NodeList list3 = elemnt.getElementsByTagName_r("to");
Element element2 = (Element) list3.item(0);
String type = element2.getAttribute("type");
String toValue = element2.getFirstChild().getNodeValue();
String rewriteUrl = url.replaceAll(formValue, toValue);
if (url != null && !"".equals(url.trim()) &&
!url.equals(rewriteUrl)) {

return rewriteUrl;

}

}

} catch (Exception ex) {

ex.printStackTrace();

}

return null;

}

}

2、 Tomcat的過濾器組件
1：下載urlrewrite-2.6.0.如今最新版本是3.1 的。
http://tuckey.org/urlrewrite/dist/urlrewritefilter-2.6.zip
http://urlrewritefilter.googlecode.com/files/urlrewritefilter-3.1.0.zip
把 urlrewrite-2.6.0.jar拷到classpath下。
2：在WEB-INF目錄下建一個urlrewrite.xml文件。
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE urlrewrite PUBLIC "-//tuckey.org//DTD UrlRewrite 2.6//EN"
"http://tuckey.org/res/dtds/urlrewrite2.6.dtd">
<urlrewrite>
<rule>
<from>^/(\w+)_(\w+)_(\d+)\.shtml$</from>
<to type="forward">/$1.do?$2=$3&amp;pageSize=15</to>
</rule>
</urlrewrite>
解釋：
<from></from>寫上你本身定義的訪問地址
<to type="forward></to>就是實際的訪問地址。
好比咱們實際的訪問地址是：
/URLRewriterDemo/ uRLTestAction.do?pageNumber=123
而咱們想把它重寫：
/URLRewriterDemo/uRLTestAction_pageNumber_123.shtml
這樣看起來比咱們實際的要好看的多。咱們就應該這樣的寫
<rule>
<from>^/(\w+)_(\w+)_(\d+)\.shtml$</from>
<to type="forward">/$1.do?$2=$3&amp;pageSize=15</to>
</rule>
注意：經常使用的&要用 &amp; 來表示。$1,$2表明與你配置正規表達式>/(\w+)/(\w+)/相對應的參數。<to type="forward">默認的是 type="forward".

3：在web.xml中初始化。加上下面的代碼：
<filter>
<filter-name>UrlRewriteFilter</filter-name>
<filter-class>
org.tuckey.web.filters.urlrewrite.UrlRewriteFilter
</filter-class>
</filter>
<filter-mapping>
<filter-name>UrlRewriteFilter</filter-name>
<url-pattern>*.shtml</url-pattern>
</filter-mapping>
3、使用系統的404錯誤進行
當請求時確定是找不見相關頁面了，那就跳到Error.jsp 進行相應的處理
1.加入錯誤跳轉配置 web.xml
<error-page>
<error-code>404</error-code>
<location>/error.jsp</location>
</error-page>
2.寫錯誤頁面 Error.jsp
<%@ page language="java" contentType="text/html; charset=GBK" pageEncoding="GBK"%>
<%
response.setStatus(HttpServletResponse.SC_OK);
String key = (String)
request.getAttribute("javax.servlet.forward.servlet_path");
String reg = "^/(\\w+)_(\\w+)_(\\d+).shtml$";
String rewriteUrl = key.replaceAll(reg,"/$1.do?$2=$3&amp;pageSize=15");
if(key != null || !key.equals(rewriteUrl)){
request.getRequestDispatcher(rewriteUrl).forward(request,response);
}
else{
out.print("對不起，您請求的頁面沒有找到! ");
}
%>