/*這個(gè)Servlet要用到后面給出的SearchSpec類*/
package search;

import java.io.*; 
import javax.servlet.*; 
import javax.servlet.http.*; 
import java.net.*; 

public class SearchEngines extends HttpServlet { 
public void doGet(HttpServletRequest request,HttpServletResponse response) 
throws ServletException, IOException { 
/*getParameter自動(dòng)解碼URL編碼的查詢字符串。
由于我們要把查詢字符串發(fā)送給另一個(gè)服務(wù)器，因此再次使用URLEncoder進(jìn)行URL編碼 */
String searchString = 
	URLEncoder.encode(request.getParameter("searchString")); 
String numResults = 
	request.getParameter("numResults"); 
String searchEngine = 
	request.getParameter("searchEngine"); 
SearchSpec[] commonSpecs = SearchSpec.getCommonSpecs(); 
for(int i=0; i<commonSpecs.length; i++) 
{ 
	SearchSpec searchSpec = commonSpecs[i]; 
	//如果匹配了用戶指定的搜索引擎
	if (searchSpec.getName().equals(searchEngine)) { 
	//
	String url = response.encodeURL(searchSpec.makeURL(searchString,numResults)); 
	//將響應(yīng)重定位到url
	response.sendRedirect(url); 
	return; 
	} 
} 

//發(fā)一個(gè)錯(cuò)誤重定位，SC_NOT_FOUND是HTTP狀態(tài)代碼，即404 page not found
response.sendError(response.SC_NOT_FOUND, 
"No recognized search engine specified."); 
} 

public void doPost(HttpServletRequest request, 
HttpServletResponse response) 
throws ServletException, IOException { 
doGet(request, response); 
} 
}