有人問我,我再問別人也沒看到更好的提示,還是自己google。看到這個例子(http://www.51ajax.com/bbs/viewthread.php?tid=565):
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在此說明解決方法: 同樣類似使用代理的意念,在java內寫一個servlet來處理這個問題。
詳細處理方式是:1.首先,同樣使用xmlhttp方式處理;
2.然後,在進行open提交的時候,不直接提交到對應數據源所在的URL地址。而是提交到代理程序,而通過代理程序打開需要讀取的數據源URL,同時處理讀取並返回。
3.最後,重新用xmlhttp進行解析顯示處理即可以實現跨域讀取RSS源。
修改上面的js代碼:
var PROXY_SERVLET_URL="../../proxyServlet?url=";//對應配置的servlet參數
if(url.toLowerCase().indexOf("[url=http://]http://")==-1[/url]){
readRSS(url);
}else{
url = PROXY_SERVLET_URL + url;
readRSS(url);
}
java源代碼如下:
package action;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;
import java.net.URLConnection;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ProxyServletUtil extends HttpServlet {
/**
*
*/
private static final long serialVersionUID = 1L;
private int READ_BUFFER_SIZE = 1024;
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String urlString = request.getParameter("url");
writeResponse(response, urlString);
}
private void writeResponse(HttpServletResponse response, String urlString) throws ServletException{
try {
URL url = new URL(urlString);
URLConnection urlConnection = url.openConnection();
response.setContentType(urlConnection.getContentType());
InputStream ins = urlConnection.getInputStream();
OutputStream outs = response.getOutputStream();
byte[] buffer = new byte[READ_BUFFER_SIZE];
int bytesRead = 0;
while ((bytesRead = ins.read(buffer, 0, READ_BUFFER_SIZE)) != -1) {
outs.write(buffer, 0, bytesRead);
}
System.out.println(outs);
outs.flush();
outs.close();
ins.close();
} catch (Exception e) {
try {
response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, e.getMessage());
} catch (IOException ioe) {
throw new ServletException(ioe);
}
}
}
}
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原來想用一個javascript寫的例子就最好了,直接給不大會編程的人也容易懂些。現在看,可以採用上面的方式,不過我覺得我還是直接用java寫個程序來實現就得了。servlet + xmlhttp 稍微有點不大好懂。