使用 servlet 和“setHeader"重定向请求方法不起作用 [英] Redirecting a request using servlets and the "setHeader" method not working
本文介绍了使用 servlet 和“setHeader"重定向请求方法不起作用的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我是 servlet 开发的新手，我正在阅读一本电子书，发现我可以使用
I am new to servlet development, and I was reading an ebook, and found that I can redirect to a different web page using
setHeader("Location", "http://www.google.com")
但这不起作用，因为我已将此代码编写为:
But this is not working, as I have written this code as:
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class ModHelloWorld extends HttpServlet{
public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException{
// response.addHeader("Location", "http://www.google.com");
response.setHeader("Location", "http://www.google.com");
response.setContentType("text/html");
PrintWriter pw = response.getWriter();
pw.println("<html><head><title>Modified Hello World</title></head><body>");
pw.println("<h1>");
//getInitParameter function reads the contents ot init-param elements.
pw.println(getInitParameter("message"));
pw.println("</h1>");
pw.println("</body></html>");
pw.close();
}
}
我已经使用我的程序检查了标题以获得网页的标题，如下所示:
i have checked the headers using my program to get the headers of the webpage which is as under:
import java.net.*;
import java.io.*;
class getHeaders{
public static void main(String args[]){
URL url = null;
URLConnection urc = null;
try {
url = new URL(args[0]);
urc = url.openConnection();
for(int i=0 ; ; i++) {
String name = urc.getHeaderFieldKey(i);
String value = urc.getHeaderField(i);
if(name == null && value == null)//both null so end of header
break;
else if(name == null){//first line of header{
System.out.println("Server HTTP version, Response code: ");
System.out.println(value);
System.out.println("ENd of first header field");
} else {
System.out.println("name of header is: " + name + " and its value is : " + value);
}
}
} catch(MalformedURLException e){
System.out.println("Malformed URL " + e.getMessage());
} catch(IOException e){
e.printStackTrace();
}
}
}
我得到的输出为:
Server HTTP version, Response code:
HTTP/1.1 200 OK
ENd of first header field
name of header is: Server and its value is : Apache-Coyote/1.1
name of header is: Location and its value is : http://www.google.com
name of header is: Content-Type and its value is : text/html
name of header is: Content-Length and its value is : 101
name of header is: Date and its value is : Sat, 05 Mar 2011 15:27:29 GMT
但我没有从浏览器重定向到 google 页面.
But I was not redirected to google's page from my browser.
提前致谢:)
推荐答案
如您所见，响应仍然是 HTTP/1.1 200 OK.要指示重定向，您需要发回 302 状态代码:
As you can see, the response is still HTTP/1.1 200 OK. To indicate a redirect, you need to send back a 302 status code:
response.setStatus(HttpServletResponse.SC_FOUND); // SC_FOUND = 302
这篇关于使用 servlet 和“setHeader"重定向请求方法不起作用的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
查看全文
