今天想复习一下servlet,采用Myeclipse新建了一个TestServlet类继承httpservlet,代码如下:
package edu.hubu.cst.testServlet;
import java.io.IOException;
import java.io.OutputStream;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class TestServlet extends HttpServlet {
public TestServlet(){
System.out.println("第一步:实例化");
}
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// super.doGet(req, resp);-------屏蔽此处即可
System.out.println("第三步:doGet请求");
System.out.println(req.getRequestURL());
// req.getRequestDispatcher("success.jsp").forward(req, resp);
resp.sendRedirect("success.jsp");
}
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// super.doPost(req, resp);------屏蔽此处即可
System.out.println("第三步:doPost请求");
}
public void destroy() {
super.destroy();
System.out.println("第四步:销毁");
}
public void init() throws ServletException {
super.init();
System.out.println("第二步:初始化");
}
}
访问时,一直报错:
type: Status report
message: HTTP method GET is not supported by this URL
description: The specified HTTP method is not allowed for the requested resource (HTTP
method GET is not supported by this URL).
经过上网查询,原因如下:
1,继承自HttpServlet的Servlet没有重写对于请求和响应的处理方法:doGet或doPost等方法;默认调
用父类的doGet或doPost等方法;
2,父类HttpServlet的doGet或doPost等方法覆盖了你重写的doGet或doPost等方法;
不管是1或2,父类HttpServlet的doGet或doPost等方法的默认实现是返回状态代码为405的HTTP错误表示
对于指定资源的请求方法不被允许。
解决方法:
1,子类重写doGet或doPost等方法;
2,在你扩展的Servlert中重写doGet或doPost等方法来处理请求和响应时 不要调用父类HttpServlet的
doGet或doPost等方法,即去掉super.doGet(request, response)和super.doPost(request, response);