java - 使用 <a href =""> 从 servlet doGet() 方法从一个 servlet 重定向到另一个 servlet

Question

您好，我有一个问题:如何从启动 servlet 主体(doGet() 或 doPost())重定向到另一个 servlet 站点？

第一个 servlet:

public class StartingServlet extends HttpServlet 
{
private static final long serialVersionUID = 1L;

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException,IOException
    {
    PrintWriter out=response.getWriter();
    out.println("Strona startowa");
//      String go  ="http://localhost:8080/HelloWorld/test";        
//      response.sendRedirect(response.encodeRedirectURL(go));
        out.println("<a href=”http://localhost:8080/HelloWorld/test”> Hello World Servlet </a>");
    }

}

第二个servlet(我点击链接后想要进入的那个):

public class HelloWorldServlet extends HttpServlet
{

    private static final long serialVersionUID = 1L;

    protected void doGet(HttpServletRequest request,HttpServletResponse response)throws ServletException,IOException
    {
        PrintWriter out= response.getWriter();
        out.println("Hello World Servlet");

    }
}

web.xml 文件(启动 servlet 的 servlet-mappings url-pattern 故意为空):

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>HelloWorld</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>

  <servlet>
    <servlet-name>Starting servlet</servlet-name>
    <servlet-class>pl.javastart.servlets.StartingServlet</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>Starting servlet</servlet-name>
    <url-pattern></url-pattern>
  </servlet-mapping>

  <servlet>
    <servlet-name>Hello World Servlet</servlet-name>
    <servlet-class>pl.javastart.servlets.HelloWorldServlet</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>Hello World Servlet</servlet-name>
    <url-pattern>/test</url-pattern>
  </servlet-mapping>

</web-app>

我该怎么做？ 预先感谢您。

Answer 1

要重定向来自 servlet 的请求，您可以使用 sendRedirect 方法:

    response.sendRedirect("http://localhost:8080/HelloWorld/test");

顺便说一句，这个声明:

out.println("<a href=”http://localhost:8080/HelloWorld/test”> Hello World Servlet </a>");

只会在响应正文中发送链接，但不会重定向。