Question

这是一个Maven项目，我试图从servlet类打印hello，但它不打印。

这是我的web.xml文件

<!DOCTYPE web-app PUBLIC
 "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
 "http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>
  <display-name>Json</display-name>
   <servlet>
    <servlet-name>Login_Bridge</servlet-name>
    <servlet-class>com.ebooks.login.main.Login_Bridge</servlet-class>
  </servlet>

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

</web-app>

有人能弄明白我哪里错了吗？

这是我的index.jsp类，它包含一个简单的按钮。

    <html>
<body>
<h2>Hello World!!</h2>
    <form action="/Login_Bridge" method="get"><button>submit</button></form>

</body>

</html>

Login_Bridge代码

package com.ebooks.login.main;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.PrintWriter;
/**
 * Servlet implementation class Login_Bridge
 */
@WebServlet("/Login_Bridge")
public class Login_Bridge extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * Default constructor. 
     */
    public Login_Bridge() {
        // TODO Auto-generated constructor stub

    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        PrintWriter out=response.getWriter();
        out.println("hello");
        System.out.println("hello");
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub


        System.out.println("hello");
    }

}

Answer 1

尝试在此处具体说明servlet的url-pattern：

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

好的，试着改变这一行：

 <form action="Login_Bridge" method="get"><button>submit</button></form>

使用：

  <form action="Login_Bridge" method="get"> 
     <input type="submit" value="Submit"/>
  </form>

Answer 2

<!DOCTYPE web-app PUBLIC
 "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
 "http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>
  <display-name>Json</display-name>
   <servlet>
    <servlet-name>Login_Bridge</servlet-name>
    <servlet-class>com.ebooks.login.main.Login_Bridge</servlet-class>
  </servlet>

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

</web-app>

使用此代码更改您的web.xml文件，并阅读此link

并用此更改你的jsp。

<form action="/IN/Login_Bridge1" method="post"> 
     <input type="submit" value="Submit"/>
  </form>

无法打印＆＃34;您好＆＃34;来自servlet类的get方法

2 个答案: