不能與這個servlet

這是我的servlet不能與這個servlet

import java.io.IOException; 
import java.io.PrintWriter; 
import java.sql.Connection; 
import java.sql.DriverManager; 
import java.sql.PreparedStatement; 
import java.sql.ResultSet; 
import java.sql.SQLException; 

import javax.servlet.Servlet; 
import javax.servlet.ServletConfig; 
import javax.servlet.ServletContext; 
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 org.json.JSONObject; 
import org.json.simple.JSONObject; 

import com.mysql.jdbc.Statement; 
/** 
* Servlet implementation class Login 
*/ 
@WebServlet("/Login") 
public class Login extends HttpServlet { 
    private static final long serialVersionUID = 1L; 
    private Connection connection; 
    /** 
    * @see HttpServlet#HttpServlet() 
    */ 
    public Login() { 
     super(); 
     // TODO Auto-generated constructor stub 
    } 

    public void init(ServletConfig config) throws ServletException { 
     ServletContext context = config.getServletContext(); 
     String url = context.getInitParameter("dbUrl"); 
     String dbUser = context.getInitParameter("dbUser"); 
     String dbPassword = context.getInitParameter("dbPassword"); 
     try { 
      Class.forName("com.mysql.jdbc.Driver"); 
      connection = DriverManager.getConnection(url, dbUser, dbPassword); 
     } catch (ClassNotFoundException | SQLException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } 
    } 

    public void destroy() { 
     if (connection != null) { 
      try { 
       connection.close(); 
      } catch (SQLException e) { 
      } 
     } 
    } 
    /** 
    * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) 
    */ 
    @Override 
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
     doPost(request, response); 

    } 

    /** 
    * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) 
    */ 
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
     response.setContentType("plain/text"); 

     JSONObject json = new JSONObject(); 
     PrintWriter out = response.getWriter(); 
     String usernameV = request.getParameter("usernameV"); 
     String passwordV = request.getParameter("passwordV"); 

     json.put("ris", 0); 
     try { 
      String sql = "SELECT * FROM user WHERE username = ? AND password = ? ";   
      PreparedStatement stmt = connection.prepareStatement(sql); 
      stmt.setString(1, usernameV); 
      stmt.setString(2, passwordV); 
      json.put("password", usernameV); 
      json.put("username", usernameV); 

      out.print(json.toJSONString()); 
      ResultSet rs = stmt.executeQuery(); 
      if (rs.next()) { 
       json.replace("ris", 1); 
       out.print(json.toJSONString()); 
       stmt.close(); 
       rs.close(); 
       return; 
      } 
      stmt.close(); 
      rs.close(); 
     } catch (SQLException e) { 
      json.replace("err", e.getMessage()); 
      out.print(json.toJSONString()); 

     } 


     out.print(json.toJSONString());`` 
    } 

    }

處理POST請求，這裏是我的javascript

$(document).ready(function() { 
 
\t $(window).keydown(function(event){//impedisco l'invio del form premendo invio 
 
\t \t if(event.keyCode == 13) { 
 
\t \t \t event.preventDefault(); 
 
\t \t \t return false; 
 
\t \t } 
 
\t }); 
 
\t 
 
\t $("#bottone").click(function(){ 
 
\t \t $("#risultato").attr("style", "color: black;"); 
 
\t \t $("#risultato").html("Caricamento..."); \t 
 
\t \t var username = $("#username").val(); 
 
\t \t var password = $("#password").val(); 
 
\t \t $.ajax({ 
 
\t \t \t type: "POST", 
 
\t \t \t url: "Register", 
 
\t \t \t //data: {"username" : username, "password": password}, 
 
\t \t \t data: "username=" + username + "&password=" + password, 
 
\t \t \t dataType: "text", 
 
\t \t \t success: function(msg) 
 
\t \t \t { \t \t \t \t 
 
\t \t \t \t var result = $.parseJSON(msg); \t \t \t \t 
 
\t \t \t \t if(result.error){ 
 
\t \t \t \t \t switch (result.error) { 
 
\t \t \t \t \t case 1: 
 
\t \t \t \t \t \t Step(); 
 
\t \t \t \t \t \t  
 
\t \t \t \t \t \t break; 
 
\t \t \t \t \t default: 
 
\t \t \t \t \t \t $("#risultato").html(msg); 
 
\t \t \t \t \t break; 
 
\t \t \t \t \t } 
 
\t \t \t \t }else{ 
 
\t \t \t \t \t $("#bottone").prop('disabled', true); 
 
\t \t \t \t \t $("#risultato").attr("style", "color: black;"); 
 
\t \t \t \t \t $("#risultato").html("Benvenuto " + username + "!"); 
 
\t \t \t \t } \t \t \t \t \t   
 
\t \t \t }, 
 
\t \t \t error: function() 
 
\t \t \t { 
 
\t \t \t \t $("#risultato").attr("style", "color: red;"); 
 
\t \t \t \t $("#risultato").html("Errore di connessione!"); 
 
\t \t \t } 
 
\t \t }); 
 
\t }); 
 
}); 
 

 
function Step() { 
 
\t $("#risultato").attr("style", "color: red;"); 
 
\t $("#risultato").html("Username gi&agrave; esistente!<br>"); 
 
\t $("#risultato").append("<p>Inserisci la tua password : <input type='password' name='passwordV' id='passwordV'> <input type='button' id='bottone1' value='Login'> </p>"); 
 
\t 
 
\t $("#bottone1").click(function(){ 
 
\t \t $("#res").attr("style", "color: black;"); 
 
\t \t $("#res").html("Caricamento..."); \t 
 
\t \t var username = $("#username").val(); 
 
\t \t var password = $("#passwordV").val(); 
 
\t $.ajax({ 
 
\t \t type: "POST", 
 
\t \t url: "Login", 
 
\t \t data: "usernameV=" + username + "&passwordV=" + password, 
 
\t \t dataType: "text", 
 
\t \t success: function(msg) 
 
\t \t { \t \t \t \t 
 
\t \t \t var resulto = $.parseJSON(msg); \t \t \t \t 
 
\t \t \t if(resulto.ris){ 
 
\t \t \t \t switch (resulto.ris) { 
 
\t \t \t \t case 1: 
 
\t \t \t \t \t $("#res").attr("style", "color: red;"); 
 
\t \t \t \t \t $("#res").html("Benvenuto " + username + "!"); 
 
\t \t \t \t \t  
 
\t \t \t \t \t break; 
 
\t \t \t \t default: 
 
\t \t \t \t \t $("#res").html(msg); 
 
\t \t \t \t break; 
 
\t \t \t \t } 
 
\t \t \t }else{ 
 
\t \t \t \t $("#bottone1").prop('disabled', true); 
 
\t \t \t \t $("#res").attr("style", "color: black;"); 
 
\t \t \t \t $("#res").html("password errata:"+ password); 
 
\t \t \t \t $("#stack").attr("style", "color: black;"); 
 
\t \t \t \t $("#stack").html(msg); 
 
\t \t \t } \t \t \t \t \t   
 
\t \t }, 
 
\t \t error: function() 
 
\t \t { 
 
\t \t \t $("#res").attr("style", "color: red;"); 
 
\t \t \t $("#res").html("Errore di connessione!"); 
 
\t \t } 
 
\t }); 
 
\t }); 
 
} 
 

 
\t 
 
\t \t \t \t 
 
\t 
 
\t 
 
\t

如果有幫助，我也張貼的Default.jsp頁：

<%@ page language="java" contentType="text/html; charset=ISO-8859-1" 
    pageEncoding="ISO-8859-1"%> 
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 
<html> 
<head> 
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> 
<title>Chat Room</title> 
<script type="text/javascript" src="jquery-3.2.0.js"></script> 
<script type="text/javascript" src="script.js"></script> 
</head> 
<body> 

    <form name="modulo" action=""> 
     <p> 
      Nome utente: <input type="text" name="username" id="username"> 
      Password: <input type="password" name="password" id="password"> 
      <input type="button" id="bottone" value="Registrati!"> 
     </p> 
    </form> 
    <div id="risultato"></div> 
    <div id ="res"></div> 
    <div id="stack"></div> 


</body> 
</html>

我還添加Register.java s ervlet ..這個可以工作，而且，正如你所看到的，它幾乎和登錄一樣。

package it.marco.chat.servlets; 

import java.io.IOException; 
import java.io.PrintWriter; 
import java.sql.Connection; 
import java.sql.DriverManager; 
import java.sql.PreparedStatement; 
import java.sql.ResultSet; 
import java.sql.SQLException; 

import javax.servlet.Servlet; 
import javax.servlet.ServletConfig; 
import javax.servlet.ServletContext; 
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 org.json.JSONObject; 
import org.json.simple.JSONObject; 

import com.mysql.jdbc.Statement; 

/** 
* Servlet implementation class Register 
*/ 
@WebServlet("/Register") 
public class Register extends HttpServlet { 
    private static final long serialVersionUID = 1L; 
    private Connection connection; 

    /** 
    * @see HttpServlet#HttpServlet() 
    */ 
    public Register() { 
     super(); 
    } 

    /** 
    * @see Servlet#init(ServletConfig) 
    */ 
    public void init(ServletConfig config) throws ServletException { 
     ServletContext context = config.getServletContext(); 
     String url = context.getInitParameter("dbUrl"); 
     String dbUser = context.getInitParameter("dbUser"); 
     String dbPassword = context.getInitParameter("dbPassword"); 
     try { 
      Class.forName("com.mysql.jdbc.Driver"); 
      connection = DriverManager.getConnection(url, dbUser, dbPassword); 
     } catch (ClassNotFoundException | SQLException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } 
    } 

    /** 
    * @see Servlet#destroy() 
    */ 
    public void destroy() { 
     if (connection != null) { 
      try { 
       connection.close(); 
      } catch (SQLException e) { 
      } 
     } 
    } 

    @Override 
    protected void doGet(HttpServletRequest request, HttpServletResponse response) 
      throws ServletException, IOException { 
     doPost(request, response); 
    } 

    /** 
    * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse 
    *  response) 
    */ 
    protected void doPost(HttpServletRequest request, HttpServletResponse response) 
      throws ServletException, IOException { 
     response.setContentType("plain/text"); 

     JSONObject json = new JSONObject(); 
     PrintWriter out = response.getWriter(); 
     json.put("error", 0); 


     String username = request.getParameter("username"); 
     String password = request.getParameter("password"); 


     try { 
      String sql = "SELECT * FROM user WHERE username = ?";   
      PreparedStatement stmt = connection.prepareStatement(sql); 
      stmt.setString(1, username); 
      ResultSet rs = stmt.executeQuery(); 
      if (rs.next()) { 
       json.replace("error", 1); 
       out.print(json.toJSONString()); 
       stmt.close(); 
       rs.close(); 
       return; 
      } 
      stmt.close(); 
      rs.close(); 
     } catch (SQLException e) { 
     } 


     int uid = -1; 

     try { 
      String sql = "INSERT INTO user(username,password) VALUES(?,?)"; 
      PreparedStatement stmt = connection.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS); 
      stmt.setString(1, username); 
      stmt.setString(2, password); 
      stmt.execute(); 
      ResultSet rs = stmt.getGeneratedKeys(); 
      if (rs.next()) { 
       uid = rs.getInt(1); 
      } 
      stmt.close(); 
      rs.close(); 
     } catch (SQLException e) { 
      e.printStackTrace(); 
     } 


     json.put("uid", uid); 

     out.print(json.toJSONString()); 
    } 

}

我不明白爲什麼在servlet無法處理POST請求。我的意思是，我已經建立了一個servlet，它hanldles寄存器組成部分，它完美的作品。我已經嘗試了所有的晚上，使其工作，我很確定有一個愚蠢的錯誤，我無法看到，這就是爲什麼我來到這裏。我希望有人能夠幫助我。謝謝

來源

2017-04-01 cancer

什麼是你得到的迴應？如果您在瀏覽器中打開檢查元素>網絡，響應是什麼？ –

它打印「Errore迪CONNESSIONE！」，這是印刷時，我在$就 – cancer

錯誤，您可以將您的HTML請 – Yussef

改變這一點：

@WebServlet("/Login")

到

@WebServlet(name = "Login", urlPatterns = { "/Login" })

，將工作相信我

來源

2017-04-01 22:18:39 Yussef

不，不幸的是，我剛剛嘗試過。順便說一句，處理註冊部分的其他servlet幾乎與這個一樣寫。所以我不明白爲什麼登錄。java不起作用 – cancer

好的，你可以讓我告訴你的改變，然後編譯和刷新並重新啓動服務器，請我真的做你說的話 – Yussef

不能與這個servlet

回答

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