我尝试连接到我的Java EE项目上的mysql数据库，但是我收到错误，我不知道问题出在哪里。 这是SERVLET，CLASS和ERRORS
Java EE Servlet：
package com.hopital.servlet;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import com.hopital.database.Recup_Insert;
import com.hopital.forms.Connections;
@WebServlet("/hopital")
public class hopital extends HttpServlet {
private static final long serialVersionUID = 1L;
public hopital() {
super();
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//extrait les cookies
Cookie[] cookies= request.getCookies();
if(cookies != null){
for(Cookie cookie: cookies){
if(cookie.getName().equals("login")){
request.setAttribute("login", cookie.getValue());
}
}
}
//session
HttpSession session= request.getSession();
String login= (String) session.getAttribute("login");
request.setAttribute("login", login);
//extrait les chambers
Recup_Insert tableChamber= new Recup_Insert();
request.setAttribute("chambres",tableChamber.recup_chmabre());
this.getServletContext().getRequestDispatcher("/WEB-INF/home.jsp").forward(request,response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//verification de champs
Connections form= new Connections();
form.verifie(request);
request.setAttribute("form", form);
//stocke les champs entre
String login=request.getParameter("login");
String pass=request.getParameter("pass");
//cree un cookies
Cookie cookie=new Cookie("login",login);
cookie.setMaxAge(60*60*24*30);
response.addCookie(cookie);
// cree un session sur login et mot de passe
HttpSession session= request.getSession();
session.setAttribute("login", login);
session.setAttribute("pass", pass);
this.getServletContext().getRequestDispatcher("/WEB-INF/home.jsp").forward(request,response);
}
}
我的包含数据库连接的类：
package com.hopital.database;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.PreparedStatement;
import java.util.ArrayList;
import java.util.List;
import com.hopital.projet.chamber;
public class Recup_Insert {
public List<chamber> recup_chmabre(){
List<chamber> chambers= new ArrayList<chamber>();
//charger les drivers
try{
Class.forName("com.mysql.jdbc.Driver");
}catch( ClassNotFoundException e){
}
//Connexion
Connection connexion=null;
Statement statement=null;
ResultSet resultat = null;
try {
connexion = DriverManager.getConnection("jdbc:mysql://localhost:3306/hopital", "root", "3636");
statement= connexion.createStatement();
resultat= statement.executeQuery("SELECT * FROM CHAMBER;");
while(resultat.next()){
int etage = resultat.getInt("etage");
int ID_pat = resultat.getInt("ID_pat");
int num = resultat.getInt("num");
int nom_lits = resultat.getInt("nom_lits");
int occupee = resultat.getInt("occupee");
chamber chamber = new chamber();
chamber.setEtage(etage);
chamber.setID_pat(ID_pat);
chamber.setNum(num);
chamber.setOccupee(occupee);
chamber.setNom_lits(nom_lits);
chambers.add(chamber);
}
} catch (SQLException e) {
e.printStackTrace();
}finally{
try{
if(resultat != null)resultat.close();
if(statement != null)statement.close();
if(connexion != null)connexion.close();
}catch(SQLException ignore){
}
}
return chambers;
}
}
这是运行后的错误：
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:404)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:983)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:339)
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2252)
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2285)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2084)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:795)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:44)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:404)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:400)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:327)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at com.hopital.database.Recup_Insert.recup_chmabre(Recup_Insert.java:29)
at com.hopital.servlet.hopital.doGet(hopital.java:44)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:217)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:673)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1500)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1456)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Unknown Source)
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:214)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:298)
... 39 more
答案 0 :(得分：0)
检查连接URL和凭据。尝试使用某个SQL客户端连接相同的参数。
答案 1 :(得分：0)
您收到此错误，因为您无法连接到数据库。 很可能你没有启动服务器。检查它是否正在运行，然后仔细检查它运行的端口。还要检查数据库中表名的拼写，它应该是“hopital”。
答案 2 :(得分：0)
检查添加到属性=＆gt; libraries =＆gt; 的 mysql-connector-java-5.1.21-bin.jar 文件 如果没有那么添加外部jar =＆gt; mysql-connector-java-5.1.21-bin.jar
还要检查tomcat服务器和mysql的端口号。