Java 已连接到数据库，但无法执行操作

我正在尝试从应用程序访问SQL server数据库。从我的连接工厂类连接成功，但由于某种原因，我为登录而触发的JDBC查询无法获取任何详细信息。SQL Server安装在本地计算机中，并且所有用户和数据库都存在。所有依赖库都已成功导入并放置在WEB-INF/lib文件夹中，供WEB应用程序访问。（基本上没有外部依赖关系。）我已经使用SQLServerManagementStudio从前端测试了登录servlet中使用的查询，它正确地获取了详细信息。我无法理解查询在哪里失败

以下是connection factory类的代码

package com.util;
import java.sql.*;

public class ConnectionFactory {

    static String url="jdbc:sqlserver://localhost:1433;DatabaseName=Portal";
    static String uname="Portal";
    static String pass="portal_1";
    static String driverclass="com.microsoft.sqlserver.jdbc.SQLServerDriver";

    private ConnectionFactory(){

    }

    public static Connection getConn() throws ClassNotFoundException, SQLException{
        Class.forName(driverclass);
        Connection connection = DriverManager.getConnection(url, uname, pass);
        return connection;
    }
}

我使用这个类创建并返回一个连接对象，只要需要连接到数据库

下面是登录模块，它是一个servlet，当用户在输入凭证后单击索引页面中的登录时，我使用它执行登录操作

import com.util.CommonOps;
import com.util.ConnectionFactory;

/**
 * Servlet implementation class Login
 */
public class Login extends HttpServlet {
    private static final long serialVersionUID = 1L;

/**
 * @see HttpServlet#HttpServlet()
 */
public Login() {
    super();
    // TODO Auto-generated constructor stub
}

/**
 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
 *      response)
 */
protected void doPost(HttpServletRequest request,
        HttpServletResponse response) throws ServletException, IOException {

    HttpSession sess = request.getSession();

    String uname = (String) request.getParameter("uname");
    String pass = (String) request.getParameter("pass");

    // System.out.println(pass);
    uname = CommonOps.sanitzeData(uname);
    pass = CommonOps.sanitzeData(pass);

    // System.out.println(pass);

    // Username can be in any case.can It will take the upper case value by
    // default.

    uname = uname.toUpperCase();
    uname = uname.trim();

    if (uname == null) {
        response.sendRedirect("index.jsp");
        sess.setAttribute("msg", "Invalid Username or Password");
    } else if (pass == null) {
        sess.setAttribute("msg", "Invalid Username or Password");
        response.sendRedirect("index.jsp");
    } else {
        String pass_hash = CommonOps.getHash(pass);

        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;

        try {
            // System.out.println("Inside Try block");
            conn = ConnectionFactory.getConn();
            if(conn == null){
                System.out.println("Connection Failed");
            }
            else{
                System.out.println("Connection Successful");
            }
            System.out.println(conn);
            try {
                stmt = conn.createStatement();
                try {

                    System.out.println(uname);
                    System.out.println(pass_hash);

                    sql = "select lg_uname, lg_pwd, lg_u_role from login where lg_uname='"
                                    + uname
                                    + "' and lg_pwd='"
                                    + pass_hash
                                    + "' "
                                    + "and lg_del_flg='N'"
                                    + "and lg_entity_cre_flg='Y'";

                    System.out.println(sql);

                    rs = stmt.executeQuery(sql);

                    if (rs.next()) {

                        sess.setAttribute("uname", uname);
                        String role = rs.getString(3);
                        sess.setAttribute("role", role);

                        response.sendRedirect("redirect_home.jsp");

                    } else {
                        // System.out.println("Outside while block");
                        sess.setAttribute("msg",
                                "Invalid Username or Password");
                        response.sendRedirect("index.jsp");
                    }
                } catch (SQLSyntaxErrorException sql) {
                    sess.setAttribute("msg", "Invalid Username or Password");
                    response.sendRedirect("index.jsp");
                } catch (Exception e) {
                    e.printStackTrace();
                } finally {
                    if (rs != null)
                        rs.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
                System.out.println("Error when closing result set");
            } finally {
                if (stmt != null)
                    stmt.close();
            }

        } catch (Exception e) {
            e.printStackTrace();
            System.out.println("Error when closing statement");
        } finally {
            if (conn != null)
                try {
                    conn.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                    System.out.println("Error when closing connection");
                }
        }

    }
}
}

我插入了一些print语句，以检查是否正在建立连接，以及是否正在将有效数据传递给servlet和数据库

下面是我点击登录按钮时得到的错误堆栈跟踪

Dec 8, 2016 11:51:52 AM org.apache.catalina.core.AprLifecycleListener init
INFO: The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: C:\Program Files\Java\jre6\bin;C:\Windows\Sun\Java\bin;C:\Windows\system32;C:\Windows;C:/Program Files/Java/jre6/bin/client;C:/Program Files/Java/jre6/bin;C:/Program Files/Java/jre6/lib/i386;E:\app\IAS_Admin\product\11.2.0\client_1;E:\app\IAS_Admin\product\11.2.0\client_1\bin;E:\oracle\oraclient\bin;C:\Program Files\Oracle\jre\1.1.7\bin;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Program Files\Microsoft SQL Server\80\Tools\Binn\;C:\Program Files\Microsoft SQL Server\90\Tools\binn\;C:\Program Files\Microsoft SQL Server\90\DTS\Binn\;C:\Program Files\Microsoft SQL Server\90\Tools\Binn\VSShell\Common7\IDE\;C:\Program Files\Microsoft Visual Studio 8\Common7\IDE\PrivateAssemblies\;E:\oracle\oraclient\orb\bin;C:\Program Files\Microsoft SQL Server\100\Tools\Binn\;C:\Program Files\Microsoft SQL Server\100\DTS\Binn\;C:\Program Files\Microsoft SQL Server\100\Tools\Binn\VSShell\Common7\IDE\;C:\Program Files\Microsoft Visual Studio 9.0\Common7\IDE\PrivateAssemblies\;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\StaffPortalWork\Software\eclipse-jee-indigo-SR2-win32\eclipse;;.
Dec 8, 2016 11:51:52 AM org.apache.tomcat.util.digester.SetPropertiesRule begin
WARNING: [SetPropertiesRule]{Server/Service/Engine/Host/Context} Setting property 'source' to 'org.eclipse.jst.jee.server:StaffPortalMasterTemplate' did not find a matching property.
Dec 8, 2016 11:51:52 AM org.apache.coyote.http11.Http11Protocol init
INFO: Initializing Coyote HTTP/1.1 on http-8020
Dec 8, 2016 11:51:52 AM org.apache.catalina.startup.Catalina load
INFO: Initialization processed in 375 ms
Dec 8, 2016 11:51:52 AM org.apache.catalina.core.StandardService start
INFO: Starting service Catalina
Dec 8, 2016 11:51:52 AM org.apache.catalina.core.StandardEngine start
INFO: Starting Servlet Engine: Apache Tomcat/6.0.41
Dec 8, 2016 11:51:52 AM org.apache.coyote.http11.Http11Protocol start
INFO: Starting Coyote HTTP/1.1 on http-8020
Dec 8, 2016 11:51:52 AM org.apache.jk.common.ChannelSocket init
INFO: JK: ajp13 listening on /0.0.0.0:8009
Dec 8, 2016 11:51:52 AM org.apache.jk.server.JkMain start
INFO: Jk running ID=0 time=0/16  config=null
Dec 8, 2016 11:51:52 AM org.apache.catalina.startup.Catalina start
INFO: Server startup in 332 ms
Inside Try block
Connection successful
ConnectionID:1 ClientConnectionId: 2ce17bbd-c66d-4461-9276-e23302f4d8ba
ADMIN1
5058f1af8388633f609cadb75a75dc9d
select lg_uname, lg_pwd, lg_u_role from dbo.login where lg_uname='ADMIN1' and lg_pwd='5058f1af8388633f609cadb75a75dc9d' and lg_del_flg='N'and lg_entity_cre_flg='Y'
com.microsoft.sqlserver.jdbc.SQLServerException: The statement did not return a result set.
    at com.microsoft.sqlserver.jdbc.SQLServerException.makeFromDriverError(SQLServerException.java:190)
    at com.microsoft.sqlserver.jdbc.SQLServerStatement.doExecuteStatement(SQLServerStatement.java:800)
    at com.microsoft.sqlserver.jdbc.SQLServerStatement$StmtExecCmd.doExecute(SQLServerStatement.java:689)
    at com.microsoft.sqlserver.jdbc.TDSCommand.execute(IOBuffer.java:5696)
    at com.microsoft.sqlserver.jdbc.SQLServerConnection.executeCommand(SQLServerConnection.java:1715)
    at com.microsoft.sqlserver.jdbc.SQLServerStatement.executeCommand(SQLServerStatement.java:180)
    at com.microsoft.sqlserver.jdbc.SQLServerStatement.executeStatement(SQLServerStatement.java:155)
    at com.microsoft.sqlserver.jdbc.SQLServerStatement.executeQuery(SQLServerStatement.java:616)
    at com.serv.Login.doPost(Login.java:116)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:643)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:723)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:861)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:606)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
    at java.lang.Thread.run(Unknown Source)

我正在使用Eclipse Indigo IDE，JDK版本1.6具有相同的目标运行时。我使用ApacheTomcat版本6作为部署的首选应用服务器。因此，我使用MSSQL Server 2008的快速版作为数据库。与此同时，操作系统是MicrosoftServer2008。所有都是32位版本

感谢您的帮助

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编辑日期：2016年12月9日（年月日）： 根据请求，这是删除打印堆栈跟踪后的错误语句。它在我试图关闭try-catch块中语句的部分抛出错误

Dec 9, 2016 8:27:55 AM org.apache.catalina.core.AprLifecycleListener init
INFO: The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: C:\Program Files\Java\jre6\bin;C:\Windows\Sun\Java\bin;C:\Windows\system32;C:\Windows;C:/Program Files/Java/jre6/bin/client;C:/Program Files/Java/jre6/bin;C:/Program Files/Java/jre6/lib/i386;E:\app\IAS_Admin\product\11.2.0\client_1;E:\app\IAS_Admin\product\11.2.0\client_1\bin;E:\oracle\oraclient\bin;C:\Program Files\Oracle\jre\1.1.7\bin;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Program Files\Microsoft SQL Server\80\Tools\Binn\;C:\Program Files\Microsoft SQL Server\90\Tools\binn\;C:\Program Files\Microsoft SQL Server\90\DTS\Binn\;C:\Program Files\Microsoft SQL Server\90\Tools\Binn\VSShell\Common7\IDE\;C:\Program Files\Microsoft Visual Studio 8\Common7\IDE\PrivateAssemblies\;E:\oracle\oraclient\orb\bin;C:\Program Files\Microsoft SQL Server\100\Tools\Binn\;C:\Program Files\Microsoft SQL Server\100\DTS\Binn\;C:\Program Files\Microsoft SQL Server\100\Tools\Binn\VSShell\Common7\IDE\;C:\Program Files\Microsoft Visual Studio 9.0\Common7\IDE\PrivateAssemblies\;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\StaffPortalWork\Software\eclipse-jee-indigo-SR2-win32\eclipse;;.
Dec 9, 2016 8:27:55 AM org.apache.tomcat.util.digester.SetPropertiesRule begin
WARNING: [SetPropertiesRule]{Server/Service/Engine/Host/Context} Setting property 'source' to     'org.eclipse.jst.jee.server:StaffPortalMasterTemplate' did not find a matching property.
Dec 9, 2016 8:27:55 AM org.apache.coyote.http11.Http11Protocol init
INFO: Initializing Coyote HTTP/1.1 on http-8020
Dec 9, 2016 8:27:55 AM org.apache.catalina.startup.Catalina load
INFO: Initialization processed in 553 ms
Dec 9, 2016 8:27:55 AM org.apache.catalina.core.StandardService start
INFO: Starting service Catalina
Dec 9, 2016 8:27:55 AM org.apache.catalina.core.StandardEngine start
INFO: Starting Servlet Engine: Apache Tomcat/6.0.41
Dec 9, 2016 8:27:56 AM org.apache.coyote.http11.Http11Protocol start
INFO: Starting Coyote HTTP/1.1 on http-8020
Dec 9, 2016 8:27:56 AM org.apache.jk.common.ChannelSocket init
INFO: JK: ajp13 listening on /0.0.0.0:8009
Dec 9, 2016 8:27:56 AM org.apache.jk.server.JkMain start
INFO: Jk running ID=0 time=0/25  config=null
Dec 9, 2016 8:27:56 AM org.apache.catalina.startup.Catalina start
INFO: Server startup in 519 ms
Error when closing statement

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在SQL中，在“lg_del_flg='N'and”处缺少一个空格，这可能会导致查询失败。其他的一切都随之而来

如果连接到除java以外的db，是否可以执行任何语句？我没有尝试过，也没有尝试的选项。问题是它在我的本地机器上运行得很好，现在当我把它移到测试服务器时，它面临着这个问题。你能在捕获块的时候切换每个e.printStackTrace（）和system.out.println（）吗？我看不出错误到底发生在哪里。不幸的是，这只能在明天的工作中完成。刚刚测试了一个缺少空格的查询，没有错误，不会。我告诉过你们我从前端测试过它，当我回复@XtremeBaumer时，我已经在我的本地机器上测试过了。空间不是问题。