JSP向SERVLET页面跳转问题

if(objdbc.isUsers(name, pass))
{
response.sendRedirect("../main.jsp");
}
else
{
response.sendRedirect("../err.jsp");
}
}
}
问题是为什么执行的时候只执行else而不执行if里面的条件呢?
=======================================================================那就是你的if(objdbc.isUsers(name, pass))一直是else啊
这是程序执行的规则肯定不会错的

就是public boolean isUsers(String name,String pass)一直是false

package login;import java.sql.*;/**
* 本类完成数据库连接管理
* 调用时直接调用该类的静态变量来获取该类实例
*/public class ConnectionManagerBean {  static Connection objConn = null;
  private static ConnectionManagerBean me = new ConnectionManagerBean();  public ConnectionManagerBean() {
  }  public static ConnectionManagerBean newInstance() {
    return me;
  }  public static Connection getConnection()
  {
    try {
            Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
            objConn = DriverManager.getConnection("jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=mydb","sa","sa");
            //Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
            //objConn = DriverManager.getConnection("jdbc:odbc:mydb");
        } catch (Exception e) {
            System.out.print(e.toString());
        }
        return objConn;  }
}

package login;import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;public class checkusersrv extends HttpServlet {
  private static final String CONTENT_TYPE = "text/html; charset=GBK";
  //Initialize global variables
  public void init() throws ServletException {
  }
  //Process the HTTP Get request
  public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    response.setContentType(CONTENT_TYPE);
    //从会话中得到原来生成的验证码
    HttpSession session = request.getSession();
    String randSource = (String)session.getAttribute("rand");
    session.removeAttribute("rand");
    //得到表单数据
    String userName = request.getParameter("userName");
    String password = request.getParameter("password");
    String rand = request.getParameter("rand");
    String userSf = request.getParameter("userSf");
    //验证
    if(!rand.equals(randSource))
    {
      response.sendRedirect("Fail.jsp?error=1");
    }
    else
    {
      //个人用户
      if(userSf.equals("2")){
        UserinfoBean objUserinfoBean = new UserinfoBean();
        objUserinfoBean.setUserName(userName);
        objUserinfoBean.setPassword(password);
        if (objUserinfoBean.loginValidate()) {
          session.setAttribute("userName", userName);
          response.sendRedirect("Welcome.jsp?sf=2");
        }
        else {
          response.sendRedirect("Fail.jsp?error=2");
        }
      }
      //企业用户
      else
      {
        qyuserinfoBean objqyuserinfoBean = new qyuserinfoBean();
        objqyuserinfoBean.setQyuserName(userName);
        objqyuserinfoBean.setPassword(password);
        if(objqyuserinfoBean.loginValidate()){
          session.setAttribute("userName", userName);
          response.sendRedirect("Welcome.jsp?sf=1");
        }
        else {
          response.sendRedirect("Fail.jsp?error=2");
        }
      }
    }
  }
  //Process the HTTP Post request
  public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    doGet(request, response);
  }
  //Clean up resources
  public void destroy() {
  }
}

package login;import java.sql.*;/*
*   封装Userinfo表中的列,提供get/set方法以及验证用户合法性的方法
*/
public class UserinfoBean {
  private int userID;
  private String userName;
  private String password;
  Connection conn = null;
  ConnectionManagerBean objConnManager = ConnectionManagerBean.newInstance();  public UserinfoBean() {
  }  public void setUserID(int userID) {
    this.userID = userID;
  }  public void setUserName(String userName) {
    this.userName = userName;
  }  public void setPassword(String password) {
    this.password = password;
  }  public int getUserID() {
    return userID;
  }  public String getUserName() {
    return userName;
  }  public String getPassword() {
    return password;
  }  public boolean loginValidate() {
    try {
      Connection conn = objConnManager.getConnection();
      String sqlStr = "select * from userinfo where userName=? and password=?";
      PreparedStatement pstmt = conn.prepareStatement(sqlStr);
      pstmt.setString(1, this.getUserName());
      pstmt.setString(2, this.getPassword());
      ResultSet rs = pstmt.executeQuery();
      if (rs.next()) {
        return true;
      }
      else {
        return false;
      }
    }
    catch (SQLException ex) {
      System.out.println("数据库操作失败！"+ex.getMessage());
      return false;
    }
    finally {
      try {
        if (conn != null)
          conn.close();
      }
      catch (SQLException sqlex) {
        System.out.println("关闭数据库连接失败！"+sqlex.getMessage());
      }
    }
  }
}package login;import java.sql.*;/*
*   封装qyuserinfo表中的列,提供get/set方法以及验证用户合法性的方法
*/public class qyuserinfoBean {  private int qyuserID;
  private String qyuserName;
  private String password;
  Connection conn = null;
  ConnectionManagerBean objConnManager = ConnectionManagerBean.newInstance();
  public qyuserinfoBean() {
  }  public int getQyuserID() {
    return qyuserID;
  }  public void setQyuserID(int qyuserID) {
    this.qyuserID = qyuserID;
  }  public String getQyuserName() {
    return qyuserName;
  }  public void setQyuserName(String qyuserName) {
    this.qyuserName = qyuserName;
  }  public String getPassword() {
    return password;
  }  public void setPassword(String password) {
    this.password = password;
  }  public boolean loginValidate() {
    try {
      Connection conn = objConnManager.getConnection();
      String sqlStr = "select * from qyuserinfo where qyuserName=? and password=?";
      PreparedStatement pstmt = conn.prepareStatement(sqlStr);
      pstmt.setString(1, this.getQyuserName());
      pstmt.setString(2, this.getPassword());
      ResultSet rs = pstmt.executeQuery();
      if (rs.next()) {
        return true;
      }
      else {
        return false;
      }
    }
    catch (SQLException ex) {
      System.out.println("数据库操作失败！" + ex.getMessage());
      return false;
    }
    finally {
      try {
        if (conn != null)
          conn.close();
      }
      catch (SQLException sqlex) {
        System.out.println("关闭数据库连接失败！" + sqlex.getMessage());
      }
    }
  }}

p=con.prepareStatement("select * from bbsusers where uname=? and upassword=?");这一句话你查询时字符串里时候要加单引号否则查询结果肯定没有。

你为什么一定要写预处理语句呢，可以直接Statement stmt=con.createStatement();

public boolean isUsers(String name,String pass)
这个方法返回的一直都是false，所以下面的页面调用会出错。
改成这样：
public boolean isUsers(String name,String pass)
{
try {
p=con.prepareStatement("select * from bbsusers where uname=? and upassword=?");
p.setString(1,name);
p.setString(2,pass);
r=p.executeQuery();
System.out.print(name);
System.out.print(pass);
if(r.next())
{
return true;
}else{
return false;
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return false;
}
}

你可以把objdbc.isUsers(name, pass) 的值打印出来看一下结果阿。

调试易

JSP向SERVLET页面跳转问题

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