我先建了个类,作用是读取数据库:
Conn.javapackage bdgq;
import java.io.*;
import java.sql.*;public class Conn {
public ResultSet Connect( String strSqls)
{
try{
String strSql=new String();
Connection con;
Statement stmt;
ResultSet rs;
Class.forName("com.mysql.jdbc.Driver");
String dbUrl="jdbc:mysql://localhost:3306/bdgq";
String dbUser="root";
String dbPwd="";
con=java.sql.DriverManager.getConnection(dbUrl,dbUser,dbPwd);
stmt=con.createStatement();
rs=stmt.executeQuery(strSql); return rs;
}
catch(Exception fe){
}
return null;
}
}然后在servlet中读取:loginsys.javapackage bdgq.ManageSys;import java.io.*;
import java.sql.*;
import java.net.*;
//import.java.util.*;import javax.servlet.*;
import javax.servlet.http.*;
//
import bdgq.Conn;public class LoginSys extends HttpServlet { private String Name="";
private String Password="";
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
}
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { doPost(request,response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//
Name=request.getParameter("Name");
Password=request.getParameter("Password");
//
Conn cons=new Conn();
String strSql="select MiMa from ManageSys while Name='"+Name+"'";
ResultSet rs=cons.Connect(strSql);
String Names="";
String Mimas="";
if(rs!=null)
{
//////////////////////////////////////////////////////////////
///////////////////////这一句编译通不过////////////////////////
if(Password==rs.getString("MiMa"))
///////////////////////这一句编译通不过////////////////////////
//////////////////////////////////////////////////////////////
{
response.sendRedirect("ManageMain.jsp");
}
else
{
response.sendRedirect("login.jsp?cw=aaa");
}
}
}
public String getServletInfo() {
return "Short description";
}
}
Conn.javapackage bdgq;
import java.io.*;
import java.sql.*;public class Conn {
public ResultSet Connect( String strSqls)
{
try{
String strSql=new String();
Connection con;
Statement stmt;
ResultSet rs;
Class.forName("com.mysql.jdbc.Driver");
String dbUrl="jdbc:mysql://localhost:3306/bdgq";
String dbUser="root";
String dbPwd="";
con=java.sql.DriverManager.getConnection(dbUrl,dbUser,dbPwd);
stmt=con.createStatement();
rs=stmt.executeQuery(strSql); return rs;
}
catch(Exception fe){
}
return null;
}
}然后在servlet中读取:loginsys.javapackage bdgq.ManageSys;import java.io.*;
import java.sql.*;
import java.net.*;
//import.java.util.*;import javax.servlet.*;
import javax.servlet.http.*;
//
import bdgq.Conn;public class LoginSys extends HttpServlet { private String Name="";
private String Password="";
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
}
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { doPost(request,response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//
Name=request.getParameter("Name");
Password=request.getParameter("Password");
//
Conn cons=new Conn();
String strSql="select MiMa from ManageSys while Name='"+Name+"'";
ResultSet rs=cons.Connect(strSql);
String Names="";
String Mimas="";
if(rs!=null)
{
//////////////////////////////////////////////////////////////
///////////////////////这一句编译通不过////////////////////////
if(Password==rs.getString("MiMa"))
///////////////////////这一句编译通不过////////////////////////
//////////////////////////////////////////////////////////////
{
response.sendRedirect("ManageMain.jsp");
}
else
{
response.sendRedirect("login.jsp?cw=aaa");
}
}
}
public String getServletInfo() {
return "Short description";
}
}
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.................
这样
Password是读取用户在login.jsp的登陆框中输入的值
rs.getString("MiMa")是读取数据库中的值,出错的是这名(rs.getString("MiMa"))
if(Password!=null&&Password.equals(rs.getString("MiMa"))){
.................
if(rs!=null && rs.next())//////这一句出错
{
if(rs.getString("MiMa").equals(Password))//////这一句也出错
{
response.sendRedirect("ManageMain.jsp");
}
else
{
response.sendRedirect("login.jsp?cw=aaa");
}
}
你检查一下
{ if(Password.equals(rs.getString("MiMa"))) {
response.sendRedirect("ManageMain.jsp");
}
else
{
response.sendRedirect("login.jsp?cw=aaa");
}
}
改成这样呢?
改成:String strSql="select MiMa from ManageSys where Name='"+Name+"'";
不是用while做条件的吧
一个是rs.next()出错
一个是rs.getString("MiMa")出错是什么原因?
一个是rs.getString("MiMa")出错这是怎么回事?
ResultSet rs=cons.Connect(strSql);用了ResultSet的
deps-module-jar:
deps-ear-jar:
deps-jar:
Compiling 1 source file to /root/bdgq/build/web/WEB-INF/classes
/root/bdgq/src/java/bdgq/ManageSys/LoginSys.java:63: 未报告的异常 java.sql.SQLException;必须对其进行捕捉或声明以便抛出
if(rs!=null && rs.next())
/root/bdgq/src/java/bdgq/ManageSys/LoginSys.java:65: 未报告的异常 java.sql.SQLException;必须对其进行捕捉或声明以便抛出
if(rs.getString("MiMa").equals(Password))
2 错误
/root/bdgq/nbproject/build-impl.xml:323: The following error occurred while executing this line:
/root/bdgq/nbproject/build-impl.xml:149: Compile failed; see the compiler error output for details.
BUILD FAILED (total time: 0 seconds)
ResultSet rs=null;
rs=cons.Connect(strSql);
rs.next()……
没有try catch
编程工具应该会提示的啊~~~