用servlet校验密码2

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一、相关代码

package Login;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
import java.io.*;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
* Servlet implementation class Login
*/
@WebServlet("/Login")
public class Login extends HttpServlet {
private static final long serialVersionUID = 1L;
static final String driverName="com.microsoft.jdbc.sqlserver.SQLServerDriver";
static final String dbURL="jdbc:sqlserver://localhost:1433;DatabaseName=TextDB";
static final String userName="sa";
static final String userPwd="123";

/**
* Default constructor.
*/
public Login() {
// TODO Auto-generated constructor stub
}

/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub

Connection conn=null;
Statement stmt = null;
response.setContentType("text/html;charset=utf-8");
try {
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");//驱动
PrintWriter out =response.getWriter();
conn=DriverManager.getConnection(dbURL,userName,userPwd);//连接数据库
stmt =conn.createStatement();

String un=request.getParameter("UersName");
String upwd = request.getParameter("PassWrd");
//out.println(upwd+"/n");
String sql = "Select pwd from Uers_Table where uname ='"+un+"'";
ResultSet rs = stmt.executeQuery(sql);//执行sql语句
boolean isTrue = false;
// boolean isLoginIn = false;
while(rs.next()){//遍历整个数据库
String pswd = rs.getString("pwd");//取出数据库数据
//out.println(pswd.replace(" ", ""));
if(pswd.replace(" ", "").equals(upwd))
{
isTrue=true;
out.println("登陆成功");
break;
}
else
{
isTrue= true;
out.println("密码错误，登陆失败");
}

}
if(isTrue==false)
{
out.println("用户名不存在");
}

rs.close();
stmt.close();
conn.close();


} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
finally
{
try {
if(stmt!=null)
{
stmt.close();

}
} catch (Exception e) {
// TODO: handle exception
}
try {
if(conn!=null)
{
conn.close();
}
} catch (Exception e) {
// TODO: handle exception
}


}

}

/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
public void destroy()
{

}

}

二、效果图

　　　　　　　　　　　　　　　　　　　　　　　　　　登录失败

　　　　　　　　　　　　　　　　　　　　　　　　　　 该用户不存在