Java 登录表单在我的应用程序中不起作用
我的登录表不工作,请任何人帮我Java 登录表单在我的应用程序中不起作用,java,Java,我的登录表不工作,请任何人帮我 public class LoginServlet extends HttpServlet { @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String userName=request.getParameter("userName");
public class LoginServlet extends HttpServlet {
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String userName=request.getParameter("userName");
String password=request.getParameter("password");
DataPersistor d=new DataPersistor();
try {
if( d.isValidateUser(userName, password)){
HttpSession session=request.getSession();
session.setAttribute("name", userName);
response.sendRedirect("index.jsp");
}
else{
response.sendRedirect("login.jsp");
}
} catch (SQLException ex) {
Logger.getLogger(LoginServlet.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
这是我的数据持久化类。我从数据库中获取值
public class DataPersistor {
Connection con;
public DataPersistor() {
con = DBConnector.getConnection();
}
public void registerUser(User user) {
try {
Statement stmt = con.createStatement();
String query = "INSERT INTO user VALUES ('" + user.getUserName() + "','" + user.getPassword() + "','" + user.getEmail() + "','" + user.getLastName() + "','" + user.getFirstName() + "','false')";
stmt.execute(query);
} catch (SQLException ex) {
Logger.getLogger(DataPersistor.class.getName()).log(Level.SEVERE, null, ex);
}
}
public boolean isValidateUser(String username,String password) throws SQLException{
boolean result=false;
PreparedStatement ps;
Statement stmt = con.createStatement();
String query = "SELECT * FROM user WHERE username='" + username + "' and password='"+password+"'";
ps=con.prepareStatement(query);
ps.setString(1,username);
ps.setString(2, password);
ResultSet rs=ps.executeQuery();
if(rs.next()==true){
result=true;
}
return result;
}
}
经过清洁和建设
Jul 29, 2012 8:51:46 PM com.asiahospital.servlet.LoginServlet doPost
SEVERE: null
java.sql.SQLException: Parameter index out of range (1 > number of parameters, which is 0).
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1073)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:987)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:982)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:927)
at com.mysql.jdbc.PreparedStatement.checkBounds(PreparedStatement.java:3729)
at com.mysql.jdbc.PreparedStatement.setInternal(PreparedStatement.java:3713)
at com.mysql.jdbc.PreparedStatement.setString(PreparedStatement.java:4553)
at com.asiahospital.db.DataPersistor.isValidateUser(DataPersistor.java:50)
at com.asiahospital.servlet.LoginServlet.doPost(LoginServlet.java:32)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:225)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:999)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:565)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:309)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:619)`enter code here`
您的连接似乎未正确初始化
Statement stmt = con.createStatement();
检查从中返回的内容
DBConnector.getConnection()
从您更新的帖子(!)来看,问题在于您准备的语句不包含任何“?”占位符字符
public boolean isValidateUser(String username, String password) throws SQLException {
boolean result = false;
String query = "SELECT * FROM user WHERE username='?' and password='?'";
PreparedStatement ps = con.prepareStatement(query);
ps.setString(1, username);
ps.setString(2, password);
ResultSet rs = ps.executeQuery();
if (rs.next() == true) {
result = true;
}
return result;
}
1.请删除代码中不必要的换行符,并正确设置其格式。2.它怎么不起作用呢?看起来你在使用Netbeans。您可以使用快捷方式“ALT+SHIFT+F”进行代码格式化。。。。。。。。。您能告诉我们在
DataPersistor.java
语句stmt=con.createStatement()中哪一行是#47吗;公共静态连接getConnection(){return con;}