login.java/////////
public class Login extends ActionSupport {
@Override
public String execute() throws Exception {
// TODO Auto-generated method stub
if (isInvalid(username) || isInvalid(password)) {
msg = "用户名或者密码不能为空";
return INPUT;
}
if (null == new UserDAO().checkAccount(username, password)) {
msg = "用户名或者密码错误";
return INPUT;
}
..............................................................................................................................
UserDAO.java
public String checkAccount(String account, String password) {
String sql = "SELECT ConNumber FROM Consumer WHERE ConNumber=? AND ConPass=?";
PreparedStatement pstat = null;
ResultSet rs = null;
Connection conn = new DBHelper().getConn();
String userid = null;
try {
pstat = conn.prepareStatement(sql);
pstat.setString(1, account);
pstat.setString(2, password);
rs = pstat.executeQuery();
while (rs.next()) {
userid = rs.getString(1);
}
........................................................................................................................
public class DBHelper {
private String driver ="com.microsoft.jdbc.sqlserver.SQLServerDriver";
private String url = "jdbc:microsoft:sqlserver://localhost:1433;databaseName=dbps";
private String user = "sa";
private String pwd = ""; public Connection getConn(){
Connection conn = null;
try {
Class.forName(driver);
conn = DriverManager.getConnection(url, user, pwd); } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (SQLException e) { e.printStackTrace();
}
return conn;
}
public static void main(String[] args) {
System.out.println("DBHelper.main()" + new DBHelper().getConn());
}
} 页面打开错误提示:
HTTP Status 500 ..................................................................... .........................................
type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
java.lang.NullPointerException
com.dao.UserDAO.checkAccount(UserDAO.java:104)
action.Login.execute(Login.java:23)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
java.lang.reflect.Method.invoke(Unknown Source)
com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:440)
com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:279)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:242)
com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:163)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:249)
org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68) eclipse 里面错误是:
ava.sql.SQLException: [Microsoft][SQLServer 2000 Driver for JDBC]Error establishing socket.
at com.microsoft.jdbc.base.BaseExceptions.createException(Unknown Source)
at com.microsoft.jdbc.base.BaseExceptions.getException(Unknown Source)
at com.microsoft.jdbc.base.BaseExceptions.getException(Unknown Source)
at com.microsoft.jdbc.sqlserver.tds.TDSConnection. <init>(Unknown Source)
at com.microsoft.jdbc.sqlserver.SQLServerImplConnection.open(Unknown Source)
at com.microsoft.jdbc.base.BaseConnection.getNewImplConnection(Unknown Source)
at com.microsoft.jdbc.base.BaseConnection.open(Unknown Source)
at com.microsoft.jdbc.base.BaseDriver.connect(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at com.db.DBHelper.getConn(DBHelper.java:14)
at com.dao.UserDAO.checkAccount(UserDAO.java:101)
at action.Login.execute(Login.java:23)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
........................................................................................................... pstat = conn.prepareStatement(sql); 就是104行这里出现了错误。。我输入了用户名和密码 就出现错误了。。是怎么回事呢??
请指教
public class Login extends ActionSupport {
@Override
public String execute() throws Exception {
// TODO Auto-generated method stub
if (isInvalid(username) || isInvalid(password)) {
msg = "用户名或者密码不能为空";
return INPUT;
}
if (null == new UserDAO().checkAccount(username, password)) {
msg = "用户名或者密码错误";
return INPUT;
}
..............................................................................................................................
UserDAO.java
public String checkAccount(String account, String password) {
String sql = "SELECT ConNumber FROM Consumer WHERE ConNumber=? AND ConPass=?";
PreparedStatement pstat = null;
ResultSet rs = null;
Connection conn = new DBHelper().getConn();
String userid = null;
try {
pstat = conn.prepareStatement(sql);
pstat.setString(1, account);
pstat.setString(2, password);
rs = pstat.executeQuery();
while (rs.next()) {
userid = rs.getString(1);
}
........................................................................................................................
public class DBHelper {
private String driver ="com.microsoft.jdbc.sqlserver.SQLServerDriver";
private String url = "jdbc:microsoft:sqlserver://localhost:1433;databaseName=dbps";
private String user = "sa";
private String pwd = ""; public Connection getConn(){
Connection conn = null;
try {
Class.forName(driver);
conn = DriverManager.getConnection(url, user, pwd); } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (SQLException e) { e.printStackTrace();
}
return conn;
}
public static void main(String[] args) {
System.out.println("DBHelper.main()" + new DBHelper().getConn());
}
} 页面打开错误提示:
HTTP Status 500 ..................................................................... .........................................
type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
java.lang.NullPointerException
com.dao.UserDAO.checkAccount(UserDAO.java:104)
action.Login.execute(Login.java:23)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
java.lang.reflect.Method.invoke(Unknown Source)
com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:440)
com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:279)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:242)
com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:163)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:249)
org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68) eclipse 里面错误是:
ava.sql.SQLException: [Microsoft][SQLServer 2000 Driver for JDBC]Error establishing socket.
at com.microsoft.jdbc.base.BaseExceptions.createException(Unknown Source)
at com.microsoft.jdbc.base.BaseExceptions.getException(Unknown Source)
at com.microsoft.jdbc.base.BaseExceptions.getException(Unknown Source)
at com.microsoft.jdbc.sqlserver.tds.TDSConnection. <init>(Unknown Source)
at com.microsoft.jdbc.sqlserver.SQLServerImplConnection.open(Unknown Source)
at com.microsoft.jdbc.base.BaseConnection.getNewImplConnection(Unknown Source)
at com.microsoft.jdbc.base.BaseConnection.open(Unknown Source)
at com.microsoft.jdbc.base.BaseDriver.connect(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at com.db.DBHelper.getConn(DBHelper.java:14)
at com.dao.UserDAO.checkAccount(UserDAO.java:101)
at action.Login.execute(Login.java:23)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
........................................................................................................... pstat = conn.prepareStatement(sql); 就是104行这里出现了错误。。我输入了用户名和密码 就出现错误了。。是怎么回事呢??
请指教
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请在命令行下:
telnet localhost 1433
端口可用?如果不行,将localhost换成127.0.0.1或者本机IP试试。