pst=conn.prepareStatement(sql);为空请问怎么解决

[qq_40503645]

public class DButil {
private static final String DRIVER="com.microsoft.sqlserver.jdbc.SQLServerDriver";
private static final String URL="jdbc:sqlserver://localhost:1433;databaseName=project";
private static final String USER="sa";
private static final String PWD="sa123456";


public static Connection getConnection(){
Connection conn=null;
try {
Class.forName(DRIVER);
conn=DriverManager.getConnection(URL,USER,PWD);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.getMessage();
}catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return conn;
}
public static void CloseAll(ResultSet re,Statement sat,Connection conn){
try {
if(re!=null){
re.close();
}
if(sat!=null){
sat.close();
}
if(conn!=null){
conn.close();
}
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
}
}
//这是数据库连接类

public class SQLdao {
public static User logincheck(String name,String pwd){
User user=null;
PreparedStatement pst=null;
ResultSet rs=null;
Connection conn=null;
try {
conn=DButil.getConnection();
String sql="select * from background where baName=? and baPwd=?";
pst=conn.prepareStatement(sql);//这里用了if(conn==null)判断过，表示为空。求大哥教教怎么解决
pst.setString(1, name);
pst.setString(2, pwd);
rs=pst.executeQuery();
if(rs.next()){
user=new User(name,pwd);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
DButil.CloseAll(rs, pst, conn);
}
return user;
}
}
//这是操作类

[qq_40503645]

有大神帮帮忙不

[Defonds]

conn=DriverManager.getConnection(URL,USER,PWD);

此处加断点，跟一下报的啥错。

[QWERT4745]

conn为空说明数据库没连接上

[zhang_yl777]

public static Connection getConnection(){
Connection conn=null;
try {
Class.forName(DRIVER);
conn=DriverManager.getConnection(URL,USER,PWD);
}
试试在try里面return conn