package chat;import java.sql.*;public class ChatUserDB {  Connection con=null;  Statement sql=null;  ResultSet rs=null;  String name=null;  String pd=null;  public ChatUserDB(){    try{      //驅(qū)動(dòng)類(lèi)型＋目標(biāo)數(shù)據(jù)庫(kù)IP＋數(shù)據(jù)庫(kù)端口     String address="jdbc:microsoft:sqlserver://localhost:1433";     //數(shù)據(jù)庫(kù)用戶(hù)密碼     String user="sa";     //口令     String passwd="";     //目標(biāo)數(shù)據(jù)庫(kù)     String database="chat";     //驅(qū)動(dòng)申明     Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");     //建立鏈接     con=DriverManager.getConnection(address,user,passwd);     //確定目標(biāo)數(shù)據(jù)庫(kù)     con.setCatalog(database);     //建立描述，設(shè)定結(jié)果集支持滾動(dòng)光標(biāo)且敏感，不可編輯     sql=con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet. CONCUR_READ_ONLY);     //查詢(xún)語(yǔ)句     //String selCode="SELECT username,userkey FROM usertable";     //結(jié)果集    // ResultSet rs=smt.executeQuery(selCode);    }catch(Exception e){      e.printStackTrace();    }  }  public boolean checkUser(String name,String key){    this.name=name;    this.pd=key;    boolean b=false;    try{      String selCode="select * from usertable where username ="+"'"+name+"'"+"and userkey="+"'"+pd+"'";      rs=sql.executeQuery(selCode);     if(rs.next()){       b=true;     }     rs.close();     sql.close();     con.close();    }catch(SQLException e){      e.printStackTrace();    }    return b;  }  public byte registerUser(String userId,String key,String name,String email){    byte sucessed=0;    try{      String selCode="select * from usertable where username ="+"'"+userId+"'";      rs=sql.executeQuery(selCode);      if(rs.next()){        return -1;      }else{        selCode="insert  usertable  values("+"'"+userId+"','"+key+"','"+name+"','"+email+"')";        sql.executeUpdate(selCode);        sucessed=1;      }    }catch(SQLException e){      e.printStackTrace();    }    return sucessed;  }  public static void main(String[] args) {    ChatUserDB db=new ChatUserDB();    db.registerUser("e","e","e","e");    /*if(db.checkUser("user2","2")){      System.out.println("ok");    }*/  }}