datafriends.java

一个采用Java Socket编程实现的QQ软件

package database;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;


public class Datafriends {
    
    public Datafriends() {}
    private Connection getconnection(){
        Connection con = null;
        String JDriver="sun.jdbc.odbc.JdbcOdbcDriver";   //声明jdbc驱动程序类型
        String conURL="jdbc:odbc:user";                //定义jdbc的url对象
        try {
            Class.forName(JDriver);
        }catch(java.lang.ClassNotFoundException e){ 
            System.out.println("forname:"+e.getMessage());
        }
        try {
            con=DriverManager.getConnection(conURL);//连接数据库URl
        }catch(SQLException e){
            System.out.println("建立Statement类对象失败");
        }
        return con;
    }
    
    public boolean validateUser(String uid, String pwd){   //由用户名和密码验证用户信息
        boolean vaild = false;
        Connection con = null;
        Statement datastate = null;
        con = this.getconnection();
         String query = "Select * From usertable Where username='"+uid+"' And password='"+pwd+"'";
         ResultSet Rs = null;
        if(con != null){           
            try {
                datastate = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
                Rs = datastate.executeQuery(query); 
                vaild = Rs.first();
                if(vaild) {
                    System.out.println("用户名:"+Rs.getString("message"));
                }
            } catch (SQLException ex) {
                System.out.println("错误信息:"+ ex.toString());
            } finally {
                try {
                    Rs.close();
                    Rs = null;
                } catch (SQLException ex) {
                    System.out.println("Rs释放失败");
                }
            }
            try {
                datastate.close();
                con.close();
            } catch (SQLException ex) {
                ex.printStackTrace();
            }    
        }
        return vaild;
    }
    public String getanycharacter(String username,String character){  //传入用户名和任意字段名，可以查询该用户的该字段 
        String buff = "";
        Connection con = null;
        Statement datastate = null;
        String name = username;
        ResultSet Rs = null;
        String query = "Select "+character+" From usertable Where username='"+name+"'";
        con = this.getconnection();
        if(con != null){
            try {
                datastate = con.createStatement();
                Rs = datastate.executeQuery(query);            
                while(Rs.next()){
                    if(buff.equals("")){
                        buff = Rs.getString(character);
                    }else{
                        buff = buff + "," + Rs.getString(character);
                    }               
                }              
            } catch (SQLException ex) {
                ex.printStackTrace();
            } finally {
                try {
                    Rs.close();
                    Rs = null;
                } catch (SQLException ex) {
                ex.printStackTrace();
            }
        }
            try {
                datastate.close();
                con.close();
            } catch (SQLException ex) {
                ex.printStackTrace();
            }
       
         }else{
             System.out.println("连接失败");
         }
        return buff;
    }
    
   public String getAllusername(){     //查询表中所有的用户的用户名
         String buff = "";
         ResultSet Rs = null;
         Connection con = null;
         Statement datastate = null;
         String query = "Select * From usertable";
         con = this.getconnection();
         if(con != null){
             try {            
                 datastate = con.createStatement();
                 Rs = datastate.executeQuery(query);
                 while(Rs.next()){
                     
                     if(buff.equals("")){
                         buff = Rs.getString("username");
                     }else{
                         buff = buff + "," + Rs.getString("username");
                     }
                 }
             } catch (SQLException ex) {
                 ex.printStackTrace();
             } finally{
                 try {
                     Rs.close();
                     Rs = null;
                 } catch (SQLException ex) {
                     ex.printStackTrace();
                 }
             }
             try {
                 datastate.close();
                 con.close();
             } catch (SQLException ex) {
                 ex.printStackTrace();
             }
             
         }else{
             System.out.println("连接失败"); 
         }  
         return buff;
   }
   public boolean insertuser(String username,String password,String message,String friends,int type){ //添加用户
       Connection con = null;
       Statement datastate = null;
       String query = "insert into usertable values('"+username+"','"+password+"','"+message+"','"+
               friends +"'," + type+ ")";
       con = this.getconnection();
       if(con != null){
           try {
               datastate = con.createStatement();
               int i = datastate.executeUpdate(query);  
               System.out.println("插入成功"+ i);
           } catch (SQLException ex) {
               
               // ex.printStackTrace();
               System.out.println("插入失败");
           }
           try {
               datastate.close();
               con.close();
               return true;
           } catch (SQLException ex) {
               ex.printStackTrace();
               return false;
           }
           
       }else{
           System.out.println("连接失败"); 
           return false;
       }     
   }
   
   
   
   public boolean Upadateuser(String username,String chractor,String content){
       Connection con;
       String query ="UPDATE usertable set "+chractor+"=? where username=?";
       PreparedStatement datastate = null;
       con = this.getconnection();  
       if(con != null){
           
           try {
               datastate = con.prepareStatement(query);
               datastate.setString(1,content); 
               datastate.setString(2,username);
               datastate.executeUpdate();
               datastate.close();
               System.out.println("修改成功");
              
           } catch (SQLException ex) {
               ex.printStackTrace();
               return false;
           }
           try {
               con.close();
                return true;
           } catch (SQLException ex) {
               ex.printStackTrace();
               return false;
           }
       }else{
           System.out.println("连接失败");  
           return false;
       }
       
   }
}