在jsp中用bean和servlet联合实现用户注册、登录(2)

//此方法用于获取大段文本，
                //将其中的回车换行替换为<br>
                //输出到html页面
 public String rs_getHtmlString(String column)
 {
  try{
   String str1 = this.rs.getString(column);
   String str2 = "\r\n";
   String str3 = "<br>";
   return this.replaceAll(str1,str2,str3);
  }catch(SQLException e){
   System.out.println(e.toString());
   return null;
  }
 }

                //把str1字符串中的str2字符串替换为str3字符串
 private static String replaceAll(String str1,String str2,String str3)
 {
  StringBuffer strBuf = new StringBuffer(str1);
     int index=0;
  while(str1.indexOf(str2,index)!=-1)
  {
   index=str1.indexOf(str2,index);
   strBuf.replace(str1.indexOf(str2,index),str1.indexOf(str2,index)+str2.length(),str3);
   index=index+str3.length();

str1=strBuf.toString();
  }
  return strBuf.toString();
 }

public int rs_getInt(String column)
 {
  try{
   return this.rs.getInt(column);
  }catch(SQLException e){
   System.out.println(e.toString());
   return -1;
  }
 }

public int rs_getInt(int column)
 {
  try{
   return this.rs.getInt(column);
  }catch(SQLException e){
   System.out.println(e.toString());
   return -1;
  }
 }

public boolean rs_next()
 {
  try{
   return this.rs.next();
  }catch(SQLException e){
   System.out.println(e.toString());
   return false;
  }
 }

//判断结果集中是否有数据
 public boolean hasData()
 {
  try{
   boolean has_Data = this.rs.first();  
   this.rs.beforeFirst();
   return has_Data;
  }catch(SQLException e){
   System.out.println(e.toString());
   return false;
  }
 }

public boolean rs_last()
 {
  try{
   return this.rs.last();
  }catch(SQLException e){
   System.out.println(e.toString());
   return false;
  }
 }

public boolean rs_previous()
 {
  try{
   return this.rs.previous();
  }catch(Exception e){
   System.out.println(e.toString());
   return false;
  }
 }

//main方法，调试用
 public static void main(String args[])
 {
  try{
   DBConn myconn = new DBConn();
   //myconn.setDBName("shopping");
   //myconn.DBConn();
   //myconn.execute("Insert Into tbl_test(id,name) values('10','shandaer')");
   //myconn.execute("Update tbl_test set where id=10");
   //myconn.execute("Delete from tbl_test where id=1");
   ResultSet rs = myconn.executeQuery("select * from tbl_user order by id desc limit 1");
   //boolean hasData = myconn.hasData();
   //System.out.println("has data:" + hasData);
   //rs.first();
   while (myconn.rs.next()) 
   {
    int id = myconn.rs_getInt("id") + 1;
    System.out.print(id);
    System.out.println(myconn.rs_getInt("id") + myconn.rs_getString("name"));

    //System.out.println('\n' + myconn.rs_getHtmlString("name"));
    //System.out.println(myconn.rs.getString("name") + myconn.rs_getInt(1));
   }
  }catch(Exception e){
   System.err.println(e.toString());
  }
 }

}

声明：因为使用的是MySQL数据库，所以需要MySQL数据库的驱动
下载后请将org包放至DBConn.java所在目录下
以确保该bean能正常运行

三、编写用户注册的bean：reg.java

//reg.java

//import required classes
import java.sql.*;

public class reg
{
 public int newID = 0;
 public boolean result = false;
 public boolean reg(String username,String password,String confirm,String email)
 {
  try{
   if(!this.checkUser(username))
    return false;
   if(!this.checkPwd(password))
    return false;
   if(!this.verifyPwd(password,confirm))
    return false;
   if(!this.checkEmail(email))
    return false;
   if(!this.userNotExit(username))
    return false;
   this.getNewID(); 
   this.result = this.register(username,password,confirm,email);
   return this.result;
  }catch(Exception e){
   System.out.println(e.toString());
   return false;
  }
 }//End boolean reg

 public boolean checkUser(String user)
 {
  try{  
   if(user.indexOf("'")!=-1)
   {
    System.out.println("姓名中含有非法字符！");
    return false;
   }else
    return true;
  }catch(Exception e){
   System.out.println(e.toString());
   return false;
   }
 }

 public boolean checkPwd(String pwd)
 {
  try{
   if(pwd.indexOf("'")!=-1)
   {
    System.out.println("密码中含有非法字符！");
    return false;
   }else
    return true;
  }catch(Exception e){
   System.out.println(e.toString());
   return false;
  }
 }

 public boolean verifyPwd(String pwd,String confirm)
 {
  try{
   if(!pwd.equals(confirm))
   {
    System.out.println("两次输入的密码不一致！");
    return false;
   }else
    return true;
  }catch(Exception e){
   System.out.println(e.toString());
   return false;
  }
 }

 public boolean checkEmail(String email)
 {
  try{
   if(email.indexOf("'")!=-1)
   {
    System.out.println("E-mail中含有非法字符！");
    return false;
   }else
    return true;
  }catch(Exception e){
   System.out.println(e.toString());
   return false;
  }
 }

 public boolean userNotExit(String user)
 {
  try{
   DBConn userDBConn = new DBConn();
   userDBConn.executeQuery("select * from tbl_user where");
   if(userDBConn.rs_next())
   {
    System.out.println("用户名已存在，请选择其它的用户名！");
    return false;
   }else
    return true;
  }catch(Exception e){
   System.out.println(e.toString());
   return false;
   }
 }

 public int getNewID()
 {
  try{
   DBConn newIDDBConn = new DBConn();
   newIDDBConn.executeQuery("select * from tbl_user order by id desc limit 1");
   if(newIDDBConn.rs_next())
   {
    this.newID = newIDDBConn.rs_getInt("id") + 1;
    System.out.println(this.newID);
   }else{
    this.newID = 1;
   }
   return this.newID;
  }catch(Exception e){
   System.out.println(e.toString());
   return -1;
   }   
 }

 public int getID()
 {
  return this.newID;
 }

 public boolean register(String username,String password,String confirm,String email)
 {
  try{
   DBConn regDBConn = new DBConn();
   String strSQL = "insert into tbl_user(id,name,pwd,email) values('" + this.newID +"','" + username + "','" + password + "','" + email + "')";
   regDBConn.execute(strSQL);
   return true;
  }catch(Exception e){
   System.out.println(e.toString());
   return false;
   }
 }