这样的错误咋解决?在线等待!!!!!马上给分

Question

str==null是可以的。  改成：
if((str！=null)&&(str.trim().length()>2)&(str.trim.length()<19)){
}
else
{}

Answer 1

import java.lang.String??? 这个包里的会自动引用，你不用这样
str.trim.length()>20) 你忘了写trim() 应该是str.trim().length()>20)

Answer 2

：（
漏了个字。str==null是不可以的。

Answer 3

：（忙中出错：if((str！=null)&&(str.trim().length()>2)&(str.trim().length()<19)){
}
else
{}

Answer 4

同意
wellsoon(wellsoon)
当str为null时对它操作会有空指针的错误

Answer 5

package user;
import java.sql.*;public class check
{boolean right=true;
//检查是否数据为空
 public boolean check_blank (String string){
  boolean blank=true;
  if (string==null||string.trim().compareTo("")==0)
  blank=false;
  return blank;
 }
 //检查模个字符是否位合法字符
 public boolean check_hava(String[] words,String temp)
  {
 boolean have=true,have_tmp=false;
   int I,J;
   for(I=0;I<temp.length();I++)
     { String t=temp.substring(I,I+1);
        for(J=0;J<words.length;J++)
 {  have_tmp=false;
         if(words[J].equals(t)){
           have_tmp=true;
           break;}
         }
       if(!have_tmp){
   have=false;
   break;
         }
     }
  return have;
}
//检查字符串中是非包含模个字符
public boolean check_str_char(String str,String tag)
{boolean have_tag=false;
int I;
for(I=0;I<str.length();I++){
if (str.substring(I,I+1).equals(tag))
have_tag=true;
        }
   return have_tag;
}//检查用户名是否合法
public boolean check_user(String str){
String[] word={"a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z","A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z","0","1","2","3","4","5","6","7","8","9","_"};
if(str==null||str.trim().length()<3||str.trim().length()>20)
right=false;
else{
  if (!check_have(word,str)){
  right=false;
     }
return right;
    }}
//检查密码是否合法
public boolean check_pass(String pass,String repass)
{
if (pass==null||pass.trim().length()<5||pass.trim().length()>20)
right=false;
else if (!pass.trim().equals(repass))
right=false;
return right;
}
//检查E_MAIL地址的合法性
public boolean check_email(String email){
if (!check_str_char(email,"@")||!check_str_char(email,"."))
right=false;
return right;
}
//检查邮编合法性
public boolean check_postzip(String postzip){
String[] post={"0","1","2","3","4","5","6","7","8","9"};
if (postzip==null||postzip.trim().length()!=6)
right=false;
else if (!check_have(post,postzip.trim()))
right=false;
return right;
}//检查身份证号码合法性
public boolean check_idcard(String idcard)
{ String[] id_card={"0","1","2","3","4","5","6","7","8","9"};
      if(idcard=null||(idcard.trim().length()!=15 && idcard.trim().length()!=18))
right=false;
  else if (!check_have(id_card,idcar.trim()))
  right=false;
  return right;
}//检查用户已注册否
public boolean chec_user_have(String user){
java.sql.Connection Conn;
java.sql.Statement Stmt;
java.sql.ResultSet Rst;
try{
Class.forName("sun.jdbc.odbc.jdbcodbcDriver");
}
catch(java.lang.ClassNotFoundException e){
system.out.print(e);
}
try{ 
 Conn=DriverManager.getConnection("jdbc.odbc:shop","Adminstrator","duanshuy");
 Stmt=Conn.createStatement();
 Rst=Stmt.executeQuery("select( from user_info where nick_name='"+user+"'");
 if(Rst.next())
 right=false;
     Rst.close();
 Stmt.close();
 Conn.close();
   }
  catch(SQLException ex){
    system.out.print(ex);}
  return right;
}}  上面是我程序
你帮调试一下好吗？

Answer 6

if(str==null||str.trim().length()<3||str.trim.length()>20)to---->if(str==null||str.trim().length()<3||str.trim().length()>20)

Answer 7

package user;
import java.sql.*;public class check
{boolean right=true;
//检查是否数据为空
 public boolean check_blank (String string){
  boolean blank=true;
  if (string==null||string.trim().compareTo("")==0)
  blank=false;
  return blank;
 }
 //检查模个字符是否位合法字符
 public boolean check_have(String[] words,String temp)
  {
 boolean have=true,have_tmp=false;
   int I,J;
   for(I=0;I<temp.length();I++)
     { String t=temp.substring(I,I+1);
        for(J=0;J<words.length;J++)
 {  have_tmp=false;
         if(words[J].equals(t)){
           have_tmp=true;
           break;}
         }
       if(!have_tmp){
   have=false;
   break;
         }
     }
  return have;
}
//检查字符串中是非包含模个字符
public boolean check_str_char(String str,String tag)
{boolean have_tag=false;
int I;
for(I=0;I<str.length();I++){
if (str.substring(I,I+1).equals(tag))
have_tag=true;
        }
   return have_tag;
}//检查用户名是否合法
public boolean check_user(String str){
String[] word={"a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z","A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z","0","1","2","3","4","5","6","7","8","9","_"};
if(str==null||str.trim().length()<3||str.trim().length()>20)
right=false;
else{
  if (! check_have(word,str)){
  right=false;
     }
    }
return right;
}
//检查密码是否合法
public boolean check_pass(String pass,String repass)
{
if (pass==null||pass.trim().length()<5||pass.trim().length()>20)
right=false;
else if (!pass.trim().equals(repass))
right=false;
return right;
}
//检查E_MAIL地址的合法性
public boolean check_email(String email){
if (!check_str_char(email,"@")||!check_str_char(email,"."))
right=false;
return right;
}
//检查邮编合法性
public boolean check_postzip(String postzip){
String[] post={"0","1","2","3","4","5","6","7","8","9"};
if (postzip==null||postzip.trim().length()!=6)
right=false;
else if (!check_have(post,postzip.trim()))
right=false;
return right;
}//检查身份证号码合法性
public boolean check_idcard(String idcard)
{ String[] id_card={"0","1","2","3","4","5","6","7","8","9"};
      if((idcard==null)||(idcard.trim().length()!=15 && idcard.trim().length()!=18))
right=false;
  else if (!check_have(id_card,idcard.trim()))
  right=false;
  return right;
}//检查用户已注册否
public boolean chec_user_have(String user){
java.sql.Connection Conn;
java.sql.Statement Stmt;
java.sql.ResultSet Rst;
try{
Class.forName("sun.jdbc.odbc.jdbcodbcDriver");
}
catch(java.lang.ClassNotFoundException e){
System.out.print(e);
}
try{ 
 Conn=DriverManager.getConnection("jdbc.odbc:shop","Adminstrator","duanshuy");
 Stmt=Conn.createStatement();
 Rst=Stmt.executeQuery("select( from user_info where nick_name='"+user+"'");
 if(Rst.next())
 right=false;
     Rst.close();
 Stmt.close();
 Conn.close();
   }
  catch(SQLException ex){
    System.out.print(ex);}
  return right;
}}  

Answer 8

package user;
import java.sql.*;public class check
{boolean right=true;
//检查是否数据为空
 public boolean check_blank (String string){
  boolean blank=true;
  if (string==null||string.trim().compareTo("")==0)
  blank=false;
  return blank;
 }
 //检查模个字符是否位合法字符
 public boolean check_hava(String[] words,String temp)
  {
 boolean have=true,have_tmp=false;
   int I,J;
   for(I=0;I<temp.length();I++)
     { String t=temp.substring(I,I+1);
        for(J=0;J<words.length;J++)
 {  have_tmp=false;
         if(words[J].equals(t)){
           have_tmp=true;
           break;}
         }
       if(!have_tmp){
   have=false;
   break;
         }
     }
  return have;
}
//检查字符串中是非包含模个字符
public boolean check_str_char(String str,String tag)
{boolean have_tag=false;
int I;
for(I=0;I<str.length();I++){
if (str.substring(I,I+1).equals(tag))
have_tag=true;
        }
   return have_tag;
}//检查用户名是否合法
public boolean check_user(String str){
String[] word={"a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z","A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z","0","1","2","3","4","5","6","7","8","9","_"};
if(str==null||str.trim().length()<3||str.trim().length()>20)
right=false;
else{
  if (!check_have(word,str)){
  right=false;
     }
return right;
    }}
//检查密码是否合法
public boolean check_pass(String pass,String repass)
{
if (pass==null||pass.trim().length()<5||pass.trim().length()>20)
right=false;
else if (!pass.trim().equals(repass))
right=false;
return right;
}
//检查E_MAIL地址的合法性
public boolean check_email(String email){
if (!check_str_char(email,"@")||!check_str_char(email,"."))
right=false;
return right;
}
//检查邮编合法性
public boolean check_postzip(String postzip){
String[] post={"0","1","2","3","4","5","6","7","8","9"};
if (postzip==null||postzip.trim().length()!=6)
right=false;
else if (!check_have(post,postzip.trim()))
right=false;
return right;
}//检查身份证号码合法性
public boolean check_idcard(String idcard)
{ String[] id_card={"0","1","2","3","4","5","6","7","8","9"};
      if(idcard=null||(idcard.trim().length()!=15 && idcard.trim().length()!=18))
right=false;
  else if (!check_have(id_card,idcar.trim()))
  right=false;
  return right;
}//检查用户已注册否
public boolean chec_user_have(String user){
java.sql.Connection Conn;
java.sql.Statement Stmt;
java.sql.ResultSet Rst;
try{
Class.forName("sun.jdbc.odbc.jdbcodbcDriver");
}
catch(java.lang.ClassNotFoundException e){
system.out.print(e);
}
try{ 
 Conn=DriverManager.getConnection("jdbc.odbc:shop","Adminstrator","duanshuy");
 Stmt=Conn.createStatement();
 Rst=Stmt.executeQuery("select( from user_info where nick_name='"+user+"'");
 if(Rst.next())
 right=false;
     Rst.close();
 Stmt.close();
 Conn.close();
   }
  catch(SQLException ex){
    system.out.print(ex);}
  return right;
}}  上面是我程序
你帮调试一下好吗？

Answer 9

你有无数的拼写错误  have->hava  System->system idcard->idcar 找个好的代码编辑器 再细心点