servlet(或Java)里面实现用户名唯一性验证问题??
servlet(或Java)里面实现用户名唯一性验证问题??
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麻烦大家帮我看看,我写的这个验证方法问题在哪里?可否帮我修改修改,谢谢!
public boolean validateUserName(String userName) {
//UserDto userDto = null;
try {
boolean flag = false;
// 获得Connection连接对象
conn = DBConnection.getConnection();
// 创建prepareStatement对象
ps = conn.prepareStatement("select user_name from user_Table ");
rs = ps.executeQuery();
if (rs.next()) {
//for(i =0;i<rs.length();i++)
if (rs.equals(userName)) {
return true;
//break;
} else{
return false;
}
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
System.out.println("数据库操作错误");
} finally {
// 释放资源
DBConnection.clear(conn, ps, rs);
}
//return false;
//return true;
return false;
}