Java / JSP中的字符串到整数的转换

Question

I have a variable cost defined in a DB2 table as String . I'm getting it into a value object where it is defined as a String as well. I need to check if the value coming in from DB2 is only spaces. If it is only spaces, I need to move 0 into it. I also need to remove leading zeros from it. I may get cost as 0000123 . But in JSP I need to display it as 123 . How do you do that? I'm storing the vo data into a session variable and using this, I'm displaying the data in JSP.

Answer 1

I would consider changing your database schema to store the value in a numeric field. If you can't do that, consider changing the value object to store it as a numeric field and parse the string you retrieve from the database.

Answer 2

Understanding that most of what you have described sounds like extremely poor design, you can continue the path and use a scriptlet. The following example uses Apache Commons Lang to accomplish your task:

<%= org.apache.commons.lang.math.NumberUtils.toInt(org.apache.commons.lang.StringUtils.trimToNull(cost),0) %>

Answer 3

If you can't change your database. Use Integer.parseInt (javadoc) . (This is assuming we are dealing with integers here, otherwise use the equivalent in Double ). Create a function to process your String number and use it in your JSP.

<%
function String processNumber(String value){
  if(value == null || value.trim().length() == 0){
     value = "0"//use a zero if all we have is whitespace or if the value is null
  }

  int intValue = 0;//store the integer version (which won't have leading zeros)
  try{
    int intValue = Integer.parseInt(value);//process the number
  }
  catch(Exception e){
    intValue = 0;//use 0 if there's a problem
  }
  return "" + intValue;//return the String version free of leading zeros
}
%>
<p>Number: <%= processNumber(getValue()) //replace getValue with however you get your value %></p>