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Wildcards in Java PreparedStatements

Here’s my current SQL statement:

SEARCH_ALBUMS_SQL = "SELECT * FROM albums WHERE title LIKE ? OR artist LIKE ?;";

It’s returning exact matches to the album or artist names, but not anything else. I can’t use a ‘%’ in the statement or I get errors.

How do I add wildcards to a prepared statement?

(I’m using Java5 and MySQL)

Thanks!

Answer

You put the % in the bound variable. So you do

   stmt.setString(1, "%" + likeSanitize(title) + "%");
   stmt.setString(2, "%" + likeSanitize(artist) + "%");

You should add ESCAPE ‘!’ to allow you to escape special characters that matter to LIKE in you inputs.

Before using title or artist you should sanitize them (as shown above) by escaping special characters (!, %, _, and [) with a method like this:

public static String likeSanitize(String input) {
    return input
       .replace("!", "!!")
       .replace("%", "!%")
       .replace("_", "!_")
       .replace("[", "![");
} 
Categories
discuss

Is there a library similar to pyparsing in Java? [closed]

I need to quickly build a parser for a very simplified version of a html-like markup language in Java. In python, I would use pyparsing library to do this. Is there something similar for Java? Please, don’t suggest libraries already out there for html parsing, my application is a school assignment which will demonstrate walking a tree of objects and serializing to text using visitor pattern, so I’m not thinking in real world terms here. Basically all I need here is tags, attributes and text nodes.

Answer

Another good parser generator is ANTLR, that might be what you’re looking for.

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What’s the best way to calculate date difference in Javascript

I doing a function in Javascript like the VisualBasic DateDiff.

You give two dates and the returning time interval (Seconds, Minutes, Days, etc…)

DateDiff(ByVal Interval As Microsoft.VisualBasic.DateInterval, _
  ByVal Date1 As Date, ByVal Date2 As Date) as Long

So what’s the best way to calculate the difference of Javascript Dates?

Answer

Use the Date object like so:

function DateDiff(var /*Date*/ date1, var /*Date*/ date2) {
    return date1.getTime() - date2.getTime();
}

This will return the number of milliseconds difference between the two dates. Converting it to seconds, minutes, hours etc. shouldn’t be too difficult.

Source: stackoverflow
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