I'm trying to write a Java routine to evaluate math expressions from String
values like:
"5+3"
"10-40"
"(1+10)*3"
I want to avoid a lot of if-then-else statements. How can I do this?
With JDK1.6, you can use the built-in Javascript engine.
import javax.script.ScriptEngineManager;
import javax.script.ScriptEngine;
import javax.script.ScriptException;
public class Test {
public static void main(String[] args) throws ScriptException {
ScriptEngineManager mgr = new ScriptEngineManager();
ScriptEngine engine = mgr.getEngineByName("JavaScript");
String foo = "40+2";
System.out.println(engine.eval(foo));
}
}