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Java Program to evaluate mathematical expressions in String
To evaluate mathematical expression in String, use Nashorn JavaScript in Java i.e. scripting. Nashorn invoke dynamics feature, introduced in Java 7 to improve performance.
For scripting, use the ScriptEngineManager class for the engine −
ScriptEngineManager scriptEngineManager = new ScriptEngineManager();
ScriptEngine scriptEngine = scriptEngineManager.getEngineByName("JavaScript");Now for JavaScript code from string, use eval i.e. execute the script. Here, we are evaluating mathematical expressions in a string −
Object ob = scriptEngine.eval("9 + 15 + 30");
System.out.println("Result of evaluating mathematical expressions in String = "+ob);Example
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
public class Main {
public static void main(String[] args) throws Exception {
ScriptEngineManager scriptEngineManager = new ScriptEngineManager();
ScriptEngine scriptEngine = scriptEngineManager.getEngineByName("JavaScript");
// JavaScript code from String
Object ob = scriptEngine.eval("9 + 15 + 30");
System.out.println("Result of evaluating mathematical expressions in String = "+ob);
}
}Output
Result of evaluating mathematical expressions in String = 54
Updated on: 30-Jul-2019
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