Java Parsing Logical Expressions_DangerousRoy’s Blog

java parses logical expressions (strings that perform logical operators)

import javax.script.ScriptEngine;

import javax.script.ScriptEngineManager;

public class expression

{

public static void main(String[] args) throws Exception {

String str = “(a and b) or (c and d)”;

str = str. replaceAll(“or”, “||”);

str = str. replaceAll(“and”, “&&”);

System.out.println(str);

ScriptEngineManager manager = new ScriptEngineManager();

ScriptEngine engine = manager.getEngineByName(“js”);

engine. put(“a”,true);

engine. put(“b”,false);

engine.put(“c”,false);

engine.put(“d”,true);

Object result = engine.eval(str);

System.out.println(“Result type: ” + result.getClass().getName() + “, calculation result: ” + result);

}

}

Original address: http://blog.sina.com.cn/s/blog_acdc06250101p5dh.html