巧用javascript的eval()

import javax.script.Invocable;
import javax.script.ScriptContext;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;
import javax.script.SimpleBindings; public class JsTest {
ScriptEngineManager sem = new ScriptEngineManager();
ScriptEngine engine = sem.getEngineByExtension("js"); public static void main(String[] args) {
System.out.println(new JsTest().eval("1+2*9"));
} public Object eval(String str) {
Object result = null;
try {
result = engine.eval(str);
} catch (Exception ex) {
ex.printStackTrace();
}
return result;
}
}

加上｛｝可能都行

什么？

我也是学过编译原理的

应试教育