HelloWorld 善戰者,求之于勢,不責于人;故能擇人而任勢。

import java.io.File;
import javax.script.Invocable;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;

public class ScriptTest {
 public static void main(String[] args) throws Exception {
  ScriptEngineManager manager = new ScriptEngineManager();
  ScriptEngine engine = manager.getEngineByName("JavaScript");
  testScriptVariables(engine);// 演示如何暴露Java對象為腳本語言的全局變量
  testInvokeScriptMethod(engine);// 演示如何在Java中調用腳本語言的方法
  testScriptInterface(engine);// 演示腳本語言如何實現Java的接口
  testUsingJDKClasses(engine);// 演示腳本語言如何使用JDK平臺下的類
 }

 public static void testScriptVariables(ScriptEngine engine)
   throws ScriptException {
  File file = new File("e:/test/aaa.txt");
  engine.put("f", file);
  engine.eval("println('Total Space:'+f.getTotalSpace())");
 }

 public static void testInvokeScriptMethod(ScriptEngine engine)
   throws Exception {
  String script = "function hello(name) { return 'Hello,' + name;}";
  engine.eval(script);
  Invocable inv = (Invocable) engine;
  String res = (String) inv.invokeFunction("hello", "Scripting");
  System.out.println("res:" + res);
 }

 public static void testScriptInterface(ScriptEngine engine)
   throws ScriptException {
  String script = "var obj = new Object(); obj.run = function() { println('run method called'); }";
  engine.eval(script);
  Object obj = engine.get("obj");
  Invocable inv = (Invocable) engine;
  Runnable r = inv.getInterface(obj, Runnable.class);
  Thread th = new Thread(r);
  th.start();
 }

 public static void testUsingJDKClasses(ScriptEngine engine)
   throws Exception {
  // Packages是腳本語言里的一個全局變量,專用于訪問JDK的package
  String js = "function doSwing(t){var f=new Packages.javax.swing.JFrame(t);f.setSize(400,300);f.setVisible(true);}";
  engine.eval(js);
  Invocable inv = (Invocable) engine;
  inv.invokeFunction("doSwing", "Scripting Swing");
 }
}

</script>