java6内置JS引擎初接触
yeqinglong8888
9年前
来自： http://blog.csdn.net/sdyy321/article/details/6959199
test01.js:
if(age>=18){ print('Old enough to vote!'); }else{ print('Back to school!'); } test02.js:
if(age<25){ riskFactor = 1.5; }else if(noClaims){ ristFactor = 0.75; }else{ ristFactor = 1.0; } test03.js:
function Hello(){} Hello.prototype.sayHello = function(value) { println('hello!'+value); } Hello.prototype.increment = function(value) { return i+1; } var hello = new Hello(); hello.sayHello('World1'); Hello.java:
package com.hjr.demo.util.js; public interface Hello { public int increment(int value); public void sayHello(String name); }ScriptEngineDemo.java: package com.hjr.demo.util.js; import java.io.BufferedReader; import java.io.FileNotFoundException; import java.io.FileReader; import java.io.IOException; import java.io.PipedReader; import java.io.PipedWriter; import java.io.PrintWriter; import javax.script.*; public class ScriptEngineDemo { public static void main(String[] args) throws Exception { test10(); } // 使用脚本引擎运行脚本程序 public static void test01() throws ScriptException { // 如果调用者可访问线程上下文 ClassLoader，则调用此构造方法的效果与调用 ScriptEngineManager(Thread.currentThread().getContextClassLoader()) 相同 // ScriptEngineManager检索感兴趣的脚本编写的语言的ScriptEngine对象 ScriptEngineManager manager = new ScriptEngineManager(); ScriptEngine engine = manager.getEngineByName("js"); engine.put("age", 26); engine.eval("if(age>=18){println('Old enough to vote!');}else{println('Back to school!');}"); } // 使用脚本引擎执行外部资源中的脚本 public static void test02() throws FileNotFoundException, ScriptException { ScriptEngineManager manager = new ScriptEngineManager(); ScriptEngine engine = manager.getEngineByName("js"); engine.put("age", 26); engine.eval(new FileReader("E:/ScriptEngine/test01.js"));// 对文件或其它外部资源中得脚本表达式进行求值 } // 使用脚本引擎检索结果 public static void test03() throws FileNotFoundException, ScriptException { ScriptEngineManager manager = new ScriptEngineManager(); ScriptEngine engine = manager.getEngineByName("js"); engine.put("age", 26); engine.put("noClaims", Boolean.TRUE); Object result = engine.eval(new FileReader("E:/ScriptEngine/test02.js"));// eval()函数返回执行脚本后所返回的值，默认情况下，将返回上次执行的表达式的值 System.out.println(result.toString()); } // 上下文属性的作用域 public static void test04() throws ScriptException { ScriptEngineManager manager = new ScriptEngineManager(); Bindings globalBindings = manager.getBindings(); // 属于ScriptEngineManager的全局上下文,每个ScriptEngineManager拥有一个Bindings globalBindings.put("name", "yangYong"); ScriptEngine engine = manager.getEngineByName("js"); Bindings globalBindings02 = engine.getBindings(ScriptContext.GLOBAL_SCOPE); // 每个引擎都共有一个ScriptEngineManager的Bindings System.out.println("name=" + globalBindings02.get("name")); System.out.println(globalBindings == globalBindings02); ScriptContext context = engine.getContext(); // 每个引擎都有自己独立的scriptContext上下文 Bindings engineDefaultBindings = engine.getBindings(ScriptContext.ENGINE_SCOPE); // 每个引擎的scriptContext中都有个默认属于自己的Bindings engineDefaultBindings.put("gender", "男"); engine.eval("name2 = name;println(name2);", engineDefaultBindings); engineDefaultBindings.put("name", "zhangSan"); engine.eval("name2 = name;println(name2)", engineDefaultBindings); Bindings engineCreateBindings = engine.createBindings(); // 每个引擎的scriptContext中也可以新建多个属于自己的Bindings engineCreateBindings.put("gender", "女"); System.out.println(engineDefaultBindings == engineCreateBindings); System.out.println(engine.getBindings(ScriptContext.ENGINE_SCOPE)); System.out.println(engineCreateBindings.get("gender")); engine.eval("name2 = name;println(name2)", engineCreateBindings); } // java应用程序与脚本交互 public static void test05() throws ScriptException { ScriptEngineManager manager = new ScriptEngineManager(); ScriptEngine engine = manager.getEngineByName("js"); Bindings bindings = engine.createBindings(); // Bindings:KV对映射，用来在Java应用程序和javascript脚本之间交换信息，即上下文 bindings.put("age", 26); bindings.put("noClaims", Boolean.TRUE); bindings.put("riskFactor", 1.0); engine.eval("if(age<25){riskFactor = 1.5;}else if(noClaims){ristFactor = 0.75;}else{ristFactor = 1.0;}", bindings);//必须绑定bindings执行脚本，否则报变量未定义异常 double risk = (Double) bindings.get("riskFactor"); System.out.println(risk); } // 脚本内部访问java资源 public static void test06() throws ScriptException { ScriptEngineManager manager = new ScriptEngineManager(); ScriptEngine engine = manager.getEngineByName("js"); engine.eval("importPackage(java.util)"); engine.eval("today = new Date();println(today)"); engine.put("name", "ZhangSan"); engine.eval("name2 = name.toUpperCase();println(name2);"); } // 重定向脚本输出 public static void test07() throws IOException, ScriptException { ScriptEngineManager manager = new ScriptEngineManager(); ScriptEngine engine = manager.getEngineByName("js"); PipedReader pr = new PipedReader(); PipedWriter pw = new PipedWriter(pr); // 用户可以通过与这个 PrintWriter 连通的 PrintReader 读取实际的输出，使 Java 应用程序能获取脚本运行输出 PrintWriter out = new PrintWriter(pw); engine.getContext().setWriter(out); engine.eval("println('hello from javascript!');"); BufferedReader br = new BufferedReader(pr); System.out.println(br.readLine()); } // 可编译且可调用的引擎 public static void test08() throws ScriptException { ScriptEngineManager manager = new ScriptEngineManager(); ScriptEngine engine = manager.getEngineByName("js"); if (engine instanceof Compilable) { // 判断脚本引擎是否支持编译操作 Compilable compilable = (Compilable)engine; CompiledScript script = compilable.compile("if(age<25){riskFactor = 1.5;}else if(noClaims){ristFactor = 0.75;}else{ristFactor = 1.0;}"); Bindings bindings = engine.createBindings(); bindings.put("age", 26); bindings.put("noClaims", Boolean.TRUE); bindings.put("riskFactor", 1.0); Object result = script.eval(bindings); System.out.println(result.toString()); } } // 调用脚本中的函数和方法 public static void test09() throws ScriptException, NoSuchMethodException, FileNotFoundException { ScriptEngineManager manager = new ScriptEngineManager(); ScriptEngine engine = manager.getEngineByName("js"); engine.eval("function increment(i){return i+1;}"); if (engine instanceof Invocable) { // 判断脚本引擎是否支持编译操作 Invocable invocable = (Invocable)engine; // Invocable允许从java代码调用定义在脚本中的单个函数 Object result = invocable.invokeFunction("increment", new Object[]{10}); // 调用脚本中定义的顶层程序和函数 System.out.println("result = "+result); } ScriptEngine engine2 = manager.getEngineByName("js"); engine2.eval(new FileReader("E:/ScriptEngine/test03.js")); if (engine2 instanceof Invocable) { Invocable invocable = (Invocable)engine2; invocable.invokeMethod(engine2.get("hello"), "sayHello", "yangYong"); // 对以前的脚本执行中已经编译的脚本对象（以 ScriptEngine 的状态保持）调用某一方法 } } // 调用脚本中的函数和方法并将他们作为java程序中的接口实现 public static void test10() throws FileNotFoundException, ScriptException { /** * TODO 这个用例存在问题，待处理 */ ScriptEngineManager manager = new ScriptEngineManager(); ScriptEngine engine = manager.getEngineByName("js"); engine.eval("function increment(i){return i+1;}"); if (engine instanceof Invocable) { Invocable invocable = (Invocable)engine; Hello hello = invocable.getInterface(Hello.class); // 返回一个接口的实现，该接口使用解释器中编译的函数 Object result = hello.increment(2); System.out.println("result = " + result); } engine.eval(new FileReader("E:/ScriptEngine/test03.js")); if (engine instanceof Invocable) { Invocable invocable2 = (Invocable)engine; Hello hello = invocable2.getInterface(engine.get("hello"), Hello.class); // 返回一个接口的实现，该接口使用解释器中已编译脚本对象的成员函数 hello.sayHello("zhangSan"); } } }