JAVA嵌入运行Groovy脚本

摘自: http://shift-alt-ctrl.iteye.com/blog/1938238

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最近设计一个数据统计系统,系统中上百种数据统计维度,而且这些数据统计的指标可能随时会调整.如果基于java编码的方式逐个实现数据统计的API设计,工作量大而且维护起来成本较高;最终确定为将"数据统计"的计算部分单独分离成脚本文件(javascript,或者Groovy),非常便捷了实现了"数据统计Task" 与 "数据统计规则(计算)"解耦,且可以动态的加载和运行的能力.顺便对JAVA嵌入运行Groovy脚本做个备忘.

Java中运行Groovy,有三种比较常用的类支持:GroovyShell,GroovyClassLoader以及Java-Script引擎(JSR-223).

1) GroovyShell: 通常用来运行"script片段"或者一些零散的表达式(Expression)

2) GroovyClassLoader: 如果脚本是一个完整的文件,特别是有API类型的时候,比如有类似于JAVA的接口,面向对象设计时,通常使用GroovyClassLoader.

3) ScriptEngine: JSR-223应该是推荐的一种使用策略.规范化,而且简便.

一.GroovyShell代码样例

1) 简单的表达式执行,方法调用

Java代码
1./**

1. • 简答脚本执行
     
2. • @throws Exception
     
3. */
   5.public static void evalScriptText() throws Exception{ 6. //groovy.lang.Binding 7. Binding binding = new Binding(); 8. GroovyShell shell = new GroovyShell(binding); 9.
   
4. binding.setVariable("name", "zhangsan"); 11. shell.evaluate("println 'Hello World! I am ' + name;"); 12. //在script中,声明变量,不能使用def,否则scrope不一致. 13. shell.evaluate("date = new Date();"); 14. Date date = (Date)binding.getVariable("date"); 15. System.out.println("Date:" + date.getTime()); 16. //以返回值的方式,获取script内部变量值,或者执行结果 17. //一个shell实例中,所有变量值,将会在此"session"中传递下去."date"可以在此后的script中获取 18. Long time = (Long)shell.evaluate("def time = date.getTime(); return time;"); 19. System.out.println("Time:" + time); 20. binding.setVariable("list", new String[]{"A","B","C"}); 21. //invoke method 22. String joinString = (String)shell.evaluate("def call(){return list.join(' - ')};call();"); 23. System.out.println("Array join:" + joinString); 24. shell = null; 25. binding = null; 26.}
   /**

• 简答脚本执行

• @throws Exception
  */
  public static void evalScriptText() throws Exception{
  //groovy.lang.Binding
  Binding binding = new Binding();
  GroovyShell shell = new GroovyShell(binding);

  binding.setVariable("name", "zhangsan");
  shell.evaluate("println 'Hello World! I am ' + name;");
  //在script中,声明变量,不能使用def,否则scrope不一致.
  shell.evaluate("date = new Date();");
  Date date = (Date)binding.getVariable("date");
  System.out.println("Date:" + date.getTime());
  //以返回值的方式,获取script内部变量值,或者执行结果
  //一个shell实例中,所有变量值,将会在此"session"中传递下去."date"可以在此后的script中获取
  Long time = (Long)shell.evaluate("def time = date.getTime(); return time;");
  System.out.println("Time:" + time);
  binding.setVariable("list", new String[]{"A","B","C"});
  //invoke method
  String joinString = (String)shell.evaluate("def call(){return list.join(' - ')};call();");
  System.out.println("Array join:" + joinString);
  shell = null;
  binding = null;
  } 2) 伪main方法执行.

Java代码
1./**

1. • 当groovy脚本,为完整类结构时,可以通过执行main方法并传递参数的方式,启动脚本.
     
2. */
   4.public static void evalScriptAsMainMethod(){ 5. String[] args = new String[]{"Zhangsan","10"};//main(String[] args) 6. Binding binding = new Binding(args); 7. GroovyShell shell = new GroovyShell(binding); 8. shell.evaluate("static void main(String[] args){ if(args.length != 2) return;println('Hello,I am ' + args[0] + ',age ' + args[1])}"); 9. shell = null; 10. binding = null; 11.}
   /**

• 当groovy脚本,为完整类结构时,可以通过执行main方法并传递参数的方式,启动脚本.
  */
  public static void evalScriptAsMainMethod(){
  String[] args = new String[]{"Zhangsan","10"};//main(String[] args)
  Binding binding = new Binding(args);
  GroovyShell shell = new GroovyShell(binding);
  shell.evaluate("static void main(String[] args){ if(args.length != 2) return;println('Hello,I am ' + args[0] + ',age ' + args[1])}");
  shell = null;
  binding = null;
  } 3) 通过Shell运行具有类结构的Groovy脚本

Java代码
1./**

1. • 运行完整脚本
     
2. • @throws Exception
     
3. */
   5.public static void evalScriptTextFull() throws Exception{ 6. StringBuffer buffer = new StringBuffer(); 7. //define API 8. buffer.append("class User{") 9. .append("String name;Integer age;") 10. //.append("User(String name,Integer age){this.name = name;this.age = age};") 11. .append("String sayHello(){return 'Hello,I am ' + name + ',age ' + age;}}\n"); 12. //Usage 13. buffer.append("def user = new User(name:'zhangsan',age:1);") 14. .append("user.sayHello();"); 15. //groovy.lang.Binding 16. Binding binding = new Binding(); 17. GroovyShell shell = new GroovyShell(binding); 18. String message = (String)shell.evaluate(buffer.toString());
   
4. System.out.println(message);
   
5. //重写main方法,默认执行 21. String mainMethod = "static void main(String[] args){def user = new User(name:'lisi',age:12);print(user.sayHello());}"; 22. shell.evaluate(mainMethod);
   
6. shell = null; 24.}
   /**

• 运行完整脚本
• @throws Exception
  */
  public static void evalScriptTextFull() throws Exception{
  StringBuffer buffer = new StringBuffer();
  //define API
  buffer.append("class User{")
  .append("String name;Integer age;")
  //.append("User(String name,Integer age){this.name = name;this.age = age};")
  .append("String sayHello(){return 'Hello,I am ' + name + ',age ' + age;}}\n");
  //Usage
  buffer.append("def user = new User(name:'zhangsan',age:1);")
  .append("user.sayHello();");
  //groovy.lang.Binding
  Binding binding = new Binding();
  GroovyShell shell = new GroovyShell(binding);
  String message = (String)shell.evaluate(buffer.toString());
  System.out.println(message);
  //重写main方法,默认执行
  String mainMethod = "static void main(String[] args){def user = new User(name:'lisi',age:12);print(user.sayHello());}";
  shell.evaluate(mainMethod);
  shell = null;
  } 4) 方法执行和分部调用

Java代码
1./**

1. • 以面向"过程"的方式运行脚本
     
2. • @throws Exception
     
3. */
   5.public static void evalScript() throws Exception{ 6. Binding binding = new Binding(); 7. GroovyShell shell = new GroovyShell(binding); 8. //直接方法调用 9. //shell.parse(new File(//)) 10. Script script = shell.parse("def join(String[] list) {return list.join('--');}"); 11. String joinString = (String)script.invokeMethod("join", new String[]{"A1","B2","C3"}); 12. System.out.println(joinString);
   
4. ////脚本可以为任何格式,可以为main方法,也可以为普通方法 14. //1) def call(){...};call(); 15. //2) call(){...}; 16. script = shell.parse("static void main(String[] args){i = i * 2;}"); 17. script.setProperty("i", new Integer(10)); 18. script.run();//运行, 19. System.out.println(script.getProperty("i")); 20. //the same as 21. System.out.println(script.getBinding().getVariable("i")); 22. script = null; 23. shell = null; 24.}
   /**

• 以面向"过程"的方式运行脚本

• @throws Exception
  /
  public static void evalScript() throws Exception{
  Binding binding = new Binding();
  GroovyShell shell = new GroovyShell(binding);
  //直接方法调用
  //shell.parse(new File(//))
  Script script = shell.parse("def join(String[] list) {return list.join('--');}");
  String joinString = (String)script.invokeMethod("join", new String[]{"A1","B2","C3"});
  System.out.println(joinString);
  ////脚本可以为任何格式,可以为main方法,也可以为普通方法
  //1) def call(){...};call();
  //2) call(){...};
  script = shell.parse("static void main(String[] args){i = i 2;}");
  script.setProperty("i", new Integer(10));
  script.run();//运行,
  System.out.println(script.getProperty("i"));
  //the same as
  System.out.println(script.getBinding().getVariable("i"));
  script = null;
  shell = null;
  }
  二. GroovyClassLoader代码示例

  1) 解析groovy文件

Java代码
1./**

1. • from source file of *.groovy
     
2. */
   4.public static void parse() throws Exception{ 5. GroovyClassLoader classLoader = new GroovyClassLoader(Thread.currentThread().getContextClassLoader()); 6. File sourceFile = new File("D:\TestGroovy.groovy");//文本内容的源代码 7. Class testGroovyClass = classLoader.parseClass(new GroovyCodeSource(sourceFile)); 8. GroovyObject instance = (GroovyObject)testGroovyClass.newInstance();//proxy 9. Long time = (Long)instance.invokeMethod("getTime", new Date()); 10. System.out.println(time);
   
3. Date date = (Date)instance.invokeMethod("getDate", time); 12. System.out.println(date.getTime());
   
4. //here 14. instance = null; 15. testGroovyClass = null; 16.}
   /**

• from source file of .groovy
  /
  public static void parse() throws Exception{
  GroovyClassLoader classLoader = new GroovyClassLoader(Thread.currentThread().getContextClassLoader());
  File sourceFile = new File("D:\TestGroovy.groovy");//文本内容的源代码
  Class testGroovyClass = classLoader.parseClass(new GroovyCodeSource(sourceFile));
  GroovyObject instance = (GroovyObject)testGroovyClass.newInstance();//proxy
  Long time = (Long)instance.invokeMethod("getTime", new Date());
  System.out.println(time);
  Date date = (Date)instance.invokeMethod("getDate", time);
  System.out.println(date.getTime());
  //here
  instance = null;
  testGroovyClass = null;
  } 2) 如何加载已经编译的groovy文件(.class)

Java代码
1.public static void load() throws Exception {

1. GroovyClassLoader classLoader = new GroovyClassLoader(Thread.currentThread().getContextClassLoader()); 3. BufferedInputStream bis = new BufferedInputStream(new FileInputStream("D:\TestGroovy.class")); 4. ByteArrayOutputStream bos = new ByteArrayOutputStream(); 5. for(;;){ 6. int i = bis.read(); 7. if( i == -1){ 8. break; 9. }
   

2.    bos.write(i);   

3. }
   
4. Class testGroovyClass = classLoader.defineClass(null, bos.toByteArray()); 13. //instance of proxy-class 14. //if interface API is in the classpath,you can do such as: 15. //MyObject instance = (MyObject)testGroovyClass.newInstance() 16. GroovyObject instance = (GroovyObject)testGroovyClass.newInstance();
   
5. Long time = (Long)instance.invokeMethod("getTime", new Date()); 18. System.out.println(time);
   
6. Date date = (Date)instance.invokeMethod("getDate", time); 20. System.out.println(date.getTime());
   
8. //here 23.bis.close();
   
9. bos.close();
   

10. instance = null; 26. testGroovyClass = null; 27.}
    public static void load() throws Exception {
    GroovyClassLoader classLoader = new GroovyClassLoader(Thread.currentThread().getContextClassLoader());
    BufferedInputStream bis = new BufferedInputStream(new FileInputStream("D:\TestGroovy.class"));
    ByteArrayOutputStream bos = new ByteArrayOutputStream();
    for(;;){
    int i = bis.read();
    if( i == -1){
    break;
    }
    bos.write(i);
    }
    Class testGroovyClass = classLoader.defineClass(null, bos.toByteArray());
    //instance of proxy-class
    //if interface API is in the classpath,you can do such as:
    //MyObject instance = (MyObject)testGroovyClass.newInstance()
    GroovyObject instance = (GroovyObject)testGroovyClass.newInstance();
    Long time = (Long)instance.invokeMethod("getTime", new Date());
    System.out.println(time);
    Date date = (Date)instance.invokeMethod("getDate", time);
    System.out.println(date.getTime());

    //here
    bis.close();
    bos.close();
    instance = null;
    testGroovyClass = null;
    }三. ScriptEngine

    1) pom.xml依赖

Xml代码
1.

1. org.codehaus.groovy 3. groovy 4. 2.1.6 5. 6. 7. org.codehaus.groovy 8. groovy-jsr223 9. 2.1.6 10.
   org.codehaus.groovy
   groovy
   2.1.6
   
   
   org.codehaus.groovy
   groovy-jsr223
   2.1.6
   2) 代码样例

Java代码
1.public static void evalScript() throws Exception{

1. ScriptEngineManager factory = new ScriptEngineManager(); 3. //每次生成一个engine实例 4. ScriptEngine engine = factory.getEngineByName("groovy"); 5. System.out.println(engine.toString());
   
2. assert engine != null; 7. //javax.script.Bindings 8. Bindings binding = engine.createBindings();
   
3. binding.put("date", new Date()); 10. //如果script文本来自文件,请首先获取文件内容 11. engine.eval("def getTime(){return date.getTime();}",binding); 12. engine.eval("def sayHello(name,age){return 'Hello,I am ' + name + ',age' + age;}"); 13. Long time = (Long)((Invocable)engine).invokeFunction("getTime", null); 14. System.out.println(time);
   
4. String message = (String)((Invocable)engine).invokeFunction("sayHello", "zhangsan",new Integer(12)); 16. System.out.println(message);
   17.}
   public static void evalScript() throws Exception{
   ScriptEngineManager factory = new ScriptEngineManager();
   //每次生成一个engine实例
   ScriptEngine engine = factory.getEngineByName("groovy");
   System.out.println(engine.toString());
   assert engine != null;
   //javax.script.Bindings
   Bindings binding = engine.createBindings();
   binding.put("date", new Date());
   //如果script文本来自文件,请首先获取文件内容
   engine.eval("def getTime(){return date.getTime();}",binding);
   engine.eval("def sayHello(name,age){return 'Hello,I am ' + name + ',age' + age;}");
   Long time = (Long)((Invocable)engine).invokeFunction("getTime", null);
   System.out.println(time);
   String message = (String)((Invocable)engine).invokeFunction("sayHello", "zhangsan",new Integer(12));
   System.out.println(message);
   } 需要提醒的是,在groovy中,\({expression} 将会被认为一个变量,如果需要输出"\)"符号,需要转义为"\$".

关于ScriptEngine更多介绍,请参考.

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