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JAVA嵌入运行Groovy脚本

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10/31
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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./**

2. * 简答脚本执行

3. * @throws Exception

4. /

5.public static void evalScriptText() throws Exception{ 6. //groovy.lang.Binding 7. Binding binding = new Binding(); 8. GroovyShell shell = new GroovyShell(binding); 9.

10. 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./**

2. * 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.

3. /

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./**

2. * 运行完整脚本

3. * @throws Exception

4. /

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());

19. System.out.println(message);

20. //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);

23. 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./**

2. * 以面向"过程"的方式运行脚本

3. * @throws Exception

4. /

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);

13. ////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./**

2. * from source file of .groovy

3. /

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);

11. Date date = (Date)instance.invokeMethod("getDate", time); 12. System.out.println(date.getTime());

13. //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 {

2. GroovyClassLoader classLoader = new GroovyClassLoader(Thread.currentThread().getContextClassLoader()); 3. BufferedInputStream bis = new BufferedInputStream(new FileInputStream("D:\TestGroovy.class")); 4. ByteArrayOutputStream bos = new ByteArrayOutputStream(); 5. for(;