Java Embedded Run Groovy script

A. Groovyshell code example1) Simple expression execution, method invocation

/** *  simple answer script execution  *  @throws  Exception */public static void  Evalscripttext ()  throws Exception{//groovy.lang.BindingBinding binding = new  Binding (); Groovyshell shell = new groovyshell (binding); Binding.setvariable ("Name",  "Zhangsan"); Shell.evaluate ("println  ' hello world! i am  '  + name;"); /in script, declare variables, do not use Def, otherwise scrope inconsistent. Shell.evaluate ("date = new date ();");D ate date =  (date) binding.getvariable ("date"); System.out.println ("Date:"  + date.gettime ());//To get the script intrinsic variable value in the return value, or to execute the result//a shell instance, all variable values will be in this " Session "in the" pass. " Date "can get long time =  (Long) shell.evaluate (" Def time = date.gettime () in the script thereafter;  return time; "); System.out.println ("Time:"  + time), binding.setvariable ("list",  new string[]{"A", "B", "C"}) ;//invoke methodstring joinstring =  (String) SHEll.evaluate ("Def call () {return list.join ('  -  ')};call ();"); System.out.println ("Array join:"  + joinstring); shell = null;binding = null;}

2) Pseudo Main method execution.

/** * When groovy scripting is the complete class structure, you can start the script by executing the main method and passing the arguments. */public static void Evalscriptasmainmethod () {string[] args = new string[]{"Zhangsan", "Ten"};//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 ;p rintln (' hello,i am ' + args[0] + ', age ' + args[1]} "); shell = null;binding = null;}

3) Run a groovy script with class structure through the shell

/** *  run full script  *  @throws  Exception */public static void  Evalscripttextfull ()  throws exception{stringbuffer buffer = new stringbuffer (); /define apibuffer.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 ");//usagebuffer.append (" Def user = new user (name: ' Zhangsan ', age:1); "). Append ("User.sayhello ();"); /groovy.lang.bindingbinding binding = new binding (); Groovyshell shell = new groovyshell (binding); string message =  (String) shell.evaluate (buffer.tostring ()); SYSTEM.OUT.PRINTLN (message);//Override Main method, default execution string mainmethod =  "Static void main ( String[] args) {DEF&NBsp;user = new user (name: ' Lisi ', age:12);p rint (User.sayhello ());} "; Shell.evaluate (Mainmethod); shell = null;}

4) method execution and partial invocation

/** *  Run scripts in a "process" way  *  @throws  Exception */public static void  Evalscript ()  throws exception{ binding binding = new binding ();  Groovyshell shell = new groovyshell (binding);  //Direct method call  //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);  ////script can be any format, can be the main method, can also be a normal method  //1)  def  Call () {...}; Call ();  //2)  call () {...};  script = shell.parse ("Static void main (String[] args) {i = i *  2;} ");  script.setproperty ("I",  new integer (Ten));  script.run ();//Run,  SYSTEM.OUT.PRINTLN ( Script.getproperty ("I"));  //the same as sYstem.out.println (Script.getbinding (). getvariable ("I")); script = null; shell =  null;}

Two. Groovyclassloader code example1) Parsing Groovy files

/** * from source file of *.groovy */public static void Parse () throws Exception{groovyclassloader ClassLoader = new Groov Yclassloader (Thread.CurrentThread (). Getcontextclassloader ()); File SourceFile = new file ("D:\\testgroovy.groovy"); Class Testgroovyclass = Classloader.parseclass (new Groovycodesource (sourcefile)); Groovyobject instance = (groovyobject) testgroovyclass.newinstance ();//proxylong time = (Long) Instance.invokemethod (" GetTime ", New Date ()); System.out.println (time);D ate Date = (date) instance.invokemethod ("GetDate", time); System.out.println (Date.gettime ());//hereinstance = Null;testgroovyclass = null;}

2) How to load the compiled groovy file (. Class)

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);D ate d ate =  (date) Instance.invokemethod ("GetDate",  time); System.out.println (Date.gettime ());//herebis.close (); Bos.close (); Instance = null;testgroovyclass  = null;}

Three. ScriptEngine1) Pom.xml Dependent

<dependency><groupid>org.codehaus.groovy</groupid><artifactid>groovy</artifactid ><version>2.1.6</version></dependency><dependency><groupId> org.codehaus.groovy</groupid><artifactid>groovy-jsr223</artifactid><version>2.1.6</ Version></dependency>

2) code sample

public static void evalscript ()  throws exception{scriptenginemanager factory = new scriptenginemanager ();// Generate an Engine instance scriptengine engine = factory.getenginebyname ("groovy") every time; System.out.println (Engine.tostring ()); assert engine != null;//javax.script.bindingsbindings  binding = engine.createbindings (); Binding.put ("Date",  new date ());//If the script text is from a file, Please first obtain the contents of the file 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);} 

To be reminded, in groovy, ${expression} will be considered a variable, and if required to output a "$" symbol, it needs to be escaped as "\$".

For more information about ScriptEngine, please refer to. http://shift-alt-ctrl.iteye.com/blog/1896690

Java Embedded Run Groovy script