Call Java__js in Java call Js,js

1 Advantages of using scripting language

Rapid turnaround, encouraging experimentation.

Changing the behavior of a running program.

Enabling customization by the program users.

2)

The site Http://scripting.dev.java.net provides engines for a wide range of scripting languages.

For example, to add support for Groovy, the class path should contain groovy/lib/*

(from http://groovy.codehaus.org) and Groovy-engine.jar (from Http://scripting.dev.java.net).

3)

Javax.script.ScriptEngineManager

Javax.script.ScriptEngineFactory

Javax.script.ScriptEngine

Javax.script.Invocable

Javax.script.CompiledScript

ScriptEngine engine = Manager.getenginebyname ("JavaScript");

Object result = Engine.eval (scriptstring);

Object result = engine.eval (reader);

Engine.put (k, 1728);

Object result = Engine.eval ("K + 1");

4 redirect Input and output

StringWriter writer = new StringWriter ();

Engine.getcontext (). Setwriter (New PrintWriter (writer, true));

5) calling scripting functions and Methods

To call a function, call the Invokefunction method and the function name, followed by the function parameters:

If (engine implements invocable)

((invocable) engine). Invokefunction ("Afunction", param1, param2);

If the scripting language is Object oriented, you call can a as this:

Code View:

((invocable) engine). InvokeMethod (Implicitparam, "Amethod", explicitParam1, EXPLICITPARAM2);

6) Compiling a Script

Reader reader = new FileReader ("Myscript.js");

Compiledscript script = null;

If (engine implements compilable)

Compiledscript script = ((compilable) engine). compile (reader);

if (script!= null)

Script.eval ();

Else

Engine.eval (reader);

7)

Download Rhino in http://www.mozilla.org/rhino/:

Adding Js.jar to the system classpath

You can invoke the JS interpreter in interactive mode:

Java Org.mozilla.javascript.tools.shell.Main

Java Org.mozilla.javascript.tools.debugger.Main

8) Call each other

HelloWorld Hello = new HelloWorld ();

Engine.put ("Script_hello", hello);

Engine.eval ("Script_hello.sayhello ()");

String script = "function say (First,second) {print (the ' + ' + second+ '//n ');}";

Engine.eval (script);

Invocable INV = (invocable) engine;

Inv.invokefunction ("Say", "Hello", "Tony");

Script = "function max (First,second)"

+ "{return (> Second) First:second;}";

Engine.eval (script);

JS and Java interface calls

Object obj = inv.invokefunction ("Max", "1", "0");