Rhino can realize mutual calls between JAVA and javascript. Sometimes we want to use javascript to interpret and execute custom JAVA statements, such as
$console.print("hello world");
At this time, you can use ScriptableObject.defineClass to achieve registration. The specific code implementation can refer to the following:
package com.zjyang.scriptable; import org.mozilla.javascript.Context; import org.mozilla.javascript.Function; import org.mozilla.javascript.Scriptable; import org.mozilla.javascript.annotations.JSFunction; import java.io.PrintStream; public class ConsoleScriptable extends org.mozilla.javascript.ScriptableObject { private static final long serialVersionUID = 1L; private java.io.PrintStream printStream; public void setPrintStream(java.io.PrintStream printStream) { this.printStream = printStream; } public ConsoleScriptable() {} @JSFunction public static void print(Context cx, Scriptable obj, Object[] args, Function funObj) { print0(obj, args, false); } @JSFunction public static void println(Context cx, Scriptable obj, Object[] args, Function funObj) { print0(obj, args, true); } private static void print0(Scriptable obj, Object[] args, boolean eol) { PrintStream printStream = checkInstance(obj).printStream; for (Object arg : args) { printStream.print(Context.toString(arg)); } if (eol) { printStream.println(); } } private static ConsoleScriptable checkInstance(Scriptable obj) { if (null == obj || !(obj instanceof ConsoleScriptable)) { throw Context.reportRuntimeError("call ed on incompatible object"); } return (ConsoleScriptable) obj; } @Override public String getClassName() { return ConsoleScriptable.class.getSimpleName(); } }
package com.zjyang.handler; import com.zjyang.scriptable.ConsoleScriptable; import org.mozilla.javascript.*; import java.io.Console; import java.lang.reflect.InvocationTargetException; public class JavaScriptHandler { private Scriptable global; private int optimizationLevel = -1; private Script script; public JavaScriptHandler() { Context ctx = Context.enter(); global = ctx.initStandardObjects(); try { ScriptableObject.defineClass(global, ConsoleScriptable.class); } catch (IllegalAccessException e) { e.printStackTrace (); } catch (InstantiationException e) { e.printStackTrace (); } catch (InvocationTargetException e) { e.printStackTrace (); } finally { Context.exit(); } } public void handle() { Context ctx = Context.enter(); try { ctx.setOptimizationLevel(optimizationLevel); if (script == null) { script = ctx.compileString("$console.println('xx');", "firstRhino", 0, null); } Scriptable scope = new NativeObject(); scope.setParentScope(global); ConsoleScriptable $console = (ConsoleScriptable) ctx.newObject(scope, ConsoleScriptable.class.getSimpleName()); $console.setPrintStream(System.out); ScriptableObject.putProperty(scope, "$console", $console); script.exec(ctx, scope); } finally { Context.exit(); } } public static void main(String args[]) { new JavaScriptHandler().handle(); System.out.println("finish"); } }
Personally, I feel that when making some applications, you can do development directly without changing the background, and it is easier to get started, because it is a weak language type.
Reference: http://my.oschina.net/yybear/blog/102018