java中使用动态语言

   jdk6增加了对动态语言的支持，我觉得他的原理就是把动态语言也编译成ＪＶＭ可以理解的JＡＶＡ字节码的形式来执行的。主要支持的有javascript ,ruby ,php,python 等
　　这样就可以利用脚本语言的动态特性。

下面是对javascript支持的几个例子。
第１个：
Java代码 
import java.util.logging.Level; 
import java.util.logging.Logger; 
import javax.script.Invocable; 
import javax.script.ScriptEngine; 
import javax.script.ScriptEngineManager; 
import javax.script.ScriptException; 
public class HelloScript { 
    public static void main(String[] args){ 
         
例子比较简单，就是打印hello word，重要的几个类：
写道
ScriptEngineManager factory=new ScriptEngineManager();
ScriptEngine engine=factory.getEngineByName("JavaScript");


Java代码 
        try { 
            engine.eval("print('hello word')"); 
        } catch (ScriptException ex) { 
            Logger.getLogger(HelloScript.class.getName()).log(Level.SEVERE, null, ex); 
        } 
    } 
} 
第二个：
java调用脚本语言的方法
Java代码 
import java.util.logging.Level; 
import java.util.logging.Logger; 
import javax.script.Invocable; 
import javax.script.ScriptEngine; 
import javax.script.ScriptEngineManager; 
import javax.script.ScriptException; 
public class TestJsFun { 
public static void main(String[] args){ 
        ScriptEngineManager factory=new ScriptEngineManager(); 
        ScriptEngine engine=factory.getEngineByName("JavaScript"); 
        try { 
            String script="function hello(name){return 'Hello'+name}"; 
            engine.eval(script); 
            javax.script.Invocable inv=(Invocable)engine; 
            try { 
                String res = (String) inv.invokeFunction("hello", "chenhua"); 
                System.out.println(res); 
            } catch (NoSuchMethodException ex) { 
                Logger.getLogger(HelloScript.class.getName()).log(Level.SEVERE, null, ex); 
            } 
 
        } catch (ScriptException ex) { 
            Logger.getLogger(HelloScript.class.getName()).log(Level.SEVERE, null, ex); 
        } 
    } 
} 
脚本引擎本身并不负责执行在脚本中定义的方法，而是转换为javax.script.Invocable　的对象ivh,有ivh的方法invokeFunction()方法来调用脚本的方法。invokeFunction（）方法的第一个参数必须是方法名。后面是参数列表。

第三个例子：脚本语言用java的变量
Java代码 
import java.io.File; 
import java.io.IOException; 
import java.util.logging.Level; 
import java.util.logging.Logger; 
import javax.script.ScriptEngine; 
import javax.script.ScriptEngineManager; 
import javax.script.ScriptException; 
public class TestScriptVariables { 
         public static void main(String[] args){ 
                ScriptEngineManager factory=new ScriptEngineManager(); 
                ScriptEngine engine=factory.getEngineByName("JavaScript"); 
                testScript(engine); 
         } 
         public static void testScript(ScriptEngine engine){ 
             File file=new File("F:\\test.txt"); 
             if(!file.exists()){ 
            try { 
                file.createNewFile(); 
            } catch (IOException ex) { 
                Logger.getLogger(TestScriptVariables.class.getName()).log(Level.SEVERE, null, ex); 
            } 
             } 
             engine.put("f", file); 
        try { 
            engine.eval("println('file size:'+f.length())"); 
        } catch (ScriptException ex) { 
            Logger.getLogger(TestScriptVariables.class.getName()).log(Level.SEVERE, null, ex); 
        } 
         } 
} 

通过 写道
engine.put("f", file);

来设置一个全局的变量。这个ＡＰＩ比较重要
这样就取到了文件的大小。

第４个例子
脚本语言适用java的类库
Java代码 
import javax.script.Invocable; 
import javax.script.ScriptEngine; 
import javax.script.ScriptEngineManager; 
import javax.script.ScriptException; 
public class TestUsingJdkClass { 
public static void main(String[] args) throws ScriptException, NoSuchMethodException{ 
                ScriptEngineManager factory=new ScriptEngineManager(); 
                ScriptEngine engine=factory.getEngineByName("JavaScript"); 
                testScript(engine); 
         } 
         public static void testScript(ScriptEngine engine) throws ScriptException, NoSuchMethodException{ 
            String js ="function doSwing(t){ var f=new Packages.javax.swing.JFrame(t);f.setSize(400,300);f.setVisible(true);}"; 
            engine.eval(js); 
            javax.script.Invocable inv=(Invocable)engine; 
            inv.invokeFunction("doSwing", "from javascript swing window"); 
         } 
} 
在脚本中使用了Ｐackages这一个全局变量，专门用于访问java的类库，程序运行后，会出现java Swing的一个窗体
看截图


最后一个例子：脚本语言实现java的接口
Java代码 
import javax.script.Invocable; 
import javax.script.ScriptEngine; 
import javax.script.ScriptEngineManager; 
import javax.script.ScriptException; 
public class TestScriptInterface { 
public static void main(String[] args) throws ScriptException, NoSuchMethodException{ 
                ScriptEngineManager factory=new ScriptEngineManager(); 
                ScriptEngine engine=factory.getEngineByName("JavaScript"); 
                testScript(engine); 
         } 
         public static void testScript(ScriptEngine engine) throws ScriptException, NoSuchMethodException{ 
            String script="var obj= new Object();obj.run=function(){println('run() was called');}"; 
            engine.eval(script); 
            Object obj=engine.get("obj"); 
            javax.script.Invocable inv=(Invocable)engine; 
            Runnable r=inv.getInterface(obj, Runnable.class); 
            Thread t=new Thread(r); 
            t.start(); 
 
         } 
} 
这里通过这句：
Object obj=engine.get("obj");
来获得脚本中的变量。
然后在通过ivh的getIntegerface()方法转化为java的接口。最后启动一个线程来执行它。


另外：在jdk6中有一个命令行工具：jrunscript
进入bin目录，下面可以运行的，默认为javascript语言，这个可以用来测试我们写的脚本是否正确

转自:http://chenhua-1984.iteye.com/blog/684237


------------------java调用perl脚本-----------------------
perl - Java调用perl

Java 调用 perl
Java代码 
Runtime.getRuntime().exec("perl C:\\Perl\\execise.pl"); 


Java 调用 perl 通过IO的方式来得到返回值
Java代码 
package fiveGame; 
 
import java.io.BufferedReader; 
import java.io.IOException; 
import java.io.InputStream; 
import java.io.InputStreamReader; 
 
public class JavaCallPerl { 
    public static void main(String[] args) throws IOException { 
 
        StringBuffer resultStringBuffer = new StringBuffer(); 
 
        String lineToRead = ""; 
        int exitValue = 0; 
 
        try { 
 
            Process proc = Runtime.getRuntime().exec("perl C:\\Perl\\execise.pl"); 
            InputStream inputStream = proc.getInputStream(); 
            BufferedReader bufferedRreader = new BufferedReader(new InputStreamReader(inputStream)); 
 
            // save first line 
            if ((lineToRead = bufferedRreader.readLine()) != null) { 
                resultStringBuffer.append(lineToRead); 
            } 
 
            // save next lines 
            while ((lineToRead = bufferedRreader.readLine()) != null) { 
                resultStringBuffer.append("\r\n"); 
                resultStringBuffer.append(lineToRead); 
            } 
 
            // Always reading STDOUT first, then STDERR, exitValue last 
            proc.waitFor(); // wait for reading STDOUT and STDERR over 
            exitValue = proc.exitValue(); 
        } catch (Exception ex) { 
            resultStringBuffer = new StringBuffer(""); 
            exitValue = 2; 
        } 
 
        System.out.println("exit:" + exitValue); 
 
        System.out.println(resultStringBuffer.toString()); 
 
    } 
 
} 



perl
Java代码 
#!/usr/bin/perl -w 
$pi = 3.141592654; 
$circ = 2 * $pi * 12.5; 
print "The circumference of a circle of radius 12.5 is $circ.\n";