JDK1.6版添加了新的ScriptEngine類，允許用戶直接執行js代碼。
在Java中直接調用js代碼
不能調用瀏覽器中定義的js函數，會拋出異常提示ReferenceError: “alert” is not defined。
| | package com.sinaapp.manjushri; import javax.script.ScriptEngine; import javax.script.ScriptEngineManager; import javax.script.ScriptException; /** * 直接調用js代碼 */ public class ScriptEngineTest { public static void main(String[] args) { ScriptEngineManager manager = new ScriptEngineManager(); ScriptEngine engine = manager.getEngineByName("javascript"); try{ engine.eval("var a=3; var b=4;print (a+b);"); // engine.eval("alert(\"js alert\");"); // 不能調用瀏覽器中定義的js函數 // 錯誤，會拋出alert引用不存在的異常 }catch(ScriptException e){ e.printStackTrace(); } } } |
輸出結果：7
在Java中綁定js變量
在調用engine.get(key);時，如果key沒有定義，則返回null
| | package com.sinaapp.manjushri; import javax.script.Bindings; import javax.script.ScriptContext; import javax.script.ScriptEngine; import javax.script.ScriptEngineManager; import javax.script.ScriptException; public class ScriptEngineTest2 { public static void main(String[] args) { ScriptEngineManager manager = new ScriptEngineManager(); ScriptEngine engine = manager.getEngineByName("javascript"); engine.put("a", 4); engine.put("b", 3); Bindings bindings = engine.getBindings(ScriptContext.ENGINE_SCOPE); try { // 只能為Double，使用Float和Integer會拋出異常 Double result = (Double) engine.eval("a+b"); System.out.println("result = " + result); engine.eval("c=a+b"); Double c = (Double)engine.get("c"); System.out.println("c = " + c); } catch (ScriptException e) { e.printStackTrace(); } } } |
輸出：
result = 7.0
c = 7.0
在Java中調用js文件中的function，傳入調用參數，并獲取返回值
js文件中的merge函數將兩個參數a，b相加，并返回c。
| | // expression.js function merge(a, b) { c = a * b; return c; } |
在Java代碼中讀取js文件，并參數兩個參數，然后回去返回值。
| | package com.sinaapp.manjushri; import java.io.FileReader; import javax.script.Invocable; import javax.script.ScriptEngine; import javax.script.ScriptEngineManager; /** * Java調用并執行js文件，傳遞參數，并活動返回值 * * @author manjushri */ public class ScriptEngineTest { public static void main(String[] args) throws Exception { ScriptEngineManager manager = new ScriptEngineManager(); ScriptEngine engine = manager.getEngineByName("javascript"); String jsFileName = "expression.js"; // 讀取js文件 FileReader reader = new FileReader(jsFileName); // 執行指定腳本 engine.eval(reader); if(engine instanceof Invocable) { Invocable invoke = (Invocable)engine; // 調用merge方法，并傳入兩個參數 // c = merge(2, 3); Double c = (Double)invoke.invokeFunction("merge", 2, 3); System.out.println("c = " + c); } reader.close(); } } |
輸出結果：
c = 5.0
java調用腳本語言筆記（jython,jruby,groovy）
有兩種方法
1.java se 6以后實現了jsr 223規范
java代碼：
- ScriptEngineManager factory = new ScriptEngineManager();
- ScriptEngineManager scriptEngine = factory.getEngineByName("javascript");//或者"js"
- scriptEngine.eval(code);//執行一段腳本，code是js代碼
很方便調用腳本
2.可以使用腳本語方本身提供的與java的集成手段
jython集成
使用jsr223:
前提下載jython的包，已實現jsr223
(建議在官網上下載，在安裝目錄下有jython.jar，http://repo2.maven.org/maven2/org/python/jython/2.5.0/ 這里也有，但是這個包里沒有jsr223的實現，看包下存不存在org.python.jsr223)
- ScriptEngineManager factory = new ScriptEngineManager();
- ScriptEngineManager scriptEngine = factory.getEngineByName("python");//或者"jython"
- scriptEngine.eval(code);
使用PythonInterpreter，可以調用exec(String code)方法:
- PythonInterpreter interpreter = new PythonInterpreter();
- interpreter.exec(code);
訪問數據庫
使用jdbc:
- from oracle.jdbc.driver import OracleDriver
- from java.sql import DriverManager
-
- username = 'hr'
- password = '123456'
- url = 'jdbc:oracle:thin:@localhost:1521:XE'
- driver = OracleDriver()
- DriverManager.registerDriver(driver)
- conn = DriverManager.getConnection(url, username, password)
- stmt = conn.createStatement()
- sql = "select salary from EMPLOYEES t where t.salary<2300"
- rs = stmt.executeQuery(sql)
- while (rs.next()):
- print rs.getInt('salary')
- rs.close()
- stmt.close()
結果:
2200
2100
2200
使用zxJDBC :
- from com.ziclix.python.sql import zxJDBC
-
- url = 'jdbc:oracle:thin:@localhost:1521:XE'
- username = 'hr'
- password = '123456'
- driverName = 'oracle.jdbc.driver.OracleDriver'
- mysqlConn = zxJDBC.connect(url,username, password,driverName)
- cursor = mysqlConn.cursor()
- cursor.execute("select last_name from EMPLOYEES t where t.salary<2300");
- #print cursor.fetchone()
- list = cursor.fetchall()
- for record in list:
- print "name:"+record[0]
- #print cursor.description[0]
- #print cursor.description[1]
結果:
name:麥克
name:Olson
name:Philtanker
從數據庫中查出的中文內容正常的。
而在代碼里面的中文全部是亂碼或拋異常，未解決。
與jruby集成
使用jsr223:Java代碼
- ScriptEngineManager factory = new ScriptEngineManager();
- ScriptEngineManager scriptEngine = factory.getEngineByName("jruby");//或者"ruby"
- scriptEngine.eval(code);
訪問數據庫
Ruby代碼
- require 'java'
-
- module JavaLang
- include_package "java.lang"
- end
-
- module JavaSql
- include_package 'java.sql'
- end
-
- begin
- username = 'hr'
- password = '123456'
- url = 'jdbc:oracle:thin:@localhost:1521:XE'
- driverName = 'oracle.jdbc.driver.OracleDriver'
- JavaLang::Class.forName(driverName).newInstance
- conn = JavaSql::DriverManager.getConnection(url, username, password)
- stmt = conn.createStatement
- sql = "select last_name from EMPLOYEES t where t.salary<2300"
- rs = stmt.executeQuery(sql)
- while (rs.next) do
- puts "名字:"+rs.getString("last_name")
- end
- rs.close
- stmt.close
- conn.close()
- rescue JavaLang::ClassNotFoundException
- puts "ClassNotFoundException"
- rescue JavaSql::SQLException
- puts "SQLException"
- end
結果:
名字:楹﹀厠
名字:Olson
名字:Philtanker
從數據庫中查出的中文內容為亂碼的。
而在代碼里面的中文正常。
與groovy集成
使用jsr223:
Java代碼
- ScriptEngineManager factory = new ScriptEngineManager();
- ScriptEngineManager scriptEngine = factory.getEngineByName("groovy");//或者"Groovy"
- scriptEngine.eval(code);
使用GroovyShell:
Java代碼
- GroovyShell shell = new GroovyShell();
- Script script = shell.parse(code);
- Object result = script.run();
訪問數據庫
- import groovy.sql.Sql
-
- def username = 'hr'
- def password = '123456'
- def url = 'jdbc:oracle:thin:@localhost:1521:XE'
- def driverName = 'oracle.jdbc.driver.OracleDriver'
- def sql = Sql.newInstance(url, username, password, driverName)
-
- sql.eachRow("select last_name from EMPLOYEES t where t.salary<2300") {
- println "名字：${it.last_name}"
- }
結果:
名字：麥克
名字：Olson
名字：Philtanker
在使用groovy過程中碰到了一個異常
Exception in thread "main" java.lang.VerifyError: (class: groovy/runtime/metaclass/java/util/ArrayListMetaClass, method: super$2$invokeMethod signature: (Ljava/lang/Class;Ljava/lang/Object;Ljava/lang/String;[Ljava/lang/Object;ZZ)Ljava/lang/Object;) Illegal use of nonvirtual function call
這個異常解決花了很長時間
是因為在原來項目中存在json-lib-2.1.jar(有可能名稱為json-lib-2.1-jdk15.jar)，這個包是用來處理json的，與groovy1.7.5存在沖突,更新為json-lib-2.3.jar即可
(json-lib里有一些groovy運行時處理的內容)