如何使用駱駝創建數據源？

Question

我剛開始學習Apache Camel。我瞭解路由和組件的基礎知識。現在我想嘗試連接到Oracle數據庫，從一個特定的表讀取記錄並使用File組件將這些記錄寫入文件。要從數據庫中讀取，我假設我需要使用JDBC組件並給出dataSourceName。

但是，我找不到有關如何使用駱駝創建數據源的任何信息。我發現與本主題相關的所有信息都使用Spring DSL示例。我不使用Spring，我只需要使用簡單的獨立Java應用程序來測試它。

我在Apache Camel 2.12.1上使用JDK7u25。

有人可以發佈樣本從oracle表中讀取並寫入文件嗎？

[編輯]

檢查網絡上的幾個解決方案之後，我來了解以下兩種方法：

1. 駱駝爲standalone運行。這裏是我的代碼：

   import javax.sql.DataSource;  
   import org.apache.camel.main.Main; 
   import org.apache.camel.builder.RouteBuilder; 
   import org.apache.commons.dbcp.BasicDataSource; 
   
   public class JDBCExample { 
   
       private Main main; 
   
       public static void main(String[] args) throws Exception { 
        JDBCExample example = new JDBCExample(); 
        example.boot(); 
       } 
   
       public void boot() throws Exception { 
        // create a Main instance 
        main = new Main(); 
        // enable hangup support so you can press ctrl + c to terminate the JVM 
        main.enableHangupSupport(); 
   
        String url = "jdbc:oracle:thin:@MYSERVER:1521:myDB"; 
        DataSource dataSource = setupDataSource(url); 
   
        // bind dataSource into the registery 
        main.bind("myDataSource", dataSource); 
   
        // add routes 
        main.addRouteBuilder(new MyRouteBuilder()); 
   
        // run until you terminate the JVM 
        System.out.println("Starting Camel. Use ctrl + c to terminate the JVM.\n"); 
        main.run(); 
       } 
   
       class MyRouteBuilder extends RouteBuilder { 
        public void configure() { 
         String dst = "C:/Local Disk E/TestData/Destination"; 
         from("direct:myTable") 
          .setBody(constant("select * from myTable")) 
          .to("jdbc:myDataSource") 
          .to("file:" + dst); 
        } 
       } 
   
       private DataSource setupDataSource(String connectURI) { 
        BasicDataSource ds = new BasicDataSource(); 
        ds.setDriverClassName("oracle.jdbc.driver.OracleDriver"); 
        ds.setUsername("sa"); 
        ds.setPassword("devon1"); 
        ds.setUrl(connectURI); 
        return ds; 
       } 
   } 
   

2. 使用Claus lbsen提到的方法。這裏是再次驗證碼：

   import javax.sql.DataSource; 
   import org.apache.camel.CamelContext; 
   import org.apache.camel.impl.DefaultCamelContext; 
   import org.apache.camel.impl.SimpleRegistry; 
   import org.apache.camel.main.Main; 
   import org.apache.camel.builder.RouteBuilder; 
   import org.apache.commons.dbcp.BasicDataSource; 
   
   public class JDBCExample { 
   
       private Main main; 
   
       public static void main(String[] args) throws Exception { 
        String url = "jdbc:oracle:thin:@MYSERVER:1521:myDB"; 
        DataSource dataSource = setupDataSource(url); 
   
        SimpleRegistry reg = new SimpleRegistry() ; 
        reg.put("myDataSource",dataSource); 
   
        CamelContext context = new DefaultCamelContext(reg); 
        context.addRoutes(new JDBCExample().new MyRouteBuilder()); 
        context.start(); 
        Thread.sleep(5000); 
        context.stop(); 
       } 
   
       class MyRouteBuilder extends RouteBuilder { 
        public void configure() { 
         String dst = "C:/Local Disk E/TestData/Destination"; 
         from("direct:myTable") 
          .setBody(constant("select * from myTable")) 
          .to("jdbc:myDataSource") 
          .to("file:" + dst); 
        } 
       } 
   
       private static DataSource setupDataSource(String connectURI) { 
        BasicDataSource ds = new BasicDataSource(); 
        ds.setDriverClassName("oracle.jdbc.driver.OracleDriver"); 
        ds.setUsername("sa"); 
        ds.setPassword("devon1"); 
        ds.setUrl(connectURI); 
        return ds; 
       } 
   } 
   

但在這兩種情況下我得到異常如下：

Caused by: org.apache.camel.ResolveEndpointFailedException: Failed to resolve endpoint: jdbc://myDataSource due to: No component found with scheme: jdbc 
    at org.apache.camel.impl.DefaultCamelContext.getEndpoint(DefaultCamelContext.java:534) 
    at org.apache.camel.util.CamelContextHelper.getMandatoryEndpoint(CamelContextHelper.java:63) 
    at org.apache.camel.model.RouteDefinition.resolveEndpoint(RouteDefinition.java:192) 
    at org.apache.camel.impl.DefaultRouteContext.resolveEndpoint(DefaultRouteContext.java:106) 
    at org.apache.camel.impl.DefaultRouteContext.resolveEndpoint(DefaultRouteContext.java:112) 
    at org.apache.camel.model.SendDefinition.resolveEndpoint(SendDefinition.java:61) 
    at org.apache.camel.model.SendDefinition.createProcessor(SendDefinition.java:55) 
    at org.apache.camel.model.ProcessorDefinition.makeProcessor(ProcessorDefinition.java:500) 
    at org.apache.camel.model.ProcessorDefinition.addRoutes(ProcessorDefinition.java:213) 
    at org.apache.camel.model.RouteDefinition.addRoutes(RouteDefinition.java:909) 
    ... 12 more 
[Thread-0] INFO org.apache.camel.main.MainSupport$HangupInterceptor - Received hang up - stopping the main instance. 

Answer 1

太傻了！我沒有在CLASSPATH中包含camel-jdbc-2.12.1.jar。現在上面的例子工作。

Answer 2

春天是有提及，只是因爲它是用DB工作的非常有用的範例（主要是因爲templates introduced by Spring Framework。）當然，你可以連接標準的JDBC連接並自己實現DAO - 沒有任何問題。

Answer 3

還有就是SQL例子展示如何設置一個DataSource

• http://camel.apache.org/sql-example.html

是，使用的Spring XML實例。但是，如何設置DataSource也可以在Java代碼中完成。然後你需要在Camel Registry中註冊DataSource。

例如，您可以使用JndiRegistry或SimpleRegistry。後者更容易。

這是一些僞代碼，顯示創建註冊表的原理，將您的bean添加到此註冊表中，然後將註冊表提供給DefaultCamelContext的構造函數。

SimpleRegistry registry = new SimpleRegistry(); 

// code to create data source here 
DateSource ds = ... 

registry.put("myDataSource", ds); 

CamelContext camel = new DefaultCamelContext(registry);