用Java在各种框架下编译Scala项目-flink用java还是scala

【51CTO编译】51CTO曾经在“与Scala的***次亲密接触 Java如影相随”为大家讲过Java于Scala。下面是一个教程文件是我在如今***或者说***的Java框架——Spring、Hibernate/JPA、Wicket、Maven和Intellij IDEA上充分利用Java语言调用Scala的项目，希望能帮助其他的Java程序员使用一个企业级的Scala项目。

在IDE上的设置

首先，下载的IntelliJ IDEA的9.0.x（社区版），因为目前它是***的Scala的IDE。然后选择File |设置|插件，选择可用的选项卡来安装Scala插件。

创建Maven项目

在IntelliJ IDEA中，选择文件|新建项目，然后选择Maven的模块创建一个Maven项目。然后修改如下所示的pom.xml。添加所有你需要的设置，建立Scala的汇编语言：

<project xmlnsxmlns="http://maven.apache.org/POM/4.0.0"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"           
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0http://maven.apache.org/maven-v4_0_0.xsd">           
    <modelVersion>4.0.0</modelVersion>           
    <groupId>com.foo</groupId>           
    <artifactId>myapp</artifactId>           
    <packaging>war</packaging>           
    <version>1.0-SNAPSHOT</version>           
    <name>myapp Java EE 6 Webapp</name>           
    <url>http://maven.apache.org</url>           
    <properties>           
        <spring.version>3.0.3.RELEASE</spring.version>           
     </properties>          
           
    <repositories>           
        <repository>           
            <id>java.net2</id>           
            <name>Repository hosting the jee6 artifacts</name>           
            <url>http://download.java.net/maven/2</url>           
         </repository>          
           
        <repository>           
            <id>scala-tools.org</id>           
             <name>Scala-tools Maven2 Repository</name>          
            <url>http://scala-tools.org/repo-releases</url>           
           
        </repository>           
        <repository>           
             <id>wpt-release</id>          
            <url>http://wicketpagetest.sourceforge.net/m2-repo/releases</url>           
           
        </repository>           
        <repository>           
             <id>wpt-snapshot</id>          
            <url>http://wicketpagetest.sourceforge.net/m2-repo/snapshots</url>           
           
        </repository>           
    </repositories>           
    <pluginRepositories>           
        <pluginRepository>           
            <id>scala-tools.org</id>           
            <name>Scala-tools Maven2 Repository</name>           
            <url>http://scala-tools.org/repo-releases</url>           
         </pluginRepository>          
           
    </pluginRepositories>           
    <dependencyManagement>           
        <dependencies>           
            <dependency>           
                 <groupId>org.springframework</groupId>          
                <artifactId>spring-context</artifactId>           
           
                <version>${spring.version}</version>           
             </dependency>          
           
             <dependency>          
                <groupId>org.springframework</groupId>           
           
                <artifactId>spring-core</artifactId>           
                <version>${spring.version}</version>           
            </dependency>           
            <dependency>           
                <groupId>org.springframework</groupId>           
                 <artifactId>spring-web</artifactId>          
           
                <version>${spring.version}</version>           
             </dependency>          
           
             <dependency>          
                <groupId>org.springframework</groupId>           
           
                 <artifactId>spring-orm</artifactId>          
                <version>${spring.version}</version>           
           
            </dependency>           
        </dependencies>           
    </dependencyManagement>           
    <dependencies>           
        <dependency>           
            <groupId>com.h2database</groupId>           
            <artifactId>h2</artifactId>           
            <version>1.2.120</version>           
        </dependency>           
        <dependency>           
             <groupId>org.hibernate</groupId>          
            <artifactId>hibernate-entitymanager</artifactId>           
           
            <version>3.4.0.GA</version>           
        </dependency>           
        <dependency>           
            <groupId>org.springframework</groupId>           
            <artifactId>spring-orm</artifactId>           
        </dependency>           
        <dependency>           
            <groupId>com.ttdev</groupId>           
            <artifactId>wpt-core</artifactId>           
            <version>1.5.2-SNAPSHOT</version>           
            <scope>test</scope>           
        </dependency>           
        <dependency>           
            <groupId>com.ttdev</groupId>           
            <artifactId>wpt-runtime-spring</artifactId>           
             <version>1.5.2-SNAPSHOT</version>          
           
        </dependency>           
        <dependency>           
             <groupId>javax</groupId>          
            <artifactId>javaee-web-api</artifactId>           
           
            <version>6.0</version>           
            <scope>provided</scope>           
        </dependency>           
        <dependency>           
            <groupId>junit</groupId>           
            <artifactId>junit</artifactId>           
            <version>3.8.2</version>           
            <scope>test</scope>           
        </dependency>           
        <dependency>           
            <groupId>org.scala-lang</groupId>           
            <artifactId>scala-library</artifactId>           
            <version>2.8.0.RC3</version>           
        </dependency>           
        <dependency>           
            <groupId>org.apache.wicket</groupId>           
            <artifactId>wicket</artifactId>           
            <version>1.4.9</version>           
        </dependency>           
        <dependency>           
            <groupId>org.slf4j</groupId>           
            <artifactId>slf4j-log4j12</artifactId>           
            <version>1.4.2</version>           
        </dependency>           
    </dependencies>           
    <build>           
        <pluginManagement>           
            <plugins>           
                 <plugin>          
                    <groupId>org.apache.maven.plugins</groupId>           
           
                    <artifactId>maven-compiler-plugin</artifactId>           
                     <version>2.0.2</version>          
           
                </plugin>           
                <plugin>           
                     <groupId>org.scala-tools</groupId>          
                    <artifactId>maven-scala-plugin</artifactId>           
           
                    <version>2.9.1</version>           
                </plugin>           
            </plugins>           
        </pluginManagement>           
        <plugins>           
            <plugin>           
                 <groupId>org.apache.maven.plugins</groupId>          
                <artifactId>maven-compiler-plugin</artifactId>           
           
                <executions>           
                    <execution>           
                        <phase>compile</phase>           
                        <goals>           
                            <goal>compile</goal>           
                        </goals>           
                    </execution>           
                </executions>           
                <configuration>           
                    <source>1.6</source>           
                    <target>1.6</target>           
                </configuration>           
            </plugin>           
            <plugin>           
                <groupId>org.apache.maven.plugins</groupId>           
                 <artifactId>maven-war-plugin</artifactId>          
           
                <version>2.1-beta-1</version>           
                <configuration>           
                    <failOnMissingWebXml>false</failOnMissingWebXml>           
                 </configuration>          
           
            </plugin>           
            <plugin>           
                 <groupId>org.scala-tools</groupId>          
                <artifactId>maven-scala-plugin</artifactId>           
           
                <executions>           
                    <execution>           
                         <id>scala-compile-first</id>          
                        <phase>process-resources</phase>           
           
                         <goals>          
                            <goal>add-source</goal>           
           
                            <goal>compile</goal>           
                        </goals>           
                    </execution>           
                    <execution>           
                         <id>scala-test-compile</id>          
                        <phase>process-test-resources</phase>           
           
                         <goals>          
                            <goal>testCompile</goal>           
           
                        </goals>           
                    </execution>           
                </executions>           
            </plugin>           
        </plugins>           
        <finalName>myapp</finalName>           
    </build>           
</project>

等待一段时间，IDEA将提示导入的项目是否需要更改。回答是肯定。

#p#

web.xml中设置

接下来，修改main/webapp/WEB-INF/web.xml。从而确立了Wicket的过滤器，打开Spring的JPA实体管理器和Spring监听器，进行Spring的初始化。

 <?xml version="1.0" encoding="UTF-8"?>          
<web-app version="3.0"xmlns="http://java.sun.com/xml/ns/javaee"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"           
           
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaeehttp://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">           
     <filter>          
           
         <filter-name>f2</filter-name>          
        <filter-class>org.springframework.orm.jpa.support.OpenEntityManagerInViewFilter</filter-class>           
           
    </filter>           
    <filter>           
         <filter-name>f1</filter-name>          
        <filter-class>org.apache.wicket.protocol.http.WicketFilter</filter-class>           
           
         <init-param>          
            <param-name>applicationClassName</param-name>           
           
            <param-value>com.foo.myapp.MyApp</param-value>           
         </init-param>          
           
    </filter>           
    <filter-mapping>           
        <filter-name>f1</filter-name>           
        <url-pattern>/app/*</url-pattern>           
    </filter-mapping>           
    <filter-mapping>           
        <filter-name>f2</filter-name>           
        <url-pattern>/*</url-pattern>           
    </filter-mapping>           
    <context-param>           
        <param-name>contextConfigLocation</param-name>           
        <param-value>classpath:/beans.xml</param-value>           
    </context-param>           
    <listener>           
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>           
     </listener>          
           
</web-app>

#p#

设置Spring bean访问和调用的数据库

要定义这些Spring bean，创建main/resources的beans.xml以及一下的内容：

<?xml version="1.0" encoding="UTF-8" ?>         
<beansxmlnsbeansxmlns="http://www.springframework.org/schema/beans"          
          
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"         
       xmlns:context="http://www.springframework.org/schema/context"          
          
        xmlns:tx="http://www.springframework.org/schema/tx"         
       xsi:schemaLocation="http://www.springframework.org/schema/beans          
          
        http://www.springframework.org/schema/beans/spring-beans-3.0.xsd          
         http://www.springframework.org/schema/context         
          
        http://www.springframework.org/schema/context/spring-context-3.0.xsd          
         http://www.springframework.org/schema/tx         
          
        http://www.springframework.org/schema/tx/spring-tx-3.0.xsd">          
     <context:component-scan base-package="com.foo.myapp"/>         
          
    <bean id="emf"class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">          
        <property name="persistenceXmlLocation"value="classpath:/META-INF/my-persistence.xml"/>          
     </bean>         
    <bean id="transactionManager"class="org.springframework.orm.jpa.JpaTransactionManager">          
          
        <property name="entityManagerFactory" ref="emf"/>          
     </bean>         
          
    <tx:annotation-driven />          
</beans>

读取数据库配置中persistence.xml文件。在这里，您将获得一个主目录中名为MyApp的H2数据库。因此，创建main/resources/META-INF文件的内容如下。

<persistencexmlnspersistencexmlns="http://java.sun.com/xml/ns/persistence"          
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"           
          
            xsi:schemaLocation="http://java.sun.com/xml/ns/persistencehttp://java.sun.com/xml/ns/persistence/persistence_2_0.xsd"           
             version="2.0">          
          
   <persistence-unit name="myapp" transaction-type="RESOURCE_LOCAL">           
        <provider>org.hibernate.ejb.HibernatePersistence</provider>          
          
        <properties>          
           <propertynamepropertyname="hibernate.connection.driver_class"value="org.h2.Driver"/>           
          
           <property name="hibernate.connection.url"value="jdbc:h2:tcp://localhost/~/myapp"/>           
            <propertynamepropertyname="hibernate.connection.username" value="sa"/>          
          
            <propertynamepropertyname="hibernate.connection.password" value=""/>          
           <property name="hibernate.dialect"value="org.hibernate.dialect.H2Dialect"/>           
          
           <property name="hibernate.hbm2ddl.auto"value="create"/>           
        </properties>          
          
   </persistence-unit>           
/persistence>

#p#

创建Wicket的页面

在这里，您将创建一个Wicket页面显示从数据库加载一些内容。因此，创建主/Scala文件夹，右键单击它并选择新建|Scala类。命名为我的页面类和投入com.foo.myapp包中。如下所示：

package com.foo.myapp           
           
import org.apache.wicket.markup.html._           
import basic.Label           
 import list.{ListItem, ListView}          
importorg.apache.wicket.spring.injection.annot.SpringBean           
           
import org.apache.wicket.model.CompoundPropertyModel           
           
class MyPage extends WebPage {           
  @SpringBean           
   var ps: ProductService = _          
  val productListView = newListView[Product]("productListView", ps.getAll) {           
           
     def populateItem(item: ListItem[Product]) = {          
      item.setModel(newCompoundPropertyModel[Product](item.getDefaultModelObject))           
           
      item.add(new Label("name"))           
      item.add(new Label("price"))           
    }           
  }           
  add(productListView)           
}

请注意，在创建ProductService对象加载的文件之后使用。此外，请注意该字段被分配到一个下划线（_），Scala编译为不可初始化的，而是留在默认状态。在你将覆盖作为编译之前，执行Spring bean的页面构造。现在，创建在src/main/resources/com/foo/myapp的的mypage.html文件：

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">           
<html>           
    <table border="1">           
        <tr wicket:id="productListView">           
            <td wicket:id="name"></td>           
            <td wicket:id="price"></td>           
        </tr>           
    </table>           
</html>

#p#

创建ProductService：

右键单击在in the src/main/scala文件夹中的com.foo.myapp包并选择New | Scala的类，然后选择创建ProductService：

package com.foo.myapp           
           
import java.util.List           
           
trait ProductService {           
  def getAll: List[Product]           
}

这是接口。对创造一个DefaultProductService的Scala在同一个包内进行执行操作：

package com.foo.myapp           
           
import javax.persistence.{PersistenceContext, EntityManager}           
import org.springframework.stereotype.{Service}           
importorg.springframework.transaction.annotation.Transactional           
 importorg.springframework.beans.factory.annotation.Autowired          
           
           
@Service           
@Transactional           
class DefaultProductService extends ProductService {           
  @Autowired           
  var products: Products = _           
           
  def getAll = products.getAll           
}

请注意，把它使用类型文件命名为DAO。

创建文件的DAO

要创建的DAO，创建一个名为在同一文件夹：

package com.foo.myapp           
           
import java.util.List           
           
trait Products {           
   def getAll: List[Product]           
}

然后创建在同一文件夹中的执行Scala的DefaultProducts文件：

package com.foo.myapp           
           
import javax.persistence.{PersistenceContext, EntityManager}           
import org.springframework.stereotype.Repository           
import java.util.List           
           
@Repository           
class DefaultProducts extends Products {           
  @PersistenceContext           
  var em: EntityManager = _           
           
  def getAll = {           
    em.createQuery("select p from Product p").getResultList.asInstanceOf[List[Product]]           
  }           
}

#p#

创建entity程序

创建entity程序并将其映射到数据库：

package com.foo.myapp           
           
import javax.persistence.{GeneratedValue, Id, Entity}           
           
@Entity           
class Product {           
  @Id           
  @GeneratedValue           
  var id: Long = _           
  var name: String = _           
  var price: Double = _           
}

创建Wicket的应用程序

***，创建在同一个MyApp的Scala程序：

package com.foo.myapp           
           
 import org.apache.wicket.protocol.http.WebApplication          
importcom.ttdev.wicketpagetest.MockableSpringBeanInjector           
           
           
class MyApp extends WebApplication {           
  def getHomePage = classOf[MyPage]           
           
   override def init = {          
    MockableSpringBeanInjector.installInjector(this)           
           
  }           
}

在这里，您指定为首页我的目录，植入Spring Bean中。

运行应用程序

随着IntelliJ IDEA的版本不断改进，您将嵌入到应用服务器运行您的应用程序。这非常容易，在刚刚创建的测试com.foo.myapp的ManualTest在刚刚创建的测试com.foo.myapp包一类ManualTest/scala文件（不是main/scala文件），以下内容是：

package com.foo.myapp           
           
importcom.ttdev.wicketpagetest.{WebAppJettyConfiguration, WicketAppJettyLauncher}           
           
           
object ManualTest {           
  def main(args: Array[String]) {           
    val l = new WicketAppJettyLauncher           
    l.startAppInJetty(new WebAppJettyConfiguration)           
  }           
}

要运行的应用程序，首先需要运行数据库服务器上的H2程序。所以，在http://www.h2database.com下载和解压。然后变成h2/bin和运行h2.bat（或在Linux上h2.sh）。ManualTest是在IDEA的编辑器上，在IDEA选择运行DEA。它将运行ManualTest，Jetty的运行您的应用程序。

为了测试它，请尝试通过在浏览器http://localhost:8888/app。

不知道各位感觉如何。感谢各位支持！谢谢！

原文地址：agileskills2.org/blog/2010/06/19/getting-started-with-scala-spring-hibernate-wicket/

原文名：Getting started with Scala, Spring, Hibernate & Wicket

【51CTO译稿，非经授权谢绝转载，合作媒体转载请注明原文出处及作者！】

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