maven 开发 ejb ear

基于EJB开发业务简介

在复杂的企业IT架构中 web模块主要用途其实在展现层,它接收到用户的请求后委托后端的 ejb 完成业务逻辑(将业务交由ejb处理,可方便地获得保障业务事务及分布式事务、多客户端调用等好处),然后将ejb的处理结果以可视化形式展现给用户,如此的分层架构可以方便地对ejb业务层实施可复用和分布式。


ejb通常都是jar文件,web通常是war文件,一般都是独立部署,但是,有的时候我们也希望将某些ejb和web打包的一起部署,这就是企业应用ear。


maven 支持 ear 的管理


假设要完成的ear中包行一个ejb和一个web,名称分别为:ejb3和webdemo,两个模块独立开发完成后执行 install 安装到本地maven库,建立一个ear模块(其实就是普通的maven项目,只是设置pom打包类型<packaging>ear</packaging>),如果要开发一个ejb,那么就设置<packaging>ejb</packaging>。


1.开发一个ejb

名称ejb3,其pom大致为:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>eden</artifactId>
        <groupId>com.conquer.eden</groupId>
        <version>1.0</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <packaging>ejb</packaging>

    <artifactId>ejb3</artifactId>

    <dependencies>
        <dependency>
            <groupId>javax.ejb</groupId>
            <artifactId>ejb-api</artifactId>
            <version>3.0</version>
            <scope>provided</scope>
        </dependency>
        <!--<dependency>-->
            <!--<groupId>org.eclipse.persistence</groupId>-->
            <!--<artifactId>javax.persistence</artifactId>-->
            <!--<version>2.0.5</version>-->
            <!--<scope>provided</scope>-->
        <!--</dependency>-->
    </dependencies>
    <build>
        <finalName>${artifactId}</finalName>
        <plugins>
            <plugin>
                <!--<groupId>org.apache.maven.plugins</groupId>-->
                <artifactId>maven-ejb-plugin</artifactId>
                <version>2.5</version>
                <configuration>
                    <ejbVersion>3.0</ejbVersion>

                    <!--<filterDeploymentDescriptor>true</filterDeploymentDescriptor>-->

                    <!-- this is false by default -->
                    <generateClient>true</generateClient>
                    <!--用下面的方式进行 客户端生成定制-->
                    <clientIncludes>
                        <!-- 包含 test 下面的所有文件和文件夹 -->
                        <!--<clientInclude>test/**</clientInclude>-->
                        <!-- 包含 com/example 下面所有的文件,PS:不含文件夹-->
                        <!--<clientInclude>com/example/*</clientInclude>-->
                    </clientIncludes>
                    <clientExcludes>
                        <!-- 不包含 com/example 下的所有文件-->
                        <!--<clientExclude>com/example/*</clientExclude>-->
                        <!-- this will exclude all files and directories with the name sparrow under com/jack -->
                        <!--<clientExclude>com/jack/**/sparrow</clientExclude>-->
                    </clientExcludes>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

以上的pom文件需要注意的点:

1.打包类型:

<packaging>ejb</packaging>
2.EJB插件

<artifactId>maven-ejb-plugin</artifactId>
3.是否生成EJB客户端jar

<generateClient>true</generateClient>

关于 <generateClient>的介绍:

<generateClient>用于生成简单版的ejb客户端,通常只包含客户端使用到的接口而不包含实现类,

他的默认排除规则是:

  • **/*Bean.class
  • **/*CMP.class
  • **/*Session.class
  • **/package.html
所以加入我们的实现类是以 Bean结尾的话,在打包成的*-client.jar中会自动去除,

当然,该规则也可以定制,可以定制需要添加和排除的文件,如下:

        <configuration>
          <clientIncludes>
             <!-- this will include all files and directories under com/foo/bar -->
             <clientInclude>com/foo/bar/**</clientInclude>
             <!-- this will include all files and directories under com/foo/acme -->
             <clientInclude>com/foo/acme/**</clientInclude>
             <!-- this will include all files under com/example -->
             <clientInclude>com/example/*</clientInclude>
          </clientIncludes>
          <clientExcludes>
             <!-- this will exclude all files under com/example -->
             <clientExclude>com/example/*</clientExclude>
             <!-- this will exclude all files and directories with the name
                  sparrow under com/jack -->
             <clientExclude>com/jack/**/sparrow</clientExclude>
          </clientExcludes>
        </configuration>

最后:在模块中添加此client的依赖时候,其类型要指定为ejb-client,如

<dependency>
    <groupId>com.conquer.eden</groupId>
    <artifactId>xaejb</artifactId>
    <version>1.0</version>
    <!--<classifier>client</classifier>-->
    <type>ejb-client</type>
</dependency>

官网参考:

http://maven.apache.org/plugins/maven-ejb-plugin/

http://maven.apache.org/plugins/maven-ejb-plugin/examples/generating-ejb-client.html

ejb的java代码:

public interface TestDAOEJB {
    String insertData(String data) throws Exception;
    String insertData2(String data) throws Exception;
    String insertData3(String data) throws Exception;
}
import javax.ejb.*;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.sql.DataSource;
import java.io.IOException;
import java.sql.Connection;
import java.sql.Statement;
import java.util.Properties;

//@Stateless
//@Stateless(mappedName = "TestDAOBean")
@Stateful
@Remote(value = TestDAOEJB.class)
public class TestDAOBean implements TestDAOEJB {

    private static String otherNode1;
    private static String otherNode2;
    static {
        try {
            Properties properties = new Properties();
            properties.load(TestDAOBean.class.getResourceAsStream("/config.properties"));
            otherNode1 = properties.getProperty("otherNode1");
            otherNode2 = properties.getProperty("otherNode2");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * CREATE TABLE wangpl(name VARCHAR2(200))
     */

    @Override
    @TransactionAttribute(TransactionAttributeType.REQUIRED)//这是默认值,可以省略,或修改为其它事务策略
    public String insertData(String data) throws Exception {
        String returnString = "insertData-OK";
        Connection con = null;
        Statement statement = null;
        try {
            DataSource dataSource = (DataSource) new InitialContext().lookup("DataSource1");
            con = dataSource.getConnection();
            statement = con.createStatement();
            String sql = "INSERT INTO wangpl VALUES('" + data + ":insertData')";
            statement.execute(sql);
        } finally {
            // close xxx
        }

        // 调用远程节点
        Properties p = new Properties();
        p.put(Context.INITIAL_CONTEXT_FACTORY, "com.xxx.RemoteInitialContextFactory");
        p.put(Context.PROVIDER_URL, otherNode1);
        InitialContext ctx = new InitialContext(p);
        TestDAOEJB remote = (TestDAOEJB) ctx.lookup("TestDAOBeanRemote");
        remote.insertData2(data + "1");

        return returnString;
    }
    @Override
    @TransactionAttribute(TransactionAttributeType.SUPPORTS)
    public String insertData2(String data) throws Exception {
        String returnString = "insertData2-OK";
        Connection con = null;
        Statement statement = null;
        try {
            DataSource dataSource = (DataSource) new InitialContext().lookup("DataSource1");
            con = dataSource.getConnection();
            statement = con.createStatement();
            String sql = "INSERT INTO wangpl VALUES('" + data + ":insertData2')";
            statement.execute(sql);
        } finally {
            // close xxx
        }

        // 调用远程ejb
        Properties p = new Properties();
        p.put(Context.INITIAL_CONTEXT_FACTORY, "com.xxx.RemoteInitialContextFactory");
        p.put(Context.PROVIDER_URL, otherNode2);
        InitialContext ctx = new InitialContext(p);
        TestDAOEJB remote = (TestDAOEJB) ctx.lookup("TestDAOBeanRemote");
        remote.insertData3(data + "1");

        if (data.equals("11")) {
            throw new RuntimeException("************* Runtime Exception **************");
        }
        return returnString;
    }
    @TransactionAttribute(TransactionAttributeType.REQUIRES_NEW)
    public String insertData3(String data) throws Exception {
        String returnString = "insertData3-OK";
        Connection con = null;
        Statement statement = null;
        try {
            DataSource dataSource = (DataSource) new InitialContext().lookup("DataSource1");
            con = dataSource.getConnection();
            statement = con.createStatement();
            String sql = "INSERT INTO wangpl VALUES('" + data + ":insertData3')";
            statement.execute(sql);
        } finally {
            // close xxx
        }

        if (data.equals("211")) {
            throw new RuntimeException("************* Runtime Exception **************");
        }

        return returnString;
    }
}

2.开发web模块

其pom大致如下:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
    <parent>
        <artifactId>eden</artifactId>
        <groupId>com.conquer.eden</groupId>
        <version>1.0</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
    <artifactId>webdemo</artifactId>
    <packaging>war</packaging>
    <name>webdemo</name>
    <build>
        <finalName>${artifactId}</finalName>
    </build>
    <dependencies>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>com.conquer.eden</groupId>
            <artifactId>ejb3</artifactId>
            <version>1.0</version>
            <!--<classifier>client</classifier>-->
            <type>ejb-client</type>
         </dependency>
    </dependencies>
</project>
以上pom,要注意的是添加ejb的client依赖,指明类型是: <type>ejb-client</type>

web层业务代码 ,可以使用 @EJB  @Resource 的注解方式,或者手工: new InitialContext(xx)来访问ejb。


3.开发ear

其pom文件为:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>eden</artifactId>
        <groupId>com.conquer.eden</groupId>
        <version>1.0</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
    <packaging>ear</packaging>

    <artifactId>ear</artifactId>

    <dependencies>
        <dependency>
            <groupId>com.conquer.eden</groupId>
            <artifactId>ejb3</artifactId>
            <version>1.0</version>
            <type>ejb</type>
        </dependency>
        <dependency>
            <groupId>com.conquer.eden</groupId>
            <artifactId>webdemo</artifactId>
            <version>1.0</version>
            <type>war</type>
        </dependency>
    </dependencies>

    <build>
        <finalName>${artifactId}</finalName>
        <plugins>
            <plugin>
                <artifactId>maven-ear-plugin</artifactId>
                <version>2.10</version>
                <configuration>
                    <!--<generateModuleId>true</generateModuleId>-->

                    <!--指定打包范围,避免无用jar混乱加入-->
                    <!--<packagingIncludes>META-INF/**,**/acme-*.jar,**/acme-*.war</packagingIncludes>-->
                    <!--<packagingExcludes></packagingExcludes>-->

                    <!--打包指定目录lib-->
                    <defaultLibBundleDir>lib/</defaultLibBundleDir>
                    <!--将多个war的共享包提取到父级别-->
                    <skinnyWars>true</skinnyWars>

                    <!--<includeLibInApplicationXml>true</includeLibInApplicationXml>-->

                    <!--jboss 定制-->
                    <!--<jboss>-->
                        <!--<version>5</version>-->
                        <!--<module-order>strict</module-order>-->
                        <!--<unauthenticated-principal>guest</unauthenticated-principal>-->
                        <!--<loader-repository>com.foo:loader=foo-application-1.0.ear</loader-repository>-->
                    <!--</jboss>-->

                    <modules>

                        <!--jarModule:用于添加第三方库,配合includeInApplicationXml,可使其像一个开发的模块-->
                        <jarModule>
                            <!--<groupId>com.conquer.eden</groupId>-->
                            <!--<artifactId>ejb3</artifactId>-->
                            <!--<bundleFileName>ejb3.jar</bundleFileName>-->

                            <!--<includeInApplicationXml>true</includeInApplicationXml>-->

                            <!--<bundleDir>APP-INF/lib</bundleDir> 只更改位置,名称保持不变-->
                            <!--<uri>APP-INF/lib/anotherName-1.2.3.jar</uri> 可定制位置和名称,需要指定名称-->
                            <!--<excluded>true</excluded>-->

                            <!--<moduleId>ejb3-id</moduleId>-->
                        </jarModule>
                        <ejbModule>
                            <groupId>com.conquer.eden</groupId>
                            <artifactId>ejb3</artifactId>
                            <bundleFileName>ejb3.jar</bundleFileName>
                        </ejbModule>
                        <webModule>
                            <groupId>com.conquer.eden</groupId>
                            <artifactId>webdemo</artifactId>
                            <bundleFileName>webdemo.war</bundleFileName>

                            <!--<moduleId>webdemo-id</moduleId>-->
                        </webModule>
                    </modules>
                    <!--<security>-->
                        <!--<security-role id="SecurityRole_1234">-->
                            <!--<role-name>manager</role-name>-->
                        <!--</security-role>-->
                        <!--<security-role id="SecurityRole_5678">-->
                            <!--<description>My cool description</description>-->
                            <!--<role-name id="RoleName_12">teller</role-name>-->
                        <!--</security-role>-->
                    <!--</security>-->

                    <!--<version>6</version>-->
                    <!--<env-entries>-->
                        <!--<env-entry>-->
                            <!--<description>A complete entry.</description>-->
                            <!--<env-entry-name>complete</env-entry-name>-->
                            <!--<env-entry-type>java.lang.Integer</env-entry-type>-->
                            <!--<env-entry-value>4</env-entry-value>-->
                        <!--</env-entry>-->
                        <!--<env-entry>-->
                            <!--<env-entry-name>no-type</env-entry-name>-->
                            <!--<env-entry-value>4</env-entry-value>-->
                        <!--</env-entry>-->
                        <!--<env-entry>-->
                            <!--<env-entry-name>no-value</env-entry-name>-->
                            <!--<env-entry-type>java.lang.String</env-entry-type>-->
                        <!--</env-entry>-->
                    <!--</env-entries>-->

                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

以上pom要注意的是:

1.添加的两个依赖一个是ejb,一个是war包,指明的类型分别是:

<type>ejb</type>和<type>war</type>
2.EAR的打包插件

<artifactId>maven-ear-plugin</artifactId>

3.添加的ejb和war需要分别指明:<ejbModule> <webModule> 并且都可以定制打进ear的名称,通过:<bundleFileName>


执行ear模块的package目标或执行ear模块maven的ear:ear可完成 ear的打包工作。

关于 maven-ear-plugin ,官网参考:http://maven.apache.org/plugins/maven-ear-plugin/


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