使用JBoss和PostgreSQL-----快速开发EJB和J2EE Web Application

Developing J2EE Web Application on Jboss and PostgreSQL(chinese version)

作者：Han QW,

先安装JSDK，再安装JBoss.

安装JSDK,必须获得一套对应于用户的操作系统的JDK，

我的安装的文件目录是

WINDOWS2000: d:s1studio_jdkj2sdk1.4.1

Linux： /root/s1studio_jdk/j2sdk1.4.1

为了用EJB, 需要一个j2ee-1.3.jar或者j2ee-1.2.jar,

如果安装了Sun One Studio 或者 J2EE （www.sun.com ）这个文件已经有.

把这个文件放在classpath路径上.

或者使用jboss-j2ee.jar, 安装JBoss后在$JBossclient中可找到.

建议安装Sun One Studio, 用Sun One Studio编译Java源程序,

不用设置classpath, 省去不少过程.

安装JBoss:

把JBoss的压缩包解开，放在任一目录上,

我的安装的文件目录是

/dose/jboss-3.0.4_tomcat-4.1.12 (REDHAT8.0)

E:jboss-3.0.4_tomcat-4.1.12 (WINDOWS2000)

WINDOWS2000, linux共用同一套JBoss.

配置JBoss：

启动JBoss需要执行一个脚本文件：

linux：run.sh

WINDOWS对应的是：run.bat

(1)

在JBossin un.bat (for Windows)开头插入一行

set JAVA_HOME = d:s1studio_jdkj2sdk1.4.1

在JBossin un.sh (for Linux)开头插入一行

JAVA_HOME="/root/s1studio_jdk/j2sdk1.4.1"

或者

(2)设置系统环境变量JAVA_HOME,指向JDK

运行JBoss, run.sh或者run.bat

当看到启动JBoss的信息时，说明启动了.

服务器简单的测试：

JBoss默认的WEB端口为8080，我们可以在打开一个浏览器输入地址

http://localhost:8080/jmx-console

当在浏览器看到JBoss的信息时，说明安装配置JBoss成功了.

建立下面的目录和文件(注意大小写).

FIRST.EAR

-----META-INF (application.XML)

-----First.jar

-----META-INF (ejb-jar.xml,jboss.xml)

`-----Dev

-----First(FirstSession.java, FirstSessionHome.java, FirstSessionBean.java)

-----Delegate(NewDelegate.java)

`-----Dao(mysqlDao.java)

`-----First.war(index.jsp)

`-----WEB-INF (jboss-web.xml, web.xml)

-----classes

`-----lib

**MysqlDao.java

package Dev.Dao;import java.sql.Connection;import java.sql.SQLException;import java.sql.Statement;import java.sql.ResultSet;import javax.naming.InitialContext;import javax.sql.DataSource;public class MysqlDao { public Connection getConnection() throws Exception { InitialContext ctx = new InitialContext(); DataSource ds = (DataSource) ctx.lookup("java:/PostgresDS"); Connection conn = null; Statement stmt = null; try { conn = ds.getConnection(); } catch (SQLException sqlEx) { System.out.println("Error connect to pool."); } return conn; } public String getName(String id) throws Exception { Connection conn = null; Statement stmt = null; ResultSet rs = null; String name = ""; try { conn = getConnection(); if ( conn !=null )System.out.println("Get conecttion. "+ conn.toString()); stmt = conn.createStatement(); if ( stmt !=null )System.out.println("Get Statement. "+ stmt.toString()); String sql = "SELECT * from users where id = ′"+id+"′"; System.out.println("Sql from getId(): "+sql); rs = stmt.executeQuery(sql); if ( rs !=null )System.out.println("Get result. "); if (rs.next()){ name = rs.getString("name"); } } catch (Exception sqlEx) { System.out.println("Error from getName()."); System.out.println("Error from DAO.getName() :" + sqlEx.getMessage()); }finally { if (conn != null) { try { conn.close(); } catch (Exception sqlEx) { } } } return name; } public String getCountry(String id) throws Exception { Connection conn = null; Statement stmt = null; String name = ""; try { conn = getConnection(); stmt = conn.createStatement(); String sql = "SELECT * from users where id = ′"+id+"′"; System.out.println("Sql from getCountry(): "+sql); java.sql.ResultSet rs = stmt.executeQuery(sql); if (rs.next()) { name = rs.getString("Country"); } } catch (SQLException sqlEx) { System.out.println("Error from getCountry()."); }finally { if (conn != null) { try { conn.close(); } catch (Exception sqlEx) { } } } return name; }}

**NewDelegate.java

package Dev.Delegate;import java.lang.*;import Dev.First.*;public class NewDelegate { Dev.First.FirstSession bean = null; public NewDelegate( ){ try { javax.naming.InitialContext ctx = new javax.naming.InitialContext(); Object objref = ctx.lookup("ejb/FirstSession"); Dev.First.FirstSessionHome testBean = (Dev.First.FirstSessionHome) javax.rmi.PortableRemoteObject.narrow (objref,Dev.First.FirstSessionHome.class); bean = testBean.create(); System.out.println("From JSP"); } catch (Exception NamingException) { NamingException.printStackTrace(); } } public String Welcome() { String msg = ""; try { msg = bean.Welcome(); } catch (Exception NamingException) { NamingException.printStackTrace(); } return msg; } public String getName(String id) { String name = ""; try { name = bean.getName(id); } catch (Exception NamingException) { NamingException.printStackTrace();} return name; } public String getCountry(String id) { String country = ""; try { country = bean.getCountry(id); } catch (Exception NamingException) { NamingException.printStackTrace();} return country; } }

**FirstSession.java

package Dev.First;import java.lang.*;import java.rmi.RemoteException;import javax.ejb.CreateException;import javax.ejb.EJBException;import javax.ejb.SessionBean;import javax.ejb.SessionContext;public interface FirstSession extends javax.ejb.EJBObject{ public String Welcome() throws java.rmi.RemoteException; public String getName(String id) throws java.rmi.RemoteException; public String getCountry(String id) throws java.rmi.RemoteException;}

**FirstSessionHome.java

package Dev.First;import java.lang.*;import java.rmi.RemoteException;import javax.ejb.CreateException;import javax.ejb.EJBException;import javax.ejb.SessionBean;import javax.ejb.SessionContext;public interface FirstSessionHome extends javax.ejb.EJBHome{public FirstSession create() throws javax.ejb.CreateException, java.rmi.RemoteException;}

**FirstSessionBean.java

package Dev.First;import java.rmi.RemoteException;import javax.ejb.CreateException;import javax.ejb.EJBException;import javax.ejb.SessionBean;import javax.ejb.SessionContext;public class FirstSessionBean implements SessionBean{public void ejbCreate() throws CreateException {}public String Welcome(){ String msg="Hello! This My Session Bean From Jboss."; System.out.println(msg); return msg;}public String getName(String id){ String name = ""; System.out.println("From bean before getName :"+ name); try{ Dev.Dao.MysqlDao dao = new Dev.Dao.MysqlDao(); name = dao.getName(id); System.out.println("From bean after getName :"+ name); }catch(Exception e){ System.out.println(e.getMessage());} return name;}public String getCountry(String id){ String country = ""; try{ Dev.Dao.MysqlDao dao = new Dev.Dao.MysqlDao(); country = dao.getCountry(id); }catch(Exception e){ } return country;}public void setSessionContext( SessionContext aContext ) throws EJBException {}public void ejbActivate() throws EJBException {}public void ejbPassivate() throws EJBException {}public void ejbRemove() throws EJBException {}}

/*Don′t put the following lines into index.jsp

**index.jsp

*/Don′t put the above lines into index.jsp

<%@page language="java" %><% String msg = ""; String msg1 = ""; Dev.Delegate.NewDelegate nn = new Dev.Delegate.NewDelegate(); if (request.getParameter("id") != null && request.getParameter("id") != ""&& !request.getParameter("id").equals("")){ String id = request.getParameter("id"); String name = ""; Dev.Dao.MysqlDao dao = new Dev.Dao.MysqlDao(); name = nn.getName(id); //Access database through session bean //name = dao.getName(id); //access database directly if(name!= null && !name.equals("")){ msg1 ="Welcome " + name +" ! You are from "+ dao.getCountry(id)+ " ."; }else{ msg1 ="Please Check Your ID. : " + id; } } msg = nn.Welcome() ;%><Html><head><title>Welcome</title></head><body bgcolor="#FFFFCC"><br> <%= msg %> <br><FORM ACTION="index.jsp" method="post"><P>Your ID:<INPUT TYPE="TEXT" NAME="id" size = "10"></P><P><INPUT TYPE="SUBMIT" NAME="SUBMIT"></P></FORM><br><br><%=(msg1 == "")? "":msg1 + "<br> <br> <br>Connect to Database OK." %></body></html>

<!--不要将此以下5行存入文件

**ejb-jar.xml

-->不要将此以上5行存入文件, 下同.

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE ejb-jar PUBLIC "-//Sun Microsystems, Inc.//DTD Enterprise JavaBeans 2.0//EN" "http://java.sun.com/dtd/ejb-jar_2_0.dtd"><ejb-jar> <description>First</description> <display-name>First</display-name><enterprise-beans><session id="MyFirstSession"> <display-name>My First Session Bean</display-name> <ejb-name>FirstSession</ejb-name> <home>Dev.First.FirstSessionHome</home> <remote>Dev.First.FirstSession</remote> <ejb-class>Dev.First.FirstSessionBean</ejb-class> <session-type>Stateless</session-type> <transaction-type>Container</transaction-type></session></enterprise-beans><assembly-descriptor></assembly-descriptor></ejb-jar>

<!--

**jboss.xml

-->

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE jboss PUBLIC "-//JBoss//DTD JBOSS//EN" "http://www.jboss.org/j2ee/dtd/jboss.dtd"><jboss><enterprise-beans><session><ejb-name>FirstSession</ejb-name><jndi-name>ejb/FirstSession</jndi-name></session></enterprise-beans><resource-managers></resource-managers></jboss>

<!--

**jboss-web.xml

-->

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE jboss-web PUBLIC "-//JBoss//DTD Web Application 2.2//EN" "http://www.jboss.org/j2ee/dtd/jboss-web.dtd"><jboss-web> <resource-ref> <res-ref-name>jdbc/PostgresDS</res-ref-name> <res-type>javax.sql.DataSource</res-type> <jndi-name>java:/PostgresDS</jndi-name> </resource-ref></jboss-web>

<!--

**web.xml

-->

<?xml version="1.0" encoding="ISO-8859-1"?><!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.2//EN""http://java.sun.com/j2ee/dtds/web-app_2_2.dtd"><web-app><resource-ref> <description>Postgresql driver</description> <res-ref-name>jdbc/PostgresDS</res-ref-name> <res-type>javax.sql.DataSource</res-type> <res-auth>Container</res-auth></resource-ref></web-app>

<!--

**application.xml

-->

<?xml version="1.0" encoding="ISO-8859-1"?><application><display-name>First</display-name><module><web><web-uri>First.war</web-uri><context-root>/First</context-root></web></module><module><ejb>First.jar</ejb></module></application>

编译JAVA源程序,生成class文件.

进入JAVA源程序目录, 运行:

javac -classpath %classpath%;%jboss%serverdefaultdeployFirst.earFirst.jar *.java

或者

javac -classpath %jboss%serverdefaultdeployFirst.earFirst.jar;%jboss%clientjboss-j2ee.jar *.java

Copy 目录First.ear to jbossserverdefaultdeploy.

打开浏览器输入地址 http://localhost:8080/First

到此, 在浏览器看到: Hello! This My Session Bean From Jboss.

说明这个EJB工作了.

如果按按钮, 没反应或出错. 原因没安装配置数据库, 下面安装配置Postgres数据库

For Windows2000

下载 PgSQL731wina1.exe (http://www.postgresql.org),

Finally you will see the next line, you need enter the passWord for Administrator

最后你将看下一个行,你必须为用户Administrator输入password.

********************

Enter password of user `.Administrator′:123456

********************

记下此password, 我的口令是123456.

从开始菜单 > Programm > PostgresSQL > Adjust PostgresSQL Configuration file

它将在Wordpad中打开PostgresSQL Configuration文件, 找到下列行,

# Connection Parameters

#tcpip_socket = false

#ssl = false

#max_connections = 32

#superuser_reserved_connections = 2

#port = 5432

修改编辑:

# Connection Parameters

tcpip_socket = true

#ssl = false

#max_connections = 32

#superuser_reserved_connections = 2

port = 5432

接着，保存文件.

起动PostgresSQL服务器:

开始菜单>Programm>PostgresSQL>Utilies>Start PostgresSQL server

起动命令行:

开始菜单>Programm>PostgresSQL>Utilies>Command Shell

执行下列命令,准备数据,

Administrator@SAN /

$ dir

$ cd bin

$ createdb test

$ psql test

test=# create table users

test-# (name varchar(20),

test(# id varchar(20),

test(# country varchar(20));

test=# insert into users values (′Sam′, ′123′, ′China′);

test=# insert into users values (′Tom′, ′321′, ′USA′);

test=# insert into users values (′Sean′, ′231′, ′France′);

test=# select * from users;

name id country

------+-----+---------

Sam 123 China

Tom 321 USA

Sean 231 France

(3 rows)

test=#

到此, 数据准备就绪.

For RedHat:

以root登陆, 执行下列命令,准备数据,

mkdir /usr/local/pgsql/data

chown postgres /usr/local/pgsql/data

su - postgres

/usr/local/pgsql/bin/initdb -D /usr/local/pgsql/data

Open and edit /usr/local/pgsql/data/pg_hba.conf

local all trust

host all 127.0.0.1 255.255.255.255 trust

just delete #, and save.

[root@localhost root]# su - postgres

-bash-2.05b$ /usr/bin/postmaster -i -D /usr/local/pgsql/data >logfile 2>&1 &

-bash-2.05b$ /usr/bin/createdb test

-bash-2.05b$ /usr/local/pgsql/bin/psql test

test=# .......the following same as Windows2000

到此, 数据准备就绪.

执行shutdown.bat or shutdown.sh, 停止Jboss Server.

找到JDBC drive.

为了在Jboss中使用连接池,需要拷贝jdbc drive 到Jboss/server/default/deploy , 在linux 我们能找到/usr/share/pgsql/pgjdbc2.jar,在wondows2000,我们能找到PostgreSQLusrsharepostgresqljavapostgresql.jar

把其中之一复制到Jboss/server/default/deploy

配置Jboss

(1) 复制 $Jboss/examples/jca/postgres-service.xml 到 $Jboss/server/default/deploy/

(2) 打开编辑Jboss/server/default/deploy/postgres-service.xml

<attribute name="JndiName">PostgresDS</attribute>

<config-property name="ConnectionURL" type="java.lang.String">jdbc:postgresql://localhost/test</config-property>

<config-property name="DriverClass" type="java.lang.String">org.postgresql.Driver</config-property>

<config-property name="UserName" type="java.lang.String">Administrator</config-property>

<config-property name="Password" type="java.lang.String">123456</config-property>

</properties>

In my example, set Username Administrator, password 123456 for windows 2000

set Username Postgres, no password for Linux.

在我的例子中，

windows2000, 用户:Administrator，password:123456

Linux(RH8.0), 用户:Postgres, 没有password

因为PostgresSQL和windows2000使用不同的default用户名,所以在linux和window2000中这文件不同.当然，你可以加相同的PostgresSQL用户名和password在linux和window2000中, 这样这文件就相同了.

保存文件.

(3) 打开编辑 $Jboss/server/default/conf/standardjbosscmp-jdbc.xml

找到:

<datasource>java:/DefaultDS</datasource>

<datasource-mapping>Hypersonic SQL</datasource-mapping>

加入:

<datasource>java:/PostgresDS</datasource>

<datasource-mapping>Postgres</datasource-mapping>

保存文件.

(4) open and edit $Jboss/server/default/conf/standardjaws.xml

找到:

<datasource>java:/DefaultDS</datasource>

<type-mapping>Hypersonic SQL</type-mapping>

<debug>false</debug>

加入:

<datasource>java:/PostgresDS</datasource>

<type-mapping>Postgres</type-mapping>

<debug>false</debug>

保存文件.

现在重起JBoss.

打开浏览器输入地址 http://localhost:8080/First

输入ID,按按钮.

（出处：http://www.knowsky.com）