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

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

1. package Dev.Dao;
3. import java.sql.Connection;
4. import java.sql.SQLException;
5. import java.sql.Statement;
6. import java.sql.ResultSet;
8. import javax.naming.InitialContext;
9. import javax.sql.DataSource;
12. public class MysqlDao {
14. public Connection getConnection() throws Exception {
16. InitialContext ctx = new InitialContext();
18. DataSource ds = (DataSource) ctx.lookup("java:/PostgresDS");
21. Connection conn = null;
22. Statement stmt = null;
24. try {
25. conn = ds.getConnection();
27. } catch (SQLException sqlEx) {
28. System.out.println("Error connect to pool.");
29. }
31. return conn;
32. }
34. public String getName(String id) throws Exception {
36. Connection conn = null;
37. Statement stmt = null;
38. ResultSet rs = null;
39. String name = "";
41. try {
42. conn = getConnection();
43. if ( conn !=null )System.out.println("Get conecttion. "+ conn.toString());
44. stmt = conn.createStatement();
45. if ( stmt !=null )System.out.println("Get Statement. "+ stmt.toString());
46. String sql = "SELECT * from users where id = '"+id+"'";
47. System.out.println("Sql from getId(): "+sql);
48. rs = stmt.executeQuery(sql);
49. if ( rs !=null )System.out.println("Get result. ");
50. if (rs.next()){
51. name = rs.getString("name");
52. }
54. } catch (Exception sqlEx) {
55. System.out.println("Error from getName().");
56. System.out.println("Error from DAO.getName() :" + sqlEx.getMessage());
57. }finally {
58. if (conn != null) {
59. try { conn.close(); } catch (Exception sqlEx) { }
60. }
61. }
62. return name;
63. }
65. public String getCountry(String id) throws Exception {
67. Connection conn = null;
68. Statement stmt = null;
69. String name = "";
71. try {
72. conn = getConnection();
73. stmt = conn.createStatement();
74. String sql = "SELECT * from users where id = '"+id+"'";
75. System.out.println("Sql from getCountry(): "+sql);
76. java.sql.ResultSet rs = stmt.executeQuery(sql);
77. if (rs.next())
78. {
79. name = rs.getString("Country");
80. }
82. } catch (SQLException sqlEx) {
83. System.out.println("Error from getCountry().");
84. }finally {
85. if (conn != null) {
86. try { conn.close(); } catch (Exception sqlEx) { }
87. }
88. }
89. return name;
90. }
92. }

/*
**
**NewDelegate.java
**
*/

1. package Dev.Delegate;
3. import java.lang.*;
4. import Dev.First.*;
7. public class NewDelegate {
9. Dev.First.FirstSession bean = null;
11. public NewDelegate( ){
12. try {
13. javax.naming.InitialContext ctx = new javax.naming.InitialContext();
14. Object objref = ctx.lookup("ejb/FirstSession");
15. Dev.First.FirstSessionHome testBean = (Dev.First.FirstSessionHome)
16. javax.rmi.PortableRemoteObject.narrow
17. (objref,Dev.First.FirstSessionHome.class);
18. bean = testBean.create();
19. System.out.println("From JSP");
20. } catch (Exception NamingException) {
21. NamingException.printStackTrace();
22. }
23. }
25. public String Welcome() {
26. String msg = "";
27. try {
28. msg = bean.Welcome();
29. } catch (Exception NamingException) {
30. NamingException.printStackTrace();
31. }
32. return msg;
33. }
35. public String getName(String id) {
36. String name = "";
37. try {
38. name = bean.getName(id);
39. } catch (Exception NamingException) { NamingException.printStackTrace();}
40. return name;
41. }
43. public String getCountry(String id) {
44. String country = "";
45. try {
46. country = bean.getCountry(id);
47. } catch (Exception NamingException) { NamingException.printStackTrace();}
48. return country;
49. }
50. }

/*
**
**FirstSession.java
**
*/

1. package Dev.First;
3. import java.lang.*;
4. import java.rmi.RemoteException;
5. import javax.ejb.CreateException;
6. import javax.ejb.EJBException;
7. import javax.ejb.SessionBean;
8. import javax.ejb.SessionContext;
11. public interface FirstSession extends javax.ejb.EJBObject{
13. public String Welcome() throws java.rmi.RemoteException;
15. public String getName(String id) throws java.rmi.RemoteException;
17. public String getCountry(String id) throws java.rmi.RemoteException;
19. }

/*
**
**FirstSessionHome.java
**
*/

1. package Dev.First;
3. import java.lang.*;
4. import java.rmi.RemoteException;
5. import javax.ejb.CreateException;
6. import javax.ejb.EJBException;
7. import javax.ejb.SessionBean;
8. import javax.ejb.SessionContext;
11. public interface FirstSessionHome extends javax.ejb.EJBHome{
13. public FirstSession create() throws javax.ejb.CreateException, java.rmi.RemoteException;
15. }

/*
**
**FirstSessionBean.java
**
*/

1. package Dev.First;
3. import java.rmi.RemoteException;
4. import javax.ejb.CreateException;
5. import javax.ejb.EJBException;
6. import javax.ejb.SessionBean;
7. import javax.ejb.SessionContext;
10. public class FirstSessionBean implements SessionBean{
12. public void ejbCreate() throws CreateException {
14. }
16. public String Welcome(){
17. String msg="Hello! This My Session Bean From Jboss.";
18. System.out.println(msg);
19. return msg;
20. }
22. public String getName(String id){
23. String name = "";
24. System.out.println("From bean before getName :"+ name);
25. try{
26. Dev.Dao.MysqlDao dao = new Dev.Dao.MysqlDao();
27. name = dao.getName(id);
28. System.out.println("From bean after getName :"+ name);
29. }catch(Exception e){ System.out.println(e.getMessage());}
30. return name;
31. }
33. public String getCountry(String id){
34. String country = "";
35. try{
36. Dev.Dao.MysqlDao dao = new Dev.Dao.MysqlDao();
37. country = dao.getCountry(id);
38. }catch(Exception e){ }
39. return country;
40. }
42. public void setSessionContext( SessionContext aContext ) throws EJBException {
44. }
46. public void ejbActivate() throws EJBException {
48. }
50. public void ejbPassivate() throws EJBException {
52. }
54. public void ejbRemove() throws EJBException {
56. }
58. }

/*Don't put the following lines into index.jsp
**
**index.jsp
**
*/Don't put the above lines into index.jsp

1. <%@page language="java" %>
3. <%
5. String msg = "";
6. String msg1 = "";
7. Dev.Delegate.NewDelegate nn = new Dev.Delegate.NewDelegate();
8. if (request.getParameter("id") != null &&
9. request.getParameter("id") != ""&&
10. !request.getParameter("id").equals("")){
11. String id = request.getParameter("id");
12. String name = "";
13. Dev.Dao.MysqlDao dao = new Dev.Dao.MysqlDao();
14. name = nn.getName(id); //access database through session bean
15. //name = dao.getName(id); //access database directly
16. if(name!= null && !name.equals("")){
17. msg1 ="Welcome " + name +" ! You are from "+ dao.getCountry(id)+ " .";
18. }else{
19. msg1 ="Please Check Your ID. : " + id;
20. }
22. }
23. msg = nn.Welcome() ;
24. %>
27. <head>
29. </head>
31. <body bgcolor="#FFFFCC">
32. 
    <%= msg %>
    
34. <form ACTION="index.jsp" method="post">

36. Your ID:

37. <input TYPE="TEXT" NAME="id" size = "10">

40. <input TYPE="SUBMIT" NAME="SUBMIT">

41. </form>
42. 
    
43. 
    
45. <%=(msg1 == "")? "":msg1 + "
    
    
    Connect to Database OK." %>
47. </body>

1. <?xml version="1.0" encoding="UTF-8"?>
2. ejb-jar PUBLIC "-//Sun Microsystems, Inc.//DTD Enterprise JavaBeans 2.0//EN"
3. "http://java.sun.com/dtd/ejb-jar_2_0.dtd">
7. First
8. First
14. My First Session Bean
15. FirstSession
16. Dev.First.FirstSessionHome
17. Dev.First.FirstSession
18. class>Dev.First.FirstSessionBeanclass>
19. Stateless
20. <transaction-type>Container</transaction-type>

1. <?xml version="1.0" encoding="UTF-8"?>
2. jboss PUBLIC "-//JBoss//DTD JBOSS//EN" "http://www.jboss.org/j2ee/dtd/jboss.dtd">
9. FirstSession
10. ejbFirstSession

1. <?xml version="1.0" encoding="UTF-8"?>
2. jboss-web PUBLIC "-//JBoss//DTD Web Application 2.2//EN"
3. "http://www.jboss.org/j2ee/dtd/jboss-web.dtd">
9. jdbcPostgresDS
10. javax.sql.DataSource
11. java:/PostgresDS

1. <?xml version="1.0" encoding="ISO-8859-1"?>
3. web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.2//EN"
4. "http://java.sun.com/j2ee/dtds/web-app_2_2.dtd">
9. Postgresql driver
10. jdbcPostgresDS
11. javax.sql.DataSource
12. Container

1. <?xml version="1.0" encoding="ISO-8859-1"?>
4. First
7. First.war
8. /First
13. First.jar

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%\server\default\deploy\First.ear\First.jar *.java
或者
javac -classpath %jboss%\server\default\deploy\First.ear\First.jar;%jboss%\client\jboss-j2ee.jar *.java

Copy 目录First.ear to jboss\server\default\deploy.
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PostgreSQL\usr\share\ postgresql\java\postgresql.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

PostgresDS


jdbc:postgresql://localhost/test
org.postgresql.Driver

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