用JBuilder2005开发Web应用
高科华
JBuilder是一个开放的Java IDE，它集成了Tomcat、Weblogic等服务器。虽然JDK、Tomcat、Weblogic不断升级，我们仍可以在JBuilder中使用它们的最新版本。由于Tomcat服务器的配置比较复杂，习惯了Windows平台的程序员常常对Tomcat的使用感到困惑。本文给出了一个使用Tomcat环境下的数据库连接池Database Connection Pool (DBCP) 的例子，说明了用JBuilder开发Web应用的一般步骤，并回答了一些经常遇到的问题。
JBuilder2005所带JDK的版本是1.4.2_04-b05,其文件放在目录JBuilder_HOME\jdk1.4下，Tomcat的最新版本是5.0.27，其文件放在目录JBuilder_HOME\thirdparty\ jakarta-tomcat-5.0.27下。下面首先给出给出了一个使用Tomcat环境下的数据库连接池Database Connection Pool (DBCP) 的例子。
1. File-New Project新建工程文件,输入工程文件名称myWeb和目录C:\myWeb
2. Project-Project Properties设置工程文件的属性，选择Tomcat为服务器
3. File-New新建Web Module（WAR）
输入Web Module的名称DBTest和目录DBTest
4. File-New新建JSP，输入jsp文件的名称test.jsp，产生test.jsp文件后修改test.jsp的内容
Test.jsp:
<%@ page contentType="text/html; charset=Big5" %>
<html>
<head>
<title>DB Test</title>
</head>
<body>
<%
foo.DBTest tst = new foo.DBTest();
tst.init();
%>
<h2>Results</h2>
Foo <%= tst.getFoo() %><br/>
Bar <%= tst.getBar() %>
</body>
</html>
将会生成一个名称为test的runtime configuration。
选Run-Configurations-Edit可修改runtime configuration，特别是可以指定服务器的端口号和是否自动搜索为被占用的端口。
5. File-New Class，输入类名DBTest和包名foo，产生DBTest.java文件后修改它的内容
DBTest.java
package foo;
import javax.naming.*;
import javax.sql.*;
import java.sql.*;
public class DBTest {
String foo = "Not Connected";
int bar = -1;
public void init() {
try{
Context ctx = new InitialContext();
if(ctx == null )
throw new Exception("Boom - No Context");
DataSource ds =
(DataSource)ctx.lookup(
"java:comp/env/jdbc/TestDB");
if (ds != null) {
Connection conn = ds.getConnection();
if(conn != null) {
foo = "Got Connection "+conn.toString();
Statement stmt = conn.createStatement();
ResultSet rst =
stmt.executeQuery(
"select id, foo, bar from testdata");
if(rst.next()) {
foo=rst.getString(2);
bar=rst.getInt(3);
}
conn.close();
}
}
}catch(Exception e) {
e.printStackTrace();
}
}
public String getFoo() { return foo; }
public int getBar() { return bar;}
}
6. 修改web.xml的内容
web.xml:
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd" version="2.4">
<description>MySQL Test App</description>
<resource-ref>
<description>DB Connection</description>
<res-ref-name>jdbc/TestDB</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>
</web-app>
7. F9运行应用，myWeb目录中将会生成Tomcat子目录，其中包含了conf子目录，
在Tomcat_HOME\conf\Catalina\localhost目录中生成了DBTest.xml文件
8. 将myWeb\Tomcat\conf目录中的文件server8080.xml加入工程文件，修改server8080.xml的内容
server8080.xml:
<?xml version="1.0" encoding="UTF-8"?>
<Server debug="0" port="8081" shutdown="SHUTDOWN">
<Service name="Catalina">
<Connector acceptCount="10" connectionTimeout="60000" debug="0" maxThreads="75" minSpareThreads="5" port="8080"/>
<Engine debug="0" defaultHost="localhost" name="Catalina">
<Host appBase="C:\myWeb\Tomcat\webapps" autoDeploy="false" debug="0" deployXML="false" name="localhost" unpackWARs="false">
<Context path="/DBTest" docBase="C:\myWeb\DBTest" debug="5" reloadable="true" crossContext="true" workDir="C:\myWeb\Tomcat\work\DBTest">
<Logger className="org.apache.catalina.logger.FileLogger" prefix="localhost_DBTest_log." suffix=".txt" timestamp="true"/>
<Resource name="jdbc/TestDB" auth="Container" type="javax.sql.DataSource"/>
<ResourceParams name="jdbc/TestDB">
<parameter>
<name>factory</name>
<value>org.apache.commons.dbcp.BasicDataSourceFactory</value>
</parameter>
<!--
Maximum number of dB connections in pool. Make sure you
configure your mysqld max_connections large enough to handle
all of your db connections. Set to 0 for no limit.
-->
<parameter>
<name>maxActive</name>
<value>100</value>
</parameter>
<!--
Maximum number of idle dB connections to retain in pool.
Set to 0 for no limit.
-->
<parameter>
<name>maxIdle</name>
<value>30</value>
</parameter>
<!--
Maximum time to wait for a dB connection to become available
in ms, in this example 10 seconds. An Exception is thrown if
this timeout is exceeded. Set to -1 to wait indefinitely.
-->
<parameter>
<name>maxWait</name>
<value>10000</value>
</parameter>
<!-- MySQL dB username and password for dB connections -->
<parameter>
<name>username</name>
<value>sa</value>
</parameter>
<parameter>
<name>password</name>
<value>topcomputer</value>
</parameter>
<!-- Class name for mm.mysql JDBC driver -->
<parameter>
<name>driverClassName</name>
<value>com.microsoft.jdbc.sqlserver.SQLServerDriver</value>
</parameter>
<!--
The JDBC connection url for connecting to your MySQL dB.
The autoReconnect=true argument to the url makes sure that the
mm.mysql JDBC Driver will automatically reconnect if mysqld closed the
connection. mysqld by default closes idle connections after 8 hours.
-->
<parameter>
<name>url</name>
<value>jdbc:microsoft:sqlserver://nt04:1433;DatabaseName=test</value>
</parameter>
</ResourceParams>
</Context>
</Host>
</Engine>
</Service>
</Server>
9. 将JDBC驱动放在C:\Borland\JBuilder2005\thirdparty\jakarta-tomcat-5.0.27\common\lib目录中
10. 在SQL Server中建立数据库test，数据库表文件testdata
creatTable.sql:
if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[testdata]') and OBJECTPROPERTY(id, N'IsUserTable') = 1)
drop table [dbo].[testdata]
GO
CREATE TABLE [dbo].[testdata] (
[id] [int] NOT NULL ,
[foo] [varchar] (50) COLLATE Chinese_Taiwan_Stroke_CI_AS NULL ,
[bar] [int] NOT NULL
) ON [PRIMARY]
GO
输入几条记录作为测试数据。
11. F9
12. 在c:\myWebmulu中建立批处理文件startup.bat和shutdown.bat内容分别如下：
startup.bat:
C:\Borland\JBuilder2005\jdk1.4\bin\javaw -classpath "C:\Borland\JBuilder2005\thirdparty\jakarta-tomcat-5.0.27\bin\bootstrap.jar;C:\Borland\JBuilder2005\jdk1.4\lib\tools.jar" "-Dcatalina.home=C:/Borland/JBuilder2005/thirdparty/jakarta-tomcat-5.0.27" org.apache.catalina.startup.Bootstrap -config "C:\myWeb\Tomcat\conf\server8080.xml" start
Shutdown.bat:
C:\Borland\JBuilder2005\jdk1.4\bin\javaw -classpath "C:\Borland\JBuilder2005\thirdparty\jakarta-tomcat-5.0.27\bin\bootstrap.jar;C:\Borland\JBuilder2005\jdk1.4\lib\tools.jar" "-Dcatalina.home=C:/Borland/JBuilder2005/thirdparty/jakarta-tomcat-5.0.27" org.apache.catalina.startup.Bootstrap -config "C:\myWeb\Tomcat\conf\server8080.xml" stop
13. 运行startup.bat,在浏览器输入http://localhost:8080/DBTest/test.jsp
如何部署Web应用？
1. 打包生成war文件
2. 将DBTest.war拷贝到Tomcat_HOME\webapps
3. 在Tomcat_HOME\conf\Catalina\localhost目录中建立文件DBTest.xml
DBTest.xml
<!--
Context configuration file for the Tomcat Administration Web App
$Id: admin.xml,v 1.2 2002/07/23 12:13:05 remm Exp $
-->
<Context path="/DBTest" docBase="/DBTest" debug="5" reloadable="true" crossContext="true" workDir="../work/DBTest">
<Logger className="org.apache.catalina.logger.FileLogger" prefix="localhost_DBTest_log." suffix=".txt" timestamp="true"/>
<Resource name="jdbc/TestDB" auth="Container" type="javax.sql.DataSource"/>
<ResourceParams name="jdbc/TestDB">
<parameter>
<name>factory</name>
<value>org.apache.commons.dbcp.BasicDataSourceFactory</value>
</parameter>
<!--
Maximum number of dB connections in pool. Make sure you
configure your mysqld max_connections large enough to handle
all of your db connections. Set to 0 for no limit.
-->
<parameter>
<name>maxActive</name>
<value>100</value>
</parameter>
<!--
Maximum number of idle dB connections to retain in pool.
Set to 0 for no limit.
-->
<parameter>
<name>maxIdle</name>
<value>30</value>
</parameter>
<!--
Maximum time to wait for a dB connection to become available
in ms, in this example 10 seconds. An Exception is thrown if
this timeout is exceeded. Set to -1 to wait indefinitely.
-->
<parameter>
<name>maxWait</name>
<value>10000</value>
</parameter>
<!-- MySQL dB username and password for dB connections -->
<parameter>
<name>username</name>
<value>sa</value>
</parameter>
<parameter>
<name>password</name>
<value>topcomputer</value>
</parameter>
<!-- Class name for mm.mysql JDBC driver -->
<parameter>
<name>driverClassName</name>
<value>com.microsoft.jdbc.sqlserver.SQLServerDriver</value>
</parameter>
<!--
The JDBC connection url for connecting to your MySQL dB.
The autoReconnect=true argument to the url makes sure that the
mm.mysql JDBC Driver will automatically reconnect if mysqld closed the
connection. mysqld by default closes idle connections after 8 hours.
-->
<parameter>
<name>url</name>
<value>jdbc:microsoft:sqlserver://nt04:1433;DatabaseName=test</value>
</parameter>
</ResourceParams>
</Context>
4. 启动Tomcat，DBTest.war将会解压到Tomcat_HOME\webapps\DBTest,并且在Tomcat_HOME\work\Catalina\localhost目录中生成DBTest目录
为什么不能生成war文件？
在proterties for Web Module对话框中设置与Build有关的属性Build Web archive。
如何在Web应用中加入目录和文件？
右击Module directory，在弹出的菜单中选择New-directory，输入目录名称；或右击拟在其中建立文件的目录，在弹出的菜单中选择New-File，选择文件类型，输入文件名。注意这样加入的文件只能是指定的文件类型。这样加入的目录和文件都会打包到war文件中。
如何加入其它类型的文件？
可以将文件拷贝到指定的目录，在proterties for Web Module对话框中设置属性Content，选择include all classes and resources，这样也可以将加入的文件打包到war文件中。
如何使用指定的JDK？
选择菜单Tools-Configure-JDKs，在弹出的对话框中按New按钮，然后选择JDK的路径。
选择菜单Project-Project Properties，在弹出的对话框中选择加入的JDK。
如何使用指定的Tomcat？
选择菜单Enterprise-Configure Servers,在弹出的对话框中选择Tomcat5.0后按Copy按钮，
选择Copy产生的服务器Copy of Tomcat 5.0，选择Home Directory
选择菜单Project-Project Properties，在弹出的对话框中设置属性server,选择加入的Tomcat服务器
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