答案: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_HOMEjdk1.4下,Tomcat的最新版本是5.0.27,其文件放在目录JBuilder_HOME hirdparty 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_HOMEconfCatalinalocalhost目录中生成了DBTest.xml文件
8. 将myWebTomcatconf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:myWebTomcatwebapps" autoDeploy="false" debug="0" deployXML="false" name="localhost" unpackWARs="false">
<Context path="/DBTest" docBase="C:myWebDBTest" debug="5" reloadable="true" crossContext="true" workDir="C:myWebTomcatworkDBTest">
<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:BorlandJBuilder2005 hirdpartyjakarta-tomcat-5.0.27commonlib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:BorlandJBuilder2005jdk1.4injavaw -classpath "C:BorlandJBuilder2005 hirdpartyjakarta-tomcat-5.0.27inootstrap.jar;C:BorlandJBuilder2005jdk1.4lib ools.jar" "-Dcatalina.home=C:/Borland/JBuilder2005/thirdparty/jakarta-tomcat-5.0.27" org.apache.catalina.startup.Bootstrap -config "C:myWebTomcatconfserver8080.xml"
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