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ZhuJun — Mon, 02 Jan 2006 15:42:00 GMT

安装了Oracle�?启动Tomcat时出现错�?

Error starting endpoint
java.net.BindException: Address already in use: JVM_Bind:8080

原来Oracle的Servlet Engine也��用了8080端口.那就来修改Tomcat的端�?

首相扑ֈ�Tomcat 5.0\conf\server.xml文�g,然后扑ֈ�下面的代�?

    port="8080"               maxThreads="150" minSpareThreads="25" maxSpareThreads="75"
               enableLookups="false" redirectPort="8443" acceptCount="100"
               debug="0" connectionTimeout="20000"
               disableUploadTimeout="true" />

修改 port="8080" ��Z��惌��的端口就可以�?

ZhuJun 2006-01-02 23:42 发表评论

ZhuJun — Mon, 02 Jan 2006 15:25:00 GMT

摘要: Velocity 参考资�? John Zhu 2005-4-7 原文:http://jakarta.apache.org/velocity/user-guide.html VTL Reference: http://jakarta.apache.org/velocity/vtl-reference-guide.html Develop... 阅读全文

ZhuJun 2006-01-02 23:25 发表评论

[Eclipse] 在Eclipse中安装Visual Editor插�g

ZhuJun — Mon, 02 Jan 2006 15:22:00 GMT

在Eclipse中进行GUI开发需要安装Visual Editor插�g:
1.Install Omondo UML(包括了VE插�g所需要的EMF,GEF,�q�包括UML2插�g):

�?/FONT>http://www.omondo.com/download/index.html下蝲eclipseUML_E302_freeEdition_2.0.0.20050407.jar;
Install by java -jar eclipseUML_E301_freeEdition_2.0.0.beta.20041026.jar;

2.Install Visual Editor插�g:

�?/FONT>http://www.eclipse.org/vep/下蝲VE-runtime-1.0.2.1.zip;
��VE -runtime-1.0.2.1.zip解压到c:\eclipse-plugins(可以是�Q何目�?�?在Eclipse的安装�\径下的links 目录中徏立一个link文�g,比如gui.ve.link,文�g内容�?nbsp; path=c:/eclipse-plugins/VE-runtime- 1.0.2.1, 卌��个link文�g要对应一个刚解压后的插�g目录�?注意:此目录中应包含eclipse/(features|plugins)�l�构);
启动eclipse卛_��,安装完成;

3.后期讄��:

点击Window菜单�Q�选择Customize Perspective�?/SPAN>
Submenus栏目下选择New
Shortcut Categories下选择Java
Shortcuts中在Visual Class前划�?/SPAN>
Submenus栏目下选择Show View
Shortcut Categories下选择Basic
Shortcuts中在Palette前划�?/SPAN>
通过菜单调出Palette�Q?/SPAN>Window | Show View | Palette
�?SPAN lang=EN-US>Menu打开Properties View�Q?SPAN lang=EN-US style="COLOR: blue">Windows | Show View | Basic | Properties

好了,现在new->Visual Class��可以进行GUI的开发了.

ZhuJun 2006-01-02 23:22 发表评论

ZhuJun — Mon, 02 Jan 2006 15:18:00 GMT

在模板中老是讉K��不到对象的属�?最后发现原来是应�ؓ模板中访问的对象不是一个Public�c?��Class改�ؓPublic后一切OK.后来分析可能是因��问权限的问题,当Class未加Public�?是包内可讉K��(friendly),而模板如果与对象的Class不在同一包中时自然访问不�?

ZhuJun 2006-01-02 23:18 发表评论

[Hibernate] 为Hibernate提供JDBC�q�接

ZhuJun — Mon, 02 Jan 2006 15:15:00 GMT

可以通过3钟方式�ؓHibernate提供JDBC�q�接:

1.直接提供JDBC�q�接对象Connection:

Class.forName("com.mysql.jdbc.Driver");
String url = "jdbc:mysql://localhost:3306/HibernateTest?user=root&password=";
java.sql.Connection conn = DriverManager.getConnection(url);
SessionFactory sessionFactory = cfg.buildSessionFactory();
Session session = sessionFactory.openSession(conn);

2.通过属性文�?/SPAN>hibernate.properties配置JDBC来源:

hibernate.show_sql = true
hibernate.dialect = net.sf.hibernate.dialect.MySQLDialect
hibernate.connection.driver_class = com.mysql.jdbc.Driver
hibernate.connection.url = jdbc:mysql://localhost/HibernateTest
hibernate.connection.username = root
hibernate.connection.password =

3.�?SPAN style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; LETTER-SPACING: 0.75pt; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana; mso-bidi-font-size: 12.0pt">�q?/SPAN>XML文�ghibernate.cfg.xml�q�行配置:

xml version='1.0' encoding='big5'?>
DOCTYPE hibernate-configuration
 PUBLIC "-//Hibernate/Hibernate Configuration DTD//EN"
 "http://hibernate.sourceforge.net/hibernate-configuration-2.0.dtd">

<hibernate-configuration>

 <session-factory>


 <property name="show_sql">trueproperty>

 <property name="dialect">net.sf.hibernate.dialect.MySQLDialectproperty>

 <property name="connection.driver_class">com.mysql.jdbc.Driverproperty>

 <property name="connection.url">jdbc:mysql://localhost/HibernateTestproperty>

 <property name="connection.username">caterpillarproperty>

 <property name="connection.password">123456property>


 <mapping resource="User.hbm.xml"/>
 session-factory>

hibernate-configuration>

ZhuJun 2006-01-02 23:15 发表评论

ZhuJun — Tue, 27 Dec 2005 11:35:00 GMT

org.apache.commons.lang.StringUtils中提供许多有用的字符串操作方法，了解�q�些�Ҏ��Q�我们可以避免许多不必要的重复工作。下面介�l�其中比较有用的几个�Ҏ��Q?BR>
��查空字符�Ԍ��

StringUtils.isBlank(String str);
StringUtils.isNotBlank(String str);

�~�写字符�Ԍ��

String test = "This is a test of the abbreviation."
System.out.println( StringUtils.abbreviate( test, 10 ) );

[Console输出]
This is

查找嵌套字符�Ԍ��

String htmlContent = "\n" +
                     "  \n" +
                     "    Test Page\n" +
                     "  \n" +
                     "  \n" +
                     "

This is a TEST!

\n" +
" \n" +
"";

// Extract the title from this XHTML content
String title = StringUtils.substringBetween(htmlContent, "", "");
System.out.println( "Title: " + title );

[Console输出]
Title: Test Page

验证字符�Ԍ��

String test1 = "ORANGE";

String test2 = "ICE9";

String test3 = "ICE CREAM";

String test4 = "820B Judson Avenue";

boolean t1val = StringUtils.isAlpha( test1 ); // returns true

boolean t2val = StringUtils.isAlphanumeric( test2 ); // returns true

boolean t3val = StringUtils.isAlphaSpace( test3 ); // returns true

boolean t4val =

StringUtils.isAlphanumericSpace( test4 ); // returns true

计算字符串出现频率：StringUtils.countMatches()

File manuscriptFile = new File("manuscript.txt");

Reader reader = new FileReader( manuscriptFile );

StringWriter stringWriter = new StringWriter( );

while( reader.ready( ) ) { writer.write( reader.read( ) ); }

String manuscript = stringWriter.toString( );

// Convert string to lowercase

manuscript = StringUtils.lowerCase(manuscript);

// count the occurrences of "futility"

int numFutility = StringUtils.countMatches( manuscript, "futility" );

比较不同字符�Ԍ��

int dist = StringUtils.getLevenshteinDistance( "Word", "World" );

String diff = StringUtils.difference( "Word", "World" );

int index = StringUtils.indexOfDifference( "Word", "World" );

System.out.println( "Edit Distance: " + dist );

System.out.println( "Difference: " + diff );

System.out.println( "Diff Index: " + index );

[Console输出]
Edit Distance: 2

Difference: ld

Diff Index: 3

参考资料：
《Jakarta Commons Cookbook�?BR>By Timothy M. O'Brien

Publisher : O'Reilly
Pub Date : November 2004
ISBN : 0-596-00706-X
Pages : 400

ZhuJun 2005-12-27 19:35 发表评论

[Hibernate�W�记] �l��g(Component)映射

ZhuJun — Thu, 22 Dec 2005 10:46:00 GMT

�l��g(Component)映射多用来表�C�对象的从属关系(�l�合,聚合).比如一个学生可能有姓名,�q�龄,性别,成�W�{�属�?其中成�W是另一个对�?又有�U�目,分数属�?�q�里��需要用�l��g映射来表是之间的关系.

Java代码:

// 学生
class Student{
  private String name;
  private int age;
  private String sex;
  private Grade grade;

}
// 成�W
class Grade{
  private String subject;
  private float score;

}

数据�?

-- 学生�?/SPAN>
create table STUDENT (
    ID char(32) not null,
    NAME varchar(16) not null,
    SEX char(1),
    AGE integer,
    primary key (ID)
);

-- 成�W�?/SPAN>
create table GRADE (
    ID char(32) not null,
    student_id char(32) not null,
    SUBJECT varchar(10),
    SCORE float,
    primary key (ID),
    foreign key (student_id)
);

Hibernate映射文�g:

xml version="1.0"?>
DOCTYPE hibernate-mapping
 PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN"
 "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">
<hibernate-mapping>
 <class name="Student" table="STUDENT">

 <id name="id" type="string" unsaved-value="null">
 <column name="ID" sql-type="char(32)"/>
 <generator class="uuid.hex"/>
 id>

 <property name="name" type="string" not-null="true">
 <column name="NAME" length="16" not-null="true"/>
 property>
 <property name="sex" type="char" column="SEX"/>
 <property name="age" type="int" column="AGE"/>

 <component name="grade" class="Grade">
 <property name="subject" type="string" column="SUBJECT" not-null="true"/>
 <property name="score" type="float" column="SCORE" not-null="true"/>
 component>

 class>
hibernate-mapping>

ZhuJun 2005-12-22 18:46 发表评论

[发掘Jakarta Commons] 使用LRUMap

ZhuJun — Thu, 15 Dec 2005 11:59:00 GMT

LRUMap(Least Recently Used Cache)可用来保存最�q��用的几条记录,例如:保存Blog中的最�q?0条留�a�.大多数情�는�作缓�?�?EHCache)的一�U�策�?具体使用�Ҏ��如下:

import java.util.Map;
import org.apache.commons.collections.map.LRUMap;

cache = new LRUMap( 5 );

// Populate the cache with 5 stock prices
cache.put( "MSFT", new Float( 0.03 ) );
cache.put( "TSC", new Float( 0.001 ) );
cache.put( "LU", new Float( 23.30 ) );
cache.put( "CSCO", new Float( 242.20 ) );
cache.put( "P", new Float( 10.23 ) );

// Now use some of the entries in the cache
Float cscoPrice  = (Float) cache.get( "CSCO" );
Float msPrice = (Float) cache.get( "MSFT" );
Float tscPrice = (Float) cache.get( "TSC" );
Float luPrice = (Float) cache.get( "LU" );
Float pPrice = (Float) cache.get( "P" );
Float msPrice2 = (Float) cache.get( "MSFT" );

// Add another price to the Map, this should kick out the LRU item.
cache.put( "AA", new Float( 203.20 ) );

此时,�~�存中的元素�?
[CSCO]
[MSFT]
[TSC]
[LU]
[P]
[AA]
�׃��LRU最�q�没有被讉K��,所以当AA加入�?�׃��过了缓存的最大容�?5),所以被剔除了缓�?

参考资�?
<<Jakarta Commons Cookbook>>
By Timothy M. O'Brien

Publisher : O'Reilly
Pub Date : November 2004
ISBN : 0-596-00706-X
Pages : 400

ZhuJun 2005-12-15 19:59 发表评论

[Hibernate�W�记] �l�承映射

ZhuJun — Sat, 10 Sep 2005 16:21:00 GMT

对于对象的��承关�p? ��“每一��늱��l�承树对应一个表�?卛_��每一个子�c�都�q�行使用声明�?例如:

有一个基�c? class User, 两个子类: class Admin�?class Guest.

则新��Z��个表格来对应�q�个�l�承�c�L��:

create table USER (
    ID char(32) not null,
    DISCRIMINATOR_USERTYPE varchar(255) not null,
    NAME varchar(16) not null,
    PASSWORD varchar(16) not null,
    USER_LEVEL integer,
    POWER_OTHER varchar(255),
    GUEST_OTHER varchar(255),
    primary key (ID)
);

其中字段DISCRIMINATOR_USERTYPE来记录储存的�c�d��是属�?/SPAN>User�?/SPAN>Admin或是Guest的记录，如果该字�D�|��ParentUser�Q�则表示该笔数据�?/SPAN>User�c�d��Q�如果是ADMIN�Q�表�C�是Admin的记录，如果�?/SPAN>GUEST�Q�表�C�是Guest的记�?

映像文�g:

xml version="1.0"?>
DOCTYPE hibernate-mapping
 PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN"
 "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">

<hibernate-mapping>

 <class name="com.zj.User" table="USER" discriminator-value="ParentUser">

 <id name="id" type="string" unsaved-value="null">
 <column name="ID" sql-type="char(32)"/>
 <generator class="uuid.hex"/>
 id>

 <discriminator column="DISCRIMINATOR_USERTYPE" type="string"/>

 <property name="name" type="string" not-null="true">
 <column name="NAME" length="16" not-null="true"/>
 property>

 <property name="password" type="string" not-null="true">
 <column name="PASSWORD" length="16" not-null="true"/>
 property>

 <subclass name="com.zj.Admin" discriminator-value="ADMIN">
 <property name="level" type="integer" column="ADMIN_LEVEL"/>

 <property name="otherOfPower" type="string" column="POWER_OTHER"/>
 subclass>

 <subclass name="com.zj.Guest" discriminator-value="GUEST">
 <property name="otherOfGuest" type="string" column="GUEST_OTHER"/>
 subclass>
 class>

hibernate-mapping>

注意上面文�g�?在映像子�c�d��Ӟ��使用指明映像的子�c�d��以及�?/SPAN>discriminator-value来指�?

ZhuJun 2005-09-11 00:21 发表评论