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glassfish下的Eclipse的wtp插件的server runtime library问题

wilesun — Wed, 14 Aug 2013 01:27:00 GMT

See the thread GlassFish Tools does not provide a Server Runtime for Java Build Path in the Oracle forum.

Summary: They no longer provide a "Server Runtime" for plain Java projects. Instead, the project needs to be a faceted project and have a target runtime.

To configure this, do the following:

Go to the project properties > Project Facets
If necessary, click on Convert to faceted form...
In the Runtimes tab, select GlassFish 3.1

In case you need to export the GlassFish libraries to dependent projects, also do the following:

In Project Facets properties, select Utility Module and click Apply
In Java Build Path > Order and Export, select GlassFish System Libraries

见：http://stackoverflow.com/questions/17204096/glassfish-server-library-not-available-in-eclipse-kepler

wilesun 2013-08-14 09:27 发表评论

MessageFormat的format和StringBuilder组合字符串比较

wilesun — Tue, 30 Jul 2013 05:59:00 GMT

简单的测试代码如下:
时间为:
StringBuilder 346887ns
MessageFormat 2956450ns
看来StringBuilder快了一个数量级，因此还是用StringBuilder好

1 String str[] = { "11111", "222222222", "333333333333", "444444444444444444444444444" };
2         long l = System.nanoTime();
3         for (int i = 0; i < 100; i++) {
4             String c = new StringBuilder(str[0]).append(str[1]).append(str[2]).append(str[3]).toString();
5         }
6         System.out.println(System.nanoTime() - l);
7
8         MessageFormat format = new MessageFormat("{0}{1}{2}{3}");
9         l = System.nanoTime();
10         for (int i = 0; i < 100; i++) {
11             String c = format.format(str);
12         }
13         System.out.println(System.nanoTime() - l);

wilesun 2013-07-30 13:59 发表评论

Configuring Oracle for XA

wilesun — Fri, 26 Jul 2013 01:45:00 GMT

Configuring Oracle for XA

Oracle 10.2.0.3 and lower
Oracle 10.2.0.4, 11g and higher

Oracle 10.2.0.3 and lower

NOTE: this tip was written with Oracle DBMS version 10.2.0.2.0

How can you know if your Oracle server is correctly configured for XA?

The simplest and usually the most effective way is the following:

logon to SQLPlus (or use another tool if you like); make sure to use the user/password that you are using for your application
execute the query: select * from SYS.DBA_PENDING_TRANSACTIONS;

If this works then XA is configured.

If not then you should do one or all of the following:

run the oracle scripts 'initxa.sql' and 'xaview.sql' (or ask your DBA to do this for you).
ask your DBA to grant select rights (to your user) on SYS.DBA_PENDING_TRANSACTIONS
for the driver ojdbc14.jar, you also need execute rights on SYS.DBMS_SYSTEM

The last step is NOT needed for the older (JDK 1.2) drivers in classes12.jar

Oracle 10.2.0.4, 11g and higher

For Oracle 10.2.0.4 and up, you no longer need execute rights on SYS.DBMS_SYSTEM. This was fixed in Oracle 10.2.0.4 (BUG 5945463).

Make sure you are also using client driver ojdbc14 version 10.2.0.4 and up.

wilesun 2013-07-26 09:45 发表评论

FWK005 parse may not be called while parsing.

wilesun — Wed, 09 May 2012 09:18:00 GMT

最近在使用javax.xml.parsers.DocumentBuilder解析xml文件的时候偶尔会出错：

org.xml.sax.SAXException: FWK005 parse may not be called while parsing.
        at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:263)
        at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:284)
        at javax.xml.parsers.DocumentBuilder.parse(DocumentBuilder.java:208)

跟踪了一下代码，发现这个异常是在com.sun.org.apache.xerces.internal.parsers.DTDConfiguration.parse(DTDConfiguration.java:546)抛出来的。该段代码结构如下：

if(fParseInProgress) {
throw new XNIException("FWK005 parse may not be called while parsing.");
}

fParseInProgress = true;

// 解析xml文件

finally {
fParseInProgress = false;
}

从程序逻辑来看，如果当前DocumentBuilder对象正在转换文档，此时再次请求转换文档，那么直接抛出XNIException(“FWK005 parse may not be called while parsing.”);异常。

这个问题也比较好解决，一种是对转换xml文档的方法，增加synchronized关键字，这样子不会有两个线程同时访问方法。

还有一种方法是创建一个DocumentBuilder类型的ThreadLocal变量，这样子每个线程都拥有自己的DocumentBuilder对象，能够同时转换多个xml文件。代码如下：

private static ThreadLocal docBuildeIns = new ThreadLocal() {
    protected DocumentBuilder initialValue() {
        try {
            return DocumentBuilderFactory.newInstance().newDocumentBuilder();
        } catch (ParserConfigurationException e) {
            String msg = "DocumentBuilder 对象初始化失败！";
            log.error(msg, e);
            throw new IllegalStateException(msg, e);
        }
    }
};

wilesun 2012-05-09 17:18 发表评论

js也走JSP,并且可以中js文件中使用EL

wilesun — Mon, 26 Mar 2012 11:00:00 GMT

JS Configuration

/impl/pages/*

false

UTF-8

false

true

wilesun 2012-03-26 19:00 发表评论

java动态创建Enum

wilesun — Wed, 19 Aug 2009 01:07:00 GMT

public class DayFactory {
    static {
        try {
            Constructor con = Day.class.getDeclaredConstructors()[0];
            Method[] methods = con.getClass().getDeclaredMethods();
            for (Method m : methods) {
                if (m.getName().equals("acquireConstructorAccessor")) {
                    m.setAccessible(true);
                    m.invoke(con, new Object[0]);
                }
            }
            Field[] fields = con.getClass().getDeclaredFields();
            Object ca = null;
            for (Field f : fields) {
                if (f.getName().equals("constructorAccessor")) {
                    f.setAccessible(true);
                    ca = f.get(con);
                }
            }
            Method m = ca.getClass().getMethod("newInstance", new Class[] { Object[].class });
            m.setAccessible(true);
            Day v = (Day) m.invoke(ca, new Object[] { new Object[] { "VACATION", Integer.MAX_VALUE } });
            System.out.println(v.getClass() + ":" + v.name() + ":" + v.ordinal());
            for(Day day:Day.values()) {
                System.out.println(day);
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }

    public static void say() {
    }

    @Test
    public void ddd() {
        DayFactory.say();
    }

wilesun 2009-08-19 09:07 发表评论

PowerDesigner不让code name同步改变

wilesun — Wed, 05 Aug 2009 09:18:00 GMT

PowerDesigner中，但修改了某个字段的name，其code也跟着修改，这个问题很讨厌，因为一般来说，name是中文的，code是字段名。
解决方法如下：
1、选择Tools->GeneralOptions...菜单，出现General Options对话框。
2、从Category中选择Dialog项。
3、取消右边“Name to Code mirroring”复选框。

wilesun 2009-08-05 17:18 发表评论

delphi实现静态方法

wilesun — Wed, 07 Jan 2009 04:32:00 GMT

使用过c++的人都知道在c++的类中有静态属性及静态方法,为程序设计带来很多方便.那么在Delphi中静态属性及静态方法是怎么实现的呢?请看下面的实例:

unit Unit2;

interface

type
  TMyClass = Class
  public
    {静态过程:设置静态属性的值}
    class procedure SetStaticMemberValue(AString: string);
    {静态函数:读取静态属性的值}
    class function GetStaticMemberValue: string;
  end;

implementation
{在此声明静态属性,这一点与c++有很大的不同}
var
  AStaticMember: string;

class function TMyClass.GetStaticMemberValue: string;
begin
  Result := AStaticMember;
end;

class procedure TMyClass.SetStaticMemberValue(AString: string);
begin
  AStaticMember := AString;
end;

end.

    那么在TMyClass中声明的属性及方法是否是静态属性或静态方法呢?请看下面的实例:

...
uses unit2
...

procedure TForm1.Button2Click(Sender: TObject);
begin
  {不需声明TMyClass的实例,可直接设置及读取静态属性的值}
  TMyClass.SetStaticMemberValue('MyClass');
  showmessage(TMyClass.GetStaticMemberValue);
end;

wilesun 2009-01-07 12:32 发表评论

Windows的远程控制问题

wilesun — Tue, 16 Dec 2008 04:51:00 GMT

远程桌面超出连接数

通过net use \\servername password /user:administrator shutdown -m \\servername -r -f远程重启服务器
通过mstsc

用mstsc /v:IP /console强行连接到0会话,如果0会话在,它将被踢出
mstsc参数的了解，可通过mstsc /?学习一下。
MSTSC [＜Connection File＞] [/v:＜sever[:port]＞] [/console] [/f[ullscreen]]
[/w:＜width＞ /h:＜height＞] | /Edit"ConnectionFile" | /Migrate | /?
＜Connection File＞ -- 指定连接的 .rdp 文件的名称。
/v:＜sever[:port]＞ -- 指定要连接到的终端服务器。
/console -- 连接到服务器的控制台会话。
/f -- 以全屏模式启动客户端。
/w: ＜width＞ -- 指定远程桌面屏幕的宽度。
/h:＜height＞ -- 指定远程桌面屏幕的亮度。
/edit -- 打开指定的 .rdp 文件来编辑。
/migrate -- 将客户端连接管理器创建的旧版连接文件迁移到新的 .rdp 连接文件。
/? -- 生成这个用法消息。

wilesun 2008-12-16 12:51 发表评论

ORM-你在做领域Entity建模吗?

wilesun — Mon, 15 Dec 2008 02:57:00 GMT

ORM-你在做领域Entity建模吗?

ORM在我所接触过的项目或听说过的项目中70%以上根本没有领域实体对象建模（有些项目是想做，但不知怎样才能做好），通常都是直接采用数据库物理模型来生成一个实体层。从这层面上讲，大家讨厌ORM是对的，因为，大家其实只想需要一个JDBCTemplete就行了。说实话，其实ORM本身的精髓是在实体对象建模这一层。

但要建好领域实体对象模型，却实在是太难了.如果先建数据库的物理模，一般都会偷赖,但如果一开始就从对象角度来做实体对象建模，需要花费相当代价,最后通过OOM->PDM,来生成物理模型。

wilesun 2008-12-15 10:57 发表评论