c++ difference from java
1. take charge of object management , negotiate ownershiop ,use scoped_ptr,
   not to transfer other's ownership
2. use c++ template to express seperation corncern ,such as (static)polymorphy and policy
3. disable copy constructor and assign operator by yourself
4. polymorphy by pointer
5. 使用 template ,macro 取得類似動態(tài)語言的能力
6. 偏好無狀態(tài)的 函數(shù)

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Myisam is preferred without transaction and little update(delete)

Big than 4G datafile can user Myisam merge table.

InnoDB with auto_increment primary key is preferred.

Few storage process

Guess: 20m records max per table , 500G data max per tablespace , 256 tables per database (may problem)

Use prepared statement and  batch

Optimize Your Queries For the Query Cache

// query cache does NOT work

$r = mysql_query("SELECT username FROM user WHERE signup_date >= CURDATE()");

// query cache works!

$today = date("Y-m-d");

$r = mysql_query("SELECT username FROM user WHERE signup_date >= '$today'");

EXPLAIN Your SELECT Queries

LIMIT 1 When Getting a Unique Row

Index and Use Same Column Types for Joins

Do Not ORDER BY RAND()

Avoid SELECT *

t is a good habit to always specify which columns you need when you are doing your SELECT’s.

Use ENUM over VARCHAR

Use NOT NULL If You Can

Store IP Addresses as UNSIGNED INT (?)

Fixed-length (Static) Tables are Faster

Vertical Partitioning

Vertical Partitioning is the act of splitting your table structure in a vertical manner for optimization reasons.

Example 1: You might have a users table that contains home addresses, that do not get read often. You can choose to split your table and store the address info on a separate table. This way your main users table will shrink in size. As you know, smaller tables perform faster.

Example 2: You have a “last_login” field in your table. It updates every time a user logs in to the website. But every update on a table causes the query cache for that table to be flushed. You can put that field into another table to keep updates to your users table to a minimum.

But you also need to make sure you don’t constantly need to join these 2 tables after the partitioning or you might actually suffer performance decline.

Split the Big DELETE or INSERT Queries

If you have some kind of maintenance script that needs to delete large numbers of rows, just use the LIMIT clause to do it in smaller batches to avoid this congestion.

Smaller Columns Are Faster

Use an Object Relational Mapper

f you do not need the time component, use DATE instead of DATETIME.

Consider horizontally spitting many-columned tables if they contain a lot of NULLs or rarely used columns.

Be an SQL programmer who thinks in sets, not procedural programming paradigms

InnoDB can’t optimize SELECT COUNT(*) queries. Use counter tables! That’s how to scale InnoDB.

Prefer MM with hive

refer :

http://blog.tuvinh.com/top-20-mysql-best-practices/

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從時序圖中可以看到，createNewIO()就是新建了一個com.mysql.jdbc.MysqlIO，利用 com.mysql.jdbc.StandardSocketFactory來創(chuàng)建一個socket。然后就由這個mySqlIO來與MySql服務(wù)器進行握手(doHandshake())，這個doHandshake主要用來初始化與Mysql server的連接，負責(zé)登陸服務(wù)器和處理連接錯誤。在其中會分析所連接的mysql server的版本，根據(jù)不同的版本以及是否使用SSL加密數(shù)據(jù)都有不同的處理方式，并把要傳輸給數(shù)據(jù)庫server的數(shù)據(jù)都放在一個叫做packet的 buffer中，調(diào)用send()方法往outputStream中寫入要發(fā)送的數(shù)據(jù)。


useServerPreparedStmts置為true的話，mysql驅(qū)動可以通過PreparedStatement的子類ServerPreparedStatement來實現(xiàn)真正的PreparedStatement的功能




第一位表示數(shù)據(jù)包的開始位置，就是數(shù)據(jù)存放的起始位置，一般都設(shè)置為0，就是從第一個位置開始。第二和第三個字節(jié)標(biāo)識了這個數(shù)據(jù)包的大小，注意的是，這個大小是出去標(biāo)識的4個字節(jié)的大小，對于非最后一個數(shù)據(jù)包來說，這個大小都是一樣的，就是splitSize，也就是maxThreeBytes，它的值是 255 * 255 * 255。
最后一個字節(jié)中存放的就是數(shù)據(jù)包的編號了，從0開始遞增。
在標(biāo)識位設(shè)置完畢之后，就可以把255 * 255 * 255大小的數(shù)據(jù)從我們準備好的待發(fā)送數(shù)據(jù)包中copy出來了，注意，前4位已經(jīng)是標(biāo)識位了，所以應(yīng)該從第五個位置開始copy數(shù)據(jù)

 # packetToSend = compressPacket(headerPacket, HEADER_LENGTH,    
#                 splitSize, HEADER_LENGTH); 

LoadBalancingConnectionProxy
package java.lang.reflect 。 proxy .


http://developer.51cto.com/art/200907/137823.htm

http://dev.mysql.com/doc/refman/5.1/en/connector-j-reference-implementation-notes.html

PreparedStatements are implemented by the driver, as MySQL does not have a prepared statement feature. Because of this, the driver does not implement getParameterMetaData() or getMetaData() as it would require the driver to have a complete SQL parser in the client.

Starting with version 3.1.0 MySQL Connector/J, server-side prepared statements and binary-encoded result sets are used when the server supports them.

但這是不是說PreparedStatement沒用呢？不是的，PreparedStatement有其他的好處：
1.代碼的可讀性和可維護性
2.最重要的一點是極大地提高了安全性，可以防止SQL注入

然后我又看了一些網(wǎng)上其他人的經(jīng)驗，基本和我的判斷一致，有兩點要特別提請大家注意：

1.并不是說PreparedStatement在所有的DB上都不會提高效率，PreparedStatement需要服務(wù)器端的支持，比如在 Oracle上就會有顯著效果。上面說的測試都是在MySQL上測試的，我找到了一個MySQL架構(gòu)師的帖子，比較明確地說明了MySQL不支持 PreparedStatement。

2.即便PreparedStatement不能提高性能，在少數(shù)使用時甚至?xí)档托剩匀粦?yīng)該使用PreparedStatement！因為其他好 處實在是太大了！當(dāng)然，當(dāng)SQL查詢比較復(fù)雜時，可能PreparedStatement好處會更大，只是我沒有測試，不敢肯定。

3.既然PreparedStatement不能提高效率，那PreparedStatement Pool也就沒有必要了。但可以看到每次新建Connection的開銷實在很大，因此Connection Pool絕對必要。

download ,annatation and tools 兩個項目。
添加相關(guān)的 jar.

<taskdef name="hibernatetool" classname="org.hibernate.tool.ant.HibernateToolTask" classpathref="master.classpath" />

<target name="create_table">

<hibernatetool destdir="${script.dir}">
    <annotationconfiguration configurationfile="src/hibernate.cfg.xml" />
    <hbm2ddl export="false" create="true" delimiter=";" format="true" outputfilename="create-tables.sql" />
</hibernatetool>

</target>

<!DOCTYPE hibernate-configuration PUBLIC
    "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
    "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
    <session-factory name="logi">
        <property name="show_sql">true</property>
        <mapping class="com.tt.logi.target.Target"/>
   
    </session-factory>
</hibernate-configuration>

import java.io.Serializable;

import javax.persistence.Basic;
import javax.persistence.Entity;
import javax.persistence.Id;

@Entity
public class Target implements Serializable{
   
    private Long id;
    private String name;
    @Id
    public Long getId() {
        return id;
    }
    public void setId(Long id) {
        this.id = id;
    }
    @Basic
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
   
   
   

wget ftp://ftp.jaist.ac.jp/pub/mysql/Downloads/MySQL-5.1/mysql-5.1.41.tar.gz
tar -xzf



./configure --prefix=/usr/local/mysql51m --without-debug  --enable-local-infile --enable-assembler --enable-thread-safe-client --with-plugins=all

make
su -
make install


groupadd mysql
useradd -g mysql mysql


bin/mysql_install_db --user=mysql  --datadir=/var/lib/mysql51m/data

chown -R mysql /var/lib/mysql51m/
chgrp -R mysql /var/lib/mysql51m/


cp share/mysql/my-innodb-heavy-4G.cnf my.cnf
vi my.cnf

datadir = /var/lib/mysql51m/data

.bin/mysqld_safe --defaults-file=/usr/local/mysql51m/my.cnf &

bin/mysql  --defaults-file=my.cnf -uroot

./mysqladmin -u root password ‘humber’
grant all on *.* to root@% identified by 'humber'

default-character-set=utf8
init_connect='SET NAMES utf8'
default-storage-engine = INNODB

jmap -heap 16761
jstat -gcutil 16761
jmap -finalizerinfo 16761
jmap -histo 16761
jstack -l 16761
jinfo 16761

Examine the fatal error log file. Default file name is hs_err_pidpid.log in the working-directory.

-XX:+HeapDumpOnOutOfMemoryError
java -agentlib:hprof=heap=dump,format=b application
$ jmap -dump:format=b,file=snapshot.jmap process-pid

1、在jvm啟動時加上：-agentlib:hprof=heap=sites,file=heap.txt  ，然后執(zhí)行一段時間后執(zhí)行 kill -3 <pid>，就可以獲取jvm的內(nèi)存鏡像。類似的通過-agentlib:hprof=cpu=samples,file=cpu.txt查 看cpu的狀況。

http://java.sun.com/javase/6/webnotes/trouble/other/matrix6-Unix.html

Quick Troubleshooting Tips on Solaris OS and Linux for Java SE 6

This "Quick Start Guide" gives you some quick tips for troubleshooting. The subsections list some typical functions that can help you in troubleshooting, including one or more ways to get the information or perform the action.

These tips are organized as follows:

Hung, Deadlocked, or Looping Process
Post-mortem Diagnostics, Memory Leaks
Monitoring
Actions on a Remote Debug Server
Other Functions

Hung, Deadlocked, or Looping Process

• Print thread stack for all Java threads:
  • Control-"
  • kill -QUIT pid
  • jstack pid (or jstack -F pid if jstack pid does not respond)
• Detect deadlocks:
  • Request deadlock detection: JConsole tool, Threads tab
  • Print information on deadlocked threads: Control-"
  • Print list of concurrent locks owned by each thread: -XX:+PrintConcurrentLocks set, then Control-"
  • Print lock information for a process: jstack -l pid
• Get a heap histogram for a process:
  • Start Java process with -XX:+PrintClassHistogram, then Control-"
  • jmap -histo pid (with -F option if pid does not respond)
• Dump Java heap for a process in binary format to file:
  • jmap -dump:format=b,file=filename pid (with -F option if pid does not respond)
• Print shared object mappings for a process:
  • jmap pid
• Print heap summary for a process:
  • Control-"
  • jmap -heap pid
• Print finalization information for a process:
  • jmap -finalizerinfo pid
• Attach the command-line debugger to a process:
  • jdb -connect sun.jvm.hotspot.jdi.SAPIDAttachingConnector:pid=pid

Post-mortem Diagnostics, Memory Leaks

• Examine the fatal error log file. Default file name is hs_err_pidpid.log in the working-directory.
• Create a heap dump:
  • Start the application with HPROF enabled: java -agentlib:hprof=file=file,format=b application; then Control-"
  • Start the application with HPROF enabled: java -agentlib:hprof=heap=dump application
  • JConsole tool, MBeans tab
  • Start VM with -XX:+HeapDumpOnOutOfMemoryError; if OutOfMemoryError is thrown, VM generates a heap dump.
• Browse Java heap dump:
  • jhat heap-dump-file
• Dump Java heap from core file in binary format to a file:
  • jmap -dump:format=b,file=filename corefile
• Get a heap histogram for a process:
  • Start Java process with -XX:+PrintClassHistogram, then Control-"
  • jmap -histo pid (with -F option if pid does not respond)
• Get a heap histogram from a core file:
  • jmap -histo corefile
• Print shared object mappings from a core file:
  • jmap corefile
• Print heap summary from a core file:
  • jmap -heap corefile
• Print finalization information from a core file:
  • jmap -finalizerinfo corefile
• Print Java configuration information from a core file:
  • jinfo corefile
• Print thread trace from a core file:
  • jstack corefile
• Print lock information from a core file:
  • jstack -l corefile
• Attach the command-line debugger to a core file on the same machine:
  • jdb -connect sun.jvm.hotspot.jdi.SACoreAttachingConnector:javaExecutable=path,core=corefile
• Attach the command-line debugger to a core file on a different machine:
  • On the machine with the core file: jsadebugd path corefile
    and on the machine with the debugger: jdb -connect sun.jvm.hotspot.jdi.SADebugServerAttachingConnector:debugServerName=machine
• libumem can be used to debug memory leaks.

Monitoring

Note: The vmID argument for the jstat command is the virtual machine identifier. See the jstat man page for a detailed explanation.

• Print statistics on the class loader:
  • jstat -class vmID
• Print statistics on the compiler:
  • Compiler behavior: jstat -compiler vmID
  • Compilation method statistics: jstat -printcompilation vmID
• Print statistics on garbage collection:
  • Summary of statistics: jstat -gcutil vmID
  • Summary of statistics, with causes: jstat -gccause vmID
  • Behavior of the gc heap: jstat -gc vmID
  • Capacities of all the generations: jstat -gccapacity vmID
  • Behavior of the new generation: jstat -gcnew vmID
  • Capacity of the new generation: jstat -gcnewcapacity vmID
  • Behavior of the old and permanent generations: jstat -gcold vmID
  • Capacity of the old generation: jstat -gcoldcapacity vmID
  • Capacity of the permanent generation: jstat -gcpermcapacity vmID
• Monitor objects awaiting finalization:
  • JConsole tool, VM Summary tab
  • jmap -finalizerinfo pid
  • getObjectPendingFinalizationCount method in java.lang.management.MemoryMXBean class
• Monitor memory:
  • Heap allocation profiles via HPROF: java -agentlib:hprof=heap=sites
  • JConsole tool, Memory tab
  • Control-" prints generation information.
• Monitor CPU usage:
  • By thread stack: java -agentlib:hprof=cpu=samples application
  • By method: java -agentlib:hprof=cpu=times application
  • JConsole tool, Overview and VM Summary tabs
• Monitor thread activity:
  • JConsole tool, Threads tab
• Monitor class activity:
  • JConsole tool, Classes tab

Actions on a Remote Debug Server

First, attach the debug daemon jsadebugd, then execute the command:

• Dump Java heap in binary format to a file: jmap -dump:format=b,file=filename hostID
• Print shared object mappings: jmap hostID
• Print heap summary : jmap -heap hostID
• Print finalization information : jmap -finalizerinfo hostID
• Print lock information : jstack -l hostID
• Print thread trace : jstack hostID
• Print Java configuration information: jinfo hostID

Other Functions

• Interface with the instrumented Java virtual machines:
  • Monitor for the creation and termination of instrumented VMs: jstatd daemon
  • List the instrumented VMs: jps
  • Provide interface between remote monitoring tools and local VMs: jstatd daemon
  • Request garbage collection: JConsole tool, Memory tab
• Print Java configuration information from a running process:
  • jinfo pid
• Dynamically set, unset, or change the value of certain Java VM flags for a process:
  • jinfo -flag flag
• Print command-line flags passed to the VM:
  • jinfo -flags
• Print Java system properties:
  • jinfo -sysprops
• Pass a Java VM flag to the virtual machine:
  • jconsole -Jflag ...
  • jhat -Jflag ...
  • jmap -Jflag ...
• Print statistics of permanent generation of Java heap, by class loader:
  • jmap -permstat
• Report on monitor contention.
  • java -agentlib:hprof=monitor=y application
• Evaluate or execute a script in interactive or batch mode:
  • jrunscript
• Interface dynamically with an MBean, via JConsole tool, MBean tab:
  • Show tree structure.
  • Set an attribute value.
  • Invoke an operation.
  • Subscribe to notification.
• Run interactive command-line debugger:
  • Launch a new VM for the class: jdb class
  • Attach debugger to a running VM: jdb -attach address
  http://www.tkk7.com/justinchen/archive/2009/01/08/248738.html

netstat -n | awk '/^tcp/ {++state[$NF]} END {for(key in state) print key,""t",state[key]}'

set nocompatible
set autoindent
set smartindent
set ignorecase
syntax enable
set wrap
set showmatch
set foldmarker={{{,}}}
set tabstop=4
set shiftwidth=4
set ruler
set expandtab
set backspace=eol,start,indent
set whichwrap+=<,>,h,l
set nobackup
setlocal noswapfile
set bufhidden=hide
syntax on
set tags=./tags,~/apsara/tags
set path+=/usr/include/c++/**,~/apsara/include/**
filetype plugin on
filetype indent on
autocmd filetype java,c,cpp setlocal textwidth=100
set pastetoggle=<F7>

nmap <F2>  :set nonumber!<CR>
nmap <F8>  :TlistToggle<CR>
imap <F11> <C-x><C-p>
map <F12>  :!ctags -R --c++-kinds=+p --fields=+iaS --exclude=build --extra=+q .<CR>
map <F6> :w<CR>
imap <F6> <ESC>:w<CR>a
map <F3> /<C-R><C-W><CR>

有 c support 支持，很棒。

1. 
   避免對shared_ptr所管理的對象的直接內(nèi)存管理操作，以免造成該對象的重釋放
   shared_ptr并不能對循環(huán)引用的對象內(nèi)存自動管理（這點是其它各種引用計數(shù)管理內(nèi)存方式的通病）。
2. 
   不要構(gòu)造一個臨時的shared_ptr作為函數(shù)的參數(shù)。
   如下列代碼則可能導(dǎo)致內(nèi)存泄漏：
   void test()
   {
       foo(boost::shared_ptr<implementation>(new    implementation()),g());
   }
   正確的用法為：
   void test()
   {
       boost::shared_ptr<implementation> sp    (new implementation());
       foo(sp,g());
   }

3. Employee boss("Morris, Melinda", 83000);

   Employee* s = &boss;

   This is usually not a good idea. As a rule of thumb, C++ pointers should only refer to objects allocated wth new.

copy:http://www.diybl.com/course/3_program/c++/cppjs/20090403/163770.html

抄錄備忘：
其實沒有.h也能很好的工作,但是當(dāng)你發(fā)現(xiàn)一個外部鏈接的函數(shù)或外部變量,需要許多份

聲明,因為c++這種語言,在使用函數(shù)和變量的時候,必須將他聲明,為何要聲明?聲明之后才

知道他的規(guī)格,才能更好的發(fā)現(xiàn)不和規(guī)格的部分.你別妄想一個編譯單元,會自動從另一個

編譯單元那里得到什么信息,知道你是如何定義這個函數(shù)的.

    所以說,只要使用到該函數(shù)的單元,就必須寫一份聲明在那個.cpp里面,這樣是不是很麻煩,

而且,如果要修改,就必須一個一個修改.這真讓人受不了.

.h就是為了解決這個問題而誕生,他包含了這些公共的東西.然后所有需要使用該函數(shù)的.cpp,只需要

用#include包含進去便可.以后需要修改,也只是修改一份內(nèi)容.

請注意不要濫用.h,.h里面不要寫代碼,.h不是.cpp的倉庫,什么都塞到里面.

如果在里面寫代碼,當(dāng)其他.cpp包含他的時候,就會出現(xiàn)重復(fù)定義的情況,

比如將函數(shù)func(){printf}；放到頭文件a.h,里面還有一些a.cpp需要的聲明等；

然后你發(fā)現(xiàn)b.cpp需要用到a.cpp里面的一個函數(shù),就很高興的將a.h包含進來.

注意,#include并不是什么申請指令,他就是將指定的文件的內(nèi)容,原封不動的拷貝

進來.

這時候?qū)嶋H上a.cpp和b.cpp都有一個func()函數(shù)的定義.

如果這個函數(shù)是內(nèi)部鏈接static的話,還好,浪費了一倍空間；

如果是extern,外部鏈接(這個是默認情況),那么根據(jù)在同一個程序內(nèi)不可出現(xiàn)

同名函數(shù)的要求,連接器會毫不留情給你一個連接錯誤!

http://www.cnblogs.com/shelvenn/archive/2008/02/02/1062446.html

 一.    Perspective and Metaphor

Platform
Kernel
Framework

二.    Philosophy and discipline

Be aware of context
Extreme maintenance
Be pragmatic
Extreme abstract: Program to an interface (abstraction), not an implementation
  
Extreme separation of concerns
Extreme readability
Testability
No side effect
Do not repeat yourself

三.    Principle

DIP ，dependency inversion of control
OCP , open close
LSP , liskov substitute
ISP , interface segregation
SRP , single responsibility
LKP, Lease knowledge principle

四.    design pattern

Construction
Behavior
Structure

五.    anti-pattern、bad smell

Long method
Diverse change
    Repeated code
    Talk to stranger
    Pre optimize

六.    algorithms

 nLongN
 Divided and conqueror

 

七.    architecture

Hierarchal
Pipes and filter
Micro kernel
Broker
Black Board
    Interpreter

   
八.    Distributed & concurrent

What to concurrent

Scalability
    Stretch key dimensions to see what breaks

九.    languages

Ruby
Erlang
assemble
C
C++
Java
Python
Scala

Be ware of different program paradigms.

十.    Performance

 Minimize remote calls and other I/O
 Speed-up data conversion
 release resource as soon as possible 

十一.    architectures' future

軟件設(shè)計思想的發(fā)展邏輯，大致是提高抽象程度 ，separation of concern 程度。
    fn(design )=  fn1(abstraction )+ fn2(separation of concern).

由于大規(guī)模數(shù)據(jù)處理時代的來臨，下一代設(shè)計范式的重點：
1.    將是如何提高distributed(--concurrent) programing 的抽象程度 和 separation of concern 程度。
2.    dsl ，按照以上的公式，也確實是一個好的方向。

十二.    Reference

<art agile software development>
<prerefactor>
<design patterns>
<beautiful architecture>
<refactor>
<pattern oriented software architecture>
<extreme software development>
<beautiful code>
<patterns for parallel programming>
<java concurrent programming in practice>
<java performance tuning>
<the definite guide to hadoop>
<greenplum>
<DryadLINQ>
<software architecture in practice>
<97 things architecture should known>
http://en.wikipedia.org/wiki/Programming_paradigm

拷貝
mingliu.ttc  simsun.ttf  SURSONG.TTF  tahomabd.ttf  tahoma.ttf  verdanab.ttf  verdanai.ttf  verdana.ttf  verdanaz.ttf

 #mv simsun.ttc /usr/share/fonts/local/simsun.ttf
#cd /usr/share/fonts/local/
sudo mkfontscale
sudo mkfontdir

sudo fc-cache
cp fonts.scale fonts.dir
sudo chmod 755 *
sudo chkfontpath --add /usr/share/fonts/local/

#/etc/init.d/xfs restart
查檢是否安裝成功

fc-list |grep Sim

 NSimSun:style=Regular
SimSun:style=Regular
SimSun\-PUA:style=Regular

experience learned.

1. first think algorithm before concurrent
2. first solve top problem
3. memory can be problem with huge data processing
4.  not to use refletion frequently
5. prefering strategy that can optimize both cpu and memory .

technical
1. thread synchronizing is how to queuing
   be sure to use "while(!Thread.currentThread.isInterupted())

2. prefer high level  synchronizing facility to low level methodology such as await,notify

3. dedicated sorter is much faster


 

以前聽過用友的牛人關(guān)于軟件設(shè)計范型的時代劃分，記得不太準確，不過基本上是業(yè)界公認的。
大致上是：過程式、面向?qū)ο蟆⒔M件、面向服務(wù)。
未來呢？我忘記了，抑或是 dsl ？

我以往也沒有自己的認識，不過，最近我有自己的看法

軟件設(shè)計思想的發(fā)展邏輯，大致是提高抽象程度 ，seperation of concern 程度。
    fn(design )=  fn1(abstraction )+ fn2(seperation of concern).


由于大規(guī)模數(shù)據(jù)處理時代的來臨，下一代設(shè)計范式的重點：

1. 將是如何提高concurrent programing 的抽象程度 和 seperation of concern 程度。
2. 至于dsl ，我研究不多，不過，按照以上的公式，也確實是一個好的方向。

對于英文詞語的使用，是因為，我想更能表達我的意思，不至于誤解。見諒。
歡迎批評指正！

    只有注冊用戶登錄后才能閱讀該文。閱讀全文

最近看的東西，備忘。
Dryad
DryadLinq
GreenPlum。

技術(shù)上看：
 Dryad 牛
 
商業(yè)上看，
  只有microsoft(Dryad),oracle (?),ibm (?)

  其他的cloud data engine 似乎難免被收購宿命，一如bea 。。。。etc .
  ?google (Sawzall) ？amazon
  ?hadoop ,pig

中國：
  ?友友系統(tǒng)
 

Saas business

一.    chain
    customer : operator :application :feature: platform .
   
二.    operator
三.    application
    office
    erp
    mall
    game
四.    feature

    search engine
    monitor system
    security
    dynamic language
    special db system
    special file system
五.    platform
    virtual computing resource system
    cloud file system
    cloud db system
    cloud os

六.    chance
    big fish or small fish should find their way to survive.

     摘要:   閱讀全文

安裝和配置簡述

    * 英文指南
    * 配置tomcat
          o 修改 server.xml ,在connector 加 URIEncoding="UTF-8"
          o 修改 catalina.sh ,加一行 CATALINA_OPTS="-DHUDSON_HOME=~/apprun/hudsonhome/ -Xms512m -Xmx512m"
                + 其中 HUDSON_HOME 是 hudson 的配置和運行文件所在地
          o 修改 tomcat-users.xml
                + <role rolename="admin"/>
                + <user username="hudson" password="hudson" roles="admin"/>
    * 把下載的hudson.war 放在 tomcat 的webapps 下，hudson 會自動啟動起來，部署就完成了
          o 可以訪問，比如 http://****:18080/hudson/
    * 安裝 jdk
    * 安裝 ant
    * 配置hudson
          o 配置和管理需要登陸 ，login
          o 打開管理頁面，比如 http://****:18080/hudson/configure
          o 配置安全 ，Enable security ，兩個選項：Delegate to servlet container --〉Legacy mode
          o 配置 jdk 路徑， 比如 /home/**/tools/jdk1.6.0_13/
          o 配置 ant 路徑， 比如 /home/**/apprun/ant171
          o 配置 System Admin E-mail Address ，//寫一個很多項目公用的email
          o 記得 save
    * 新建一個job
          o 配置和管理需要登陸 ，login
          o new job ,選項 ：Build a free-style software project
          o 配置 ，比如 ：**:18080/hudson/job/icontent/configure
                + 填寫svn 路徑 ，比如 ：http://svn.****
                + Build Triggers，選Poll SCM ，schedule 符合 cron 規(guī)則
                + Build ，invoke ant ,填寫 ant target
                + Post-build Actions ,選 E-mail Notification , Recipients 填寫郵件地址
    * 配置linux 的環(huán)境變量
          o vi .bash_profile
          o JAVA_HOME=$HOME/tools/jdk1.6.0_13
          o PATH=$JAVA_HOME/bin:$PATH:$HOME/bin:$HOME/apprun/ant171/bin
          o LANG=zh_CN.GB2312 //encoding 與.java 源代碼文件的編碼一致 ，這樣javadoc 不會有警告
          o LC_CTYPE=zh_CN.GB2312

easy！
great tool!

1. hibernate 變得不太重要了，jdbc 就很好
2. 數(shù)據(jù)庫不夠用了,bdb
3. bdb 不夠用了， 自己寫b+ tree
4. java 不行了，得用 c++

看來，這個轉(zhuǎn)變是個革命。搞不好得丟飯碗。

從想做一個創(chuàng)業(yè)者，到想做一個proferssional 。

<西津渡圖解軟件項目管理 〉從1年半之前，每當(dāng)有新的感受，就修訂一些。為自己的成長作個備注吧。

code-block with mingw ,setup .
set path=c:\program file\code blocks\mingw\bin;%path%
bjam --toolset=gcc-3.4.5 --prefix=d:\boost\b137345 --build-type=complete install

很久沒有來blogjava 了。
一個原因是，關(guān)注的內(nèi)容與blogjava 的東西，重疊的太少了。
不過，我也納悶，我該去哪里找自己的同好？
blogjava 在云計算，web2.0 ，這些前途領(lǐng)域，沒有什么內(nèi)容。
struts,hibernate,spring, acegi,lucene 這些都是成熟的東西了。
說一下我最近用過的東西：
hadoop,hbase,zookeeper，深入研究了java concurrent.

下一步的方向是寫一個,distribute document oriented file system.

技術(shù)和互聯(lián)網(wǎng)的發(fā)展，絕對是web2.0,云計算，兩端厚的架構(gòu)。blogjava 也該多這方面的內(nèi)容了。

Conducting and Reviewing the Software Design Model

      The design model resides at the core of the software engineering process. It is the place where quality is built into the software (and the place where quality is assessed. For this checklist, the more questions that elicit a negative response, the higher the risk that the analysis model will adequately serve its purpose. . For this checklist, the more questions that elicit a negative response, the higher the risk that the design model will not adequately serve its purpose.

      General issues:

          o Does the overall design implement all explicit requirements? Has a traceability table been developed?

      設(shè)計對需求的匹配？



          o Does the overall design achieve all implicit requirements?

          
    
          o Is the design represented in a form that is easily understood by outsiders?

        易理解？

          o Is design notation standardized? Consistent?

        

          o Does the overall design provide sufficient information for test case design?

        可測試。

          o Is the design created using recognizable architectural and procedural patterns?

        常用的架構(gòu) 和模式？
        

          o Does the design strive to incorporate reusable components?

        重用組件？

          o Is the design modular?

        模塊化

          o Has the design defined both procedural and data abstractions that can be reused?
        重用的過程 / 數(shù)據(jù) 抽象？
        

          o Has the design been defined and represented in a stepwise fashion?
        逐漸細化的表述？    

          o Has the resultant software architecture been partitioned for ease of implementation? Maintenance?
        可部署性？ 可維護性？


          o Have the concepts of information hiding and functional independence been followed throughout the design?

           封裝性？

          o Has a Design Specification been developed for the software?

        文檔？


      For data design:

          o Have data objected defined in the analysis model been properly translated into required data structured?

        數(shù)據(jù)映射with analysis？        

          o Do the data structures contain all attributes defined in the analysis model?
        數(shù)據(jù)屬性？

          o Have any new data structures and/or attributes been defined at design time?

        新的數(shù)據(jù)結(jié)構(gòu)？

          o How do any new data structures and/or attributes related to the analysis model and to overall user requirements?

        用戶需求與數(shù)據(jù)結(jié)構(gòu)匹配嗎？

          o Have the simplest data structures required to do the job been chosen?

        數(shù)據(jù)結(jié)構(gòu)簡單嗎？

          o Can the data structures be implemented directly in the programming language of choice?

        編程語言適合數(shù)據(jù)結(jié)構(gòu)？

          o How are data communicated between software components?
        軟件組件之間的數(shù)據(jù)交換？

          o Do explicit data components (e.g., a database) exist? If so, what is their role?

        數(shù)據(jù)庫？

      For architectural design:

          o Has a library of architectural styles been considered prior to the definition of the resultant software architecture?
        
        架構(gòu)模式？

          o Has architectural tradeoff analysis been performed?
        架構(gòu)分析的tradeoff？

          o Is the resultant software architecture a recognizable architectural style?

        認可的架構(gòu)風(fēng)格？

          o Has the architecture been exercised against existing usage scenarios?
        架構(gòu)有應(yīng)用示例嗎？    

          o Has an appropriate mapping been used to translate the analysis model into the architectural model?
        
        分析和架構(gòu)之間的mapping？

          o Can quality characteristics associated with the resultant architecture (e.g., a factored call-and-return architecture) be readily identified from information provided in the design model?
        架構(gòu)的質(zhì)量特點？


      For user interface design:

          o Have the results of task analysis been documented?
          o Have goals for each user task been identified?
          o Has an action sequence been defined for each user task?
          o Have various states of the interface been documented?
          o Have objects and actions that appear within the context of the interface been defined?
          o Have the three "golden rules" (SEPA, 5/e, p. 402) been maintained throughout the GUI design?
          o Has flexible interaction been defined as a design criterion throughout the interface?
          o Have expert and novice modes of interaction been defined?
          o Have technical internals been hidden from the causal user?
          o Is the on-screen metaphor (if any) consistent with the overall applications?
          o Are icons clear and understandable?
          o Is interaction intuitive?
          o Is system response time consistent across all tasks?
          o Has an integrated help facility been implemented?
          o Are all error message displayed by the interface easy to understand? Do they help the user resolve the problem quickly?
          o Is color being used effectively?
          o Has a prototype for the interface been developed?
          o Have user's impressions of the prototype been collected in an organized manner?

      For component-level design:

    * Have proof of correctness techniques (SEPA, 5/e, Chapter 26) been applied to all algorithms?

    算法正確性？

    * Has each algorithm been "desk-tested" to uncover errors? Is each algorithm correct?

    算法？

    * Is the design of the algorithm consistent with the data structured that the component manipulates?

    算法？
    * Have algorithmic design alternatives been considered? If yes, why was this design chosen?

    替代算法考慮了嗎？

    * Has the complexity of each algorithm been computed?
    
    每個算法的復(fù)雜性考慮了嗎？

    * Have structured programming constructs been used throughout?
    
    結(jié)構(gòu)好嗎？

     摘要:   閱讀全文

西津渡最近在修改 99街購物搜索引擎，www.99jie.com
根據(jù)體會，修訂了圖解軟件項目管理一文。這是今年以來的第三次較大修訂。
有需要者請下載。西津渡圖解軟件項目管理
下邊是目錄。
第一章 項目管理的目標(biāo)
一、    產(chǎn)品，周期，成本的約束。
二、    關(guān)鍵路徑管理
三、    可行性分析很重要
四、    人際技巧
五、    談判技巧
第二章 項目過程
一、    計劃階段
二、    架構(gòu)階段和技術(shù)攻關(guān)
三、    迭代階段
四、    結(jié)束階段
第三章 分析,形成specification
一、    最重要的是specification 發(fā)揮作用
二、    重要的創(chuàng)造性工作
三、    選擇適合的表達方式
四、    數(shù)據(jù)以及數(shù)據(jù)的key 和約束
五、    測試腳本
六、    Review ,評審
第四章 設(shè)計系統(tǒng)UI
一、    一幅圖勝過千句話
第五章 設(shè)計,code ,build ,test
第六章 部署和重構(gòu)
第七章 風(fēng)險
一、    分析風(fēng)險
二、    技術(shù)風(fēng)險
三、    所有的風(fēng)險是人的風(fēng)險，trust and capable
四、    記住50%以上的軟件項目以失敗告終
五、    所有的風(fēng)險是管理的風(fēng)險，遵循一套項目管理哲學(xué)
第八章 保持項目的進展
一、    對項目負責(zé)，做出決定
二、    讓進展可見，持續(xù)集成
三、執(zhí)行，并檢查
四、    解決沖突，大家都是兄弟姐妹
五、    能擔(dān)當(dāng)者是項目經(jīng)理
六、    關(guān)鍵路徑的變更
第九章 總結(jié)經(jīng)驗
第十章 一些效率關(guān)鍵指標(biāo)
第十一章 項目管理工具
第十二章 參考
第十三章 口訣

http://www.xker.com/edu/dev/104/0652109570034579.html

十二、不要在循環(huán)中調(diào)用synchronized(同步)方法

方法的同步需要消耗相當(dāng)大的資料，在一個循環(huán)中調(diào)用它絕對不是一個好主意。

例子：
import java.util.Vector;
public class SYN {
    public synchronized void method (Object o) {
    }
    private void test () {
        for (int i = 0; i < vector.size(); i++) {
            method (vector.elementAt(i));    // violation
        }
    }
    private Vector vector = new Vector (5, 5);
}

更正：
不要在循環(huán)體中調(diào)用同步方法，如果必須同步的話，推薦以下方式：
import java.util.Vector;
public class SYN {
    public void method (Object o) {
    }
private void test () {
    synchronized{//在一個同步塊中執(zhí)行非同步方法
            for (int i = 0; i < vector.size(); i++) {
                method (vector.elementAt(i));   
            }
        }
    }
    private Vector vector = new Vector (5, 5);
}

十三、將try/catch塊移出循環(huán)

把try/catch塊放入循環(huán)體內(nèi)，會極大的影響性能，如果編譯JIT被關(guān)閉或者你所使用的是一個不帶JIT的JVM，性能會將下降21%之多!
         
例子：         
import java.io.FileInputStream;
public class TRY {
    void method (FileInputStream fis) {
        for (int i = 0; i < size; i++) {
            try {                                      // violation
                _sum += fis.read();
            } catch (Exception e) {}
        }
    }
    private int _sum;
}
         
更正：         
將try/catch塊移出循環(huán)         
    void method (FileInputStream fis) {
        try {
            for (int i = 0; i < size; i++) {
                _sum += fis.read();
            }
        } catch (Exception e) {}
    }
         
參考資料：
Peter Haggar: "Practical Java - Programming Language Guide".
Addison Wesley, 2000, pp.81 – 83

十九、不要在循環(huán)體中實例化變量

在循環(huán)體中實例化臨時變量將會增加內(nèi)存消耗

例子：         
import java.util.Vector;
public class LOOP {
    void method (Vector v) {
        for (int i=0;i < v.size();i++) {
            Object o = new Object();
            o = v.elementAt(i);
        }
    }
}
         
更正：         
在循環(huán)體外定義變量，并反復(fù)使用         
import java.util.Vector;
public class LOOP {
    void method (Vector v) {
        Object o;
        for (int i=0;i<v.size();i++) {
            o = v.elementAt(i);
        }
    }
}

二十一、盡可能的使用棧變量

如果一個變量需要經(jīng)常訪問，那么你就需要考慮這個變量的作用域了。static? local?還是實例變量？訪問靜態(tài)變量和實例變量將會比訪問局部變量多耗費2-3個時鐘周期。
         
例子：
public class USV {
    void getSum (int[] values) {
        for (int i=0; i < value.length; i++) {
            _sum += value[i];           // violation.
        }
    }
    void getSum2 (int[] values) {
        for (int i=0; i < value.length; i++) {
            _staticSum += value[i];
        }
    }
    private int _sum;
    private static int _staticSum;
}     
         
更正：         
如果可能，請使用局部變量作為你經(jīng)常訪問的變量。
你可以按下面的方法來修改getSum()方法：         
void getSum (int[] values) {
    int sum = _sum;  // temporary local variable.
    for (int i=0; i < value.length; i++) {
        sum += value[i];
    }
    _sum = sum;
}
         
參考資料：         
Peter Haggar: "Practical Java - Programming Language Guide".
Addison Wesley, 2000, pp.122 – 125

http://www.javafan.net/menu/jczs/200701/20070108185247.html

1). 簡單的認為 .append() 效率好于 "+" 是錯誤的！
    2). 不要使用 new 創(chuàng)建 String
    3). 注意 .intern() 的使用
    4). 在編譯期能夠確定字符串值的情況下，使用"+"效率最高
    5). 避免使用 "+=" 來構(gòu)造字符串
    6). 在聲明StringBuffer對象的時候，指定合適的capacity，不要使用默認值(18)
    7). 注意以下二者的區(qū)別不一樣
        - String s = "a" + "b";
        - String s = "a";
          s += "b";

關(guān)鍵點
1. 無論何時只要可能的話使用字符串字面量來常見字符串而不是使用new關(guān)鍵字來創(chuàng)建字符串。
2. 無論何時當(dāng)你要使用new關(guān)鍵字來創(chuàng)建很多內(nèi)容重復(fù)的字符串的話，請使用String.intern()方法。
3. +操作符會為字符串連接提供最佳的性能――當(dāng)字符串是在編譯期決定的時候。
4. 如果字符串在運行期決定，使用一個合適的初期容量值初始化的StringBuffer會為字符串連接提供最佳的性能。

q16 版.
安裝后，把所有的dll 拷貝到system32.