<?xml version="1.0" encoding="utf-8" ?><rss version="2.0"><channel><title><![CDATA[程序员码工的专栏]]></title><description><![CDATA[]]></description><link>https://blog.youkuaiyun.com/HiHui</link><language>zh-cn</language><generator>https://blog.youkuaiyun.com/</generator><copyright><![CDATA[Copyright &copy; HiHui]]></copyright><item><title><![CDATA[javascript函数内的this关键字]]></title><link>https://blog.youkuaiyun.com/HiHui/article/details/65939244</link><guid>https://blog.youkuaiyun.com/HiHui/article/details/65939244</guid><author>HiHui</author><pubDate>Sat, 25 Mar 2017 19:08:02 +0800</pubDate><description><![CDATA[在javascript函数内的this指的是谁？一句话： The word "this" within a function refers to the object calling that function.


举例子，如下javascript代码

  function Ball(p) {
    // alert(this)
    // alert(this.construct]]></description><category></category></item><item><title><![CDATA[step-by-step构造Maven Jersey Web Application]]></title><link>https://blog.youkuaiyun.com/HiHui/article/details/65938995</link><guid>https://blog.youkuaiyun.com/HiHui/article/details/65938995</guid><author>HiHui</author><pubDate>Sat, 25 Mar 2017 18:57:43 +0800</pubDate><description><![CDATA[使用maven创建Jersey Web应用



1. 使用maven创建jersey web应用框架
   $ mvn archetype:generate \
   
-DarchetypeArtifactId=jersey-quickstart-webapp \
   
-DarchetypeGroupId=org.glassfish.jersey.archetypes \]]></description><category></category></item><item><title><![CDATA[step-by-step构造Jersey Web Application]]></title><link>https://blog.youkuaiyun.com/HiHui/article/details/63685463</link><guid>https://blog.youkuaiyun.com/HiHui/article/details/63685463</guid><author>HiHui</author><pubDate>Sun, 19 Mar 2017 16:42:22 +0800</pubDate><description><![CDATA[这是一个Hello World例子如何使用Jersey构造一个Web Application
使用工具
1. Apache Tomcat 7.x
1. Eclipse Java EE IDE for Web Developers； Version: Neon.2 Release
2. Jersey库
(比较方便的构造Jersey应用是使用maven生产框架，但是由于国内访问maven库的]]></description><category></category></item><item><title><![CDATA[python嵌套函数]]></title><link>https://blog.youkuaiyun.com/HiHui/article/details/61418300</link><guid>https://blog.youkuaiyun.com/HiHui/article/details/61418300</guid><author>HiHui</author><pubDate>Sat, 11 Mar 2017 15:27:32 +0800</pubDate><description><![CDATA[也叫内部函数




嵌套函数里面两个重要的概念：变量作用域和函数闭包




1. 变量作用域

   内部函数可以直接读取访问外部函数变量，但是不能修改；访问规则是从内到外函数逐级寻找变量

#!/usr/bin/env python

def outer(a):
    i = a + 1
    def inner():
        j = i + 1
  ]]></description><category></category></item><item><title><![CDATA[python函数局部变量]]></title><link>https://blog.youkuaiyun.com/HiHui/article/details/61418141</link><guid>https://blog.youkuaiyun.com/HiHui/article/details/61418141</guid><author>HiHui</author><pubDate>Sat, 11 Mar 2017 15:23:43 +0800</pubDate><description><![CDATA[python简单变量(不考虑类变量)分为两类: 函数内定义的局部变量，和函数外定义的全局变量




基本访问规则

1. 在函数内部，可以直接读取访问全局变量(注意只读)

   #!/usr/bin/env python
   i = 10
   def f():
     j = i + 1        # 读取全局变量i
   f()
   print "i=%d" %]]></description><category></category></item><item><title><![CDATA[sed 提取匹配的字符串内容]]></title><link>https://blog.youkuaiyun.com/HiHui/article/details/60467055</link><guid>https://blog.youkuaiyun.com/HiHui/article/details/60467055</guid><author>HiHui</author><pubDate>Sun, 05 Mar 2017 14:38:30 +0800</pubDate><description><![CDATA[# STR="MAIL FROM(CCC) TO(DDD)"


#echo $STR | sed -n 's/.*FROM(\([^)]\{1,\}\)).*TO(\(.*\))/\1-\2/g'p


提取括号里面的内如
STR="MAIL FROM(ABCD) BODY"
echo $STR | sed 's/^.*FROM(\(.*\)).*$/\1/g'      # A]]></description><category></category></item><item><title><![CDATA[C++ char和unsigned char]]></title><link>https://blog.youkuaiyun.com/HiHui/article/details/60466835</link><guid>https://blog.youkuaiyun.com/HiHui/article/details/60466835</guid><author>HiHui</author><pubDate>Sun, 05 Mar 2017 14:34:27 +0800</pubDate><description><![CDATA[signed char 和 unsigned char 的区别


1. 如果它们只是作为字符处理，那么是没有区别
2. 只有当它们被作为数字值处理的时候，考虑到符号位扩展的时候是有区别的
    char ch1 = -8;
    unsigned char ch2 = -8;


    printf("signed=%d, unsigned=%d\n", ch1, ch2]]></description><category></category></item><item><title><![CDATA[C++ std::string能否存储二进制字符]]></title><link>https://blog.youkuaiyun.com/HiHui/article/details/60466755</link><guid>https://blog.youkuaiyun.com/HiHui/article/details/60466755</guid><author>HiHui</author><pubDate>Sun, 05 Mar 2017 14:06:55 +0800</pubDate><description><![CDATA[1. std::string 是否可以包含二进制字符，答案是能




    std::string ss = std::string("XXX") + '\2' + "YYY" + '\11' + "ZZZ";

    std::cout 
// len=[11],data=[XXXYYY  ZZZ]




2. std::string 是否可以包含字符0，答案是]]></description><category></category></item><item><title><![CDATA[C++ ostream 常用格式]]></title><link>https://blog.youkuaiyun.com/HiHui/article/details/60466730</link><guid>https://blog.youkuaiyun.com/HiHui/article/details/60466730</guid><author>HiHui</author><pubDate>Sun, 05 Mar 2017 13:58:25 +0800</pubDate><description><![CDATA[注意一点: std::setw只对下一个输出值有效，其他选项所有随后的输出都有效，比如:


case: std::cout 

可见"AAAA"被扩展成了6个字符宽度，而BBBB没有被扩展；因为std::setw只对紧跟着的输出有效, 即只对输出"AAAA"有效，而对"BBBB"输出无效。虽然std::setfill对输出"BBBB"还是有效的, 但是因为长度限定, "BBBB"的输出]]></description><category></category></item><item><title><![CDATA[COBOL Decimal Numbers]]></title><link>https://blog.youkuaiyun.com/HiHui/article/details/57414502</link><guid>https://blog.youkuaiyun.com/HiHui/article/details/57414502</guid><author>HiHui</author><pubDate>Sun, 26 Feb 2017 15:13:37 +0800</pubDate><description><![CDATA[There are two type of formats for decimal numbers:




1. Zoned Decimal

2. Packed Decimal




1. Zoned Decimal Numbers

-- each byte present 1 numeric value.

-- the sign mark is plac]]></description><category></category></item><item><title><![CDATA[Java重载成员变量]]></title><link>https://blog.youkuaiyun.com/HiHui/article/details/55805449</link><guid>https://blog.youkuaiyun.com/HiHui/article/details/55805449</guid><author>HiHui</author><pubDate>Sun, 19 Feb 2017 16:29:31 +0800</pubDate><description><![CDATA[如果子类中变量的名字和父类的变量的名字一样，不管他们的类型是否一致，那么在子类中，父类的同名变量无法直接通过变量名访问。
(个人认为这是一个很差的设计，对于代码的可读性可维护性非常不友好，编译器应该直接报错，禁止这种同名变量的重载)



定义父类:
package com.xxx.test.inherit;

public class TestParent {

	public in]]></description><category></category></item><item><title><![CDATA[Java函数作用域的原理]]></title><link>https://blog.youkuaiyun.com/HiHui/article/details/55804706</link><guid>https://blog.youkuaiyun.com/HiHui/article/details/55804706</guid><author>HiHui</author><pubDate>Sun, 19 Feb 2017 15:49:24 +0800</pubDate><description><![CDATA[从代码导入问题
class testParent
package cm.xxx.test.inherit;

public class TestParent {
	private void doTest() {
		System.out.println("in TestParent::doTest()");
	}
	
	public static void main(String[] args]]></description><category></category></item><item><title><![CDATA[Java编译错误:Cannot reduce the visibility of the inherited method from <class>]]></title><link>https://blog.youkuaiyun.com/HiHui/article/details/55804644</link><guid>https://blog.youkuaiyun.com/HiHui/article/details/55804644</guid><author>HiHui</author><pubDate>Sun, 19 Feb 2017 15:03:35 +0800</pubDate><description><![CDATA[原因：java类的继承关系中，只能扩大一个函数的作用域范围，不能缩小。
解决方法：在子类中保持父类的作用域范围，或者扩大范围。
 
1.      父类中private的成员函数，可以在子类中重新声明为private, (default), protected, public
2.      父类中(default)的成员函数，可以在子类中重新声明为(default), protected]]></description><category></category></item><item><title><![CDATA[Java类成员的作用域概述]]></title><link>https://blog.youkuaiyun.com/HiHui/article/details/55804450</link><guid>https://blog.youkuaiyun.com/HiHui/article/details/55804450</guid><author>HiHui</author><pubDate>Sun, 19 Feb 2017 14:48:26 +0800</pubDate><description><![CDATA[所有java程序员都知道java类有三个成员作用域关键字,即public, protected, 和private; 实际上还有一个作用域, 叫做缺省作用域, 也就是当类成员被声明时没有上述三个中的任何一个。

 
四个作用域按高低排序:
1.      public ：公有，任何类都可以访问
2.      protected ：保护，类自己，子类和同一个包的类可以访问
3.    ]]></description><category></category></item><item><title><![CDATA[Constant Pool]]></title><link>https://blog.youkuaiyun.com/HiHui/article/details/54846397</link><guid>https://blog.youkuaiyun.com/HiHui/article/details/54846397</guid><author>HiHui</author><pubDate>Fri, 03 Feb 2017 13:19:10 +0800</pubDate><description><![CDATA[Java



String s1 = "Hello";
String s2 = s1;
String s3 = "Hello";
String s4 = new String("Hello");
String s5 = s4;
String s6 = new String("Hello");

System.out.println(s1 == s2);		// true
System.o]]></description><category></category></item><item><title><![CDATA[UNICODE和UCS]]></title><link>https://blog.youkuaiyun.com/HiHui/article/details/54836017</link><guid>https://blog.youkuaiyun.com/HiHui/article/details/54836017</guid><author>HiHui</author><pubDate>Thu, 02 Feb 2017 15:28:23 +0800</pubDate><description><![CDATA[编码类型

UNICODE是统一码联盟组织定义的编码。
UCS是国际标准化组织iso开展的ISO/IEC 10646项目定义的编码。

(注, 到UNICODE2.0上述两种编码都基本一致了)


实现类型
UTF-8/UTF-16 是UNICODE编码的实现。
UCS-2/UCS-4 是UCS编码的实现。


例子
举例来说，汉字"汉"的编码是6C49
如果用UTF]]></description><category></category></item><item><title><![CDATA[Oracle varchar2 Chinese characters]]></title><link>https://blog.youkuaiyun.com/HiHui/article/details/54835829</link><guid>https://blog.youkuaiyun.com/HiHui/article/details/54835829</guid><author>HiHui</author><pubDate>Thu, 02 Feb 2017 14:49:32 +0800</pubDate><description><![CDATA[This doc describe how to insert a Chinese character into Oracle varchar2 datatype column



1. Check character set is correct in database

$ sqlplus scott/tiger@orcl

SQL*Plus: Release 11.2.0.1.]]></description><category></category></item><item><title><![CDATA[如何打开荣耀5A的调试模式]]></title><link>https://blog.youkuaiyun.com/HiHui/article/details/53354055</link><guid>https://blog.youkuaiyun.com/HiHui/article/details/53354055</guid><author>HiHui</author><pubDate>Sat, 26 Nov 2016 20:00:28 +0800</pubDate><description><![CDATA[今天在调试荣耀5A的时候踩了一个坑, 所以记下这个过程。
背景: 之前用的MAC开发环境都是好好的, 能够正常调试荣耀3C真机; 这不刚换了一个新的荣耀5A就不能调试了, Android Studio/Android Device Monitor怎么发现不了这个新设备。各种试验手机设置，重启，包括MAC重启都木有用；其实什么也没有变呢, 一样的电脑, 一样的开发环境, 就是换了一台新手机, 还都]]></description><category></category></item><item><title><![CDATA[DB2 how to drop overloaded functions]]></title><link>https://blog.youkuaiyun.com/HiHui/article/details/53347852</link><guid>https://blog.youkuaiyun.com/HiHui/article/details/53347852</guid><author>HiHui</author><pubDate>Sat, 26 Nov 2016 08:36:48 +0800</pubDate><description><![CDATA[When you try to drop an overloaded function/procedure, DB2 will report a SQL0476N error code.
For example: if function MY_TOCHAR is overloaded with

CREATE FUNCTION MY_TOCHAR(P DATE) RETURNS VARCHA]]></description><category></category></item><item><title><![CDATA[DB2 C language external scalar user-defined function]]></title><link>https://blog.youkuaiyun.com/HiHui/article/details/53347837</link><guid>https://blog.youkuaiyun.com/HiHui/article/details/53347837</guid><author>HiHui</author><pubDate>Sat, 26 Nov 2016 08:32:00 +0800</pubDate><description><![CDATA[Sample step of define a C language external scalar user-defined function.


1. Define function implementation using C language
$ cat mymd5.c

#include 
#include 
#include 
#include 
#include 
#i]]></description><category></category></item></channel></rss>