基础1

String[] targetArray = targetIds.split("\\@");
String[] arr = sql.split("\\?");
String[] arr = sql.split("\\|");

Class.forName("oracle.jdbc.OracleDriver");

return java.net.URLEncoder.encode(msg, "UTF-8");
native2ascii -encoding gb2312 config_zh.txt config_zh.properties
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//标准的关闭操作
finally
{
if(null != in)
{
	try
	{
		in.close();
	}
	catch (IOException e)
	{
		log.error(e.getMessage(),e);
	}
	in = null;
}
}
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//指定log4j的配置 
Properties prop = new Properties();
InputStream is = SocketServer.class.getResourceAsStream("/log4j.properties");
try
{
	prop.load(is);
	PropertyConfigurator.configure(prop);
}
catch (IOException e)
{
	e.printStackTrace();
} 

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#常用的方式，即提供一个默认值
public String getParameter(String key, String defaultvalue)
{
  String ret = defaultvalue;
  
  if (null == key || "".equals(key))
  {
      logger.error("the key is null");
  }
  else
  {
      ret = CONFIG_MAP.get(key.toLowerCase());
      
      if (null == ret)
      {
          logger.error("the value of " + key + " is null");
          
          ret = defaultvalue;
      }
  }
  return ret;
}
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#遍历map，keySet，应该使用EntryMap       

这里源的字节长度必须至少>=buf.length,否则报EOFException
dis.readFully(buf);

response.setCharacterEncoding();会覆盖response.setContentType()，
后者完全可以替代前者，前者是2.4中提供

<form action="upload" method="post" enctype="multipart/form-data">

[a-zA-Z]{1,10} 任意字母(包含大小写)组成的字串,长度为1到10