自行开发JSP HTTP服务器的绝对秘籍(三)

A）JSP编译语句块
语法如下：
形式一：语句块开始标志（＜％＠）和结束标志（％＞）在同一行。
＜％＠ 语句 ％＞
例如：＜％＠　import java.io.*; ％＞
形式二：语句块开始标志（＜％＠）和结束标志（％＞）不再同一行，且开始标志和结束标志都独占一行。
＜％＠
语句块
％＞
例如：
＜％＠
import java.io.*;
import java.lang.*;
％＞ 

//Current line contain JSP compile block start flag 
if(line.indexOf("<%@") >= 0)
{
//file .jsp contains compiled header 
is_has_compiled_header = true;
//Those statements in same line. 
if(line.indexOf("%>") >= 0) //JSP cimpile block end flag 
{
int start = line.indexOf("<%@");
int end = line.indexOf("%>");
fout.println(line.substring(start + 3, end) );
}
else //Those statements no in same line. 
{
while(true)
{
line = fin.readLine();
if(line == null) //The compiled header is broken 
{
return (false);
}
if(line.equals("%>") == true) //JSP compiled block end flag 
{
break;
}
else
{
fout.println(line); //Output the middle statements of compiled header 
}
}//while(true) 
}
}//if(line.indexOf("<%@") >= 0) 

语法为：语句块开始标志（＜％＝）和结束标志（％＞）在同一行。且同一行中只限制存在一个表达式。
＜％=　表达式 ％＞
例如：＜％=　Request.getParameter(“UserID”) ％＞ 

//Current line contain JSP expression (mark "<%=" and "%>" must be in same line) 
if(line.indexOf("<%=") >= 0)
{
//Get start flag position 
int start = line.indexOf("<%=");
//Get end flag position 
int end = line.indexOf("%>");
//Get frontal part of JSP expression block 
String pre = line.substring(0, start);
//Get expression from line 
String exp = line.substring(start + 3, end);
//Get back part of JSP expression block 
String back = line.substring(end + 2);
//Replace character " of frontal part and back part with character ' 
pre = pre.replace('\"', '\'');
back = back.replace('\"', '\'');
//Output the new line (java statement) 
fout.println("outln(\"" + pre + "\" + " + exp + " + \"" + back + "\");");
} 

语法为：语句块开始标志（＜％）和结束标志（％＞）不在同一行，且开始标志和结束标志都独占一行。
＜％
语句块
％＞
例如：
＜％
int i = 0;
for(; page_info[i] != null; ++i)
{
outln(page_info[i]);
}
％＞ 

//As to JSP statements block, mark "<%" and "%>" must be in sigle line 
while(true)
{
//Read next line 
line = fin.readLine();
if(line == null || line.equals("%>") == true) //JSP statements block end flag is "%>" 
{
break;
}
fout.println(line);
}