(Author: Blueski, the master of Xiaolongting, compiled by December 22, 2000 at 14:22)
(Continued from the previous article)
Question #3: Simple work is still tiring
Even simple tasks, such as including header and footer, are still difficult in JSP. Suppose there is a "header" and a "footer" template to include all pages, and each template to include the current page title in the content.
The best way to do it in JSP is:
...The content of your page...
Page designers should remember not to miss the semicolon on the first line and define the title as a string. Additionally, / and / must be in the root directory and must be a complete file that is accessible.
Including headers and footers in WebMacro is simpler:
#set $title = "The Page Title"
#parse ""
Your content here
#parse ""
There is no semicolon or definition of title to keep in mind for designers. The .wm file can be placed under a customizable search path.
Question #4: Very rough cycle
Looping in JSP is difficult. Here we use JSP to repeatedly print out each ISP object name.
Enumeration e = ();
while (()) {
("The next name is ");
(((ISP)()).getName());
("
");
}
%>
Maybe when will there be user-defined tags to do these loops. The same is true for "if". JSP pages may look weird java code. And at the same time, the webmacro loop is pretty:
#foreach $isp in $isps {
The next name is $
}
The #foreach directive can be easily replaced by the custom #foreach-backwards directive if necessary.
If you use jsp, it is likely to change this: (Here is a possiblemark)
The next name is
The designer will of course choose the former.
Issue #5: Useless error message
JSP often has some surprising error messages. This is because the page is first converted into a servlet and then compiled. A good JSP tool can relatively increase the possibility of finding a location for errors, but even the best tools cannot make all error information read easily. Due to the conversion process, some errors may not be recognized by the tool at all.
For example, suppose that the JSP page needs to create a common title for all pages. The following code is not wrong:
But Tomcat will provide the following error information:
work/%3A8080%2F/JC_0002ejspJC_jsp_1.java:70: Statement expected.
static int count = 0;
^
This information believes that the above script is put into the _jspService() method and static variables are not allowed to be put into the method. The syntax should be . It is difficult for page designers to understand these error messages. Even the best platforms are not doing enough in this regard. Even if all Java code is removed from the page, it doesn't solve the problem. Also, what's wrong with the following expression?
Tomcat gives:
work/8080/_0002ftest_0002ejsptest_jsp_0.java:56: Class count not found in
type declaration.
count
^
work/8080/_0002ftest_0002ejsptest_jsp_0.java:59: Invalid declaration.
("\r\n");
^
In other words, it is just a mark lost. It should be.
Since the template engine can be generated directly in the template file without any dramatic conversion to the code, it can be very easy to give appropriate error reports. And so on, when the C language command is stamped into the Unix shell's command line, you do not want the shell to generate a C program to run the command, but you just need the shell to simply interpret the command and execute it, and give it directly if there is any error.
Question #6: Need a compiler
JSP requires a compiler placed in the webserver. This became problematic because Sun refused to give up the library that included their javac compiler. The web server can be included in a third-party compiler such as ibm's jikes. However, such a compiler cannot work smoothly on all platforms (written in C++) and is not conducive to building a pure Java web server. JSP also has a precompilation option that can play a role, but it is not perfect.
Question #7: Waste of space
JSP consumes extra memory and hard disk space. For every 30K JSP file on the server, corresponding class files greater than 30K must be generated. In fact, doubles the hard disk space. Considering that JSP files can be easily passed at any time
(Continued from the previous article)
Question #3: Simple work is still tiring
Even simple tasks, such as including header and footer, are still difficult in JSP. Suppose there is a "header" and a "footer" template to include all pages, and each template to include the current page title in the content.
The best way to do it in JSP is:
...The content of your page...
Page designers should remember not to miss the semicolon on the first line and define the title as a string. Additionally, / and / must be in the root directory and must be a complete file that is accessible.
Including headers and footers in WebMacro is simpler:
#set $title = "The Page Title"
#parse ""
Your content here
#parse ""
There is no semicolon or definition of title to keep in mind for designers. The .wm file can be placed under a customizable search path.
Question #4: Very rough cycle
Looping in JSP is difficult. Here we use JSP to repeatedly print out each ISP object name.
Enumeration e = ();
while (()) {
("The next name is ");
(((ISP)()).getName());
("
");
}
%>
Maybe when will there be user-defined tags to do these loops. The same is true for "if". JSP pages may look weird java code. And at the same time, the webmacro loop is pretty:
#foreach $isp in $isps {
The next name is $
}
The #foreach directive can be easily replaced by the custom #foreach-backwards directive if necessary.
If you use jsp, it is likely to change this: (Here is a possible
The next name is
The designer will of course choose the former.
Issue #5: Useless error message
JSP often has some surprising error messages. This is because the page is first converted into a servlet and then compiled. A good JSP tool can relatively increase the possibility of finding a location for errors, but even the best tools cannot make all error information read easily. Due to the conversion process, some errors may not be recognized by the tool at all.
For example, suppose that the JSP page needs to create a common title for all pages. The following code is not wrong:
But Tomcat will provide the following error information:
work/%3A8080%2F/JC_0002ejspJC_jsp_1.java:70: Statement expected.
static int count = 0;
^
This information believes that the above script is put into the _jspService() method and static variables are not allowed to be put into the method. The syntax should be . It is difficult for page designers to understand these error messages. Even the best platforms are not doing enough in this regard. Even if all Java code is removed from the page, it doesn't solve the problem. Also, what's wrong with the following expression?
Tomcat gives:
work/8080/_0002ftest_0002ejsptest_jsp_0.java:56: Class count not found in
type declaration.
count
^
work/8080/_0002ftest_0002ejsptest_jsp_0.java:59: Invalid declaration.
("\r\n");
^
In other words, it is just a mark lost. It should be.
Since the template engine can be generated directly in the template file without any dramatic conversion to the code, it can be very easy to give appropriate error reports. And so on, when the C language command is stamped into the Unix shell's command line, you do not want the shell to generate a C program to run the command, but you just need the shell to simply interpret the command and execute it, and give it directly if there is any error.
Question #6: Need a compiler
JSP requires a compiler placed in the webserver. This became problematic because Sun refused to give up the library that included their javac compiler. The web server can be included in a third-party compiler such as ibm's jikes. However, such a compiler cannot work smoothly on all platforms (written in C++) and is not conducive to building a pure Java web server. JSP also has a precompilation option that can play a role, but it is not perfect.
Question #7: Waste of space
JSP consumes extra memory and hard disk space. For every 30K JSP file on the server, corresponding class files greater than 30K must be generated. In fact, doubles the hard disk space. Considering that JSP files can be easily passed at any time