Abstract:
A session-information preserving system includes a client to which business data are inputted and a server which processes the business data sent from the client computer. The system includes a login control component to execute a login procedure on the basis of user identification information necessary for logging in to said system; a maintenance management component to search a maintenance information table for maintenance information on said server; and a pane generator to generate data used to display a plurality of panes on the client, the pane data including the maintenance information that has been retrieved by the maintenance management component, the plurality of panes including first and second panes configured to be displayed on a display of the client to receive first information and second information, respectively, from the client that are to be stored in the server and a notification pane to display a notice relating to the maintenance information on the display of the client, the second information including a first portion and a second portion.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS  
       [0001]     This application claims priority to Japanese Patent Application No. 2004-132483, filed on Apr. 28, 2004.  
       BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates to a session-information preserving system for online systems using networks.  
         [0003]     With the development of network technologies such as the Internet, more and more processing tasks of industries are performed using web sites. Among various kinds of business data processing, the ones in particular using continuous forms are often used for placing orders in business to business transactions, inputting data of in-house systems, and so on. Since there are significant merits such as savings in labor and reduction of costs by utilizing electronic formats and web sites, Web packages for tasks using continuous forms are provided by many vendors and are commercially available. Since such Web application software handle enormous volumes of data, it is often the case to enter data while navigating through a plurality of pages shown by a browser. However, because stateless HTTP protocols are used in the Web application, a system for preserving a flow of a series of operations by a user is necessary, and SI vendors provide such systems of their own.  
         [0004]     Japanese Unexamined Patent Publication No. 2003-6018 discloses a technology which urges input of an instruction to suspend processing and accepts such input when a failure on a server machine is detected.  
       BRIEF SUMMARY OF THE INVENTION  
       [0005]     In a system where data are entered online by using Web application, it is necessary to preserve session information for navigation over a plurality of pages by some method. Further, in large-scale Web application open to the public such as on-line shopping and on-line banking, during logging-in, when a system is shut down due to regular maintenance or emergency maintenance of a server and if a user is not notified of the system shutdown or the user does not recognize the system shutdown, processing performed by the user is interrupted and contents of the processing made thus far may be lost.  
         [0006]     Also, it is a duty for a system administrator to consider details of the maintenance and what are affected by a shutdown of service, to examine a schedule for the shutdown, and to announce the shutdown of the service beforehand, which places heavy burden on the system administrator.  
         [0007]     Further, JP No. 2003-6018 discloses a measure to be taken to cope with a failure on a server, which accepts an interruption of processing after an occurrence of the failure. Therefore, preservation of session information in the case of predetermined system shutdowns such as the one due to maintenance of a system is not taken into account.  
         [0008]     One embodiment of the present invention provides a session-information preserving system in which contents of processing before shutdown can be maintained even when the system shuts down due to maintenance and so on.  
         [0009]     In such a system, when maintenance information of a server is stored, window or pane data including the maintenance information is generated and a business-data entry window or pane is shown. Also, on the basis of the maintenance information, a maintenance warning window or pane is shown and session information of the entered data is stored.  
         [0010]     As used herein, the term “pane” refers to a collection of data that are displayed on a screen or display area of the display device in an organized manner. An example of a pane is a window that displays information within a frame.  
         [0011]     As used herein, the term “screen” is used also to refer to a pane as well as a display area of the display device.  
         [0012]     Further, when a user logs in, if session information for the user is stored, a business-data entry screen including such session information is generated and shown.  
         [0013]     According to the present invention, even when logging out due to a system shutdown caused by maintenance, etc., a user can preserve session information before the log-out. Further, the user can resume his or her processing in a state before the log-out when logging in again by retrieving the preserved session information.  
         [0014]     One embodiment provides a session-information preserving system including a client to which business data are inputted and a server which processes the business data sent from the client computer. The system includes a login control component to execute a login procedure on the basis of user identification information necessary for logging in to said system; a maintenance management component to search a maintenance information table for maintenance information on said server; and a pane generator to generate data used to display a plurality of panes on the client, the pane data including the maintenance information that has been retrieved by the maintenance management component, the plurality of panes including first and second panes configured to be displayed on a display of the client to receive first information and second information, respectively, from the client that are to be stored in the server and a notification pane to display a notice relating to the maintenance information on the display of the client, the second information including a first portion and a second portion, wherein the notification pane is displayed on the client to provide information on a scheduled maintenance of the server while a user is inputting the first portion of the second information on the second pane, so that the user cane save the inputted first portion of the second information prior to the scheduled maintenance of the server, and wherein the second portion of the second information has not been inputted using the second pane and the first information has already been inputted using the first pane.  
         [0015]     In another embodiment, an application server is coupled to a client and includes a login control unit to execute a login procedure on the basis of identification information of said user, the login procedure being executed upon receiving a user identification information from the client; a pane to generate unit generating a script corresponding to maintenance information of a maintenance information table and generate pane data including the script when the maintenance information of said server is stored in the maintenance information table, the maintenance information providing information as to when the server is to be serviced; and a computer storage medium including a session information table including an session object that is associated with a user identification information, the session object including business data input by a user according to a plurality of panes presented to the user on the client, the plurality of panes being generated using the pane data generated by the pane generator unit, wherein said login control unit searches, after the login procedure, said session information table for the session object corresponding to the user identification information received from the client for the login procedure, and wherein, when the session object corresponding to the user identification information is found, said screen generating unit generates pane data containing the session object.  
         [0016]     In another embodiment, a session-information preserving method for a business operations system in which a client computer and a server are connected through a network is provided. The client computer shows a login screen on which user identification information is entered when logging in to said system. The method comprises executing a login procedure on said server on the basis of said user identification information entered on said login pane; searching a maintenance information table for maintenance information about maintenance of said server; generating pane data containing a script corresponding to the maintenance information when the maintenance information is found as a result of the search; and sending the generated screen pane to said client computer. Said client computer receives said pane data, shows a pane on which business data concerning said system are entered on the basis of the received pane data, shows a maintenance warning pane on the basis of information about the warning of maintenance contained in said maintenance information and, if it is chosen to preserve the business data already entered when the warning of maintenance is shown, sends session information about the business data to said server. Said server receives the session information sent from said client computer, links the session information with the user identification information corresponding to said login procedure, and stores it in a session information table.  
         [0017]     In yet another embodiment, a computer readable medium including a program to be executed in a business operations system which includes a client computer operated by a user and a server connected with the client computer and storing business data is provided. The program comprises code for executing a login procedure on the basis of identification information of said user; code for storing maintenance information of said server in a maintenance table; code for creating a script corresponding to the maintenance information stored in the maintenance information table; code for generating pane data including the script; code for linking, in accordance with the maintenance information of said server, session information corresponding to the business data entered on the pane shown according to said generated screen data with the user identification information used for said login procedure and stores it in a session information table; code for searching, after said login procedure, said session information table for the session information linked with the user identification information corresponding to the login procedure; and code for generating pane data including the session information when the session information corresponding to the user identification information is stored.  
         [0018]     In yet another embodiment, a session-information preserving method in a system including a client to which business data are inputted and a server which processes the business data sent from the client computer is provided. The method comprises executing a login procedure using a login control component on the basis of user identification information necessary for logging in to said system; searching a maintenance information table for maintenance information on said server; and generating pane data used to display a plurality of panes on the client, the pane data including the maintenance information that has been retrieved, the plurality of panes including first and second panes configured to be displayed on a display of the client to receive first information and second information, respectively, from the client that are to be stored in the server and a notification pane to display a notice relating to the maintenance information on the display of the client, the second information including a first portion and a second portion. The notification pane is displayed on the client to provide information on a scheduled maintenance of the server while a user is inputting the first portion of the second information on the second pane, so that the user can save the inputted first portion of the second information prior to the scheduled maintenance of the server. The second portion of the second information has not been inputted using the second pane and the first information has already been inputted using the first pane. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]      FIG. 1  shows a block diagram of a Web system, which is one embodiment of the present invention.  
         [0020]      FIG. 2  shows a data structure of a session information table  161 .  
         [0021]      FIG. 3  shows a data structure of a maintenance information table  162 .  
         [0022]      FIG. 4  shows a data structure of a user information table  163 .  
         [0023]      FIG. 5  shows a structure of HTTP data  11  to be sent from an application server  100  to a user&#39;s client computer  1100 .  
         [0024]      FIG. 6  is a flowchart of processing when registering maintenance information.  
         [0025]      FIG. 7  is a flowchart of processing when logging in to a system and entering business data.  
         [0026]      FIG. 8  is a flowchart of processing when preserving user&#39;s session before a maintenance time.  
         [0027]      FIG. 9  is a screen transition diagram when entering business data.  
         [0028]      FIG. 10  is a screen transition diagram when entering maintenance information of the system. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0029]     With reference to the drawings, embodiments of the present invention will now be described.  
         [0030]      FIG. 1  shows a detailed structure of the session-preserving system according to one embodiment of the present invention.  
         [0031]     A user&#39;s client computer  1100  and an administrator&#39;s client computer  1200  are terminals communicating with an application server  100  and are connected through a network  10 . The user&#39;s client computer  1100  communicates with the application server  100  and inputs data. The administrator&#39;s client computer  1200  communicates with the application server  100  and inputs maintenance information of the application server  100 . The server  100  is a business-application system which accepts input of business data through a network such as the Internet and processes data.  
         [0032]     The application server  100  includes a screen generating program  110 , a state-transition control program  120 , a login/logout control program  130 , a session management program  140 , and a maintenance management program  150 , which run within the application server  100 .  
         [0033]     The state-transition control program  120  receives data sent from the user&#39;s client computer  1100  or the administrator&#39;s client computer  1200 . The data received are user identification information (user IDs and passwords) to be used for logging in, business data, maintenance information, and so on.  
         [0034]     Being based on user information sent from the user&#39;s client computer  1100  or the administrator&#39;s client computer  1200 , the login/logout control program  130  controls logging in to and out of a system.  
         [0035]     A database  160  in the application server  100  contains a session information table  161  for storing session objects uniquely corresponding to user IDs of users logging in to the system, a maintenance information table  162  storing information about maintenance of the application server  100 , and a user information table  163  storing user IDs and passwords.  
         [0036]     A screen composing module  111  and a script generating module  112  are program components which function under the screen generating program  110 . The screen composing module  111  and the script generating module  112  create HTTP data  11  which are sent to a WWW browser of the user&#39;s client computer  1100  or the administrator&#39;s client computer  1200 .  
         [0037]     A session generating module  141 , a session preserving module  142 , and a session overwriting module  143  are all program components which function under the session management program  140 . The session generating module  141  generates session objects storing information about screen transition during logging-in of the user and inputted values. When the server is shut down, the session preserving module  142  stores session objects to be used by the user in the session information table  161 . After the shutdown of the application server  100 , when the user logs in, the session overwriting module  143  retrieves a session object corresponding uniquely to the user from the session information table  161 .  
         [0038]     A maintenance notification module  151  and a maintenance registration module  152  are both program components which function under the maintenance management program  150 . The maintenance notification module  151  is called up by the script generating module  112 , retrieves detailed information about maintenance from the maintenance information table  162 , and sends data back to the script generating module  112 . The maintenance registration module  152  stores the detailed information  171  about the maintenance, a parameter inputted by the administrator&#39;s client computer  1200 , in the maintenance information table  162 .  
         [0039]     A WWW browser  1101  is a program which runs on the user&#39;s client computer  1100 , and conducts data communications with the application server  100  through a network  10 . A login screen  1102  is a screen shown when the user logs in, and a user&#39;s workscreen  1104  is a screen shown in the WWW browser  1101  on which the user enters data for a business application.  
         [0040]     A WWw browser  1201  is a program which runs on the administrator&#39;s client computer  1200 , and conducts data communications with the application server  100  through the network  10 . A login screen  1202  is a screen shown when the administrator logs in, and a maintenance-information entry screen  1204  is a screen shown in the browser  1201  on which the administrator enters maintenance information.  
         [0041]      FIG. 2  shows a data management structure of the session information table  161  of the database  160  in the application server  100  according to one embodiment. Namely,  FIG. 2  shows a structure of session data which is a data format used when session information of the user is preserved.  
         [0042]     The session information table  161  includes a user ID column  211  identifying users and a session object column  212  corresponding to user IDs one by one. The session object column  212  holds session objects  220  generated by the application server  100  as binary data. The session objects  220  includes a user ID  221 , a login flag  222  showing whether a user is logging in or logging out, an original screen ID  224 , which is an ID of a screen where the user was at work when storing data, and a next screen ID  223  which is an ID of a screen after transition, and session retaining data  225  storing contents inputted by the user as session information.  
         [0043]      FIG. 3  shows a data management structure of the maintenance information table  162  in the data base  160  of the application server  100  according to one embodiment.  
         [0044]     The maintenance information table  162  stores maintenance IDs  311  each of which is an identification number identifying each maintenance uniquely, date and time  312  of starting maintenance, details of maintenance  313 , degree of warning  314 , date and time of warning  315 , and date and time of ending maintenance  316 .  
         [0045]      FIG. 4  shows a data management structure of the user information table  163  in the database  160  of the application server  100  according to one embodiment. The user information table  163  stores a user ID  411 , a password  412  uniquely corresponding to the user ID  411 , and a user type  413  indicating a user&#39;s title, a section in his or her charge, etc. The user ID  411  and the password  412  stored in the user information table  163  are identification information identifying the user when the user logs in to the system and, on the basis of such information inputted during the login, the login/logout control program  130  refers to the user information table  163  and executes a login procedure.  
         [0046]      FIG. 5  shows a data structure sent from the application server  100  to the user&#39;s client computer  1100  according to one embodiment. In the present embodiment, a case when HTTP data  11  is sent will be described.  
         [0047]     HTML data  500  are stored in the HTTP data  11 . The HTML data  500  includes a script  511  containing a logic for showing a warning screen in conjunction with the server maintenance and preserving session information, and static HTML data  512  for page design.  
         [0048]      FIG. 6  is a flowchart showing a process when the application server  100  registers system maintenance information sent from the administrator&#39;s client computer  1200  according to one embodiment.  
         [0049]     First, the administrator&#39;s client computer  1200  shows the login screen  1202  on the WWW browser  1201  (step  601 ). The login screen is sent from the application server  100  through the network  10 . The details of the login screen will be described later in  FIG. 10 . Next, the administrator&#39;s client computer  1200  accepts, on the login screen  1202 , input of an administrator&#39;s ID and a password, which are identification information of the administrator necessary for the log-in (step  602 ). In step  602 , when a system administrator enters a user ID and a password and presses a login button, the administrator&#39;s client computer  1200  sends data inputted in step  602  to the application server  100  (step  603 ).  
         [0050]     Then, the state-transition control program  120  of the application server  100  receives the inputted data sent from the administrator&#39;s client computer  1200  (step  604 ). Being based on the received data, the login/logout control program  130  refers to the user information table  163  stored in the database  160  for user information, performs user authentication of the system, and executes a login procedure (step  605 ). After the login procedure, the screen generating program  110  of the application server  100  generates a maintenance-information entry screen  1204  (step  606 ), and the application server  100  sends data of the generated maintenance-information entry screen  1204  to the administrator&#39;s client computer  1200  (step  607 ).  
         [0051]     Then, the administrator&#39;s client computer  1200  receives the data of the maintenance-information entry screen  1204  sent from the application server  100  (step  608 ), and the WWW browser  1201  displays page data of the received maintenance-information entry screen  1204  (step  609 ). The administrator&#39;s client computer  1200  accepts information about maintenance to be entered on the displayed maintenance-information entry screen  1204  (step  610 ). Information to be inputted includes a maintenance ID  311 , date and time of starting maintenance  312 , details of maintenance  313 , degree of warning  314 , date and time of warning  315 , date and time of ending maintenance  316 , and so on. The system administrator enters information about maintenance on the maintenance-information registration screen  1204 . The administrator&#39;s client computer  1200  sends the maintenance information inputted in step  610  to the application server  100  (step  611 ).  
         [0052]     Then, the state-transition control program  120  of the application server  100  receives the maintenance information (step  612 ) sent in step  611 ; and a maintenance registration module  152  of the maintenance management program  150  stores the received maintenance information in the maintenance information table  162  of the database  160  (step  613 )  
         [0053]     By conducting the above processing, the maintenance information of the system is registered in the application server.  
         [0054]      FIG. 7  is a flowchart of processing when a user logs in to the system and enters business data according to one embodiment.  
         [0055]     The WWW browser  1101  of the user&#39;s client computer  1100  shows a login screen sent from the application server  100  (step  701 ). The details of the login screen on this occasion will be described later with reference to  FIG. 9 . The WWW browser  1101  of the user&#39;s client computer  1100  accepts, on the login screen  1102 , entry of a user ID and a password which are user identification information necessary for a login procedure (step  702 ). In step  702 , when the user enters the user ID and password and presses a login button, the user&#39;s client computer  1100  sends the entered user ID and password to the application server  100  (step  703 ).  
         [0056]     The state-transition control program  120  of the application server  100  receives the user ID and password sent in step  703  from the user&#39;s client computer  1100  (step  704 ). On the basis of the data received in step  704 , the login/logout control program  130  refers to the user information table  161  of the database  160  for user information, performs user authentication of the system, and executes a login procedure (step  705 ).  
         [0057]     Then, the login/logout control program  130  searches the session table  161  stored in the database  160  (step  706 ). Using a user ID  211  as key information, the login/logout control program  130  searches for a session object  212  corresponding to the user ID. After the search in step  706 , when there is session information about an interruption of processing due to the previous maintenance (step  707 ; yes), a session overwriting module  143  of a session management program  140  obtains the session object  212  from the session information able  161 , and retrieves data  225  out of the object (step  708 ). When there is no relevant session data found in step  707  (step  707 : no), the session generating module  141  in the session management program  140  newly generates a session object (step  709 ).  
         [0058]     Then, a maintenance management program  150  of the application server  100  searches a maintenance information table  162  of the database  160  for maintenance information (step  710 ). When there is maintenance information, a maintenance notification module  151  of the maintenance management program  150  sends the maintenance information to a script generating module  112  of a screen generating program  110 , and the script generating module  112  generates a script according to the maintenance information (step  711 ).  
         [0059]     The script generating module  112  generates a script  510  to be embedded in HTML data  500  ( FIG. 5 ) to be sent to the user&#39;s client computer  1100 . In order to generate the script  510 , date and time of starting maintenance  312 , details of maintenance  313 , degree of warning  314 , and date and time of warning  315  ( FIG. 3 ), which are all included in the maintenance information stored in the maintenance information table  162  ( FIG. 3 ), are used. Then, using such information, a warning screen for the user is shown a certain time before starting maintenance (date and time of warning  315 ), and such a script  510  as to store data being processed according to the choice of the user is created. Further, when there is no maintenance information found in step  710  (step  710 : no), the screen generating program  110  creates such a script as not to include maintenance information, and generates a screen according to the script (business-data entry screen).  
         [0060]     Then, on the basis of the script  510  generated by the script generating module  112 , the screen composing module  111  generates HTML data  500  about a screen to be shown on the user&#39;s client computer  1100  (step  712 ). The screen composing module  111  generates the HTML data  500  ( FIG. 5 ) by embedding the script  510  generated by the script generating module  112  and static HTML data  520 . Further, the screen composing module  111  embeds a value of the session object  225  ( FIG. 2 ) in the form in the HTML data  500 .  
         [0061]     Further, when there is no maintenance information found in the maintenance information table  162  (step  710 : no), the processing in  FIG. 7  advances to step  712 ; and the screen composing module  111  generates only the HTML data  500  to be displayed on the user&#39;s client computer  1100  and embeds the value of the session object  225  in the form in the HTML data  500 .  
         [0062]     Next, the application server  100  sends the HTML data  500 , which is the data for screen to be sent generated in step  721 , to the user&#39;s client computer  1100  as HTTP data  11  (step  713 ). Then, the user&#39;s client computer  1100  receives the HTTP data  11  sent from the application server  100  (step  714 ). Further, on the basis of the HTTP data  11  received in step  714 , the WWW browser  1101  of the application server  100  produces a user&#39;s workscreen  1104  (step  715 ).  
         [0063]     By performing the above processing, a user can enter business data on the user&#39;s workscreen  1104  shown there. Also, when the user logs in to the system, if the session information preserved before and corresponding to the user is stored (step  707 : yes), the user can continue using it.  
         [0064]     Further, when maintenance information is stored in the maintenance information table  162 , the screen generating program  110  creates a screen script corresponding to the maintenance information (step  711 ). Therefore, it serves the purpose if the system administrator stores information about maintenance of the server in the system, and there is no need to notify the user logging in to the system of the maintenance information, reducing the burdens on the administrator.  
         [0065]      FIG. 8  is a flowchart of preserving the user&#39;s session when the starting time of the maintenance of the system is nearing (at a prescribed time before the system maintenance). As shown in  FIG. 7 , when the user has logged in to the system and entering business data, the user&#39;s workscreen  1104  is shown in step  715 . The user&#39;s workscreen  1104  is produced on the basis of the HTTP data  11  ( FIG. 5 ) sent from the application server  100  to the user&#39;s client computer  100 . Therefore, the HTTP data  11  includes the HTML data  500 , which includes the script  510 .  
         [0066]     In  FIG. 8 , first, when loaded into the WWW browser  1101 , the script  510  of the HTML data  500  compares the data and time of warning  315  described in the script  510  with a system time of the user&#39;s client computer  1100  (step  801 ). As a result of the comparison, when the date and time of warning  315  in the script  510  and the system time of the user&#39;s client computer  1100  are the same (step  801 : yes), the user&#39;s client computer  1100  gives a warning to the user informing that it is a prescribed time before the system maintenance by using a pop-up screen, etc. (step  802 ).  
         [0067]     On the pop-up screen, etc. shown in step  802 , the user&#39;s client computer  1100  urges the user to choose whether or not to preserve a session at that moment (step  803 ). When the user chooses to preserve the session in step  803  (step  803 : yes), the script  510  obtains data already entered on the user&#39;s workscreen  1104 , and the user&#39;s client computer  1100  sends the entered data to the application server  100  (step  804 ).  
         [0068]     Then, the application server  100  receives the entered data sent from the user&#39;s client computer  1100  (step  805 ), and a session preserving module  142  links the data received in step  805  with the user ID  211  to prepare a session object  212  and stores it in the session information table  161  of the database  160  (step  806 ).  
         [0069]     Further, when the user chooses not to preserve the session in step  803  (step  803 : no), the processing advances to step  807  (a logout procedure). Namely, according to the flowchart of  FIG. 8 , when the user chooses not to preserve the session, the business data entered so far are not preserved and the logout procedure is executed.  
         [0070]     However, such a configuration may be adopted that if the user chooses not to preserve the session in step  803  and when business data have been entered on two or more screens, session information corresponding to the business data already entered on screens before the current screen may be preserved and are stored in the session information table  161 . This configuration is also useful for a user who need not preserve data entered on the current screen but wishes to preserve data already entered on the preceding screens.  
         [0071]     Then, the login/logout control program  130  executes a logout procedure of the user (step  807 ). The screen generating program  110  generates screen data after the logout to be sent to the user&#39;s client computer  1100  (step  808 ), and sends HTTP data  11  containing the generated screen data to the user&#39;s client computer  1100  (step  809 ).  
         [0072]     The user&#39;s client computer  1100  receives the HTTP data  11  sent from the application server  100  and receives the screen after log-out stored in the HTTP data  11  (step  810 ). The WWW browser  1101  shows the received screen data after log-out (step  811 ).  
         [0073]     The above processing makes it possible to store session data of a logging-in user in a database a prescribed time before maintenance of the application server and to have the user log out automatically.  
         [0074]      FIG. 9  shows examples of screens shown on the user&#39;s client computer  1100  in the processing in FIGS.  7  to  8  according to one embodiment.  
         [0075]     The user&#39;s client computer  1100  shows a login screen  910  (step  701  in  FIG. 7 ). When a user ID and a password are entered into a form  911  (step  702 ) and a login button  912  is pressed, the processing moves on to a transaction-data entry screen  920 .  
         [0076]     In another embodiment, the data entered by the user is saved at the client side until the user has finished entering all data for the session. That is, the data entered are not transmitted to the database  160  until the user has finished entering the data in connection with the last pane of the session and indicates that all data are to be saved in the database  160 .  
         [0077]     The user&#39;s client computer  1100  shows the transaction-data entry screen  920  (which corresponds to user&#39;s workscreen  1104  in  FIG. 1 ). When the user enters business information into a form  921  on the screen  920  and presses a next-screen button  922 , a session entered on the screen  920  is sent to the application server  100  and stored in the database  160 . Namely, in the example of  FIG. 9 , every time a new screen is shown, information entered on the screen (session information) is stored in the database  160 .  
         [0078]     If a prescribed time before maintenance of the server comes when data entry into the form  931  on the next screen  930  hasn&#39;t completed, namely, when the date and time  315  of warning for maintenance comes (step  801  in  FIG. 8 : yes), the script  510  sent to the user&#39; client computer  1100  shows a maintenance warning screen  940  (step  802  in  FIG. 8 ). When the user presses a button  941  for preserving the session (step  803 : yes), the script  510  sends the data in the form  931  to the application server  100  (step  804  in  FIG. 8 ).  
         [0079]     The session management program  140  of the application server  100  merges the above data with the session data already entered on the preceding screens (session data already kept in the database  160 ), links it with the user ID, and stores it in the database  160  (step  806  in  FIG. 8 ). Also, after this processing, the login/logout control program  130  has the user automatically log out (step  807  in  FIG. 8 ).  
         [0080]     After the system maintenance, when the user enters user information into a form  971  on a login screen  970  and logs in again, the login/logout control program  130  calls up the session management program  140 , and obtains session data  225  linked with the user ID from the database  160  (step  707  in  FIG. 7 ). The screen generating program  110  generates an image with data embedded in a form  981  by using the obtained session data  225 . The generated screen is shown on the user&#39;s client computer  1100  as a screen  980  (step  708  of  FIG. 7 ).  
         [0081]     Thus, the user retrieves contents of the processing on the basis of the session information previously preserved, and can proceed with the rest of the processing. Namely, including data being entered during the system shutdown due to the server maintenance, the session information is stored in the session information table. Therefore, the user can resume processing as it was at the end of the last entry operation when logging in again.  
         [0082]     In  FIG. 9 , the user gains access to the application server  100  through the user&#39;s client computer  1100  according to one embodiment. Every time the application server  100  receives a page request from the user&#39;s client computer  1100 , it obtains maintenance information from the database  160  by using the maintenance management program  150 . The screen generating program  110  generates a screen by inserting maintenance information in the script  510 , and the application server  100  sends the generated image to the user&#39;s client computer  1100 . Thus, by dynamically inserting the maintenance information of the server into the HTML file, a session at a prescribed time before the maintenance can be automatically preserved. Further, a management method in a mission-critical web system can be simplified and session data can be preserved.  
         [0083]      FIG. 10  shows examples of screens shown on the administrator&#39;s client computer  1200  when the maintenance information is registered in  FIG. 6  according to one embodiment.  
         [0084]     When the login screen  1202  is shown on the administrator&#39;s client computer (step  601  in  FIG. 6 ), the system administrator enters user information (a user ID and a password) into a form  1011  on a login screen  1010  (step  602  in  FIG. 6 ). Then, when a login button  1012  is pressed, a maintenance-information entry screen  1020  is shown. On the maintenance-information entry screen  1020 , the system administrator enters maintenance information such as a maintenance ID  311 , date and time of starting maintenance  312 , and date and time of warning  315  into a form  1021 , and presses an entry button  1022 . Accordingly, the maintenance management program  150  of the application server  100  stores the maintenance information entered on the screen  1020  in the maintenance table  162  of the database  160 .  
         [0085]     The present invention has been described in terms of specific embodiments to illustrate the invention to those skilled in the art. The above embodiments may be changed or modified without departing from the scope of the present invention. Accordingly, the scope of the invention should be defined using the appended claims.