JSP novice sailing (1) JSP syntax

After learning 4 months of Java, I finally started learning JSP while reading the book. On the side of the 9CBS, the document was 4 days. After 4 days, I felt that I had a qualified leap 9CBS, although there were many documents, but they all said the same problem. Solving the method to find out the documentation, even if you find the problem that you can solve your problem is not necessarily suitable for your system. Different solutions to JSP knowledge. Different solutions are not enough, unless their understanding is quite strong. Otherwise, it is difficult to just I have to reach a unified study of unified learning. I wrote my 3 days of learning process. I believe that the newcomers who have just started learning JSP can help the first chapter JSP syntax.

0. Note The comment sent to the client does not display <% - comment -%> is not sent to the client, but will leave empty on the client Hidden Note 1. Declare <%! Variable and method%> is not to produce variables and methods in tags and methods 2.jsp expressions can be turned to TOSTRING <% = Expression%> There is no need to add a Java expression in the last; the script is used to include a Java block <% code fragment%> Fully compliant with the Java language specification can be written in the Java source program 4. Contained instructions <% @ Include File = "relativeurl"%> When you include a Static file static file in JSP: Refers to: Does not include files that need to be executed, such as: HTML or JSP, which does not contain Java programs, for example, <% @ include file = "beinCluded. JSP "%> The JSP file containing the above code will be static in the file. BeinCluded.jsp contains files that cannot use must be valid for files that must be included. Changed to include his JSP will be recompiled 5.page instruction Defines the global property of JSP file [] Represents instructions written in Page <@ page [language = "java"] [eXtens = "package.class"] [ Import = ""] //java.lang.*; javax.servlet. *; javax.servlet.jsp. *; javax.servlet.http. *; all imported, so you don't have to import [session = "True | FALSE"] Set whether the customer needs http session session to True to see the same user's access to a session [buffer = "none | 8KB | SIZEKB"] 8KB is the output buffer size of the default OUT object processing [Autoflush- "True | FALSE"] Refresh Buffer If the buffer overflows need to force the output true output false anomaly [Isthreadsafe = "true | false"] Set whether the JSP file can be multi-thread using the corresponding plural request TURE default [INFO = "TEXT"] Description Information [ErrorPage = "RelativeURL"] Set the processing exception JSP file [iSerrorPage = "true | false] is an error handling Page, if yes, you can use the Exception object [contenttype = "MIMETYPE [; Charset = Characterset]" | text / html; charset = ISO-8859-1 "] Set MIME Type Default is Text / HTML Default Character Set is ISO -8859-1 <% @ PAGE%> Because the entire JSP page does not work to dynamically include file 6.Taglib instruction define a label library and prefix <% @ taglib uri = "uritotaglibrary" prefix = "tagprefix"%>

Do not use JSP JSPX Java Javax Servlet Sun Sun to do prefix taglib instructions multiple times, but the prefix can only be used for, for example,: <@ Taglib URI = "http: //" prefix = "public"%> < Public: loop> <% - Perform code -%> 7. with Response's SendRedirect () Different SendRedirect () will send URL addresses to customers Whether to turn to is to force the server-side forced steering redirection to a JSP file, HTML file or a block non-parametric band Parameters: Its code later will not perform 8. Create a bean instance and specify the name and scope of scope language format: |> Other elements } Instance: I. ii. 9. Settings Bean properties syntax format: name = "BeanInstanceName" bean instance name must already exist { Property = "*" | Store user input All values ​​are used to match the properties in the bean comes from the Request Object Property = "PropertyName" [param = "parametername"] | Use a parameter value to set the corresponding attribute value parameter value from Requset Property = "PropertyName" value = "string | <% = expression%>}" with the specified attribute value does not need to match the match PS of the request object: If the parameter value is null, the corresponding attribute value will not be set param. And Value cannot appear at the same time} /> 10. Get the property of the bean is used to display automatically implemented Tostring type conversion 8.9.10. The above three are attributes related to bean operations 11. Advanced row analysis is dynamic file or static files According to different performance, if there is a dynamic Java return processing result contains a static or dynamic file syntax format: I. ii. Insert an applet or bean, necessary If you want to download a Java plug-in for performing a syntax format:

Bottom | Top | Middle | LEFT | Right |] Location [Height = "DisplayPixels"] High [width = "DisplayPixels"] Wide Pixels [HSpace = "Leftrightpixels"] horizontal margins [vSpace = "topbottompixels"] Vertical margins [Jreversion = "jreverssisNumber | 1.1"] The JRE version number required [nspluginURL = "URLTOPLUGIN] Netscape Navigator users can use the JRE download address [iePluginURL =" URLTOPLUGIN "]> IE users can use the JRE download address [ Advantages or parameter values ​​that need to be transferred to Applet or Bean [] ] [ Text Message for User ] Alternative message when you can't start The or element 13 will be replaced according to the version 13. Built-in Object Overview JSP is case sensitive to these built-in objects JavaBeans can build an application project The built-in object is the third parameter of each of the first rows of each built-in object generated by a particular Java class represents the sub-scope of the first row of each built-in object. : Request request object, the time from the client from the client, the client is requested in the form, and the object is generated before entering the page has its own buffer below it is: Request.getParameter ("" "

) Gets a specified name parameter getAttribute (name) getAttributeNames getCharacterEncoding () getContentLength () getContenType () getParameterNames () Gets all parameter names getParameterValues ​​(name) getProtocol () getInputStream () getScheme () acquisition request mode getServerName () getServerPort ( ) getReader () returns the character to be read Buffered objects getRemoteAddr () getRemoteHost () setAttribute (String key, Object o) getSession (boolean) () boolean isRequestedSessionId Valid effectiveness | FromCookie | FromURL getCookies () getServletPath () actually Work Path GetRequestedSession Id () Method with Session Objects RESPONSE JAVAX.SERVLET.SERVLETRESPONSE Sub-class Page Page Different Engines May Generate Different Sub-Less Response Objects Represents Data to the client's corresponding organization to the client before entering the page. there Buffer and methods getCharacterEnconding () getWriter () setContentLength (int) setContentType (String) getOutputStream () addCookie (Cookie) containsHeader (String) add a header field encodeURL (String) to encode URL encodeRedirectURL (String) to redirect URL encoding Senderror (int src, string) sendRedirect (string) Send a redirected URL setDateHeader (String, long) Set a specific date head domain setStatus (int src) Set status code setHeader (String name, string value) setting designation name Head domain setInTheader (name, int value) Setting the shaping value of the header PageContext javax.servlet.jsp.pageContext Page Conclusion Object The current page Run some attribute Attribute (property) Customized variables within the valid range You can use these properties to use some of the other methods for Java languages ​​for FindAttribute () find a property GetAttribute (String Name, Object, ) GetAtTirButessCope () Get effective range GetAttributeNamesinscope () Get effective Initig (Servlet this, request, response, string errorpageurl, boolean needssession, int buffersize, boolean autoflush);

Initialization method release () Release all references removeAttribute () can getOut () getSession () getPage () getRequest () getResponse () getException () getServletConfig () getServletContext () to obtain other built-in objects forward (UrlPath) include (UrlPath) handlePageException (Exception E) Used to handle unprocessed error session javax.servlet.http.httpsession session session object Representative Server and Client Suggestions Receipt in Cookie The client must open cookie getCreationTime () getId () getLastaccessedTime () The last visit time getMaxinActiveInterval () max interval setMaxinactiveInterval (int) getValue (name) String [] getValuenames () invalidate () makes a specific session object to disconnect Boolean isnew () to determine if the user opens the cookie function PUTVALUE Name, OBJ Value) RemoveValue (Name) // All requires that you can handle the request.getCookies () settings for the cookie object () Setting the response.setcookies () Application Javax.Servlet.ServletContext Application application object is responsible for providing the application to run the application Some global information is a CONTEXT GETMAJORVERSITION () returned to servletApi's primary version of ServletYpeText GetContext (URLPATH) NumbeType Getminorversion () gets MIMETYPE GETRESOURES JAVA.NET.URL GETRESOURCE (PATH) "throws java.net.malformedurlexception gains the specified path resource URL JAVA.IO.INPUTSTREAM GETRESOURCEASSTREAM (PATH) RequestDispathcer getRequestDispatcher (URLPATH) The above two methods are packaged separately into different types to return log (MSG) (MSG, throwable) to record the specified information to the log file GetRealPath. PATH) Conversion Virtual Path and Path Get ServerInfo () GetAttribute (Name) GetAttributeNames () SetAttribute (Name, Obj) RemovsAttribute (name) Out javax.servlet.jsp.jspwriter Page Output object Send text Data Browser Do not recognize Println's wrap in the outside

 tag to keep the original output style newline () output liner with a buffer config javax.servlet.ServletConfig Page configuration object provides some configuration information to get some initialization configuration information GetInitParameter (String) GetItParameterNames () Return Type Yes Enumeration Type GetServletContext () Returns the Application Object Page Java.Lang.Object Page Page Object Object Object Page =

this getClass () hashCode () equals (obj) clone () throws CloneNotSupportedException toString () notify () notifyAll () wait (......) throws InterruptedException finalize () throws Throwableexception java.lang.Throwable page exception objects JSP The exception object generated by the runtime will have the error object information until the error object information. Printstream S) FillInstackTrace () Fill stack trajectory When you use the above object 14.javabeans feature: a. Introspection: Enables components to post their supported properties and The mechanism is also supported by this mechanism in other components. B. Properties: The appearance and behavioral characteristics of the mobile phone bean can be changed. C. Customization: Bean is customized by publishing its properties. D. Communication: Beans communicates with each other through time (persistence): Make Beans to store and restore their status.
Property:  Creative instances can also be in <% new bean%>   JSP in a pure Java class ExecuteUpdate calling String String String String String String "Contains, use   to connect to the text section of the SQL language to use" "containing the inserted statement itself '' Don't forget the write implementation package 15.Servlet and JSP when doing a JSP server with Tomcat, Work folder below Correspondingly, the corresponding servlet WebApps folder is that JSP each JSP corresponds to a servlet. To complete the user's request servlet is a special Java Class that can handle user requests must meet some of the conditions (running environment) Javax.Servlet . * interface Servlet contains init (config) service (request, response) destroy () getServletConfig () getServletInfo () by implementing the following his completion request corresponding to an interface and JSP ServletConfig - config ServletContext - application ServletRequest --- request ServletResponse --- Response RequestDispatcher Contains Forward (Req, Res) ---  include (Req.res) ---  javax.servlet.http. * Javax.servlet.jsp. * GenericServlet Developing abstract class GenericServlets achieve a lot of interfaces with Abstract Void Service (Req, Res) Import Java.io. *; Import Java.util. *; Import Javax.Servlet. *; Public Class Helloservlet Extends GenericServlet must override service ( Req, res) method doget dopost will be called 16.jdbc SQL Language Verbs Select INSE RT Update Delete Create Drop Grant Revoke DDL Data Definition: Create ALTERD DROP DML Data Operation: SELECT INSERT DELETE UPDATE JDBC Structure Java Application - JDBC API (Java.sql. *) - JDBC Manager - JDBC Driver API Mode and Step A Loading driver class.Forname ("Sun.jdbc.odbc.jdbcodbcdriver"); b. Establish Connections Connection Con = DriverManager.getConnection ("JDBC: ODBC: Myodbcdsn"); c. Create a statement object statement stmt = con.createstatement (); B. Execute the query statement creation result set object resultset = stmt.executeQuery ("Select * from tablename"); e. Query results processing closing results set object rs.close (); f. Turn off statement object stmt.close (); G. Close Connection CON.CLOSE; http://blog.9cbs.net/tcp_ip/services/trackbackbacks/263934.aspx