Organize a JSP custom label and permission control label

JSP custom tags use the scene to local conditions, you can implement a custom label output function can also achieve the management of permissions

1: Define Label class first

1-1: Page Output tab

Package Com.suyin.web.jspsectag;

Import java.io.IOException;
Import javax.servlet.jsp.JspTagException;
Import Javax.servlet.jsp.PageContext;
Import Javax.servlet.jsp.tagext.Tag;

public class Hellotag implements TAG {
Private PageContext PageContext;
Private Tag parent;
Public Hellotag () {
Super ();
}


/**
*
* Set the context of the label's page
*/


public void Setpagecontext (final PageContext PageContext) {
This.pagecontext = PageContext;
}


/**
*
* Set up a top level label
*/


public void SetParent (final Tag parent) {
This.parent = parent;
}


/**
*
* Action when starting the tag
*/


public int doStartTag () throws Jsptagexception {


try {
Pagecontext.getout (). println ("Hello world! hello, world! <br/> ");
} catch (Java.io.IOException e) {
throw new Jsptagexception ("IO Error:" + e.getmessage ());
}
return skip_body; Returns Skip_body, indicating that the label body is not calculated
}


/**
*
* Action when closing the tag
*/


public int Doendtag () throws Jsptagexception {


try {
Pagecontext.getout (). Write ("Hello java world! hello, java world!"). ");
} catch (IOException e) {
TODO auto-generated Catch block
E.printstacktrace ();
}
return eval_page;
}


/**
*
*release is used to release resources used by the label program, such as using a database, the connection should be closed.
*/


public void release () {
}


Public Tag getParent () {
return parent;
}
}

1-2: Rights Management tab

Package Com.suyin.web.jspsectag;


Import Java.io.File;
Import java.util.ArrayList;


Import javax.servlet.jsp.JspException;
Import Javax.servlet.jsp.JspWriter;
Import Javax.servlet.jsp.tagext.BodyTagSupport;
Import Javax.xml.parsers.DocumentBuilder;
Import Javax.xml.parsers.DocumentBuilderFactory;
Import org.w3c.dom.Document;
Import org.w3c.dom.Element;
Import org.w3c.dom.NodeList;


@SuppressWarnings ("Serial")
public class Jspsecuritytag extends Bodytagsupport {
Save the corresponding collection of roles and page elements from the XML file
private static arraylist<elementandrole> rolelist;
The name of the page element
Private String elementname;

public void Setelementname (String str) {
This.elementname = str;
}


public int doafterbody () throws Jspexception {
if (rolelist = = null) {
Rolelist = GetList ();
}

try {
If authentication is displayed by the label body, otherwise skip the label body, it is so simple
if (isauthentificated (elementname)) {
if (bodycontent! = null) {
JspWriter out = Bodycontent.getenclosingwriter ();
Bodycontent.writeout (out);
} else {
}
}
} catch (Exception e) {
throw new Jspexception ();
}
return skip_body;
}


From the XML configuration file to the corresponding role and page elements, save to the static ArrayList
Private Arraylist<elementandrole> getList () {
Documentbuilderfactory dbf = Documentbuilderfactory.newinstance ();
Documentbuilder db = null;
Document doc = null;
String elementname;
String RoleName;
arraylist<elementandrole> thelist = new arraylist<elementandrole> ();
try {
db = Dbf.newdocumentbuilder ();
} catch (Exception e) {
E.printstacktrace ();
}


try {
doc = Db.parse (new File (This.getclass (). GetResource ("/"). GetPath () + "Props/security.xml"));
} catch (Exception e) {
E.printstacktrace ();
}
Reading a list of page elements
NodeList elementlist = Doc.getelementsbytagname ("HtmlElement");
for (int i = 0; i < elementlist.getlength (); i++) {
Element name = (element) Elementlist.item (i));
The name of the page element
ElementName = Name.getattribute ("name");
A list of the roles that the page element corresponds to that have permissions
NodeList rolnodelist = ((NodeList) name
. getElementsByTagName ("RoleName"));
for (int j = 0; J < Rolnodelist.getlength (); j + +) {
Name of the role with permissions
RoleName = (Element) Rolnodelist.item (j)). Getnodevalue ();
RoleName = (Element) Rolnodelist.item (j)). GetAttribute ("name");
Thelist.add (New Elementandrole (ElementName, roleName));
}
}
return thelist;
}


Checks if the role has permission for the page element
Private Boolean isauthentificated (String elementname) {
String roleName = "";
The user's role is saved to the session when the user logs in, and the role is only taken directly from the session.
RoleName = (String) this.pageContext.getSession (). getattribute ("RoleName");
Rolelist contains a//elementandrole object with the ElementName property of Elementname,rolename property as RoleName, the role has permission for the page element
if (Rolelist.contains (New Elementandrole (ElementName, RoleName))) {
return true;
}
return false;
}


Internal classes that represent the corresponding relationships of roles and page elements
Class Elementandrole {
String elementname;
String RoleName;


Public Elementandrole (String elementname, String roleName) {
This.elementname = elementname;
This.rolename = RoleName;
}


public boolean equals (Object obj) {
Return ((elementandrole) obj. Elementname.equals (this.elementname) && ((elementandrole) obj). roleName
. Equals (This.rolename));
}
}
}

2: After implementing the label definition class, it is the TLD file that defines the label

<?xml version= "1.0" encoding= "UTF-8"?>
<taglib xmlns= "Http://java.sun.com/xml/ns/j2ee" xmlns:xsi= "Http://www.w3.org/2001/XMLSchema-instance"
xsi:schemalocation= "Http://java.sun.com/xml/ns/j2ee web-jsptaglibrary_2_0.xsd"
version= "2.0" >
<tlib-version>1.0</tlib-version>
<jsp-version>2.0</jsp-version>
<description>this si....</description>
<short-name>myT</short-name>
<uri>http://mytag</uri>


<tag>
<description>extends tagsupport</description>
<name>hello</name>
<tag-class>com.suyin.web.jspsectag.HelloTag</tag-class>
<body-content>jsp</body-content>
</tag>


<tag>
<name>JspSecurity</name>
<tagclass>com.suyin.web.jspsectag.JspSecurityTag</tagclass>
<info>
Jspsecuritytag
</info>
<attribute>
<name>elementName</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
</tag>


</taglib>

Rights Management label Experimental test permission profile

<?xml version= "1.0" encoding= "UTF-8"?>
<security>
<rolename name= "Common"/>
<rolename name= "admin"/>
<rolename name= "admin"/>
</security>

Introduction of tags in 3:web.xml

<!--custom Labels--
<jsp-config>
<taglib>
<taglib-uri>http://mytag</taglib-uri>
<taglib-location>
/web-inf/tagconfig/mytld.tld
</taglib-location>
</taglib>
</jsp-config>

This way, the label definition is complete.

4: Test

4-1:indxe.jsp Show Hello feature tags and permissions-admin and common role tags

<%@ taglib uri= "Http://mytag" prefix= "MyTag"%>
<%@ page contenttype= "text/html; Charset=utf-8 "%>


<title>first cumstomed tag</title>
<body>


<form name= "Form1" >
<table width= "border=" 0 "cellspacing=" 0 "cellpadding=" 2 ">
<tr>
<td><mytag:jspsecurity elementname= "Employeedetail" >
<input type= "button" name= "detail" value= "common?" >
</mytag:JspSecurity> <mytag:jspsecurity elementname= "Employeemodify" >
<input type= "button" name= "Modify" value= "admin" >
</mytag:JspSecurity></td>
</tr>
</table>
<br>
</form>


<p> The following content is displayed from Taglib:</p>
<mytag:hello/>
</body>

4-2:INDEX1 tags Show Common role tags

<%@ taglib uri= "Http://mytag" prefix= "MyTag"%>
<%@ page contenttype= "text/html; Charset=utf-8 "%>
<title>test</title>
<body>
<form name= "Form1" >
<table width= "border=" 0 "cellspacing=" 0 "cellpadding=" 2 ">
<tr>
<td><mytag:jspsecurity elementname= "Employeedetail" >
<input type= "button" name= "detail" value= "common" >
</mytag:JspSecurity> <mytag:jspsecurity elementname= "Employeemodify" >
<input type= "button" name= "Modify" value= "admin" >
</mytag:JspSecurity></td>
</tr>
</table>
<br>
</form>
</body>

5: Run Results

Admin Role

Common role

At this end, the implementation of a rough way, right when the demo.

Organize a JSP custom label and permission control label