实现有价值的IT服务
全部博文（709）
分类： Java
2006-10-12 22:00:19
| Method Detail |
public getContext(java.lang.String uripath)
ServletContext object that corresponds to a specified URL on the server.
This method allows servlets to gain access to the context for various parts of the server, and as needed obtain objects from the context. The given path must be begin with "/", is interpreted relative to the server's document root and is matched against the context roots of other web applications hosted on this container.
In a security conscious environment, the servlet container may return null for a given URL.
uripath - a String specifying the context path of another web application in the container.
ServletContext object that corresponds to the named URL, or null if either none exists or the container wishes to restrict this access.
public int getMajorVersion()
public int getMinorVersion()
public java.lang.String getMimeType(java.lang.String file)
null if the MIME type is not known. The MIME type is determined by the configuration of the servlet container, and may be specified in a web application deployment descriptor. Common MIME types are "text/html" and "image/gif".
file - a String specifying the name of a file
String specifying the file's MIME typepublic java.util.Set getResourcePaths(java.lang.String path)
the - partial path used to match the resources, which must start with a /
public java.net.URL getResource(java.lang.String path)
throws java.net.MalformedURLException
This method allows the servlet container to make a resource available to servlets from any source. Resources can be located on a local or remote file system, in a database, or in a .war file.
The servlet container must implement the URL handlers and URLConnection objects that are necessary to access the resource.
This method returns null if no resource is mapped to the pathname.
Some containers may allow writing to the URL returned by this method using the methods of the URL class.
The resource content is returned directly, so be aware that requesting a .jsp page returns the JSP source code. Use a RequestDispatcher instead to include results of an execution.
This method has a different purpose than java.lang.Class.getResource, which looks up resources based on a class loader. This method does not use class loaders.
path - a String specifying the path to the resource
null if there is no resource at that path
public java.io.InputStream getResourceAsStream(java.lang.String path)
InputStream object.
The data in the InputStream can be of any type or length. The path must be specified according to the rules given in getResource. This method returns null if no resource exists at the specified path.
Meta-information such as content length and content type that is available via getResource method is lost when using this method.
The servlet container must implement the URL handlers and URLConnection objects necessary to access the resource.
This method is different from java.lang.Class.getResourceAsStream, which uses a class loader. This method allows servlet containers to make a resource available to a servlet from any location, without using a class loader.
name - a String specifying the path to the resource
InputStream returned to the servlet, or null if no resource exists at the specified pathpublic getRequestDispatcher(java.lang.String path)
RequestDispatcher object can be used to forward a request to the resource or to include the resource in a response. The resource can be dynamic or static.
The pathname must begin with a "/" and is interpreted as relative to the current context root. Use getContext to obtain a RequestDispatcher for resources in foreign contexts. This method returns null if the ServletContext cannot return a RequestDispatcher.
path - a String specifying the pathname to the resource
RequestDispatcher object that acts as a wrapper for the resource at the specified path
public getNamedDispatcher(java.lang.String name)
Servlets (and JSP pages also) may be given names via server administration or via a web application deployment descriptor. A servlet instance can determine its name using .
This method returns null if the ServletContext cannot return a RequestDispatcher for any reason.
name - a String specifying the name of a servlet to wrap
RequestDispatcher object that acts as a wrapper for the named servlet
public getServlet(java.lang.String name)
throws
This method was originally defined to retrieve a servlet from a ServletContext. In this version, this method always returns null and remains only to preserve binary compatibility. This method will be permanently removed in a future version of the Java Servlet API.
In lieu of this method, servlets can share information using the ServletContext class and can perform shared business logic by invoking methods on common non-servlet classes.
public java.util.Enumeration getServlets()
This method was originally defined to return an Enumeration of all the servlets known to this servlet context. In this version, this method always returns an empty enumeration and remains only to preserve binary compatibility. This method will be permanently removed in a future version of the Java Servlet API.
public java.util.Enumeration getServletNames()
This method was originally defined to return an Enumeration of all the servlet names known to this context. In this version, this method always returns an empty Enumeration and remains only to preserve binary compatibility. This method will be permanently removed in a future version of the Java Servlet API.
public void log(java.lang.String msg)
msg - a String specifying the message to be written to the log filepublic void log(java.lang.Exception exception,
java.lang.String msg)
This method was originally defined to write an exception's stack trace and an explanatory error message to the servlet log file.
public void log(java.lang.String message,
java.lang.Throwable throwable)
Throwable exception to the servlet log file. The name and type of the servlet log file is specific to the servlet container, usually an event log.
message - a String that describes the error or exception
throwable - the Throwable error or exceptionpublic java.lang.String getRealPath(java.lang.String path)
String containing the real path for a given virtual path. For example, the path "/index.html" returns the absolute file path on the server's filesystem would be served by a request for "", where contextPath is the context path of this ServletContext..
The real path returned will be in a form appropriate to the computer and operating system on which the servlet container is running, including the proper path separators. This method returns null if the servlet container cannot translate the virtual path to a real path for any reason (such as when the content is being made available from a .war archive).
path - a String specifying a virtual path
String specifying the real path, or null if the translation cannot be performedpublic java.lang.String getServerInfo()
The form of the returned string is servername/versionnumber. For example, the JavaServer Web Development Kit may return the string JavaServer Web Dev Kit/1.0.
The servlet container may return other optional information after the primary string in parentheses, for example, JavaServer Web Dev Kit/1.0 (JDK 1.1.6; Windows NT 4.0 x86).
String containing at least the servlet container name and version numberpublic java.lang.String getInitParameter(java.lang.String name)
String containing the value of the named context-wide initialization parameter, or null if the parameter does not exist.
This method can make available configuration information useful to an entire "web application". For example, it can provide a webmaster's email address or the name of a system that holds critical data.
name - a String containing the name of the parameter whose value is requested
String containing at least the servlet container name and version number
public java.util.Enumeration getInitParameterNames()
Enumeration of String objects, or an empty Enumeration if the context has no initialization parameters.
Enumeration of String objects containing the names of the context's initialization parameters
public java.lang.Object getAttribute(java.lang.String name)
null if there is no attribute by that name. An attribute allows a servlet container to give the servlet additional information not already provided by this interface. See your server documentation for information about its attributes. A list of supported attributes can be retrieved using getAttributeNames.
The attribute is returned as a java.lang.Object or some subclass. Attribute names should follow the same convention as package names. The Java Servlet API specification reserves names matching java.*, javax.*, and sun.*.
name - a String specifying the name of the attribute
Object containing the value of the attribute, or null if no attribute exists matching the given name
public java.util.Enumeration getAttributeNames()
Enumeration containing the attribute names available within this servlet context. Use the method with an attribute name to get the value of an attribute.
Enumeration of attribute names
public void setAttribute(java.lang.String name,
java.lang.Object object)
If listeners are configured on the ServletContext the container notifies them accordingly.
If a null value is passed, the effect is the same as calling removeAttribute().
Attribute names should follow the same convention as package names. The Java Servlet API specification reserves names matching java.*, javax.*, and sun.*.
name - a String specifying the name of the attribute
object - an Object representing the attribute to be boundpublic void removeAttribute(java.lang.String name)
null.
If listeners are configured on the ServletContext the container notifies them accordingly.
name - a String specifying the name of the attribute to be removedpublic java.lang.String getServletContextName()
| Method Detail |
public java.lang.String getServletName()
public getServletContext()
public java.lang.String getInitParameter(java.lang.String name)
String containing the value of the named initialization parameter, or null if the parameter does not exist.
name - a String specifying the name of the initialization parameter
String containing the value of the initialization parameterpublic java.util.Enumeration getInitParameterNames()
Enumeration of String objects, or an empty Enumeration if the servlet has no initialization parameters.
Enumeration of String objects containing the names of the servlet's initialization parameters