Java Reference
In-Depth Information
The
jrunscript
shell also creates aliases for several Java classes such as
java.io.File
, j
ava.io.Reader
, j
ava.net.URL
, and so on, so you can refer to them
by their simple names. Several other objects are also exposed as global objects by
jrunscript
. You can get the entire list of global objects and their types printed on the
command-line using the following command. Only partial output has been shown.
Notice that the output will also include a property named
p
, which is the variable name
declared in the
for
loop.
c:\>jrunscript
nashorn> for(var p in this) print(p, typeof this[p]);
engine object
JSInvoker function
jmap function
jlist function
inStream function
outStream function
streamClose function
javaByteArray function
pwd function
...
nashorn>exit()
c:\
Summary
The JDK includes a script-engine-independent command-line shell called
jrunscript
.
It can be used to evaluate scripts entered on the command-line or from files. You can find
this shell in the
JAVA_HOME\bin
directory, where
JAVA_HOME
is the directory in which you
have installed the JDK.
The
jrunscript
command-line shell can run scripts written in any scripting
language supported by Java. By default, it runs Nashorn scripts. To use a scripting
language other than Nashorn, you need to include the language's JAR file with
jrunscript
using the
-cp
or
-classpath
option. The
-l
option lets you choose the
scripting language you want to use.
You can use
jrunscript
in one-liner mode, batch mode, and interactive mode.
The one-liner mode lets you execute one line of script. You invoke the one-liner mode
using the
-e
option. The batch mode lets you execute scripts stored in a file. You invoke
the batch mode using the
-f
option. The interactive mode lets you execute scripts entered
on the command-line interactively. You invoke interactive mode by not using the
-e
and
-f
options, or by using the
-f -
option (note a following
-
after
-f
).
You can list all of the available script engines with
jrunscript
using the
-q
option.
Notice that you must include the script engine's JAR files for languages other than
Nashorn to make them available with
jrunscript
. Several useful global functions and
objects are made available by the
jrunscript
shell. For example, the
cat()
function can
be used to print the contents of a file or URL, optionally applying a filter.
Search WWH ::
Custom Search