Using [ ] operator of EL with the Map
EL expressions are always used within curly braces, and
prefixed with a dollar($) sign and $(expression). The first named variable in
the expression is either an implicit object or an attribute stored in one of the
the four scopes i.e. page, request, session, or application. The [] operator is
much more powerful than the dot, because it lets you access Map key or a bean
property name as well as the access to arrays and Lists.
Map stores the values in the form of a key- value pair.
Map can't have a duplicate keys, and each key is associated with at least one
value. In map we can retrieve the value by using ${map["0"]}.
We have made one program on map by using the EL . We
are retrieving the values of a map firstly by setting the map attribute and
thereafter retrieving the value by using the key associated with the map.
The code of the program is given below:
<%@ page import = "java.util.*"%>
<% Map map = new HashMap();
map.put("name", "Tim");
map.put("address", "200,Saint Thomas Loop");
map.put("state", "Virginia, USA");
request.setAttribute("useMap", map);
request.setAttribute("userName","name");
%>
<body>
<center>
<table>
<tr><td><b>The name is :</td></b>
<td><b>${useMap[userName]}</tr></td></b><br>
<tr><td><b>The first element in Map is
:</td></b> <td><b>${useMap["name"]}</tr></td></b><br>
<tr><td><b>The second element in Map is :
</td></b> <td><b>${useMap["address"]}</tr></td></b><br>
<tr><td><b>The third element in Map is :
</td></b> <td><b>${useMap["state"]}</tr></td></b><br>
</table>
</center>
</body> |
The output of the program is given below:
Download this
example.
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