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Do javaweb development of the most commonly used a thing El expression, this thing is a very useful thing, but sometimes we deal with complex string manipulation, it is a little bit, this time we need to use a custom method to achieve more concise and convenient things.
The following custom El expression that turns an object into a JSON string is used to illustrate this custom process:
Elfunctions.java
import net.sf.json.JSONObject;
publicclass ElFunctions{
publicstatictoJsonString(Object obj){
// 将java对象转换为json对象
JSONObject json = JSONObject.fromObject(obj);
String str = json.toString();
return str;
}
}
Mobai-el-common.tld
<?xml version= "1.0" encoding= "UTF-8"?>
<taglib xmlns="Http://java.sun.com/xml/ns/javaee" xmlns:xsi="http ://www.w3.org/2001/XMLSchema-instance " xsi:schemalocation=" Http://java.sun.com/xml/ns/javaee Http://java.sun.com/xml/ns/javaee/web-jsptaglibrary_2_1.xsd " version=" 2.1">
<tlib-version>1.0</tlib-version>
<short-name>El</short-name>
<!--format the object as a JSON string --
<function>
<name>toJSONString</name> <function-class>Com.mobai.taglib.functions.ElFunctions</function-class>
<function-signature>String tojsonstring (Java.lang.Object)</function-signature>
<description>Format the object as a JSON string</Description>
<example>${el:tojsonstring (Value)}</Example>
</function>
</taglib>Xml
<?xml version= "1.0" encoding= "UTF-8"?>
<web-app version="2.5" xmlns="Http://java.sun.com/xml/ns/javaee" xmlns:xsi= "http://www.w3.org/2001/XMLSchema-instance" xsi:schemalocation=" Http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd ">
<jsp-config>
<taglib>
<!--The reference address of the configuration label is referenced in the JSP page using the
<Taglib-uri>Mobai.com/el-common</Taglib-uri>
<!--configuration label TLD file address--
<taglib-location>/web-inf/mobai-el-common.tld</taglib-location>
</taglib>
</jsp-config>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</Web-app>index.jsp
<%@ taglib uri="mobai.com/el-common" prefix="el" %><body> ${el:toJsonString(user)}</body>
The above is probably the key code of the function, here only a way to convert the JSON string, the others can be customized according to the needs of a variety of methods to use.
Custom El expression, convert object to JSON format, key code
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