[英]How can I call a static method in jstl?
我已經看到這里已經回答了這個問題,但是當我嘗試相同的方法時,它沒有用。 這是我的代碼:
package linear_programming.matrix;
import java.lang.reflect.Array;
import java.text.DecimalFormat;
import java.text.NumberFormat;
/**
*
* @author Jevison7x
*/
public final class MatrixOperations<T extends Number>
{
/**
* This method round's off decimal numbers to two decimal places.
* @param d The decimal number to be rounded off.
* @param decPlaces The number of decimal places to round off.
* @return the rounded off decimal number.
*/
public static double roundOff(double d, int decPlaces)
{
if(decPlaces < 0)
throw new IllegalArgumentException("The number of decimal places cannot be less than 0.");
else
{
String places = "";
for(int i = 0; i < decPlaces; i++)
places += "0";
NumberFormat nf = new DecimalFormat("0."+places);
return Double.parseDouble(nf.format(d));
}
}
}
這是我的tld文件:
<?xml version="1.0" encoding="UTF-8"?>
<taglib
version="2.1"
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">
<display-name>Custom Functions</display-name>
<tlib-version>1.0</tlib-version>
<short-name>func</short-name>
<uri>/WEB-INF/tlds/Functions</uri>
<function>
<name>roundOff</name>
<function-class>linear_programming.matrix.MatrixOperations</function-class>
<function-signature>double roundOff(double int)</function-signature>
</function>
</taglib>
這是我的JSP文件:
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<%@taglib uri="/WEB-INF/tlds/Functions" prefix="func"%>
<table>
<c:forEach var="Msegment" items="${multipliedSegments}" varStatus="segmentCount">
<tr>
<td>X<sub>${segmentCount.count}</sub><sup>T</sup>X<sub>${segmentCount.count}</sub>=</td>
<td>
<table border="1">
<c:forEach var="row" items="${Msegment}">
<tr>
<c:forEach var="col" items="${row}">
<td>${col}</td><!-- Iwant to invoke the static method here -->
</c:forEach>
</tr>
</c:forEach>
</table>
</td>
</tr>
<tr><td> </td><td> </td></tr>
</c:forEach>
</table>
我只想調用靜態方法
roundOff(double d, int decPlaces)
並傳遞變量
${col}
作為雙精度參數-d,則任何數字都可以用於decPlaces。 任何幫助將不勝感激謝謝。
${func:roundOff(col, 1)}
應該做。 但是AFAIK,taglib文件中的簽名應該是
double roundOff(double, int)
^--- comma here.
如果這不起作用,請提及您得到的確切錯誤消息,而不是僅僅說“它不起作用”。
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