Java/JSP/EL

Материал из Java эксперт
Версия от 18:01, 31 мая 2010; (обсуждение)
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EL and Complex JavaBeans

<jsp:useBean id="person" class="com.jexp.Person" scope="request" />
<html>
<body>
    <h1>EL and Complex JavaBeans</h1>
    <table border="1">
      <tr>
        <td>${person.name}</td>
        <td>${person.age}</td>
        <td>${person["address"].line1}</td>
        <td>${person["address"].town}</td>
        <td>${person.address.phoneNumbers[0].std} ${person.address.phoneNumbers[0].number}</td>
        <td>${person.address.phoneNumbers[1].std} ${person.address.phoneNumbers[1].number}</td>
      </tr>    
      
  
    </table>
    
    
  </body>
</html>





EL and Complex JavaBeans 1

<jsp:useBean id="person" class="com.jexp.Person" scope="request" />
<html>
<body>
    <h1>EL and Complex JavaBeans</h1>
    <table border="1">
      <tr>
        <td>${person.name}</td>
        <td>${person.age}</td>
        <td>${person["address"].line1}</td>
        <td>${person["address"].town}</td>
        <td>${person.address.phoneNumbers[0].std} ${person.address.phoneNumbers[0].number}</td>
        <td>${person.address.phoneNumbers[1].std} ${person.address.phoneNumbers[1].number}</td>
      </tr>    
      
  
    </table>
    
    
  </body>
</html>





EL Arithmetic

<html>
<body>
    <h1>EL Arithmetic</h1>
    <table border="1">
      <tr>
        <td><b>Concept</b></td>
        <td><b>EL Expression</b></td>
        <td><b>Result</b></td>
      </tr>    
      <tr>
        <td>Literal</td>
        <td>${"${"}10}</td>
        <td>${10}</td>
      </tr>    
      <tr>
        <td>Addition</td>
        <td>${"${"}10 + 10 }</td>
        <td>${10 + 10}</td>
      </tr>  
      <tr>
        <td>Subtraction</td>
        <td>${"${"}10 - 10 }</td>
        <td>${10 - 10}</td>
      </tr>    
      <tr>
        <td>Multiplication</td>
        <td>${"${"}10 * 10 }</td>
        <td>${10 * 10}</td>
      </tr>    
      <tr>
        <td>Division / </td>
        <td>${"${"}10 / 3 }</td>
        <td>${10 / 3}</td>
      </tr>    
      <tr>
        <td>Division DIV</td>
        <td>${"${"}10 div 3 }</td>
        <td>${10 div 3}</td>
      </tr>    
      <tr>
        <td>Modulus</td>
        <td>${"${"}10 % 10 }</td>
        <td>${10 % 3}</td>
      </tr>    
      <tr>
        <td>Modulus</td>
        <td>${"${"}10 mod 10 }</td>
        <td>${10 mod 3}</td>
      </tr>    
      <tr>
        <td>Division by Zero</td>
        <td>${"${"}10 / 0 }</td>
        <td>${10 / 0}</td>
      </tr>    
      <tr>
        <td>Exponential</td>
        <td>${"${"}2E2}</td>
        <td>${2E2}</td>
      </tr>  
      <tr>
        <td>Unary Minus</td>
        <td>${"${"}-10}</td>
        <td>${-10}</td>
      </tr>    
        
    </table>
    
    
  </body>
</html>





EL Function Examples

/*
Beginning JavaServer Pages
Vivek Chopra, Jon Eaves, Rupert Jones, Sing Li, John T. Bell
ISBN: 0-7645-7485-X
*/





JSP and EL: EL Expression Examples

/*
Beginning JavaServer Pages
Vivek Chopra, Jon Eaves, Rupert Jones, Sing Li, John T. Bell
ISBN: 0-7645-7485-X
*/

<%@ taglib prefix="c" uri="http://java.sun.ru/jsp/jstl/core" %>
<%@ taglib prefix="fmt" uri="http://java.sun.ru/jsp/jstl/fmt" %>
<%@ taglib prefix="wroxtags" tagdir="/WEB-INF/tags" %>

<html>
<head>
<title>EL Expression Examples</title>
</head>
<body>
<h1>EL Expression Examples</h1>
<h2>Arithmetic Operators in Expressions</h2>
<c:set var="appleCount" value="${1 + 2 * 4 - 6 / 2}"/>
<b>There are ${1 + 2 * 4 - 6 / 2} apples on the table.</b><br/>
<b>There are 
<fmt:formatNumber pattern="#####"> ${1 + 2 * 4 - 6 / 2}</fmt:formatNumber>
apples on the table.</b><br/>

<b>It feels like ${-4 - 8} degree today.</b><br/>
<c:set var="myGrade" value="11"/><br/>
<b>The average grade is ${(myGrade == 10) ? "perfect" : "good"}. </b><br/>
<b>There are ${23/54} remaining. </b><br/>
<b>There are ${6 div 2} apples on the table.</b><br/>
<b>There are ${2003 div 8} apples on the table.</b><br/>
<b>There are ${2003 mod 8} apples on the table.</b><br/>
<b>There are ${2003 % 8} apples on the table.</b><br/>
<h2>Logical Operators</h2>
<c:set var="guess" value="12"/>
<b>Your guess is ${guess}.</b><br/>
<c:if test="${(guess >= 10)  && (guess <= 20)}">
   <b>You"re in range!</b><br/>
</c:if>
<c:if test="${(guess < 10)  || (guess > 20)}">
   <b>Try again!</b><br/>
</c:if>
<c:set var="guess" value="1"/>
<b>Your guess is ${guess}.</b><br/>
<c:if test="${(guess >= 10)  and (guess <= 20)}">
   <b>You"re in range!</b><br/>
</c:if>
<c:if test="${(guess < 10)  or (guess > 20)}">
   <b>Try again!</b><br/>
</c:if>

<h2>Comparison Operators</h2>
4 > "3"   ${4 > "3"}<br/>
"4" > 3   ${"4" > 3}<br/>
"4" > "3" ${"4" > "3"} <br/>
4 >= 3    ${4 >= 3}<br/>
4 <= 3     ${4 < 3}<br/>
4 == "4"   ${4 == 4}<br/>
<h2>empty Operator</h2>
empty "" ${empty ""}<br/>
empty "sometext" ${empty "sometext"}<br/>
empty Junk ${empty Junk}<br/>
empty guess ${empty guess}<br/> 

<h2>Boolean and Null Values</h2>
<c:set var="StrVar" value="true"/>
<c:if test="${StrVar}">
  equal!
</c:if><br/>
null == null  ${null == null}<br/>
"null" == null ${"null" == null}<br/>

</body>
</html>





JSP and EL:EL Property Access and Nested Properties

/*
Beginning JavaServer Pages
Vivek Chopra, Jon Eaves, Rupert Jones, Sing Li, John T. Bell
ISBN: 0-7645-7485-X
*/





JSP and EL: EL Type Conversion Examples

/*
Beginning JavaServer Pages
Vivek Chopra, Jon Eaves, Rupert Jones, Sing Li, John T. Bell
ISBN: 0-7645-7485-X
*/





JSP and EL: Implicit Object Example Form processor

/*
Beginning JavaServer Pages
Vivek Chopra, Jon Eaves, Rupert Jones, Sing Li, John T. Bell
ISBN: 0-7645-7485-X
*/


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