JSTL之c标签

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Student.java：

package com.myapp.beans;

public class Student {

private String sno;

private String sname;

private Integer sage;

private String ssex;

private String deptno;

public Student(String sno, String sname, Integer sage, String ssex,

String deptno) {

this.sno = sno;

this.sname = sname;

this.sage = sage;

this.ssex = ssex;

this.deptno = deptno;

}

public String getDeptno() {

return deptno;

}

public void setDeptno(String deptno) {

this.deptno = deptno;

}

public Integer getSage() {

return sage;

}

public void setSage(Integer sage) {

this.sage = sage;

}

public String getSname() {

return sname;

}

public void setSname(String sname) {

this.sname = sname;

}

public String getSno() {

return sno;

}

public void setSno(String sno) {

this.sno = sno;

}

public String getSsex() {

return ssex;

}

public void setSsex(String ssex) {

this.ssex = ssex;

}

ShowServlet.java：

package com.myapp.servlets;

import java.io.IOException;

import java.util.*;

import javax.servlet.ServletException;

import javax.servlet.http.*;

import com.myapp.beans.Student;

public class ShowServlet extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

this.doPost(request, response);

}

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

//定义10个学生对象

Student s[] = new Student[10];

s[0] = new Student("s001","张三",15,"女","d002");

s[1] = new Student("s002","李四",15,"男","d002");

s[2] = new Student("s003","王五",16,"女",null);

s[3] = new Student("s004","赵六",15,"男","d004");

s[4] = new Student("s005","田七",17,"女","d002");

s[5] = new Student("s006","周八",15,"男",null);

s[6] = new Student("s007","付九",19,"女","d003");

s[7] = new Student("s008","王莹",16,"男",null);

s[8] = new Student("s009","罗剑",15,"男","d002");

s[9] = new Student("s010","宇飞",15,"男","d002");

//将数据装入List

List l = new ArrayList();

for(int i=0;i<s.length;i++){

l.add(s[i]);

}

//将List放入session

request.getSession().setAttribute("allstudents", l);

//跳转到要显示的页面

response.sendRedirect("index.jsp");

}

web.xml：

<servlet-name>ShowServlet</servlet-name>

<servlet-class>com.myapp.servlets.ShowServlet</servlet-class>

</servlet>

<servlet-mapping>

<servlet-name>ShowServlet</servlet-name>

<url-pattern>/show</url-pattern>

</servlet-mapping>

我们通过以上代码，虚拟出一些数据，供页面的标签调用，在实际项目中，可改为由数据库读取。

<c:out>

index.jsp：

<%@page contentType="text/html;charset=gb2312"%>

<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>

<HTML>

<HEAD>

<TITLE>JSTL之C标签</TITLE>

</HEAD>

<BODY>

<c:forEach var="student" items="${allstudents}">

<tr>

</tr>

</c:forEach>

</table>

</BODY>

</HTML>

<c:set>

index.jsp：

<%@page contentType="text/html;charset=gb2312"%>

<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>

<HTML>

<HEAD>

<TITLE>JSTL之C标签</TITLE>

</HEAD>

<BODY>

<c:set var="studentTable" scope="session">

<c:forEach var="student" items="${allstudents}">

<tr>

</tr>

</c:forEach>

</table>

</c:set>

</BODY>

</HTML>

我们通过<c:set>标签，把一个可以显示的表格，保存到session对象的属性中，到下一页显示。

show.jsp：

<%@page contentType="text/html;charset=gb2312"%>

<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>

<HTML>

<HEAD>

<TITLE>JSTL之C标签</TITLE>

</HEAD>

<BODY>

<c:out value="${studentTable}" escapeXml="false"/>

</BODY>

</HTML>

注意这里的escapeXml="false"属性，如果为true，则会把HTML标签显示在网页里。

<c:if>

index.jsp：

<%@page contentType="text/html;charset=gb2312"%>

<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>

<HTML>

<HEAD>

<TITLE>JSTL之C标签</TITLE>

</HEAD>

<BODY>

<c:forEach var="student" items="${allstudents}">

<c:if test="${student.deptno == 'd002'}">

${student.sname}<br>

</c:if>

</c:forEach>

</BODY>

</HTML>

<c:choose>

index.jsp：

<%@page contentType="text/html;charset=gb2312"%>

<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>

<HTML>

<HEAD>

<TITLE>JSTL之C标签</TITLE>

</HEAD>

<BODY>

<c:forEach var="student" items="${allstudents}">

<c:choose>

<c:when test="${student.deptno == 'd003'}">

</c:when>

<c:when test="${student.deptno == 'd004'}">

</c:when>

<c:otherwise>

</c:otherwise>

</c:choose>

${student.sname}</font><br>

</c:forEach>

</BODY>

</HTML>

<c:forEach>

index.jsp：

<%@page contentType="text/html;charset=UTF-8"%>

<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>

<HTML>

<HEAD>

<TITLE>JSTL之C标签</TITLE>

</HEAD>

<BODY>

<c:forEach var="i" begin="1" end="10">

${i} •

</c:forEach>

</BODY>

</HTML>

以上是简单的定义变量，指定其变化范围，循环显示。

index.jsp：

<%@page contentType="text/html;charset=gb2312"%>

<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>

<HTML>

<HEAD>

<TITLE>JSTL之C标签</TITLE>

</HEAD>

<BODY>

<c:forEach var="student" items="${allstudents}" begin="2" end="9" step="2">

<c:out value="${student.sno}"/><br>

</c:forEach>

</BODY>

</HTML>

这个例子与<c:out>的类似，只是在循环时可以指定起始位子和步长。