jstl

jstl  jsp标准标签库一般用途的标签迭代标签条件标签url标签C标签c_out标签（用于把运算结果输出到对象）如果域对象有相同的属性名，他们的优先级是pageContext>request>session>appcationrequest.setAttribute("abc","你好<a href='http://www.baidu.com'>baidu</a>");需要<c:out value="${abc}" escapeXml="false"></c:out>当然可以输出对象信息<c:out value="${user.name}" escapeXml="false"></c:out>c_set标签(设置)<c:set var="abc" value="中国" scope="request"></c:set>    <c:out value="${abc}" escapeXml="false"></c:out>在实际中运用不多c:remove<c:out value="${abc}" escapeXml="false"></c:out>    <c:remove var="abc" ></c:remove>    <c:out value="${abc}" escapeXml="false"></c:out>c:catch<c:catch var="abc">  <% int i=8/0; %>  </c:catch>    <c:out value="${abc}" escapeXml="false"></c:out>条件标签c:if  这是单分支判断<%  request.setAttribute("abc","123");   %><c:if test="${a=='123'}">ok</c:if><c:if test="${a!='123'}">nook</c:if>c:choose<c:choose><c:when test="${a=1}">1</c：when><c:when test="${a=2}">2</c：when><c:otherwise>其他</c:otherwise></c:choose>迭代标签<c:foreach><%ArrayList<Dog> a1=new ArrayList<Rat>();Dog dog1=new Dog();dog1.setName("小黄1");Dog dog2=new Dog();dog2.setName("小黄2");Dog dog3=new Dog();dog3.setName("小黄3");a1.add(dog1);a1.add(dog2);a1.add(dog3);request.setAttribute("dogs","a1");%><% ArrayList<Dog> a2=(ArrayList<Dog>)request.getAttribute("dogs");%><c:forEach items="${a2}" var ="dog"><c:out value="${dog.name}"/></c:forEach><c:forEach var="i" begin="1" end="10" step="3"></c:forEach><c:forTokens>用于分隔字符<c:forTokens items="aa,bb,cc,dd" delims="," var="temp"><c:out value="${temp}"/></c:forTokens>jstl细节问题1.对象是在hashmap或haspset<% Map map=new HashMap();Dog dog1=new Dog();dog1.setName("小黄1");Dog dog2=new Dog();dog2.setName("小黄2");Dog dog3=new Dog();dog3.setName("小黄3");map.put("aa",dog1);map.put("aa",dog2);map.put("aa",dog3);request.setAttribute("dogs",map);%><c:forEach items="${dogs}" var ="per">key=${per.key}值=${per.value.name}</c:forEach><c:if test="$(empty dogs)">//判断集合是否为空</c:if><c:import url="index.jsp"><c:param name="name" value="123"/></c:import>index.jsp页面获取name参数  ${parma.name}就行