EL表达式+JSTL

0717.png

cookie的保存和获得

保存

    <%
        Cookie c1 = new Cookie("uname","abcd");
        c1.setMaxAge(5*60);
        
        Cookie c2 = new Cookie("uinfo","xyz");
        c2.setMaxAge(5*60);
        
        //保存cookie
        response.addCookie(c1);
        response.addCookie(c2);
    %>

获取

    
    //jsp获取
    <%
        String v1 = "";
        String v2 = "";
        
        Cookie[] cks = request.getCookies();
        for(int i = 0 ;i < cks.length ;i++){
            if("uname".equals( cks[i].getName())) v1 = cks[i].getValue();
            if("uinfo".equals( cks[i].getName())) v2 = cks[i].getValue();
        }
        
    %>
    


    ck1:<%=v1 %>

    ck2:<%=v2 %>

    

    EL表达式获取
    ck1 : ${cookie.uname.value }

    ck2 : ${cookie.uinfo.value }

获取header

    //jsp
    <%
        Enumeration keys = request.getHeaderNames();
        while( keys.hasMoreElements() ){
            String k = (String)keys.nextElement();
            out.print("
"+ k +"::"+request.getHeader( k ));
        }
    %>
    

    1.<%=request.getHeader("user-agent") %>

    2.<%=request.getHeader("accept-language") %>

    

    EL表达式
    1.${header["user-agent"] }

    2.${header["accept-language"] }

其它符号

    <%
        pageContext.setAttribute("fff", new Users(300,"周瑜",1.82));
        pageContext.setAttribute("sss", new Users(301,"太史慈",1.96));
    %>
         个子高: ${fff.uheight > sss.uheight ? fff.uname : sss.uname }

         个子高2: ${fff.uheight gt sss.uheight ? fff.uname : sss.uname }


         
         名字相等吗 : ${ fff.uname == sss.uname ? "" :"不" }相等

         名字相等吗2 : ${ fff.uname eq sss.uname ? "" :"不" }相等


    
         相等吗 : ${ fff.uname != sss.uname ? "不" :"" }是一个人
     
         相等吗 : ${ fff.uname ne sss.uname ? "不" :"" }是一个人

 
         
    <%
        pageContext.setAttribute("ttt", "asdfasdf");
        pageContext.setAttribute("qqq", "");
    %>     
          存在或为空1: ttt ${ empty ttt ? "无":"有" }数据
 
          存在或为空2: qqq ${ empty qqq ? "无":"有" }数据
 <%-- qqq!=null && qqq.size>0 --%>
          存在或为空3: www ${ empty www ? "无":"有" }数据

JSTL

JSP Standard Tag Library

jsp引入

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

定义

    
    
    
    1.${a1}

    2.${a2}

    3.${requestScope.a2}

输出

    输出:
      
    0.

    1.

    2.

    3.

    3.--${requestScope.a2.uname}

删除

    删除:

    
    1.${a1}

    2.${a2}

    3.${requestScope.a2}

异常

    异常:
 
     
     1. ${requestScope.a2.uname1} 
    

静态/动态引入

    静态/动态引入:
 
                            
    

        

            
<%@ include file="/myDiv1.jsp" %>

            
2
            
3
        
   
        

            

            

                
                    
                  
            
            
6
        
        

            
7
            

            

                    210
                 
            
        
    

路径

    路径:
    
    
        50
        
    
    
    ${aa}--${bb}

003.PNG

if

    <%  
    
        pageContext.setAttribute("upd", new Users(400,"陈宫",173));
    
        List ulist =new ArrayList();
        ulist.add( new Users(100,"诸葛亮",1.84));
        ulist.add( new Users(101,"关羽",2.12));
        ulist.add( new Users(102,"张飞",1.98));
        ulist.add( new Users(103,"刘备",1.74));
        
        pageContext.setAttribute("fff", ulist);
    %>
    if:

    
        没有要修改的对象
    
    
        有有有
    

swith

    swith:

    
        小兵
        吾长
        大将
    

for

    for:

    
        ${st.index}--${f.uname}--${f.uheight}

    
    
        ${s}

    
     
        ${x}
    
    

004.PNG

fmt标签

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

        <%
            Date d1 = new Date();
            pageContext.setAttribute("ttt", d1);
            
            SimpleDateFormat fmt = new SimpleDateFormat("yyyy年MM月dd日 hh时mm分ss秒SSS毫秒  E");
        %>
       1.<%=d1 %>

       2.<%=fmt.format(d1) %>

       


       3. 
       
       

       4.

       5.

       6.

       7.

005.PNG

functions标签

    <%
        pageContext.setAttribute("xyz", "aabbccdd");
    %>
    1.${fn:substring(xyz,2,4)   }

    2.${fn:substring(xyz,4,-1)  }

    3.${fn:replace(xyz,"bc","海洋") }

    4.${fn:toUpperCase(xyz)     }

006.PNG