JSPEL简介及实例

1、JSP EL 局部JSP EL的运算符类型定义算术型+ - * / di v % mod逻辑型and && or | not !关系型=eq != ne > gt < lt >= ge <= l e条件型a?b: c空empt yJSP EL的根本用法类型实例根本调用方法JavaBeans$ user. user name$user" username"$ user ' username' user. get Us er n a me ()数组$ s por t 1 $ s por t " 1" $

2、 sport ' 1' spor t 1List$ phone 2 $ phone " 2" $ phone ' 2' phone. get ( 2)Mb p$ phone. home$ phone " home" $ phone ' home' phone. get ( " home")三、JSP EL的内容对象pageCo ntext当前页面上下文件对象pageScope page 对象 requestScope request对象session Scope session对象app

3、licati on Scope applicati on对象param得到页面传来的参数paramValues得到页面传来的多个参数，返回一个数组header获取头信息headerValues获取头信息的值cookie获取cookie对象的值ini tParam获取设定初始的参数值例：四、如何设置JSP不使用JSP EL1、当前页面不要用JSP EL<%page isELIg no r e d = "true" % >2、整个web应用都不使用EL,修改web.xml文件五、实例1、根本运算符的实例< % page language ="java

4、" pageEncoding ="UTF-8" % >v!DOCTYPE HTML PUBLIC "-/W3C/DTD HTML 4.01 Transitional/EN" >< html >< head >< title > My JSP 'elExample1.jsp' starting page </ title >< meta-equiv="pragma" content ="no-cache"< meta-e

5、quiv="cache-c on trol" content ="no-cache"< meta-equiv="expires" content ="0">< meta-equiv="keywords" content ="keyword1,keyword2,keyword3">< meta-equiv="description" content ="This is my page"><!-&l

6、t; link rel ="stylesheet" type ="text/css" href ="styles.css">-></ head >< body ><!-以下为JSP EL的算术运算实例 ->$10+10< br>$10-10<br>$10*10< br>$10/10<br>$10 mod 10 < br><!-以下为想输入原样的表达式，需要用或者'进行转义->$10+10< br>

7、'$'10+10< br><!-以下为JSP EL的关系运算实例 ->$100>200< br>$100 gt 200 <br>$100 <200 <br >$100 It 200 < br>$100>=200< br>$100 ge 200 <br>$100 <=200 <br >$100le 200 < br>$100=200< br>$100eq 200 <br>$100!=200< br>$1

8、00ne 200 < br><!-以下为比拟字符，字符用单引号，字符串用双引号引起->$'e' eq 'h' <br>$"hit"> "him" <br><!-以下为逻辑运算符的实例->$(10>2)&&(34>25)<br>$(10>2) and (34>25)< br>$(10>2)|(34>25)< br>$(10>2)or(34>25)< br&

9、gt;$!(10>2)<br>$not(10>2)< br>< !- empty运算符的应用 empty判断时，假设对象为 ""或是null，那么都为true- ><%pageC on text.setAttribute("user name", null);pageC on text.setAttribute("password","");pageContext.setAttribute("city"," 北京");pa

10、geC on text.setAttribute("date", newjava.util.Date();%>< !-判断user name变量是否为空，以下返回true- >$emptyuser name < br>< !-判断password变量是否为空，以下返回true ->$emptypassword < br>< !-判断city变量是否为空，以下返回false- >$empty city <br>< !-判断date变量是否为空，以下返回false ->$empty dat

11、e < br></ body ></ html >2、用JSP EL 读取JavaBean 中的值< % page Ianguage ="java" pageEncoding ="UTF-8" % >< % page import ="java.util.*,com.meixin.beans.*"% >< !DOCTYPE HTML PUBLIC "-/W3C/DTD HTML 4.01Transitional/EN">< html &g

12、t;< head >< title > My JSP 'elExample1.jsp' starting page </ title >< meta-equiv ="pragma"content ="no-cache"< meta -equiv ="cache-control"content ="no-cache"< meta-equiv ="expires"content ="0">< met

13、a -equiv ="keywords" content ="keyword1,keyword2,keyword3">< meta -equiv ="description"content ="This is my page"><!-< link rel ="stylesheet" type ="text/css" href ="styles.css">-></ head >< body >

14、< !-使用 User Bea n，设置属性值 user name- >< jsp:useBeanid ="user" class ="com.meixin.beans.User"></jsp:useBean >< jsp:setProperty name ="user" property ="username" value ="meixin"/><%/建立Profile 对象，设置邮件地址Profile p = new Profile。；p

15、.setEmail("w ni ght88si na");/将不同的存入Map中，并设置在p对象的属性中Map < String,String> phone = new HashMap < String,String> ();pho ne.put("office","8383838");p.setPho ne(ph on e);/建立地址对象，设置城市名Address address = new Address();address.setCity(" 北京");Address address

16、es = address;p.setAddress(addresses);user.setProfile(p);%>< !-用JSP EL的级连方式输入值->< !-输岀user对象中的username 属性值，三种写法等价 ->$user.user name<br>$user"username" < br >$user'username' < br >< !-输岀user对象中profile属性对象中的 phone 属性Map中键值为 office 的值->$fi

17、le.phone.office < br >$user'rofile''phone''office' < br >< !-输岀user对象中profile属性对象中address 数据属性中第0个元素对象中的city的属性值->$file.address0.city < br ></ body ></ html >以下为对象的JavaBean 的内容1) Profile 类package com.meixi n.bea ns;import java.util.

18、Date;import java.util.Map;public class ProfileprivateString email;privateDatebirthday;private Address address;private Map<Str ing. Stringpho ne;public String getEmail()return email;public void setEmail(Stringemail)this .email = email;public Date getBirthday()retur n birthday;public void setBirthd

19、ay(Date birthday)this .birthday = birthday;public Address getAddress()retur n address;public void setAddress(Addressaddress)this .address = address;public MapvString. StringgetPhone()retur n phone;public void setPhone(Map<String.Stringphone)this .phone = phone;2)User 类package com. m eix in.b eans

20、;public class Use rprivate Lon g u se rID ;private St r i ng userName;private St r ing p a ssw o rd ;private Profile profile;public Long getUser I D()r et u r n userID;public void setU ser ID ( L ong use rl D)t h i s. u se r I D = use rl D ;public St r ing g et U se r Na m e ()r et u rn userName;pub

21、lic void setU ser Na m e( Str ing userName)this. userName = userName;public St r ing get Passw or d ()r et u r n p a s sw o r d ;public void setPassw ord(String password)3)Address 类3、实例：输出页面不同范围内属性的值地址功 1曲 SQtJWebPrvject 可wuinmeixinmeixmS>es sianmeixinRequestmeixmAppEc atioa- V- i - "l *S r

22、1 Lid W J rifXivr £r口vmeta-equiv = "pragma" content="no - cache"< meta-equiv = "cache-c on t r o l" content="no - cache"< meta-equiv = "expires" conten t = " 0" >< meta-equiv=" keywords" conten t="keyword1,ke

23、yword2,keyword3">< m et a-equiv="descripti on" conten t = "This i s m y page">< !-vlink rel= "stylesheet" type= "text/css" href = "styles. css">->< b o d y >< %p a g e C o ntext. s e t A11 ri b u t e (" u s e r na

24、m e "," m e i x i n"); request. setAttribute("user name","meixi n Request");s e s s i on. setAttribute("user name","meixi n S e s s i on");a p p l i ca t i on. s e t A11 ri b u t e (" u se r name","meixi nApplicati on");% >

25、;< !-输岀 meix in ->$ pageScope. user name < b r >$ pageScope'user name' < b r >< !-输岀值为 meix in S e s s i on ->$ s e s s i on S co p e. user name < b r >< !- 输岀值为 meix in Re q u e st - >$ requestScope. user name < b r>< !- 输岀值为 meixi nApplicati on

26、->$ a p p l i ca t i on Scope. user name < b r >< !- 输岀值为 meix in，此 变量系 统根据 p a g e C on text,req uest,sess ion ,applicati on 依次查找 ->$ user name < b r >< / b o d y >< / h t m l >4、实例：param用于获取上一页面传递的参数值< ! - - param用于获取上一页面传递来的参数值->$ param. user name<br>$ param. password < br>5、实例：cookie 用于获取cookie 参数的值< %resp on se. addCookie (new Cookie("user nam e ","