---
# System prepended metadata

title: 1/20 JSP 觀念
tags: [JSP]

---

# 1/20 JSP 觀念

###### tags: `JSP`
# 5-60 errorpage與isErrorPage設定
![](https://i.imgur.com/LZIxfSd.png)

# 5-61.62 errorpage屬性
轉型有問題由這支errorpage="error.jsp"處理程式
![](https://i.imgur.com/kPK0WfM.png)
true 
exception這行印出顯示過程
![](https://i.imgur.com/ky0HdRz.png)
(errorHandler.jsp)(hello.jsp)
用chrome執行 eclipse用ie會有問題
# 5-63 web.xml設定錯誤時處理
web.xml可以用通用性設定
2邊都設通用性 會以jsp程式優先 jsp沒設就以xml優先
上面靜態 下面動態(error-code):![](https://i.imgur.com/LCvfajF.png)
# 5-64 <jsp:include>標籤
include包page自行生成 add.jsp也會獨立生成
參考(5-121)
![](https://i.imgur.com/84KIsQZ.png)
(paramTest1.jsp)(paramTest1.jsp)
In paramTest1:->In paramTest2:->In paramTest1:
http://localhost:8080/JSPDemo/paramTest1.jsp(?first=Harry&last=jjj)
看順序
![](https://i.imgur.com/HdNwoRl.png)

參考(5-117)
![](https://i.imgur.com/GrSpEXV.png)
# 5-65<jsp:forward>標籤
用forward出去就不會回來
![](https://i.imgur.com/wd9367G.png)
![](https://i.imgur.com/iKL0V9y.png)
# 5-66 jps pages XML語法化
![](https://i.imgur.com/sjqgh70.png)
# 5-67 類xml格式標籤
![](https://i.imgur.com/kIhMlq1.png)
(counter_xml.jps)
# 5-68 範例(xml格式)
![](https://i.imgur.com/5634fer.png)
# 5-69 Expression Language(EL)
![](https://i.imgur.com/kSSWlll.png)
https://docs.oracle.com/javaee/6/tutorial/doc/gjddd.html
![](https://i.imgur.com/8Jbfqte.png)
Immediate Evaluation:立即驗證
Deferred Evaluation:晚一點驗證
# 5-70 EL討論範例
黃色區塊=黃色區塊 一樣
![](https://i.imgur.com/ZL9JWJa.png)
![](https://i.imgur.com/vDdDtxP.png)
![](https://i.imgur.com/DefH72f.png)
(eldemo.jsp)
![](https://i.imgur.com/CQJL90g.png)
# 5-71.72 Scripting VS.EL
![](https://i.imgur.com/M31n6RQ.png)
前面強迫轉型 context環境
上面動詞
下面名詞 字首大寫
![](https://i.imgur.com/c7ue1C1.png)
# 5-73~76 EL
對空值得處裡比較不會死當
![](https://i.imgur.com/2SWxUMV.png)
![](https://i.imgur.com/RI5roCx.png)
![](https://i.imgur.com/PXUTOb2.png)
要強迫轉型request 才能叫出.getMethod方法    context.request算是一個子類
get動詞(動作)
![](https://i.imgur.com/Bd3Hvjx.png)
全部忽略:![](https://i.imgur.com/WMBVgFj.png)
參考5-40 ![](https://i.imgur.com/SSJk8Q4.png)
![](https://i.imgur.com/HfcmISo.png)
# 5-77~83 使用EL取得屬性
我去抓一個javabean
物件:user get:proprety 取得某人的名子
登入成功
上面javabean
下面el寫法 屬性名稱.運算
![](https://i.imgur.com/7G1NJMF.png)
陣列orlist用[]
![](https://i.imgur.com/qFiwhly.png)
泛型 變數=建構子 泛型
![](https://i.imgur.com/gf7OuyI.png)
![](https://i.imgur.com/ZryHPCg.png)
names多個名稱
![](https://i.imgur.com/zXKAv4O.png)
索引值變數名稱 param.index getparamname 運算式
![](https://i.imgur.com/UXIcn12.png)
list name = 子類array
![](https://i.imgur.com/G2f0m4Q.png)
# 5-84.85 EL的隱含物件
Implicit Objects 
https://www.javatpoint.com/EL-expression-in-jsp
https://www.tutorialspoint.com/jsp/jsp_expression_language.htm
跟屬性有關![](https://i.imgur.com/8xpZmhI.png)
# 5-86.87 EL運算子
![](https://i.imgur.com/qV2lNHF.png)
![](https://i.imgur.com/L5AOF5g.png)
# 5-89.90 Implicit Object Available in JSP Pages
Implicit(隱性)<=>Explicit(顯性)
exception特別的
![](https://i.imgur.com/hMWm0dw.png)
![](https://i.imgur.com/80Crx4M.png)
![](https://i.imgur.com/uGhB71h.png)
白皮書 80 103頁
![](https://i.imgur.com/jaYdgPU.png)

![](https://i.imgur.com/siBggbd.png)
原因:![](https://i.imgur.com/jIo4Fgf.png)
# 5-91~94 Implicit Objects說明
![](https://i.imgur.com/sCasM3k.png)
網頁看的到page scope
所在的執行環境
![](https://i.imgur.com/g4jG5wT.png)
application=context
![](https://i.imgur.com/X4d3FGC.png)
![](https://i.imgur.com/pYZeck1.png)
page=this 就是自己本身
![](https://i.imgur.com/UN8kQvJ.png)
![](https://i.imgur.com/bJ2Pq1t.png)
# 5-95 Implicit Objects Available in Error Pages
選告變數 物件名稱少用這樣開頭
![](https://i.imgur.com/TzAXOza.png)
(implicit.jsp)(xml)(initTest.jsp)
![](https://i.imgur.com/uZdTNSC.png)
# 5-96.97.(98) 程式碼練習
![](https://i.imgur.com/jU89ibU.png)
![](https://i.imgur.com/SZ4ot8P.png)
![](https://i.imgur.com/9vtj8Fq.png)
# 5-99 Jsp的scope物件
Application servletContext
Session Session
Request Request
page pagecontext
setAttribute()
getAttribute()
removeattribute()
![](https://i.imgur.com/Z27Rc5t.png)
# 5-100 Scope物件
![](https://i.imgur.com/Z8VA8ge.png)
https://javaee.github.io/javaee-spec/javadocs/
![](https://i.imgur.com/rsGffLp.png)
用靜態include
不能用同樣的宣告
# 5-102 JSP page就是servlet
parse翻成java檔
![](https://i.imgur.com/ZfQ0FtZ.png)
# 5-103 JSP的life-cycle phases
七個階段
![](https://i.imgur.com/cKj23Uc.png)
# 5-104 JSP的Instance產生過程
![](https://i.imgur.com/UJ2XSXI.png)
# 5-105 JSP life-cycle中所呼叫的method
服務完實作
![](https://i.imgur.com/GMo5dDc.png)
https://javaee.github.io/javaee-spec/javadocs/
![](https://i.imgur.com/uMYvj2Z.png)
![](https://i.imgur.com/SfebXZz.png)

# 5-106.7.8 jsp to servlet
![](https://i.imgur.com/76kuWO8.png)

![](https://i.imgur.com/QV3CGzv.png)
樣板文字 out.write
(visitorcounter.jsp)
![](https://i.imgur.com/4hQoEqQ.png)

# 5-109 Translation units
a includ b 不能重複宣告
![](https://i.imgur.com/ikyQO9D.png)
(參考5-114)
# 5-110 JSP life-cycle範例
(persistent_visitorcounter.jsp)
![](https://i.imgur.com/E1oQLZA.png)
# 5-111 使用request-time attribute expressions
把資訊帶進去
下面的程式要在執行階段才能執行
![](https://i.imgur.com/30IiGup.png)
# 5-113 Static inclusion
第一行 jsp寫法
第二行 xml
![](https://i.imgur.com/v6v19Gu.png)
# 5-114 Static inclusion例
![](https://i.imgur.com/aZbMPs9.png)
# 5-115 Static inclusion的注意事項
上一張a跟b可擺pageContext
![](https://i.imgur.com/B9wPr9G.png)
# 5-116 Dynamic inclusion
page活的
flush='true'立即送出
![](https://i.imgur.com/VmboksQ.png)
# 5-117 Dynamic inclusion範例
各自有serv程式
![](https://i.imgur.com/8EjqZpm.png)
白皮書 114(參考)
![](https://i.imgur.com/m60NhDF.png)![](https://i.imgur.com/gmavF7I.png)
# 5-118.119 JSP include action說明
java語法
servlet語法
jsp include進來
	include(StringrelativeUrlPath, boolean flush)
include   
If the relativeUrlPath begins with a "/" then the URL specified is calculated relative to the DOCROOT https://javaee.github.io/javaee-spec/javadocs/
![](https://i.imgur.com/Fu3ZTtp.png)
白皮書
![](https://i.imgur.com/aFlk8IO.png)
靜態
```
• A.jsp says <%@ include file=”dir/B.jsp”%> and dir/B.jsp says <%@ include
file=”C.jsp”%>. In this case the relative specification C.jsp resolves to dir/C.jsp.
• A.jsp says <jsp:include page=”dir/B.jsp”/> and dir/B.jsp says <jsp:include
page=”C.jsp” />. In this case the relative specification C.jsp resolves to dir/
C.jsp.
• A.jsp says <jsp:include page=”dir/B.jsp”/> and dir/B.jsp says <%@ include
file=”C.jsp” %>. In this case the relative specification C.jsp resolves to dir/
C.jsp.
• A.jsp says <%@ include file=”dir/B.jsp”%> and dir/B.jsp says <jsp:include
page=”C.jsp”/>. In this case the relative specification C.jsp resolves to C.jsp.
```
1.a->b<c=c
2.a>b>c
3.a->b=c(在b裡面)
4.a靜態->b b動態->c c=a
![](https://i.imgur.com/FkuUPsn.png)
# 5-120  JSP forward action說明
forward
pagecontext特異功能送出去
![](https://i.imgur.com/7hGBQFD.png)
# 5-121 傳遞參數給dynamically included compon
送參數
![](https://i.imgur.com/wx02uwE.png)
(參考5-64頁)
# 5-122 與dynamically included components共享物件
(參考5-117圖)
![](https://i.imgur.com/TmBfSm2.png)
# 5-124 甚麼是JavaBeans?
封裝:合法的方法，讓使用者來呼叫，做控管，跟邏輯判斷
![](https://i.imgur.com/xApewlv.png)
# 5-125 JavaBeans的設計規則
沒參數的建構子
建構子的宣告 要寫"沒有參數的建構子"
類別或成員都沒有公開的變數
JavaBean需要package player;
![](https://i.imgur.com/3HHIzuh.png)![](https://i.imgur.com/Z5z9wfZ.png)
1.![](https://i.imgur.com/PVUPwPJ.png)2.![](https://i.imgur.com/NeNr9Gq.png)3.只是一個宣告 實作implements![](https://i.imgur.com/ZWH0b6C.png)
javaBeans可以把東西都包起來封裝
![](https://i.imgur.com/CdXaAUC.png)
# 5-126 Jsp tage設定JavaBeans
![](https://i.imgur.com/CWTDqbx.png)白皮書![](https://i.imgur.com/EAMN0g8.png)
# 5-127.128 <jsp:useBean>的宣告項目(attribute)
![](https://i.imgur.com/iw6G2HA.png)![](https://i.imgur.com/dSCJ1z3.png)

type跟class不能亂寫
type父類
![](https://i.imgur.com/VRgM9Hu.png)
# 5-129.130 <jsp:get(set)property>-讀取Bean的值
宣告 取得
property:轉化動作(參考131)
siraple property
index property
![](https://i.imgur.com/IWKKQWq.png)![](https://i.imgur.com/lgX36w6.png)
# 5-131 範例討論
java.io.Serializable
![](https://i.imgur.com/Yh97971.png)
# 5-132
![](https://i.imgur.com/fca8lxa.png)程式碼去寫![](https://i.imgur.com/rlQGD9Q.png)javabean去寫![](https://i.imgur.com/IAP3CP2.png)
# 5-133~135 範例討論
type沒寫
宣告變數名稱空的
![](https://i.imgur.com/VvRm35k.png)![](https://i.imgur.com/V5pgJgJ.png)

https://javaee.github.io/javaee-spec/javadocs/
![](https://i.imgur.com/IpleaMs.png)
# 5-136 <jsp:useBean>
user.setPassword("123456")
.方法
javabean沒有定義setPassword的方法javabean會當掉
大小寫要注意
![](https://i.imgur.com/7qFWCqi.png)
# 5-137 <jsp:setProperty>
![](https://i.imgur.com/WkfjMfS.png)![](https://i.imgur.com/AvvoTsf.png)

# 5-138.139 <jsp:setProperty>
138跟139相對的
138 找步道user物件，則會建立一個新的物件並設定相關屬性內容，相反則會直接使用![](https://i.imgur.com/GbJG4I1.png)139 2條獨立的![](https://i.imgur.com/yzlmlql.png)
# 5-140 <jsp:getProperty>
命名法則很重要
![](https://i.imgur.com/kqTEBxH.png)
# 5-141 Bean Class的安裝
第三方開發 通常擺lib底下
![](https://i.imgur.com/vqjVteJ.png)
(參考5-132)![](https://i.imgur.com/1hpFK4w.png)
# 5-142~145 Bean範例
(StringBean.jsp)(StringBean.java)
![](https://i.imgur.com/I6Lgx0V.png)
3個不同的寫法![](https://i.imgur.com/UZB3H43.png)(SaleEntry.jsp)(SaleEntry1.java)
import
![](https://i.imgur.com/DLbM6xo.png)
![](https://i.imgur.com/LSII7qy.png)
http://localhost:8080/JSPDemo/SaleEntry1.jsp(?itemID=a1234&numltems=10&discountCode=0.8)
(SaleEntry2.java)
![](https://i.imgur.com/wczDBR2.png)