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Jsp judges the List length and jsplist length.
Hello everyone:
One problem encountered today is that the back-end uploads a List to the front-end and the front-end judges the List length!
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<Span style = "font-size: 14px; color: # cc0000;"> in jsp development, you often need to determine the length of the list or string to do something, because if in the jstl label does not support else, select while. <% @ Taglib prefix = "c" uri = "http://java.sun.com/jsp/jstl/core" %> <% @ taglib uri = "http://java.sun.com/jsp/jstl/functions" prefix = "fn" %> -------- standard is required here. after the jar package introduces two tag libraries, the length can be determined. For example, Jsp code is added to the favorites Code <c: choose> <c: when test = "$ {fn: length (contact. <span class = "grouped"> ungrouped </span> </c: when> <c: otherwise> <c: forEach items = "$ {contact. tagscholar} "var =" tags "> <span class =" grouped ">$ {tags. tagname} </span> </c: forEach> </c: otherwise> </c: choose> </span>What I want to talk about today is just the tag <% @ taglib prefix = "c" uri = "http://java.sun.com/jsp/jstl/core" %>.
You only need to add an implicit tag to the body to easily determine
<Input type = "hidden" name = "tcMedicineList" value = "$ {tcMedicineList}"/>
<C: if test = "$ {tcMedicineList. size ()> 2}">
So OK !!!
<Span style = "font-size: 14px; "> <body> <input type =" hidden "name =" tcMedicineList "value =" $ {tcMedicineList} "/> <input type =" hidden "name =" weMedicineList "value = "$ {weMedicineList}"/> <input type = "hidden" name = "otMedicineList" value = "$ {otMedicineList}"/> <input type = "hidden" name = "trMedicineList" value = "$ {trMedicineList}"/> <input type = "hidden" name = "ptcMedicineList" value = "$ {ptcMedicineList}"/> <! -- Recipe start --> <div class = "container"> <dl class = "recipe_pay_detail recipe_detail"> <dt class = "medicine_head"> <I class = "ico ico_recipe recipe_bg6"> </I> traditional Chinese medicine: </dt> <dd id = "medicine_info_chn"> </span> <span style = "font-size: 18px; color: # ff6600; "> <span style =" background-color: rgb (102, 0,204); "> <c: forEach items = "$ {tcMedicineList}" var = "tcMedicineList" begin = "0" end = "1"> </span> <span style = "colo R: rgb (255,102, 0); font-size: 18px; font-family: Arial, Helvetica, sans-serif; "> </span> <span style =" color: rgb (255,102, 0); font-size: 18px; font-family: Arial, Helvetica, sans-serif; "> <! -- Loop List only displays the first two --> </span>
<Span style = "font-size: 14px;"> <p> <span >$ {tcMedicineList. name} </span >$ {tcMedicineList. standard} </p> </c: forEach> </span> <strong style = "font-size: 14px; "> </strong> <span style =" font-size: 18px; "> </span> <span style =" color: # ff9900; "> <span style =" font-size: 18px; "> <span style =" background-color: rgb (51,102,255); "> <c: if test = "$ {tcMedicineList. size ()! = 0 & 2> tcMedicineList. size ()} "> </span> <span style =" font-size: 14px; "> </span> <span style =" color: rgb (255,102, 0); font-size: 18px; font-family: Arial, Helvetica, sans-serif; "><! -- If the number of List entries is not equal to 0 and the number of entries is smaller than 2 --> </span> <span style = "font-size: 14px;"> <span style = "color: # ff9900; "> </span> <c: forEach items =" $ {ptcMedicineList} "var =" ptcMedicineList "<span style =" background-color: rgb (51,102,255 ); "> <span style =" color: # ff0000; "> begin =" 0 "end =" 0 "</span> <p> dose: $ {ptcMedicineList. num }$ {ptcMedicineList. unit} <br/> <% -- dose: $ {ptcMedicineList. dosage} <br> -- %> usage: $ {ptcMedicineList. us Emethod }$ {ptcMedicineList. dosage} </p> </c: forEach> </c: if> <c: if test = "$ {tcMedicineList. size ()> 2} "> </span> <span style =" color: rgb (255,102, 0); font-family: Arial, Helvetica, sans-serif; font-size: 18px; "> <! -- If the number of List entries is greater than 2 --> </span> <span style = "font-size: 14px;"> <c: forEach items = "$ {ptcMedicineList}" var = "ptcMedicineList" <span style = "background-color: rgb (51,102,255);"> <span style = "color: # ff6600; "> begin =" 0 "end =" 0 "> </span> <span style =" color: # ffff66; ">></span> <span style =" color: rgb (255,102, 0); font-family: Arial, Helvetica, sans-serif; font-size: 18px; "> <! -- Only the previous one is displayed in the cyclic List --> </span> <span style = "font-size: 14px;"> <p> dose: $ {ptcMedicineList. num }$ {ptcMedicineList. unit} <br/> usage: $ {ptcMedicineList. usemethod }$ {ptcMedicineList. dosage} <a href = "#" class = "btn btn_o_c btn_open" id = "btn_open_chn"> Expand </a> </p> </c: forEach> </c: if> </dd> <dd id = "medicine_detail_chn"> <c: forEach items = "$ {tcMedicineList}" var = "tcMedicineList"> <p> <span >$ {tcMedicineList. name} </span> $ {TcMedicineList. standard} </p> </c: forEach> <c: forEach items = "$ {ptcMedicineList}" var = "ptcMedicineList" begin = "0" end = "0"> </span> <span style = "color: rgb (255,102, 0); font-family: Arial, Helvetica, sans-serif; font-size: 18px; "> <! -- Only the previous one is displayed in the cyclic List --> </span> <span style = "font-size: 14px;"> <p> dose: $ {ptcMedicineList. num }$ {ptcMedicineList. unit} <br/> usage: $ {ptcMedicineList. usemethod }$ {ptcMedicineList. dosage} <a href = "#" class = "btn btn_o_c btn_close" id = "btn_close_chn"> collapse </a> </p> </c: forEach> </dd> <dt class = "medicine_head"> <I class = "ico ico_recipe recipe_bg4"> </I> Western medicine: </dt> <dd id = "medicine_info"> <c: forEach items = "$ {weMedicineList}" var = "weMedicineList" begin = "0" end = "1"> <p> <span >$ {weMedicineList. name} </span >$ {weMedicineList. standard} </p> </c: forEach> <c: if test = "$ {weMedicineList. size ()> 2} "> <p>... <a href = "#" class = "btn btn_o_c btn_open" id = "btn_open"> Expand </a> </p> </c: if> </dd> <dd id = "medicine_detail"> <c: forEach items = "$ {weMedicineList}" var = "weMedicineList"> <p> <span >$ {weMedicineList. name} </span >$ {weMedicineList. standard} </p> </c: forEach> <p> <a href = "#" class = "btn btn_o_c btn_close" id = "btn_close"> collapse </a> </p> </dd> <% -- <dt> <I class = "ico ico_recipe recipe_bg4"> </I> check items: </dt> <dd id = "medicine_info_check"> <c: forEach items = "$ {entity}" var = "entity" begin = "0" end = "1"> <p> <span >$ {entity. name} </span> </p> </c: forEach> <p> <a href = "#" class = "btn btn_o_c btn_open" id = "btn_open"> Expand </a> </p> </dd> <dd id = "maid"> <c: forEach items = "$ {entity}" var = "entity"> <p> <span >$ {entity. name} </span> </p> </c: forEach> <p> <a href = "#" class = "btn btn_o_c btn_close" id = "btn_close"> collapse </a> </p> </dd> -- %> <dt> <I class = "ico ico_recipe recipe_bg5"> </I> others: </dt> <dd> <c: forEach items = "$ {otMedicineList}" var = "otMedicineList"> <p> <span >$ {otMedicineList. name} </span >$ {otMedicineList. standard} </p> </c: forEach> </dd> <dt> <I class = "ico ico_recipe recipe_bg2"> </I> treatment items: </dt> <c: forEach items = "$ {trMedicineList}" var = "trMedicineList"> <dd> <p> <span >$ {trMedicineList. name} </span >$ {trMedicineList. standard} </p> </dd> </c: forEach> <dd class = "recipe_sum sum_all"> total: $ {RMB} RMB </dd> </dl> </div> </span>
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