EL运算符

来源：互联网发布：网络监控技术员编辑：程序博客网时间：2024/06/06 12:45

算术运算符： 运算符号：+、-、*、/或div、%或mod

request.setAttribute("a",1);    //request.setAttribute("a",new Integer(1));request.setAttribute("b",2);    //request.setAttribute("a",new Integer(2));                                                  两种方式都可以request.getRequestDispatcher("result.jsp").forward(request, response);

加法：${a+b}<br/>减法：${a-b}<br/>乘法：${a*b}<br/>除法：${a/b}<br/>    ${a div b}<br/>取余：${a%b}<br/>    ${a mod b}<br/>

三目运算：${a==1?"相等":"不相等"}<% request.setAttribute("a",1);%>${a==1?"相等":"不相等"}<h4>单选</h4><input type="radio" name="sex" value="0" ${a==0?"checked":""}/>女<input type="radio" name="sex" value="1" ${a==1?"checked":""}/>男<br/><br/><h4>复选</h4><c:set var="hobbies" value="${fn:join(hobbies,' ') }"></c:set><input type="checkbox" name="fruit" value="apple" ${fn:contains(hobbies,"apple")?"checked":""}/>苹果<input type="checkbox" name="fruit" value="banana" ${fn:contains(hobbies,"banana")?"checked":""}/>香蕉<input type="checkbox" name="ball" value="football" ${fn:contains(hobbies,"football")?"checked":""}/>足球<input type="checkbox" name="ball" value="basketball" ${fn:contains(hobbies,"basketball")?"checked":""}/>篮球<br/><br/><h4>下拉列表</h4><select><option value="" ${a==””?"selected":""}>--请选择--</option><option value="1" ${a==1?"selected":""}>衣服</option><option value="2" ${a==2?"selected":""}>鞋子</option></select>

<% request.setAttribute("a",1);%>  //<% request.setAttribute("a", new Integer(1));%><% request.setAttribute("b",2);%>  //<% request.setAttribute("a", new Integer(2));%>加法：${a+b}<br/>减法：${a-b}<br/>乘法：${a*b}<br/>除法：${a/b}<br/>    ${a div b}<br/>取余：${a%b}<br/>    ${a mod b}<br/>

关系运算符：

运算符符号：==或eq、

!=或ne、

<或lt（即less than）、

>或gt（即great than）、

<=或 le(即less equal)、

>=或 ge(即great equal)

<% request.setAttribute("num1",1);%><% request.setAttribute("num2",2);%><% request.setAttribute("str1","student");%><% request.setAttribute("str2","students");%><% request.setAttribute("student1",new Student(22,"临汾","阿丹"));%><% request.setAttribute("student2",new Student(22,"山东","阿洁"));%>数值：${num1==num2 }  ${num1 eq num2 }<br/><br/>字符串：${str1==str2 }  ${str1 eq str2 }<br/><br/>自定义类：${student1==student2 }  ${student1 eq student2 }<br/><br/>不等于：${num1!=num2 }  ${num1 ne num2 }<br/><br/>小于：${num1<num2 }  ${num1 lt num2 }<br/><br/>小于等于：${num1<=num2 }  ${num1 le num2 }<br/><br/>大于：${num1>num2 }  ${num1 gt num2 }<br/><br/>大于等于：${num1>=num2 }  ${num1 ge num2 }<br/><br/>

逻辑运算符：

运算符符号：&& 或 and、|| 或 or、! 或 not（注意:只能对boolean型数据运算）

empty运算符

说明：如果集合或数组中没有数据，或者其值为null，则empty判断为true；not empty判断为false。

<% request.setAttribute("a",true);%><% request.setAttribute("b",false);%>逻辑与：${a&&b }  ${a and b }<br/><br/>逻辑或：${a||b }  ${a or b }<br/><br/>逻辑非：${!b }  ${not b }<br/><br/>empty:${empty c }  ${!empty c }  ${not empty c }

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