只在本页面生效
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> </head> <body> <% pageContext.setAttribute("abc", "shunping"); %> <% String val=(String)pageContext.getAttribute("abc"); out.print(val); %>> </body> </html>
eg：计算器
caculator.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> </head> <body> <form action="result.jsp" method="post"> 请输入第一个数：<input type="text" name="num1"/><br/> 请输入第二个数：<input type="text" name="num2"/><br/> 请选择运算符号：<select name="operator"> <option value="+">+</option> <option value="-">-</option> <option value="*">*</option> <option value="/">/</option> </select><br/> <input type="submit" value="计算"/> </form> </body> </html>
result.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> </head> <body> <% String num1=request.getParameter("num1"); String num2=request.getParameter("num2"); String operator=request.getParameter("operator"); double d_num1=Double.parseDouble(num1); double d_num2=Double.parseDouble(num2); double res=0; if(operator.equals("+")){ res=d_num1+d_num2; }else if(operator.equals("-")){ res=d_num1-d_num2; }else if(operator.equals("*")){ res=d_num1*d_num2; }else{ res=d_num1/d_num2; } out.print("结果是"+res); %> </body> </html>
处理输入空值或者字母等还未考虑，日后再说